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  • Articles  (311,651)
  • Articles: DFG German National Licenses  (311,651)
  • Geosciences  (165,572)
  • Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition  (151,447)
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  • Articles  (311,651)
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  • 1
    Electronic Resource
    Electronic Resource
    Lincoln, Neb. : Berkeley Electronic Press (now: De Gruyter)
    Journal of agricultural & food industrial organization 5.2007, 1, art10 
    ISSN: 1542-0485
    Source: Berkeley Electronic Press Academic Journals
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Economics
    Notes: With increasing interest in renewable energy from agriculture, including biopower and cellulose ethanol, there is a need for better understanding of the economic organization of this emerging industry. Study of the organization of the biopower industry represents an under-researched area and a new application of transaction cost theory to an emerging industry. Refinement of the theory can also result from challenging applications. This article provides an application of transaction cost economics to the existing United States biopower industry while challenging the empirical convention of excluding production cost variables from transaction cost analysis. Utilizing survey data from 53 biopower generators we study the relationship between physical asset specificity, site specificity, and scale in explaining firms' decisions to procure inputs internally, externally, or to use both methods. Consistent with transaction cost theory, both site specificity and scale are good predictors of organizational form. Given this evidence, this article reconsiders the impact of scale and transaction costs on the choice of organizational from.
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  • 2
    Electronic Resource
    Electronic Resource
    Lincoln, Neb. : Berkeley Electronic Press (now: De Gruyter)
    Journal of agricultural & food industrial organization 5.2007, 1, art11 
    ISSN: 1542-0485
    Source: Berkeley Electronic Press Academic Journals
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Economics
    Notes: Agricultural goods sold in supermarkets often vary significantly in quality. Yet, when these goods are sold at a single price, consumers may expend significant time and effort to sort goods for quality. From the standpoint of sellers, the resources expended on sorting only serve to reallocate high quality goods to consumers who sort intensively and low quality goods to consumers who sort minimally or not at all. Because these lower quality goods are less attractive to consumers who do not sort, sellers may be forced to lower prices. Why then do sellers allow sorting when they might prevent it? This paper presents a demand model where sellers choose whether to allow sorting. Sellers may allow consumer sorting when it fosters the distribution of qualities that occurs under quality discrimination, despite the associated reduction in the total gains to trade through sorting costs and quality efficiency loss. In general, sorting may allow sellers to improve the quality of goods for marginal consumers who constrain price-setting for sellers with market power. The total effect on price, amount sold and welfare is ambiguous due to the role of market power. Simulations are provided to demonstrate these effects.
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  • 3
    Electronic Resource
    Electronic Resource
    Lincoln, Neb. : Berkeley Electronic Press (now: De Gruyter)
    Journal of agricultural & food industrial organization 5.2007, 2, art4 
    ISSN: 1542-0485
    Source: Berkeley Electronic Press Academic Journals
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Economics
    Notes: Ethanol subsidies are well established in U.S. policy and have high priority in corn growers' political agenda. This paper develops a vertical market model of ethanol, byproducts, and corn which is used to analyze whether corn growers would prefer the government's subsidy dollar to be spent directly on corn subsidies (though deficiency payments) rather than on a subsidy on ethanol made from corn. Because the subsidy dollar has to be shared with ethanol manufacturers under the ethanol subsidy, it is to be expected, and the model confirms, that a dollar spent on a direct corn subsidy increases corn growers' producer surplus more than an a dollar spent on an ethanol subsidy under many plausible values of the relevant parameters. But there are equally plausible parameter values under which the ethanol subsidy is preferred by corn growers. The economics of this result turn mainly on the price discrimination an ethanol subsidy creates between ethanol and corn used for feed and export purposes, reducing the buyers' price of ethanol and byproducts but increasing the price of corn fed and exported. This enables producers of corn and ethanol to increase their joint producer surpluses above the total value of subsidies paid. The paper also analyzes the social cost (deadweight loss) of these subsidies, and finds the ethanol subsidy to generate deadweight losses likely to be in the billions of dollars annually.
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  • 4
    Electronic Resource
    Electronic Resource
    Lincoln, Neb. : Berkeley Electronic Press (now: De Gruyter)
    Journal of agricultural & food industrial organization 5.2007, 1, art8 
    ISSN: 1542-0485
    Source: Berkeley Electronic Press Academic Journals
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Economics
    Notes: This study investigates the Indian market for GM wheat. First, we address the obvious valuation and acceptance questions for Indian consumers. Then we investigate the extent to which the provision of information about GM wheat has any significant effect on consumers' willingness to pay and the degree to which the effect varies based on the information treatment. Finally, we consider whether the type of primary beneficiary of GM wheat production affects valuation. Specifically, we assess the conjecture that consumers' willingness to pay for GM wheat changes according to whether the crop is portrayed as producer-friendly or consumer-friendly.
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  • 5
    Electronic Resource
    Electronic Resource
    Lincoln, Neb. : Berkeley Electronic Press (now: De Gruyter)
    Journal of agricultural & food industrial organization 5.2007, 1, art7 
    ISSN: 1542-0485
    Source: Berkeley Electronic Press Academic Journals
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Economics
    Notes: In this paper we investigate consumers' preferences for various environment-friendly production systems for carrots. We use discrete-choice multi-attribute stated-preference data to explore the effect of collective reputations from growers of an Alpine valley known for its environment-friendly production: Val di Gresta 'the valley of organic orchards'. Data analysis of the panel of discrete responses identifies unobserved taste heterogeneity for organic, bio-dynamic and place of origin, while observed heterogeneity for income is addressed by a piece-wise linear function. The implied sample distributions of individual-specific WTP for each of these random attributes are then compared. Results indicate that Integrated Pest Management is preferred to biodynamic as an emerging method. The presence of a premium for Val di Gresta produce is confirmed. The use of an experimental design to identify the relevant second order effects reveals the presence of a reputation effect which can be decomposed into a generic effect from place of origin and a specific one for each EFPMs. Farmers operating in geographically limited marginal areas, such as mountain valleys, may find it useful to invest in collective reputation through high quality standard to achieve higher returns. This strategy may compensate for the dwindling public support to farm income from EU programmes.
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  • 6
    Electronic Resource
    Electronic Resource
    Lincoln, Neb. : Berkeley Electronic Press (now: De Gruyter)
    Journal of agricultural & food industrial organization 5.2007, 1, art3 
    ISSN: 1542-0485
    Source: Berkeley Electronic Press Academic Journals
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Economics
    Notes: This paper revisits the analysis of generic commodity advertising under product differentiation by Crespi and Marette. Crespi and Marette had shown that a dominant firm producing high-quality goods and facing a competitive fringe of lower quality producers could be harmed by a generic advertising campaign while the fringe was left unaffected. Under this dominant-firm model, a question remained why these producers might support a program for which they were indifferent. In this paper we show that under a duopoly model a high-quality firm may be harmed while its lower-quality rival may be made better off by a generic program, thus helping to explain why some producers might favor a program while others do not. Further, this paper dismisses the claim made by some litigants that increased branded advertising is the result of a deleterious effect of generic advertising.
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  • 7
    Electronic Resource
    Electronic Resource
    Lincoln, Neb. : Berkeley Electronic Press (now: De Gruyter)
    Journal of agricultural & food industrial organization 5.2007, 1, art9 
    ISSN: 1542-0485
    Source: Berkeley Electronic Press Academic Journals
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Economics
    Notes: This article is a theoretical contribution to the debate surrounding the introduction of Fair Trade products into large-scale retail distribution. In the model, a Fair Trade certifier and a traditional producer compete to supply their product to a single retailer, consumers who are Fair Trade likers are willing to pay an "ethical" premium for the Fair Trade product, and the premium depends on the revenue of Fair Trade product producers. The conditions of existence of an equilibrium where the Fair Trade product coexists with the traditional brand product on the retailer's shelves are highlighted. In particular, we show that a Fair Trade certifier implements this equilibrium if his preferences are such that the weight devoted to the price paid to producers is smaller than the weight he grants to the quantities of Fair Trade product sold. We also show that a retailer's decision to sell the Fair Trade product is not based on the percentage of consumers who are willing to pay for it, but on how much the Fair Trade likers are willing to pay.
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  • 8
    Electronic Resource
    Electronic Resource
    Lincoln, Neb. : Berkeley Electronic Press (now: De Gruyter)
    Journal of agricultural & food industrial organization 5.2007, 2, art2 
    ISSN: 1542-0485
    Source: Berkeley Electronic Press Academic Journals
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Economics
    Notes: US and state governments have subsidized ethanol since 1978, and the rationale for these subsidies has varied over time from supporting farm prices and income, to environmental quality, and more recently to energy security and reduction of greenhouse gas emissions. The recent boom in ethanol investment and production can be considered as an unintended consequence of an ethanol subsidy keyed to $20 crude oil and fixed at 51 cents per gallon combined with oil surging to $70/bbl. Thus, in the 2005-07 period, ethanol was extremely profitable inducing substantial new investment. For the future, different political action groups and political figures propose renewable fuels targets or standards ranging from 35 to 100 billion gallons per year. To achieve anything like these levels, it is likely that the current policy set will need to be reconsidered. In addition to the current policy, this paper considers using a subsidy tied to the energy security gains and greenhouse gas emission reductions provided by renewable fuels, subsidies targeted specifically at cellulose ethanol, and different versions of a renewable fuel standard such as the one passed by the US Senate. It is clear that we must develop a better understanding of the consequences of these alternative policy pathways.
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  • 9
    Electronic Resource
    Electronic Resource
    Lincoln, Neb. : Berkeley Electronic Press (now: De Gruyter)
    Journal of agricultural & food industrial organization 5.2007, 2, art6 
    ISSN: 1542-0485
    Source: Berkeley Electronic Press Academic Journals
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Economics
    Notes: This paper examines the impact of ethanol expansion in the United States, brought about by higher crude oil prices, on agricultural commodity prices. Given the United States's stature as a major producer and exporter of many agricultural commodities, the resulting increase in commodity prices has spillover effects into the global market. Using the price changes estimated within a multi-commodity, multi-country agricultural modeling system, this paper attempts to show how an increase in world commodity prices would affect the costs of food baskets around the world and how higher food costs will impact food security, particularly in developing countries. In general, we find that countries where corn is the major food grain experience larger increases in food basket cost while countries where rice is the major food grain have smaller food basket cost increases. Countries where wheat and/or sorghum are the major food grains fall in between. Consequently, the highest percentage increases are seen in Sub-Saharan Africa and Latin America where food basket costs are estimated to increase by at least 10%. The lowest percentage increases are seen in Southeast Asia, with cost increases of less than 2.5%.
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  • 10
    Electronic Resource
    Electronic Resource
    Lincoln, Neb. : Berkeley Electronic Press (now: De Gruyter)
    Journal of agricultural & food industrial organization 5.2007, 2, art1 
    ISSN: 1542-0485
    Source: Berkeley Electronic Press Academic Journals
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Economics
    Notes: Biofuels are prominent in current discussion both as a solution to problems and as a creator of problems. They have promise as a substitute for fossil fuels, particularly for petroleum as the raw material for transportation fuel. But biofuels also have pitfalls, especially when produced at a scale sufficient to replace a significant proportion of the world's use of petroleum. The articles in this special issue analyze key aspects of both the promise and pitfalls of biofuels. They address issues in the technology of producing raw materials for biofuels and converting these raw materials into fuel, resource constraints facing expansion of biofuel production, and the demand for fuels. Particular attention is paid to the relationship between expanded biofuel production and the cost of food. The economics of biofuels is inherently linked to policy issues as well as market analysis because biofuels in every country have received subsidies from governments. Consequently several articles address the welfare economics of governmental efforts to promote biofuels, with a focus on U.S. ethanol subsidies. These subsidies generate net social losses (deadweight costs) on a global scale, although not necessarily from the U.S. national viewpoint. Governmental promotion of biofuels can be justified on the grounds of externalities created by the use of fossil fuels, most notably in recent debates on global warming caused by the release of sequestered carbon in the form of carbon dioxide. This justification is weakened and perhaps even nullified by externalities in the production and use of biofuels. The articles in this issue consider a range of topics concerning these matters, and the welfare losses caused by biofuel subsidies absent net environmental gains from biofuels.
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  • 11
    Electronic Resource
    Electronic Resource
    Lincoln, Neb. : Berkeley Electronic Press (now: De Gruyter)
    Journal of agricultural & food industrial organization 5.2007, 1, art2 
    ISSN: 1542-0485
    Source: Berkeley Electronic Press Academic Journals
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Economics
    Notes: Contracts are an increasingly common method for coordinating exchange in the food industry. Contracts often include specifications for product attributes including food safety. One of the goals of explicit safety specifications is to discourage or deter suppliers who would deliver unsafe food. In this article, we use a principal-agent model in the context of adverse selection to examine how contracts that include traceability can be used to select against producers who cannot meet a processor's safety specifications. We find that the motivation to select against unsafe producers depends on the magnitude of the failure costs and the proportion of the failure costs allocated to producers. We also identify the conditions under which the processor selects against unsafe producers regardless of traceability. Our results are important to regulators and negotiators who want to support safe producers and deter unsafe producers.
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  • 12
    Electronic Resource
    Electronic Resource
    Lincoln, Neb. : Berkeley Electronic Press (now: De Gruyter)
    Journal of agricultural & food industrial organization 5.2007, 1, art1 
    ISSN: 1542-0485
    Source: Berkeley Electronic Press Academic Journals
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Economics
    Notes: The objective of this article is to measure the degree of competition among retail stores to sell a specific brand of a product. For this purpose, we estimate brand-specific demand equations along with first order conditions from stores' profit maximization. In stores' profit maximization, we account for three sources of conjectural variation: within a store but across brands, across stores for the same brand, and across stores for other brands. Data on U.S. retail store price and sales data on cheese products from ACNielsen Homescan database are used in our empirical analysis. A set of indices representing concentration of purchases across brands within each store and across stores for each brand are used to estimate conjectural elasticities. Results show the existence of price markups suggesting imperfectly competitive behavior in retail cheese markets.
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  • 13
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    Electronic Resource
    Lincoln, Neb. : Berkeley Electronic Press (now: De Gruyter)
    Journal of agricultural & food industrial organization 5.2007, 2, art11 
    ISSN: 1542-0485
    Source: Berkeley Electronic Press Academic Journals
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Economics
    Notes: When the automobile was developed near the beginning of the last century, it was the relatively new fuel gasoline, not the familiar ethanol that became the fuel of choice. We examine the intersections of the early development of the automobile and the petroleum industry and consider the state of the agriculture sector during the same period. Through this process, we find a series of influences, such as relative prices and alternative markets, that help to explain how in the early years of automobile development, gasoline won out over the equally likely technical alternative ethanol. We also examine the industrial relations in the automobile industry that seem to have influenced the later adoption of leaded gasoline, rather than ethanol, as a solution to the problem of engine knock.
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  • 14
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    Electronic Resource
    Lincoln, Neb. : Berkeley Electronic Press (now: De Gruyter)
    Journal of agricultural & food industrial organization 5.2007, 2, art10 
    ISSN: 1542-0485
    Source: Berkeley Electronic Press Academic Journals
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Economics
    Notes: Research indicates that large biorefineries capable of handling 5000-10000MT of biomass per day are necessary to achieve process economies. However, such large biorefineries also entail increased costs of biomass transportation and storage, high transaction costs of contracting with a large number of farmers for biomass supply, potential market power issues, and local environmental impacts. We propose a network of regional biomass preprocessing centers (RBPC) that form an extended biomass supply chain feeding into a biorefinery, as a way to address these issues. The RBPC, in its mature form, is conceptualized as a flexible processing facility capable of pre-treating and converting biomass into appropriate feedstocks for a variety of final products such as fuels, chemicals, electricity, and animal feeds. We evaluate the technical and financial feasibility of a simple RBPC that uses ammonia fiber expansion pretreatment process and produces animal feed along with biorefinery feedstock.
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  • 15
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    Lincoln, Neb. : Berkeley Electronic Press (now: De Gruyter)
    Journal of agricultural & food industrial organization 5.2007, 1, art5 
    ISSN: 1542-0485
    Source: Berkeley Electronic Press Academic Journals
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Economics
    Notes: Among the dominant firms in the US meat and grain business, many produce several products, some of which are demand-related. Yet, virtually all research on collusion among those firms focuses on a single product. This paper uses a game-theoretic model to investigate the conditions under which multi-product food firms producing demand-related goods have incentives to collude, and examines the welfare implications of collusion for participants in a vertical marketing chain. I show that multi-product food firms have a greater incentive to collude when they become more efficient. In contrast to previous work, I find that the effect of the degree of product substitutability on collusion sustainability hinges on the cost effect arising from joint production. From a policy standpoint, I show that mergers between single-product firms producing demand-related goods under certain conditions may hinder collusion.
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  • 16
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    Electronic Resource
    Lincoln, Neb. : Berkeley Electronic Press (now: De Gruyter)
    Journal of agricultural & food industrial organization 5.2007, 2, art3 
    ISSN: 1542-0485
    Source: Berkeley Electronic Press Academic Journals
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Economics
    Notes: The sharp rise in energy prices in the 1980s triggered a strong interest in the production of ethanol as an additional energy component. Economists are divided as to the payoffs from ethanol derived corn in part because of the complex interrelationship between energy produced from ethanol and energy from fossil fuels. Using a welfare economic framework, we calculate that there can be treasury savings from ethanol using tax credits as these subsidies can be smaller than direct payments to corn farmers which are essentially eliminated from the expansion of ethanol. Also, to the extent that ethanol dampens fuel prices there can be a net welfare gain from ethanol production in the presence of ethanol subsidies.
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  • 17
    Electronic Resource
    Electronic Resource
    Lincoln, Neb. : Berkeley Electronic Press (now: De Gruyter)
    Journal of agricultural & food industrial organization 5.2007, 2, art7 
    ISSN: 1542-0485
    Source: Berkeley Electronic Press Academic Journals
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Economics
    Notes: The EU has set ambitious targets to raise the share of renewable energies, particularly biofuels. With an increasingly controversial public debate and more scientific evidence about the downsites of biofuels, recently the European Unions biofuel targets have been bound to the condition that they have to be produced sustainable. Therefore the European Commission is currently developing sustainability criteria for biofuels. Establishing certification schemes is a possible strategy to ensure that bioenergy crops are produced in a sustainable manner. However, many questions with regard to the design and implementation of sustainability criteria and certification schemes remain unsolved. This article discusses the role that bioenergy plays in the European policy context and the approach the EU is currently following in order to ensure the sustainability of biofuels. It addresses the limits of the chosen approach, concluding that certification schemes can not serve as the only safeguard for sustainable bioenergy, but need to be complemented by other tools and policies.
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  • 18
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    Electronic Resource
    Lincoln, Neb. : Berkeley Electronic Press (now: De Gruyter)
    Journal of agricultural & food industrial organization 5.2007, 2, art5 
    ISSN: 1542-0485
    Source: Berkeley Electronic Press Academic Journals
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Economics
    Notes: In this paper the impact of distortions on U.S. imports of ethanol from Brazil are calculated. This is achieved by using two-stage least squares to estimate a partial equilibrium trade model based on annual data from 1975 to 2006. From this the derived export supply and import demand elasticities are used to derive "back-of-the-envelope" measures of the static and cumulative deadweight losses, assuming the distortions are not eliminated. The results presented support the hypothesis that the U.S. and Brazil would reap gains from trade if distortions in the U.S. ethanol market were eliminated.
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  • 19
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    Lincoln, Neb. : Berkeley Electronic Press (now: De Gruyter)
    Journal of agricultural & food industrial organization 5.2007, 1, art4 
    ISSN: 1542-0485
    Source: Berkeley Electronic Press Academic Journals
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Economics
    Notes: This paper investigates consumer reactions to changes in information provision regarding organic production. Quantitative analyses focus on the actual implementation of mandatory labeling guidelines under the National Organic Program. The unique nature of the fluid milk market in combination with these regulatory changes allows us to place a value on information sets under different labeling regimes. Hedonic price functions provide an initial reference point for analyses of individual responses. A random utility discrete choice model serves as the primary econometric specification and allows consideration of consumer preference heterogeneity along observable household demographics. Our results indicate that the USDA organic seal increases the probability of purchasing organic milk. An initial hedonic price function approach, as well as simulations within the discrete choice framework, suggests that consumers value the change in labeling regulations with regard to organic production. Our results further suggest that consumers substitute away from milk carrying the rBGH-free label. This may indicate that consumers pay less attention to these labels in the time period investigated compared to results found in studies that use earlier time periods.
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  • 20
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    Lincoln, Neb. : Berkeley Electronic Press (now: De Gruyter)
    Journal of agricultural & food industrial organization 5.2007, 1, art6 
    ISSN: 1542-0485
    Source: Berkeley Electronic Press Academic Journals
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Economics
    Notes: In this paper, we analyze how generic advertising affects brand advertising and firm profits in differentiated oligopoly markets. We show that in the Crespi (2007) model only the high quality firm will use brand advertising when differentiation is vertical. We also demonstrate that when differentiation is horizontal, the equilibrium is likely to be more symmetric in terms of firm profits, spending on brand advertising, and firm response to generic advertising. Finally, we point out that generic advertising will increase expenditures on brand advertising when firms play a supermodular game. The results confirm that there are many reasons why generic advertising may increase firm spending on brand advertising.
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  • 21
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    Lincoln, Neb. : Berkeley Electronic Press (now: De Gruyter)
    Journal of agricultural & food industrial organization 5.2007, 2, art8 
    ISSN: 1542-0485
    Source: Berkeley Electronic Press Academic Journals
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Economics
    Notes: The governments of Asian countries are promoting biofuels programs to deal with energy security and environmental problems, and to increase farm income. However, securing raw materials for biofuels is a crucial problem, because these raw materials comprise various agricultural products which are used as food sources in Asian countries. Increasing biofuel consumption is exacerbating this problem. To address it, the governments of Asian countries are working on biofuel programs which will not compete with food security. Most of the Asian countries are food-importing countries. Increasing food prices, due to competition, could lead to social unrest. It is expected that the introduction and development of second-generation biofuels can mitigate the competition between food and energy. As various countries develop second-generation biofuels, international cooperation is needed to maximize such development in Asia and other regions. Establishing international cooperation to develop second-generation biofuels is urgently needed in Asian countries.
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  • 22
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    Lincoln, Neb. : Berkeley Electronic Press (now: De Gruyter)
    Journal of agricultural & food industrial organization 5.2007, 2, art9 
    ISSN: 1542-0485
    Source: Berkeley Electronic Press Academic Journals
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Economics
    Notes: In this paper we investigate the potential production and implications of a global biofuels industry. We develop alternative approaches to consistently introduce land as an economic factor input and in physical terms into a computable general equilibrium framework. The approach allows us to parameterize biomass production consistent with agro-engineering information on yields and a "second generation" cellulosic biomass conversion technology. We explicitly model land conversion from natural areas to agricultural use in two different ways: in one approach we introduced a land supply elasticity based on observed land supply responses and in the other approach we considered only the direct cost of conversion. We estimate biofuels production at the end of the century could reach 221 to 267 EJ in a reference scenario and 319 to 368 EJ under a global effort to mitigate greenhouse gas emissions. The version with the land supply elasticity allowed much less conversion of land from natural areas, forcing intensification of production, especially on pasture and grazing land, whereas the pure conversion cost model led to significant deforestation. These different approaches emphasize the importance of somehow reflecting the non-market value of land more fully in the conversion decision. The observed land conversion response we estimate may be a short turn response that does not fully reflect the effect of long run pressure to convert land if rent differentials are sustained over 100 years.
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  • 23
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    Lincoln, Neb. : Berkeley Electronic Press (now: De Gruyter)
    Journal of agricultural & food industrial organization 4.2006, 1, art1 
    ISSN: 1542-0485
    Source: Berkeley Electronic Press Academic Journals
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Economics
    Notes: The emergence of agricultural biotechnology and the subsequent introduction of genetically modified organisms (GMOs) into the food system have been among the most controversial issues surrounding the increasingly scrutinized agri-food system. They have received considerable attention in the economics literature with the main focus being on the optimal regulatory response to products of biotechnology. This paper builds on the literature on the regulation of products of biotechnology by placing the analysis of labeling decisions in a multi-country context. Specifically, the objective of this study is to examine the effect of the strategic interdependence between countries on their regulatory responses to products of biotechnology. The paper analyzes the strategic effects of national regulatory decisions on labeling of GM products and identifies the determinants of the non-cooperative Nash equilibrium labeling regimes in a small number of producing countries that supply the world market of an agricultural product. Analytical results show that the Nash equilibrium configuration of labeling regimes in countries that have adopted the GM technology depends on (i) the distribution of consumer preferences and the level of consumer aversion to GM products; (ii) the size of the segregation and labeling costs in these countries; (iii) the relative productive efficiency and the cost effectiveness of the GM technology; (iv) the market power of the life science companies; and (v) the strength of intellectual property rights in these countries.
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  • 24
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    Lincoln, Neb. : Berkeley Electronic Press (now: De Gruyter)
    Journal of agricultural & food industrial organization 4.2006, 1, art8 
    ISSN: 1542-0485
    Source: Berkeley Electronic Press Academic Journals
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Economics
    Notes: This paper undertakes a detailed market segmentation analysis of the demand for GM derived animal foods in the UK with the aim of illustrating how this analysis can provide distinct information that can assists in evaluating the welfare impacts of proposed changes to the EU's GM labelling policy. The specific modelling approach employed was the latent segment (LS) model which allows for the simultaneous determination and explanation of both segment membership and product choice. Based on psychometric and demographic variables as well as choice data, the LS model was able to identify three distinct and behaviourally consistent consumer segments. Further, the LS model was found to outperform alternative econometric approaches for accounting for preference heterogeneity. Finally, our analysis shows how it can yield distinct information over the segmented nature of the food market that can uniquely assist both European policy makers in designing GM labelling regimes and public awareness campaigns as well as the agricultural and food industry in developing pricing, marketing and new product development strategies.
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  • 25
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    Lincoln, Neb. : Berkeley Electronic Press (now: De Gruyter)
    Journal of agricultural & food industrial organization 4.2006, 1, art4 
    ISSN: 1542-0485
    Source: Berkeley Electronic Press Academic Journals
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Economics
    Notes: Organic farmers have traditionally relied on a variety of marketing channels, suggesting that earned organic income will depend on the farmer's experience in producing and selling organic products and their comparative advantage in bargaining and marketing skills. A discrete choice model of the choice of marketing channels is developed which accounts for the role of selectivity bias. Farmers who are most likely to sell through a diversified set of outlets or to use a single outlet have increased earnings relative to farmers who overlook these marketing options. Producers with less experience gravitate toward use of a single marketing outlet while more experienced producers tend to diversify and market through all three channels. Constraints in selling organic products tends tend to have a negative effect on farm income.
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  • 26
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    Lincoln, Neb. : Berkeley Electronic Press (now: De Gruyter)
    Journal of agricultural & food industrial organization 4.2006, 1, art2 
    ISSN: 1542-0485
    Source: Berkeley Electronic Press Academic Journals
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Economics
    Notes: In this paper we develop a model of food safety regulation that considers the employment of a differentiated food market with two types of government certified quality standards: a minimum standard and a higher one. Individuals, heterogeneous in their susceptibility to food-related health risks, choose which safety-grade of food to consume based on price and their vulnerability. The model is then extended to the case where consumers misperceive their susceptibility to health risks associated with food consumption. The theoretical presentation is followed by an application of the model to examine campylobacteriosis and salmonellosis caused by consumption of beef, pork, and chicken. The paper demonstrates that the benefits from multiple quality standards hinges fundamentally on the distribution of vulnerabilities across the population and the associated distribution of population health risks for a given level of food quality. Uniform standards are generally preferred to differentiated ones under either stringent or lax regulations on population health risk. If the population distribution of vulnerabilities is unimodal and consumers misperceive their vulnerability, the value of a differentiated policy will depend on which quality standard is attracting the majority of consumers. The empirical results confirm the importance of the population distribution of vulnerability on the relative desirability of single versus multiple quality standards.
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  • 27
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    Lincoln, Neb. : Berkeley Electronic Press (now: De Gruyter)
    Journal of agricultural & food industrial organization 4.2006, 1, art6 
    ISSN: 1542-0485
    Source: Berkeley Electronic Press Academic Journals
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Economics
    Notes: Strategic trade theory offers a way of conceptualizing and testing for strategic government interventions in imperfectly competitive international markets. This survey critically assesses recent empirical evidence, with a focus on food and agricultural markets. One finding is that while many international markets are characterized by oligopoly, price-cost markups tend to be small, and the potential gains from intervention are modest at best. In turn, empirical work has turned up few examples in which government intervention has been optimal in a strategic trade sense. Nonetheless, governments are found to frequently intervene on behalf of domestic firms and play a major role in shaping the nature of international competition. Suggestions for future research are made.
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  • 28
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    Lincoln, Neb. : Berkeley Electronic Press (now: De Gruyter)
    Journal of agricultural & food industrial organization 4.2006, 1, art5 
    ISSN: 1542-0485
    Source: Berkeley Electronic Press Academic Journals
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Economics
    Notes: Although many theoretical industrial organization models are based on the existence of a critical mass of exogenously "brand loyal" consumers, we find little empirical evidence supporting these assumptions in the orange juice retail market. There are very few loyal consumers. More importantly, the frequency with which stores conduct sales affects the share of loyal types so that loyalty is endogenous rather than exogenous. Households' demographics have statistically significant but economically minor effects on switching behavior. Switching across frozen and refrigerated states is very common, leading to more complicated substitution patterns and less loyalty than one observes looking at each state separately.
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  • 29
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    Lincoln, Neb. : Berkeley Electronic Press (now: De Gruyter)
    Journal of agricultural & food industrial organization 4.2006, 1, art3 
    ISSN: 1542-0485
    Source: Berkeley Electronic Press Academic Journals
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Economics
    Notes: Psychological experiments have revealed that more choice does not always make one better off. For example, consumers are sometimes more likely to purchase a product from a small variety than a large variety. Some have suggested that this excessive-choice effect may have implications for how well markets serve society. This paper constructs an economic model where the excessive-choice effect results from search costs. The model shows that it is possible for markets to produce too much variety, but there are also incentives inducing markets to provide an optimal variety. Advertising, retailer market power, and slotting fees are not just signs of imperfect competition, but mechanisms of ensuring consumers are presented with an ideal choice set.
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  • 30
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    Lincoln, Neb. : Berkeley Electronic Press (now: De Gruyter)
    Journal of agricultural & food industrial organization 4.2006, 1, art7 
    ISSN: 1542-0485
    Source: Berkeley Electronic Press Academic Journals
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Economics
    Notes: This paper investigates the existence of market power in the Swedish food and beverage industry and how market power has been affected by European competition (the Single Market and Swedish EU membership). The study makes use of a census of some 500 firms for the period 1990-2002. The results show that firms in the Swedish food and beverage industry do enjoy some market power, the degree of which varies significantly across the sectors of the food and beverage industry. Increased foreign competition has contributed to reducing market power in sectors that were protected by tariff and non-tariff barriers to trade prior to Swedish EU membership.
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  • 31
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    Lincoln, Neb. : Berkeley Electronic Press (now: De Gruyter)
    Journal of agricultural & food industrial organization 4.2006, 1, art9 
    ISSN: 1542-0485
    Source: Berkeley Electronic Press Academic Journals
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Economics
    Notes: Four articles have been published in this Journal about the historic cattle trial, Pickett v Tyson Fresh Meats, Inc., in which Plaintiff cattlemen alleged that Tyson/IBP--the buyer--used captive (contracted) supplies of cattle to manipulate the cash market in violation of the 1921 Packers & Stockyards Act (PSA). The first article gave a Trial's eye view by David Domina who served as co-lead counsel representing Plaintiff cattlemen. Domina's article led to a published comment by Thomas Green who was the lead attorney representing Tyson during the Trial phase of lengthy legal proceedings. Green alleged that Domina's article was "littered with rank speculation and baseless opinion." Domina countered that "proof is not litter, and evidence is not rank speculation" and that Green's commentary was "abusive." The adversarial exchange between Domina and Green was followed by another advocacy article in which William Rosales maintained that Pickett "represents an opportunity for the judiciary to reform the meatpacking industry (and) awaken the (PSA's) intended power to dethrone the economic kings of the meatpacking industry."After a five week Trial in Federal Court, the Jury found Tyson/IBP guilty on all counts and assessed actual damages of $1.28 billion over 2/1994 -10/2002. Justice for Plaintiff cattlemen was short, as the Trial Judge set aside the Jury's verdict--a rare but not unprecedented legal action--and entered summary judgment for Tyson. The Eleventh Appellate Court subsequently sided with the Trial Judge. On March 24, 2006, the United States Supreme Court denied without comment Plaintiff's Petition to rehear the case, thus ending legal activities in Pickett v Tyson and effectively killing similar legal action pending against two other major beef packers, Excel (Cargill) and Swift (ConAgra).This article emphasizes three significant and troubling legal and economic issues from the historic litigation: (1) the Courts' narrow and extreme interpretation of the antitrust rule-of-reason; (2) the Courts' endorsement of a "meeting the competition" defense, and (3) whether the Courts inserted themselves above the Jury as fact-finders in the case, contrary to the 7th Amendment to the U.S. Constitution that establishes the Jury as the only fact-finder in civil litigation.In essence Pickett was filed under the Packers and Stockyards Act, tried under Sherman and Clayton antitrust law, and overturned, in part, under the Robinson-Patman Act.
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  • 32
    ISSN: 1572-9729
    Keywords: bioremediation ; Dehalococcoides ; dechlorination ; microcosm ; tetrachloroethane ; trichloroethene
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Energy, Environment Protection, Nuclear Power Engineering , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract This study investigated the biotransformation pathways of 1,1,2,2-tetrachloroethane (1,1,2,2-TeCA) in the presence of chloroethenes (i.e. tetrachloroethene, PCE; trichloroethene, TCE) in anaerobic microcosms constructed with subsurface soil and groundwater from a contaminated site. When amended with yeast extract, lactate, butyrate, or H2 and acetate, 1,1,2,2-TeCA was initially dechlorinated via both hydrogenolysis to 1,1,2-trichloroethane (1,1,2-TCA) (major pathway) and dichloroelimination to dichloroethenes (DCEs) (minor pathway), with both reactions occurring under sulfidogenic conditions. In the presence of only H2, the hydrogenolysis of 1,1,2,2-TeCA to 1,1,2-TCA apparently required the presence of acetate to occur. Once formed, 1,1,2-TCA was degraded predominantly via dichloroelimination to vinyl chloride (VC). Ultimately, chloroethanes were converted to chloroethenes (mainly VC and DCEs) which persisted in the microcosms for very long periods along with PCE and TCE originally present in the groundwater. Hydrogenolysis of chloroethenes occurred only after highly reducing methanogenic conditions were established. However, substantial conversion to ethene (ETH) was observed only in microcosms amended with yeast extract (200 mg/l), suggesting that groundwater lacked some nutritional factors which were likely provided to dechlorinating microorganisms by this complex organic substrate. Bioaugmentation with an H2-utilizing PCE-dechlorinating Dehalococcoides spp. -containing culture resulted in the conversion of 1,1,2,2-TeCA, PCE and TCE to ETH and VC. No chloroethanes accumulated during degradation suggesting that 1,1,2,2-TeCA was degraded through initial dichloroelimination into DCEs and then typical hydrogenolysis into ETH and VC.
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  • 33
    ISSN: 1572-9729
    Keywords: community fingerprint ; polycyclic aromatic hydrocarbon ; 16S rRNA
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Energy, Environment Protection, Nuclear Power Engineering , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Microcosm experiments were conduced in which the surface of marine sediment was contaminated with naphthalene and subjected to either of three different bioremediation schemes, i.e., biostimulation (BS) by supplementing with slow-release nitrogen and phosphorus fertilizers, bioaugmentation (BA) by inoculating with Cycloclasticus sp. E2, an aromatics-degrading bacterium identified to play an important role for aromatic-hydrocarbon degradation in marine environments and combination (CB) of BS and BA. These three schemes were found to be similarly effective for removing naphthalene, while naphthalene disappearance in sediment without any treatment (WT) was slower than those in the treated sediments. Shifts in bacterial populations during and after bioremediation were analyzed by denaturing gradient gel electrophoresis (DGGE) of PCR-amplified 16S rRNA gene fragments. It was found that the Cycloclasticus rRNA type occurred as the strongest bands in the course of naphthalene degradation. Clustering analysis of DGGE profiles showed that bacterial populations in the WT, BS and CB sediments differed consistently from those in the uncontaminated control, while the profile for the BA sediment was finally included in the cluster for uncontaminated control sediments after a 150-day treatment. The results suggest that bioaugmentation with ecologically competent pollutant-degrading bacteria is an ecologically promising bioremediation scheme.
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  • 34
    ISSN: 1572-9729
    Keywords: biodegradation ; Burkholderia ; fenitrothion ; mpd gene
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Energy, Environment Protection, Nuclear Power Engineering , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract A short rod shaped, gram-negative bacterium strain Burkholderia sp. FDS-1 was isolated from the sludge of the wastewater treating system of an organophosphorus pesticides manufacturer. The isolate was capable of using fenitrothion as the sole carbon source for its growth. FDS-1 first hydrolyzed fenitrothion to 3-methyl-4-nitrophenol, which was further metabolized to nitrite and methylhydroquinone. The addition of other carbon source and omitting phosphorus source had little effect on the hydrolysis of fenitrothion. The gene encoding the organophosphorus hydrolytic enzyme was cloned and sequenced. The sequence was similar to mpd, a gene previously shown to encode a parathion-methyl-hydrolyzing enzyme in Plesiomonas sp. M6. The inoculation of strain FDS-1 (106 cells g−1) to soil treated with 100 mg fenitrothion emulsion kg−1 resulted in a higher degradation rate than in noninoculated soils regardless of the soil sterilized or nonsterilized. These results highlight the potential of this bacterium to be used in the cleanup of contaminated pesticide waste in the environment.
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  • 35
    ISSN: 1572-9729
    Keywords: Delftia acidovorans MC1 ; 2,4-dichlorophenoxyacetic acid (2,4-D) ; 2-(2,4-dichlorophenoxy) propanoic acid (2,4-DP) ; effect of tfdK gene ; simultaneous utilization of 2,4-D and 2,4-DP ; uptake characteristics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Energy, Environment Protection, Nuclear Power Engineering , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Growth of Delftia acidovorans MC1 on 2,4-dichlorophenoxyacetic acid (2,4-D) and on racemic 2-(2,4-dichlorophenoxy)propanoic acid ((RS)-2,4-DP) was studied in the perspective of an extension of the strain’s degradation capacity at alkaline pH. At pH 6.8 the strain grew on 2,4-D at a maximum rate (μmax) of 0.158 h−1. The half-maximum rate-associated substrate concentration (Ks) was 45 μM. At pH 8.5 μmax was only 0.05 h−1 and the substrate affinity was mucher lower than at pH 6.8. The initial attack of 2,4-D was not the limiting step at pH 8.5 as was seen from high dioxygenase activity in cells grown at this pH. High stationary 2,4-D concentrations and the fact that μmax with dichlorprop was around 0.2 h−1 at both pHs rather pointed at limited 2,4-D uptake at pH 8.5. Introduction of tfdK from D. acidovorans P4a by conjugation, coding for a 2,4-D-specific transporter resulted in improved growth on 2,4-D at pH 8.5 with μmax of 0.147 h−1 and Ks of 267 μM. Experiments with labeled substrates showed significantly enhanced 2,4-D uptake by the transconjugant TK62. This is taken as an indication of expression of the tfdK gene and proper function of the transporter. The uncoupler carbonylcyanide m-chlorophenylhydrazone (CCCP) reduced the influx of 2,4-D. At a concentration of 195 μM 2,4-D, the effect amounted to 90% and 50%, respectively, with TK62 and MC1. Cloning of tfdK also improved the utilization of 2,4-D in the presence of (RS)−2,4-DP. Simultaneous and almost complete degradation of both compounds occurred in TK62 up to D = 0.23 h−1 at pH 6.8 and up to D = 0.2 h−1 at pH 8.5. In contrast, MC1 left 2,4-D largely unutilized even at low dilution rates when growing on herbicide mixtures at pH 8.5.
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  • 36
    ISSN: 1572-9729
    Keywords: composting ; crude oil ; olive mill wastewater ; olive oil mills ; olive tree branches ; olive tree leaves ; sludge ; woodchips
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Energy, Environment Protection, Nuclear Power Engineering , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The aim of this paper was to evaluate the use of different bulking agents in different ratios as a means to control, optimise and eventually reduce the duration of the thermophilic period in two-phase olive oil mill sludge (OOMS) composting. The bulking agents used were: (i) olive tree leaves (OTL), (ii) olive tree shredded branches (OTB) and (iii) woodchips (WDC). The selection of these materials was based on their abundance and availability on the island of Crete, the southernmost point of Greece. The ratios studied were: Pile 1, OOMS:OTL in 1:1 v/v; Pile 2, OOMS:WDC in 1:1.5 v/v; Pile 3, OOMS:OTL in 1:2 v/v; Pile 4, OOMS:OTL:OTB in 1:1:1 v/v; and Pile 5, OOMS:OTL:OTB in 1:1:2 v/v. The composting system used was that of windrows with the volume of each pile approximately 20–25 m3. The experiments took place over two consecutive years. A composting turner was used and turnings were performed at one and two week intervals. In each pile a variety of physiochemical parameters were monitored. Temperature remained high in all five trials. Piles 1, 2, 3, 4 and 5 temperatures recorded values of above 50 °C for 106, 158, 160, 175 and 183 days, respectively. Volumes were reduced by approximately 67%, 62%, 63%, 80% and 84%, respectively. Temperature remained high, mainly due to the presence in large amounts of oily substances which during their complete oxidation release important amounts of energy and aid the cometabolism of more stable molecules such as lignin. This process is better described as the slow “burning” of a “fuel” mixture in an “engine” than composting. This approach is based on the extensive similarities of this process to that of crude oil sludge or similar waste composting.
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  • 37
    ISSN: 1572-9729
    Keywords: activated sludge ; dichlorophenol ; monooxygenation ; nicotinamide adenine dinucleotide ; phenolics ; specific growth rate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Energy, Environment Protection, Nuclear Power Engineering , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The two-tank accelerator/aerator modification of activated sludge significantly increases the biodegradation of hydrocarbons requiring initial monooxygenation reactions, such as phenol and 2,4-dichlorophenol (DCP). The small accelerator tank has a controlled low dissolved oxygen (DO) concentration that can enrich the biomass in NADH + H+. It also has a very high specific growth rate (μacc) that up-regulates the biomass’s content of the monooxygenase enzyme. Here, we develop and test the ACCEL model, which quantifies all key phenomena taking place when the accelerator/aerator system is used to enhance biodegradation of hydrocarbons requiring initial monooxygenations. Monooxygenation kinetics follow a multiplicative relationship in which the organic substrates (phenol or DCP) and DO have separate Monod terms, while the biomass’s content of NADH + H+ has a first-order term. The monooxygenase enzyme has different affinities (K values) for phenol and DCP. The biomass’s NADH + H+ content is based on a proportioning of NAD(H) according to the relative rates of NADH + H+ sources and sinks. Biomass synthesis occurs simultaneously through utilization of acetate, phenol, and DCP, but each has its own true yield. The ACCEL model accurately simulates all trends for one-tank and two-tank experiments in which acetate, phenol, and DCP are biodegraded together. In particular, DCP removal is affected most by DOacc and the retention-time ratio, Θacc/Θtotal. Adding an accelerator tank dramatically increases DCP removal, and the best DCP removal occurs for 0.2 〈 DOacc  〈 0.5 mg/l and 0.08 〈 Θacc/Θtotal 〈 0.2. The rates of phenol and DCP utilization follow the multiplicative relationship with a maximum specific rate coefficient proportional to μacc. Finally, μacc increases rapidly for Θacc/Θtotal 〈 0.25, acetate removal in the accelerator fuels the high μacc, and the biomass’s NADH + H+ content increases very dramatically for DOacc 〈 0.25 mg/l.
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  • 38
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    Biodegradation 17 (2006), S. 207-217 
    ISSN: 1572-9729
    Keywords: biodegradation ; DGGE ; K2Ni(CN)4 soil bacterial populations
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Energy, Environment Protection, Nuclear Power Engineering , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Metal cyanides are significant contaminants of many soils found at the site of former industrial activity. In this study we isolated bacteria capable of degrading ferric ferrocyanide and K2Ni(CN)4. One of these bacteria a Rhodococcus spp. was subsequently used to bioaugment a minimal medium broth, spiked with K2Ni(CN)4, containing 1 g of either an uncontaminated topsoil or a former coke works site soil. Degradation of the K2Ni(CN)4 was observed in both soils, however, bioaugmentation did not significantly impact the rate or degree of K2Ni(CN)4 removal. Statistical analysis of denaturing gradient gel electrophoresis profiles showed that the topsoil bacterial community had a higher biodiversity, and its structure was not significantly affected by either K2Ni(CN)4 or bioaugmentation. In contrast, profiles from the coke works site indicated significant changes in the bacterial community in response to these additions. Moreover, in both soils although bioaugmentation did not affect rates of biodegradation the Rhodococcus spp. did become established in the communities in broths containing both top and coke works soil. We conclude that bacterial communities from contaminated soils with low biodiversity are much more readily perturbed through interventions such as contamination events or bioaugmentation treatments and discuss the implications of these findings for bioremediation studies.
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  • 39
    ISSN: 1572-9729
    Keywords: acetochlor ; degradation ; isolation ; Pseudomonas oleovorans
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Energy, Environment Protection, Nuclear Power Engineering , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract To date, no pure bacterial cultures that could degrade acetochlor have been described. In this study, one strain of microorganism capable of degrading acetochlor, designated as LCa2, was isolated from acetochlor-contaminated soil. The strain LCa2 is Pseudomonas oleovorans according to the criteria of Bergey’s manual of determinative bacteriology and sequence analysis of the partial 16S rRNA gene. Optimum growth temperature and pH were 35 °C and 8.0, respectively. The strain could degrade 98.03% of acetochlor treated at a concentration of 7.6 mg l−1 after 7 days of incubation and could tolerate 200 mg l−1 of acetochlor. When the acetochlor concentration became higher, the degradation cycle became longer. The acetochlor biodegradation products were identified by GC–MS based on mass spectral data and fragmentation patterns. The main plausible degradative pathways involved dechlorination, hydroxylation, N-dealkylation, C-dealkylation and dehydrogenation.
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  • 40
    ISSN: 1572-9729
    Keywords: bioremediation ; composting ; ecotoxicity ; oil sludge
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Energy, Environment Protection, Nuclear Power Engineering , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The present work attempts to ascertain the efficacy of low cost technology (in our case, composting) as a bioremediation technique for reducing the hydrocarbon content of oil refinery sludge with a large total hydrocarbon content (250–300 g kg−1), in semiarid conditions. The oil sludge was produced in a refinery sited in SE Spain The composting system designed, which involved open air piles turned periodically over a period of 3 months, proved to be inexpensive and reliable. The influence on hydrocarbon biodegradation of adding a bulking agent (wood shavings) and inoculation of the composting piles with pig slurry (a liquid organic fertiliser which adds nutrients and microbial biomass to the pile) was also studied. The most difficult part during the composting process was maintaining a suitable level of humidity in the piles. The most effective treatment was the one in which the bulking agent was added, where the initial hydrocarbon content was reduced by 60% in 3 months, compared with the 32% reduction achieved without the bulking agent. The introduction of the organic fertiliser did not significantly improve the degree of hydrocarbon degradation (56% hydrocarbon degraded). The composting process undoubtedly led to the biodegradation of toxic compounds, as was demonstrated by ecotoxicity tests using luminescent bacteria and tests on plants in Petri dishes.
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  • 41
    ISSN: 1475-2743
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract. The two approaches most commonly applied to characterizing the chemical form and ‘reactivity’ of metals in the soil solid phase are sequential extraction procedures (SEPs) and isotopic dilution (ID). The development and limitations of both approaches are described and their application to contaminated soils discussed. It may be argued that ID offers a better means of discriminating between ‘reactive’ and ‘inert’ forms of metal. However, the literature on SEPs is considerably larger, providing greater scope for comparative analysis of new data. Although ID methods are subject to operational constraints, the procedural dependency of SEPs is probably much greater. Thus greater effort has been expended to standardize and verify methodologies for SEPs. However, despite achieving a level of ‘political ratification’ at the procedural level, the use of SEPs within risk assessments for planning or development purposes is currently almost absent. The future for ID methods in this context may lie in site-specific risk assessments that include improved methods for the prediction of metal solubility and bioavailability.
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  • 42
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    Soil use and management 21 (2005), S. 0 
    ISSN: 1475-2743
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract. Chemical analysis alone is inadequate for comprehensively assessing the impact of soil pollution on biota. The term bioavailability can only be applied in a context specific to a target biological receptor or a proven chemical surrogate. Integration of biological and chemical data can often yield significant advances in hazard assessment and act as a suitable baseline for making site-specific risk assessments. Here, the value of biological techniques is discussed and their application described. The relative merit of test selection is considered and the new direction being developed in sublethal assessments. Currently, however, one of the major limitations is the seeming lack of flexibility of many assays in that they are either applicable to agricultural systems or industrial scenarios, but rarely to both. As a consequence, few assays have internationally adopted protocols. The introduction of new methods and the continued improvement and refinement of assays make this area of soil science dynamic and responsive.
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  • 43
    ISSN: 1475-2743
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract. A current global trend towards intensification or specialization of agricultural enterprises has been accompanied by increasing public awareness of associated environmental consequences. Air and water pollution from losses of nutrients, such as nitrogen (N) and sulphur (S), are a major concern. Governments have initiated extensive regulatory frameworks, including various land use policies, in an attempt to control or reduce the losses. This paper presents an overview of critical input and loss processes affecting N and S for temperate climates, and provides some background to the discussion in subsequent papers evaluating specific farming systems. Management effects on potential gaseous and leaching losses, the lack of synchrony between supply of nutrients and plant demand, and options for optimizing the efficiency of N and S use are reviewed. Integration of inorganic and organic fertilizer inputs and the equitable re-distribution of nutrients from manure are discussed. The paper concludes by highlighting a need for innovative research that is also targeted to practical approaches for reducing N and S losses, and improving the overall synchrony between supply and demand.
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  • 44
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    Oxford, UK : Blackwell Publishing Ltd
    Soil use and management 21 (2005), S. 0 
    ISSN: 1475-2743
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract. Sustainable management of nutrients in agricultural systems is critical for sufficient production of nutritious foods and to minimize environmental pollution. In this overview, we discuss some of the most important factors influencing nutrient cycling, and how practices for sustainable nutrient management can be optimized. In most cases, problems are associated with excessive use of nutrients (manures, other organic amendments, and inorganic fertilizers). Options for dealing with such problems at the farm level include: reducing nutrient inputs to balance exports, increasing the land area on which manures are applied, and export of excess nutrients from the farm in the form of value-added products. These strategies can be used singly, or in combination. Nutrients in the human food chain are often not recycled back to primary crop production. To manage such issues, and avoid regional nutrient accumulations, we need to develop a better understanding of large-scale nutrient flows, and develop policies to manage them. We stress the importance of scale when considering nutrient management in the future.
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  • 45
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    Oxford, UK : Blackwell Publishing Ltd
    Soil use and management 21 (2005), S. 0 
    ISSN: 1475-2743
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract. The practice of large phosphorus (P) additions to agricultural land has resulted in an increased depletion of limited mineable rock phosphate resources, P accumulation in soils with an increased risk for P losses, and intensified eutrophication and deterioration of water quality in recipient water bodies. A number of measures have been used to reach balance between P inputs and outputs in agricultural systems, with the goal of achieving improved P use efficiency, sustained high crop yields and reduced P losses. This paper discusses how this goal may be achieved. Results from a Swedish long-term fertility experiment combined with results of a P leaching study using a selection of soils from the fertility experiment are used to evaluate the effects of a balanced P system on yields, soil P levels and P leaching. Three P fertilizer application strategies are compared (zero P, replacement P, and a treatment where surplus P fertilization was used to achieve a rapid increase in the soil P status). The replacement P strategy appeared to be the most sustainable system but P fixation in this system must be accounted for. When surplus P rates were applied, increased crop yields were counterbalanced by poorer use efficiency and P accumulation in soil. Topsoil P content was a poor predictor of P leaching. Instead, balancing P inputs and outputs represents a first step in the management of P losses, but additional, site-specific measures are required to counteract site-specific factors responsible for P losses.
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  • 46
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    ISSN: 1475-2743
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract. Low input grazing-based meat production is often practised on land where alternative land use is restricted and where high biodiversity warrants specific environmental payments. Although these systems are characterized by low external nutrient inputs, significant nutrient losses may occur per unit of produce, even though losses per unit area are low. If the aim is to have animal production without further eutrophication of watercourses, these losses should be minimized,. However, if nutrient-poor grasslands characterized by high biodiversity are the aim, some losses must be accepted to balance nutrient inputs by atmospheric deposition. The impact of grazing animals on nutrient dynamics in grasslands is reviewed in this paper, and options to further improve nutrient management are discussed. It is concluded that nutrient management should largely be addressed indirectly through management of animal behaviour in relation to grazing and supplemental feeding, as well as through optimization of the seasonal distribution of livestock size. A case study indicated that N losses from a cattle farm could be reduced considerably by these means, while animal production could actually be improved. Sustainability issues and trends in legislative and social pressures on low input grazing-based systems of animal production are discussed in relation to nutrient management and practical recommendations.
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  • 47
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    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Book reviewed in this article: Below-ground interactions in tropical agroecosystems: concepts and models with multiple plant components. M. van Noordwijk, G. Cadish and C. K. Ong (Editors).
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  • 48
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    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Book reviewed in this article: Good statistical practice for natural resources research. By R.D. Stone, R. Coe, E.F. Allan and I.C. Dale (Editors).
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  • 49
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    Soil use and management 21 (2005), S. 0 
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    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract. A model of soil variability as a continuous background process with superimposed point contamination was applied to 569 measurements of metal concentrations (Cr, Ni and Pb) in the topsoils of Sheffield, England. Robust estimators of the variogram were shown to be required to describe spatial variation of the metal concentrations at most sampled locations. This is diagnostic of the presence of a contaminant process. Values of the standardized kriging error from the cross-validation of each datum were used to identify spatial outliers for each metal. The ordinary kriged estimates of Cr, Ni and Pb were mapped after removing the outliers to estimate the background variation. Each of the 35 spatial outliers that occured in gardens have concentrations exceeding their Soil Guideline Value for residential land use with plant uptake, highlighting a potentially significant exposure pathway. The frequent observation of coal and furnace waste at these sites suggests that their dispersal, following domestic use and industrial processes, respectively, represents a significant point contaminant process. There was no evidence for spatial clustering of the point process. However, the spatial outliers of Cr and Ni showed a significant association with disturbed sites identified from historical land use maps, in part due to their prevalence in areas of historical steel manufacture. The magnitude of diffuse pollution for each metal in the urban soil was estimated by removing the spatial outliers and comparing robust measures of location with those from a survey of soils developed over the same parent materials in adjacent rural and peri-urban environments. The Winsorized mean Pb concentrations in urban topsoil (203 mg kg−1) were twice the value in the rural environment (101 mg kg−1), highlighting a very substantial diffuse Pb load to urban soils. The equivalent estimated diffuse components in urban soils for Cr and Ni were, respectively, 25% and 14% higher than the rural soils.
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    ISSN: 1475-2743
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract. Soils contaminated with organic chemicals are now widespread in industrialized and developing countries, and the risk assessment and remediation of such contaminated sites is a priority. However, containment and remediation strategies are complicated in many cases by the range of contaminants present and the historical nature of the contamination. Research has increased our understanding of the behaviour of organic contaminants in soil and the factors that control their behaviour. There is a fundamental need to understand and, where possible, quantify the bioavailable fraction as well as the total concentration of contaminant present in soil: the bioavailable fraction is key to toxicity or biodegradation. To quantify these fractions, a large number of techniques have been employed, ranging from organic and aqueous based solvent extractions to the use of biota. Many studies have been carried out investigating the use of chemical techniques to describe bioavailability, which could be used in the assessment and remediation of contaminated land. The aim of this review is to consider the behaviour of organic contaminants in soil, highlighting issues of bioavailability, and then to discuss the relevance of the various methods for assessing risk and potential remediation of organic contaminants in soil.
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  • 51
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    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract. A number of organic farms in Flanders were sampled to investigate the general phosphorus (P) status and degree of P saturation (Psat) of the soils. Where possible, the soil P status was compared to that in conventional agriculture and related to farm characteristics: agricultural land use, soil texture, fertilization intensity and time since conversion. Generally, the P status of the organic farms was high, and similar to that of conventional farms in Flanders, which is due to the restricted time since conversion to organic farming on most farms. The average soil Psat was slightly lower (37%) than the average value for East Flanders (39%) taken over the soil profile to 90 cm. However, a large proportion of the field areas on organic farms still had a Psat greater than 30% (critical Psat value), which may be an indication that P saturation will continue to be a problem for these farms.
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  • 52
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    Topics: Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Application of organic residues to soil is generally assumed to improve soil tilth. Only few studies have reported the long-term effects on the more subtle aspects of soil porosity, and no reports have considered the potential effects of organic amendments on the pore system in the subsoil. We sampled undisturbed soil cores (100 cm3 and 6280 cm3) using metal cylinders in differently fertilized plots in the long-term field experiment at Askov Experimental Station, Denmark. We selected the 0–60 cm soil layer of plots dressed for a century with either mineral fertilizers (labelled NPK) or animal manure (labelled AM) and unfertilized plots (UNF) as a reference. Both fertilization treatments were studied at two levels of nutrient application: ‘normal’ (labelled ‘1’) and 1.5 times ‘normal’ (labelled ‘1½’). Water retention, air permeability and air diffusivity were measured on the small cores, and we used the large cores for measuring near-saturated and saturated hydraulic conductivity. In the plough layer, the AM and NPK soils displayed identical pore volumes in size fractions that were larger as well as smaller than 30 μm, while the UNF soil had a significantly smaller volume of pores 〈 30 μm. No clear trends were found in treatment effects on pore organization as calculated from air diffusivity and air permeability measurements. No significant differences in hydraulic conductivity were found in the plough layer. For the subsoil below ploughing depth, significantly larger macropore volumes and near-saturated hydraulic conductivities were found for soil of plots receiving the larger (‘1½’) amount of nutrients compared with the ‘normally’ dressed soil. This effect was independent of fertilization system (AM or NPK). We attribute the larger volume of macropores to the improved root growth conditions in the soil with the higher nutrient level. We conclude that addition of animal manure at rates realistic in agriculture has only a modest effect on soil pore characteristics of the plough layer soil compared with the use of mineral fertilizers. For the subsoil below ploughing depth, a high level of nutrient application may increase soil macroporosity and near-saturated hydraulic conductivity, but the origin of nutrients is of no significance.
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  • 53
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    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract. A daily multi-layered water balance (DAMUWAB) approach has been formulated with modest input data on daily climatic records, slope gradient, physical soil properties and basic crop characteristics, for predicting the water and oxygen availability in freely drained soils of semiarid as well as subhumid tropical cropping systems. In this study, a simple one-dimensional root extension model is coupled to a water-uptake model that differentiates the uptake capacity of roots according to their depth. It has an intermediate level of detail between functional, 10-day period single-layered water balance (DESIWAB) approaches for land evaluation purposes, and the descriptive, daily water balances used in many crop growth models. Modelling capacity, functionality and expandability of DAMUWAB surpass the performance of DESIWAB. Water and oxygen shortages occurring in each compartment were found to limit water uptake and transpiration. Sensitivity analysis and comparison of DAMLWAB with the worldwide operational DESIWAB approach proved successful for model validation in the tropics and subtropics.
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    Soil use and management 21 (2005), S. 0 
    ISSN: 1475-2743
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract. A study was conducted to compare the performance of the PR1 capacitance probe (Delta-T Devices) in measuring soil volumetric moisture content (θ) with two established standard methods: the neutron probe (Didcot Instruments) and the gravimetric method. Over a two-year period, the three methods were used to measure θ in glasshouse plots containing crops of either oilseed rape (Brassica napus L.) or bambara groundnut (Vigna subterranea L.). The PR1 probe gave variable performance depending on the depth and soil profile where the measurements were made. In most cases, the PR1 probe significantly overestimated θ. In some cases, it significantly underestimated θ or gave similar values to the other methods. Despite this frequent overestimation of θ, the PR1 probe adequately registered the relative changes in θ Its measurements were linearly and positively related to those of the gravimetric and neutron-probe methods. However, the regression lines significantly deviated from the 1:l line. This paper discusses the possible reasons for the unsatisfactory performance of the PR1 probe and the practical problems associated with the installation of its access tubes.
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  • 55
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    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract. Nitrate leaching from crop rotations supporting organic grain production was investigated from 1997 to 2000 in a field experiment at three locations in Denmark on different soil types. Three experimental factors were included in the experiment in a factorial design: (1) proportion of N2-fixing crops in the rotation (crop rotation), (2) catch crop (with and without), and (3) manure (with and without). Three, four-course rotations were compared, two at each location. The nitrate leaching was measured using ceramic suction cells. Leaching losses from the crop rotation with grass–clover green manure and without catch crops were 104, 54 and 35 kg N ha−1 yr−1 on the coarse sand, the loamy sand, and the sandy loam, respectively. There was no effect of manure application or time of ploughing-in the grass–clover green manure crop on the accumulated nitrate leaching from the entire rotation. Catch crops reduced nitrate leaching significantly, by 30–38%, on the sandy soils. At all locations catch crops reduced the annual averaged nitrate concentration to meet drinking water quality standards in the crop rotation with green manure. On the coarse sand there was a time lag between the onset of drainage and the start of N-uptake by the catch crop.
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    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract. Soil organic carbon stocks to 1 m for Brazil, calculated using an updated Soil and Terrain (SOTER) database and simulation of phenoforms, are 65.9–67.5 Pg C, of which 65% is in the Amazonian region of Brazil. Other researchers have obtained similar gross results, despite very different spatial patterns mapped due to use of different methods.
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    Topics: Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract. The effects of rice-straw management (incorporation, burning or removal) on soil organic carbon content and physical and hydraulic properties were determined after five years of rice–wheat cropping in a sandy loam soil in northwest India. Soil organic carbon content was greater with straw incorporation and straw burning than with straw removal, and aggregation status, total porosity, pore-size distribution, bulk density, dispersion ratio and soil strength were correspondingly improved. The treatment effects were confined mainly to the 0–5 cm depth. Water retention was less with straw burning than straw removal, owing to increased water repellency of the soil surfaces. Cumulative infiltration and its rate after five hours were greater with straw incorporation than straw burning or removal. Air entry values were unaffected by straw management; however, the values were greater after rice harvest than after wheat harvest.
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  • 58
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    Topics: Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract. A field study was conducted to assess the effect of the nitrification inhibitor 3,4-dimethylpyrazole phosphate (DMPP), applied at a rate of 1 kg ha−1, on nitrous oxide (N2O) emissions, forage production and N extraction from a grassland soil after cattle slurry applications in autumn and spring. Nitrous oxide emissions were measured daily or weekly using the closed chamber technique. DMPP efficiency after slurry application was lower in spring (16.7 °C mean soil temperature) than in autumn (11.4 °C mean soil temperature). Thus, DMPP was able to maintain soil mineral N in the ammonium form for 22 days and reduce cumulative N2O emissions by 69% in autumn, while in spring its effect on soil mineral N lasted for 7–14 days, reducing cumulative N2O losses by 48%. Furthermore, application of DMPP after slurry did not decrease biomass yield or N uptake.
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    Topics: Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract. The effects of nitrogen fertilizer and tillage systems on soil organic carbon (SOC) storage have been tested in many field experiments worldwide. The published results of this research are here compiled for evaluation of the impact of management practices on carbon sequestration. Paired data from 137 sites with varying nitrogen rates and 161 sites with contrasting tillage systems were included. Nitrogen fertilizer increased SOC but only when crop residues were returned to the soil; a multiple regression model accounted for just over half the variance (R2=0.56, P=0.001). The model included as independent variables: cumulative nitrogen fertilizer rate; rainfall; temperature; soil texture; and a cropping intensity index, calculated as a combination of the number of crops per year and percentage of corn in the rotation. Carbon sequestration increased as more nitrogen was applied to the system, and as rainfall or cropping intensity increased. At sites with higher mean temperatures and also in fine textured soils, carbon sequestration decreased. When the carbon costs of production, transportation and application of fertilizer are subtracted from the carbon sequestration predicted by the model, it appears that nitrogen fertilizer-use in tropical regions results in no additional carbon sequestration, whereas in temperate climates, it appears to promote net carbon sequestration. No differences in SOC were found between reduced till (chisel, disc, and sweep till) and no-till, whereas conventional tillage (mouldboard plough, disc plough) was associated with less SOC. The accumulation of SOC under conservation tillage (reduced and no till) was an S-shape time dependent process, which reached a steady state after 25–30 years, but this relationship only accounted for 26% of the variance. Averaging out SOC differences in all the experiments under conservation tillage, there was an increase of 2.1 t C ha−1 over ploughing. However, when only those cases that had apparently reached equilibrium were included (all no till vs. conventional tillage comparisons from temperate regions), mean SOC increased by approximately 12 t C ha−1. This estimate is larger than others previously reported. Carbon sequestration under conservation tillage was not significantly related to climate, soil texture or rotation.
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  • 61
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    Topics: Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract. Over the last three decades there has been a great increase in the production of waste from urban, industrial and agricultural activity that could be recycled as a source of plant nutrients, and used to enhance soil quality. The use of these materials could partially offset the need for mineral fertilizers, giving both economic and environmental benefits. An incubation experiment was carried out using different organic waste materials applied to a Cambic Arenosol. Air-dried soil was mixed with increasing amounts of composted solid municipal waste, secondary pulp-mill sludge, hornmeal, poultry manure, solid phase from pig slurry, and composted pig manure, resulting in applications equivalent to 0, 40, 80, 120, 160 and 200 kg ha−1 of Kjeldahl nitrogen. The samples were incubated for 244 days under a controlled environment of 24 °C and 60% water holding capacity of the soil. The increasing amounts of waste applied always led to a greater amount of potentially available nitrogen present in the soil/waste mixture. Based on the proportion of their active N fraction, wastes were ranked: poultry manure〉hornmeal〉solid phase from pig slurry〉composted pig manure〉secondary pulp-mill sludge〉composted municipal solid waste. The results were well described by a one-pool exponential mineralization model, and mineral N formation was proportional to the quantity of waste applied. Of the wastes tested, those from animal sources showed greater nitrogen mineralisation. Nitrification was rapid, and concentrations of ammonium nitrogen remained relatively small.
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    Topics: Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract. Knowledge of the stocks and the potential range of soil organic carbon (SOC) in various land–soil combinations is an important precursor to policies aimed at linking, for example, management of SOC to greenhouse gas emission controls. To investigate the factors controlling the percentage of SOC (%SOC) of soils in England and Wales, we made a multiple regression analysis of data for the 2448 arable and ley-arable sites in the 1980 England and Wales National Soil Inventory (NSI). Clay content, average annual precipitation and depth of topsoil explained 25.5% of the variation in %SOC, when calcareous and peaty soils and those susceptible to flooding were excluded. Using ‘robust’ statistics, ‘indicative SOC management ranges’ were estimated for different physiotopes, that is, landscape units for which the environmental factors governing %SOC are similar, namely soil clay content and precipitation. These ranges describe the expected %SOC range for an arable soil in a given physiotope. They have potential to support approximate targets for the %SOC of arable soils and for estimating upper and lower limits for sequestered soil carbon in arable systems.
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    Topics: Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract. Hydraulic properties of soils after rice cropping are generally unfavourable for wheat cultivation. Poor drainage, delayed planting and oxygen stress in the root zone may adversely affect the wheat crop after lowland rice cultivation. We studied long-term effects of lantana (Lantana spp. L.) residue additions at 10, 20 and 30 t ha−1 yr−1 (fresh biomass) on physical properties of a silty clay loam soil under rice–wheat cropping in northwest India. At the end of ten cropping cycles, soil water retention, infiltration rate, saturated hydraulic conductivity and drying rate of soil increased significantly with lantana additions. The available water capacity (AWC), on volume basis, declined at rice harvest (from 22.0 to 18.8–20.9%), but increased at wheat harvest (from 12.9 to 13.4–15.0%) after lantana treatment. The volumes of water transmission (〉50 μm) and storage pores (0.5–50 μm) were greater, while the volume of residual pores (〈0.5 μm) was smaller in lantana-treated plots than in controls at both rice and wheat harvest. Infiltration rate in the lantana-treated soil was 1.6–7.9 times that of the control (61 mm d−1) at rice harvest, and 2–4.1 times that of the control (1879 mm d−1) at wheat harvest. Thus lantana addition improved soil hydraulic properties to the benefit of the wheat crop in a rice–wheat cropping sequence.
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    Notes: Abstract. Terrestrial ecosystem risk assessment remains in its infancy by comparison with the aquatic discipline, yet it is advancing quickly in response to increasing concerns surrounding soil quality and the sustainable use of soil. Several international frameworks have been developed during the last decade to aid decision-makers as the need for scientifically derived tools for determining ecological risk from land contamination has been recognized. From the regulatory viewpoint, the priority is establishing what to protect in order to prevent ecological harm. This is a complex issue requiring clear objectives in a risk assessment context. The most important factor in assessing ecological harm is whether or not ecosystem function is altered as a result of land contamination and, if it is, judging the significance. A consensus is developing that ecological risk assessment should aim to protect populations rather than individuals. This paper critically reviews recent developments in risk assessment for terrestrial ecosystems and land contamination in the UK, with emphasis on deriving a measure of ecological harm to assess ecosystem function. We seek to further justify the use of earthworms as a favoured indicator species for protecting ecological function. Guidance on how to measure harm in relation to ecological function is, however, still lacking.
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    Notes: Abstract. Effective use and recycling of manures together with occasional and judicious use of supplementary fertilizing materials forms the basis for management of phosphorus (P) and potassium (K) within organic farming systems. Replicated field trials were established at three sites across the UK to compare the supply of P and K to grass–clover swards cut for silage from a range of fertilizing materials, and to assess the usefulness of routine soil tests for P and K in organic farming systems. None of the fertilizing materials (farmyard manure, rock phosphate, Kali vinasse, volcanic tuff) significantly increased silage yields, nor was P offtake increased. However, farmyard manure and Kali vinasse proved effective sources of K to grass and clover in the short to medium term. Available P (measured as Olsen-P) showed no clear relationship with crop P offtake in these trials. In contrast, available K (measured by ammonium nitrate extraction) proved a useful measurement to predict K availability to crops and support K management decisions.
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    Notes: Abstract. We investigated whether an insoluble polyacrylate polymer could be used to improve the quality of a copper-contaminated soil. Growth of annual medic (Medicago polymorpha L.) was stimulated in the polymer-amended soil, such that total biomass produced was three times that of plants from unamended soil. Roots of plants cultivated in the polymer-amended soil had a concentration of copper that was 73% of that in plants from the unamended soil. Biological N2 fixation was enhanced in the polymer-amended soil. Soil enzymatic activities at the end of the experiment were correlated with plant growth and copper concentration of plants grown in soils with different levels of copper, which were achieved by mixing the contaminated soil with varying proportions of a soil of low copper content. Shoot dry weight was positively correlated with acid phosphatase, β-glucosidase, β-galactosidase and urease, whereas copper concentration in the roots of the annual medic was negatively correlated with acid phosphatase, β-galactosidase, cellulase and urease. The results are consistent with soil remediation by the polyacrylate polymer. Soil quality as inferred from plant growth, biological N2 fixation and soil enzymatic activities improved as a result of the remediation process.
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    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract. In Australia, stubble burning and tillage are two of the major processes responsible for the decline of soil organic carbon concentration in cropped soils, and the resulting soil degradation. However, the relative importance of these two practices in influencing the soil organic carbon concentration and the long-term impact on soil quality and productivity are not clear. The effects of stubble burning as practised by farmers in southeastern Australia were evaluated in two field trials, one of 19 years duration, the other of 5 years. Conventional tillage (three tillage passes) led to greater loss of soil organic carbon than stubble burning. Loss of total soil organic carbon attributed to stubble burning in the 0–10 cm layer was estimated to be 1.75 t C ha−1 over the period of the 19-year trial, equivalent to 29% of that lost due to tillage. In the 5-year trial, no change in soil organic carbon due to stubble burning was detectable. Changes in soil quality associated with stubble burning detected in the longer trial included a reduction in macro-aggregate stability, and increases in pH and exchangeable K+. Only the latter two were detected in the shorter trial. A higher mean wheat yield (average 0.15 t ha−1) following stubble burning was observed in the 19-year trial but not in the 5-year trial. Research to monitor the longer term effects of stubble burning is needed, and to identify conditions where loss of soil organic carbon is minimized.
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  • 69
    ISSN: 1475-2743
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract In Galicia (northwest Spain) the application of organic wastes to agricultural land is a common practice, which may increase total and bioavailable metal contents in the soil. In this study, total metal concentrations were determined in acid soils under different use (pasture, cropland, woodland) in an agricultural area where agro-industrial sludges are frequently recycled as manure. The aim was to establish baseline metal levels which could be used to determine the capacity of soils to absorb organic wastes. The estimation of baseline metal concentrations was carried out by two methods, one based on the analysis of means and geometric deviations, and another based on a modal analysis. Results suggested that the modal analysis procedure might be preferable when analysing data sets with a heterogeneous frequency distribution. In general, there was no significant difference in total metal concentrations when comparing soils from different land uses. Baseline levels for each metal indicated that all soils were suitable for organic waste application under current European Union (EU) legislation. From 2015, more restrictive metal limit values have been proposed by the EU, potentially preventing the addition of metal-containing wastes to pasture, cropland and woodland soils. The dissolved metal values in each soil were also estimated by empirical equations relating total metal concentrations, pH and organic matter content. Results showed that only the pasture soils would be suitable for organic waste disposal under the proposed EU metal limits for 2015, due to liming and substantial organic matter content. Total metal concentrations were insufficient to discriminate environmental risk in acid soils of different land use. The determination of baseline levels in reference areas and the estimation of soil metal bioavailability are suggested to define permissible values in the developing legislation.
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  • 70
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    Soil use and management 21 (2005), S. 0 
    ISSN: 1475-2743
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract. Despite considerable investment, some UK bathing waters fail to comply with mandatory standards as defined by the EU Bathing Water Directive (76/160/EEC). Continued non-compliance has been associated with diffuse sources of faecal indicator organism (FIO) contamination, in particular those deriving from agricultural land. This paper examines concentrations of FIOs in surface, subsurface and instream water samples at field sites considered to pose a high potential risk of FIO contamination. Quality of samples was compared with FIO standards for bathing water compliance in the UK. FIO concentrations exceeding mandatory and guideline standards were recorded frequently at all sites. In freely draining soils, FIO mobilization by rainfall was predominantly via subsurface flow, with occasional surface water flow linked to intensive rainfall events. In slowly permeable soils, surface mobilization of FIOs predominated, with the occurrence of limited subsurface samples linked to seasonal desiccation cracking within the soil, and to intense rainfall events. Watercourse FIO concentrations were significantly increased as the stream passed-by fields with freely draining soils. The data imply a generally higher risk of FIO transfer from freely draining soils and occasional increased risk from less permeable soils due to temporal changes in soil structure and rainfall intensity.
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  • 71
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    Soil use and management 21 (2005), S. 0 
    ISSN: 1475-2743
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract. Nutrient losses from arable land are important contributors to eutrophication of surface waters, and phosphorus (P) and nitrogen (N) usually act together to regulate production of Cyanobacteria. Concentrations and losses of both nutrients in drainage water from pipe drains were studied and compared in 15 crop rotations on a clay soil in southwest Sweden. Special emphasis was placed on P and it was possible to evaluate critical components of the crop rotations by flow-proportional water sampling. Total P concentrations in drainage water were generally small (0.04–0.18 mg L−1), but during two wetter years out of six, high P concentrations were measured following certain management practices, including ploughing-in lucerne (Medicago sativa L.) and fertilizing in advance without incorporation into the soil to meet the needs of several subsequent crops. This resulted in average flow-weighted concentrations of total P between 0.3 and 0.7 mg L−1. In crop rotations containing green manures, green fallow or leguminous leys, there was also a risk for increased P losses after these crops were ploughed in. The losses increased in the order: cash crops 〈 dairy with grass 〈 dairy with lucerne 〈 monoculture with barley 〈 organic farming with cattle slurry 〈 stockless organic farming with green manure. P balances varied between −9 and +8 kg P ha−1 and N balances between +4 and +35 kg N ha−1. The balances were not related to actual leaching losses. Phosphorus losses in drainage from set-aside were 67–82% of those from cash crops grown in ploughed and P-fertilized soil at the same site, indicating a high background P loss from this clay soil.
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  • 72
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    Soil use and management 21 (2005), S. 0 
    ISSN: 1475-2743
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract. Changes in surface soil properties of a savanna Alfisol under cultivation with applications of manure and inorganic NPK fertilizer were evaluated after 45 years of annual cropping. Soils from treatments with fertilizer only, fertilizer in combination with farmyard manure (FYM) at both high and low rates were compared to soil from a control receiving neither fertilizer nor manure. The high rate of FYM and fertilizer significantly improved soil aggregation, increased C, N and P status, while reducing soil penetration resistance. The results showed that there is a need to use both manure and inorganic fertilizer to maintain soil fertility in savanna soils under continuous cultivation.
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  • 73
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    Soil use and management 21 (2005), S. 0 
    ISSN: 1475-2743
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract. Vertisols are among the most common, high-potential soils in the central highlands of Ethiopia, where over 88% of human and 77% of the livestock population are located. Productivity from these soils is constrained by severe waterlogging due to their physical properties and intensive rainfall in summer. Traditionally, farmers plant late in the season to avoid the waterlogging, which results in harvest yields that are far below optimal. To bridge this yield gap, the broad-bed and furrow system for surface drainage has been introduced. Despite reported yields of various crops, little is known of the on-site and off-site impacts of this system. Consequently, four land preparation methods viz. (i) broad-bed and furrow (BBF), (ii) green manure (GM), (iii) the traditional system of ridge and furrow (RF) and (iv) reduced tillage (RT) were compared on standard runoff plots for 5 years (1998–2002) at Caffee Doonsaa in the central Highlands of Ethiopia. Runoff, sediment, organic carbon and nutrient (organic nitrogen and available phosphorus) losses were determined during the last two years (2001 and 2002). Over 50% of the seasonal rainfall was lost as runoff, regardless of the treatment, with significantly more of the excess water running off BBF and RT treatments in both years. The BBF system drained 67% and 54% of rainfall as runoff in 2001 and 2002, respectively, compared with 61% and 53% from the RT system during the measurement period. Although not statistically significant, the largest sediment and total nutrient losses tended to be from the BBF. The effect of the treatments on total nutrient loss and enrichment ratio was inconsistent. The nutrient concentration in the eroded sediment was greater than that of the originating surface soil but was strongly correlated. The effect of the land preparation methods was significant and varied with crops. Recommended options for best crop productivity are BBF for lentil and RT for wheat and tef.
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  • 74
    ISSN: 1475-2743
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract. Soil organic matter (SOM) controls the physical, chemical and biological properties of soil and is a key factor in soil productivity. Data on SOM quantity and quality are therefore important for agricultural sustainability. In 1990, an experiment was set up at Saria, Burkina Faso on a sandy loam Lixisol to evaluate long-term effects of tillage (hand hoeing or oxen ploughing) with or without 10 t ha−1 yr−1 of manure and fallowing on SOM and N concentrations and their distribution in particle size fractions. The field was sown annually to sorghum (Sorghum bicolor [L.] Moench). Ten years later, total organic C and total N, SOM fractions and their N concentrations, and sorghum yield were determined. Continuous sorghum cultivation without organic inputs caused significant losses of C and N in the hoed and ploughed plots. However, addition of manure to hoed plots was effective in maintaining similar levels of C and N to fallow plots. Without manure, SOM was mainly stored in the size-fraction 〈0.053 mm (fine organic matter, FOM). SOM was mainly stored in the size-fraction between 0.053 and 2 mm (particulate organic matter, POM). In plots with manure and in fallow plots, the addition of manure more than doubled POM concentrations, with levels in tilled plots exceeding those of the fallow plots, and the highest levels in manually hoed plots. Nitrogen associated with POM (POM-N) followed a similar trend to POM. Hoeing and ploughing led to a decline in sorghum grain yield. Manure application increased yields by 56% in the hoed plots and 70% in the ploughed plots. Grain yield was not correlated with total SOM but was positively correlated with total POM. This study indicated that POM was greatly affected by long-term soil management options.
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  • 75
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    Soil use and management 21 (2005), S. 0 
    ISSN: 1475-2743
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract. The impact of different tropical farming systems on soil quality was examined using a systematic sampling strategy. Total organic C, pH, extractable P, exchangeable K, bulk density, water stable aggregates, microbial biomass C, cation exchange capacity, soil depth, and clay content were determined. An assessment framework, including a minimum data set, linear scoring functions and weighted additive indices, was used to evaluate the soil quality of a tropical farm growing various crops in Hainan, China. Soil quality was evaluated according to four functions: water availability, nutrient availability, rooting suitability, and erosion resistance. Our results showed that soils were intrinsically lacking in nutrients and vulnerable to degradation, and that these problems were exacerbated by inappropriate management. There was strong evidence that long-term rubber farming caused soil acidification, soil compaction, and depletion of organic matter and nutrients. By contrast, conservation practices in coffee plantations protected or improved organic matter concentration and soil structure, resulting in higher soil quality indices.
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  • 76
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    ISSN: 1475-2743
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract. The practice of large phosphorus (P) additions to agricultural land has resulted in an increased depletion of limited mineable rock phosphate resources, P accumulation in soils with an increased risk for P losses, and intensified eutrophication and deterioration of water quality in recipient water bodies. A number of measures have been used to reach balance between P inputs and outputs in agricultural systems, with the goal of achieving improved P use efficiency, sustained high crop yields and reduced P losses. This paper discusses how this goal may be achieved. Results from a Swedish long-term fertility experiment combined with results of a P leaching study using a selection of soils from the fertility experiment are used to evaluate the effects of a balanced P system on yields, soil P levels and P leaching. Three P fertilizer application strategies are compared (zero P, replacement P, and a treatment where surplus P fertilization was used to achieve a rapid increase in the soil P status). The replacement P strategy appeared to be the most sustainable system but P fixation in this system must be accounted for. When surplus P rates were applied, increased crop yields were counterbalanced by poorer use efficiency and P accumulation in soil. Topsoil P content was a poor predictor of P leaching. Instead, balancing P inputs and outputs represents a first step in the management of P losses, but additional, site-specific measures are required to counteract site-specific factors responsible for P losses.
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  • 77
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    ISSN: 1475-2743
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract. Fertilizer and manure application rate and timing are often based on the optimal nitrogen rate and not on potassium (K) requirements. This can lead to excess or shortage of K depending on the crop and rotation. In grass-dominated agricultural production, including many organic farming systems, K has become a critical element, especially in areas dominated by coarse-textured or organic soils. In this paper we review K management in relation to long-term sustainability of both the soil resource and the production of crops of high yield and quality. One question for the future is whether we can adopt management options that favour efficient use of K and secure a sustainable future for global K reserves. For example, is it possible to enhance the release rate of K from soil mineral sources so that we require less fertilizer K from K-bearing salt deposits? A reduction in external K inputs requires improved on-farm recycling of K in order to reduce losses. We also need a better understanding of soil processes and soil–plant interactions and decision-support tools to predict the potential K release from mineral weathering. Certain areas dominated by young, clay-rich soils can potentially supply enough K, whereas other areas with coarse sandy or organic soils have a very low weathering potential and would thus need external inputs of K.
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  • 78
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    ISSN: 1475-2743
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract. The intensity of animal production around the world has increased substantially during the last half-century, which has led to large problems with the disposal of manures and waste waters. The focus of this paper is on the development of national policies to improve the nutrient management of concentrated animal feeding operations (CAFOs), where nutrients are invariably in surplus. To create proper nutrient management strategies for CAFOs, and to avoid environmental problems when surplus nutrients enter air, soil and water, we need to know the number of animals/birds in the unit, the quantity of manure/slurry produced, how this material is stored and handled and how much land is available for manure spreading. In this paper, we discuss the development of nutrient management strategies for CAFOs in Europe and North America, and the voluntary measures and environmental regulations related to this. For the planning of nutrient management to be comprehensive and efficient, we need expertise from several disciplines. This planning includes development of: animal diets that reduce the amounts of excreted nutrients; efficient storage and land application technologies; land application programmes to optimize yields and reduce nutrient losses; and strategies for use of excess manure outside the farm. Also, large-scale efforts involving many stakeholders (farmers, governments and private industry) are needed to solve problems with nutrient imbalances over the long term. Efforts along these lines include manure relocation, alternative uses of manures, nutrient trading, and a general extensification of animal agriculture. The overall guiding principle for policies and planning should be a balance of nutrients, on farms as well as at larger scales.
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  • 79
    ISSN: 1475-2743
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract This study tests relationships between, on the one hand, field-saturated infiltration rate into the uppermost sloping soil layer (Kfsi and field-saturated hydraulic conductivity in soil horizons (Kfsh) and, on the other hand, in situ determined macropore sizes in soil profile descriptions. It was carried out at six locations along a transect on a slope with loamy soils. The macropores were classified into representative size indices based on pore diameters (Ptd) and pore areas (Pta). A strong relationship was found between Kfsi and Pta, and between Kfsh and Ptd. The approach is promising and the methodology could be further developed with the aim of generalizing the functional relationships, so that Kfs can be estimated in areas where soil survey databases contain information on pore size abundance but lack Kfs values.
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  • 80
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    ISSN: 1475-2743
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Diverter berms are used to control soil erosion along restored pipeline corridors between the time the pipe is installed and the establishment of a vegetation cover. Current practice, based on standard design procedures, is often inadequate in areas of steep slopes and erosive rainfall because the resulting berm channels are too steeply graded and too widely spaced, and insufficient attention is given to their outlets. The Universal Soil Loss Equation provides a more flexible procedure for determining the spacing required to achieve a specified erosion target for given conditions of rainfall, soils and slopes. Where the required spacings are not feasible because they are too close, spacings should be based on ensuring that flow velocity does not exceed 80% of the maximum non-eroding velocity, and additional supporting erosion-control measures should be provided. Channels should be graded at 0.4% and the grade should never exceed 2%. The choice of type of outlet should be determined by the erodibility of the soil, the steepness of the slope, vegetation cover and whether the outlet slope is on undisturbed or made-up ground. Broad-based berms should be used as an alternative to narrow-based ones where there is a risk of damage from vehicles.
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  • 81
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    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract. Different types of contaminants such as polycyclic aromatic hydrocarbons (PAHs) and metals coexist in different chemical forms in soil. Although bioremediation of organics has been widely studied, little attention has been paid to changes in metal behaviour during the bioremediation process. In this study, the diffusion gradient in thin-film (DGT) technique was used to assess changes in potentially bioavailable Cd and Cr fluxes in soil during the bioremediation of phenanthrene. Fluxes of Cd were low (〈 0.2pgcm−2 s−1) and increased to 0.4–0.9 pg cm−2 s−1, while Cr(III) fluxes showed an approximately tenfold increase. Results showed that there was increased mobilization of metals associated with the fungal reduction of phenanthrene concentrations by Penicillium frequentans.
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    ISSN: 1475-2743
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract. The rate and extent to which cattle or pig slurry infiltrates into soil after application is one of the important factors determining the rate and extent of subsequent ammonia (NH3) volatilization. Better characterization of the infiltration process is required to improve predictive models of NH3 losses after land spreading. This paper describes a laboratory system using time domain reflectometry to measure slurry infiltration into soil columns. This system enabled semi-continuous, non-destructive infiltration measurements to be made, assessing the influence of slurry type, dry matter (DM) content, soil type and soil water tension. Differences were noted in the infiltration behaviour of cattle and pig slurries. For cattle slurry, DM content (range 1.7–7.1%) was the main influencing factor. Infiltration rate rapidly decreased with increasing DM content and there was no influence of soil type or water tension. For pig slurry, all of the slurry infiltrated into a sandy clay loam soil within the first hour, regardless of DM content (range 1.5–4.7%), whereas only 60% infiltrated into a clay loam soil over the same time period (slurry DM content 2.1%).
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    ISSN: 1475-2743
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract. Nuclear weapons' testing, mineral extraction industries and nuclear power generation are among the activities which have led to radioactively contaminated land. In the United Kingdom (UK), current activities such as the decommissioning of nuclear licensed sites and the sale of Ministry of Defence land require that the legislation, remediation and management of radioactively contaminated land be addressed. With an emphasis on the UK, this paper reviews potential management/remediation strategies for radioactively contaminated land, including consideration of the environmental mobility of potentially important radionuclides.
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    ISSN: 1475-2743
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract. Methods that can be used to determine the distribution of metal species in soil solution are critically reviewed and assessed. They are divided into two groups: those that can provide free ion activity, and those that measure labile species in solution. Ion selective electrodes have long been regarded as a promising technique, but there are practical problems in performing accurate measurements and only the Cu electrode has been used routinely. The Donnan membrane technique is capable of measuring the free ion activity of many metals, but adequate sensitivity can be a problem. Although resin competition methods are versatile, care must be exercised to avoid perturbing the solution excessively. Anodic stripping voltammetry (ASV) measures labile species, so the approximation involved in interpretation as simple inorganic species, from which free ion activities can be derived, should be recognized. Diffusive gradients in thin-films also measures labile species, but it is applicable to a much wider range of metals than ASV. It requires larger volumes of solution, but it can be used directly on the whole soil where it also measures the metal that can be rapidly supplied to solution. Other techniques such as permeable liquid membranes have yet to be used for measurements on soil solution. All of these methods have strength and weaknesses, and measure different aspects of speciation. Knowledge of the availability of the metals to biota is likely to be best advanced by the critical use of one or more of these speciation methods with a thorough understanding of exactly what is being measured.
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  • 85
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    ISSN: 1475-2743
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract. Sustainable nutrient management includes economizing on finite natural resources such as fossil energy and limited phosphorus (P) resources. Arable farms with exclusively crop production are characterized by large nutrient export in farm products. In the long term, nutrient export from soils and losses must be balanced by adequate inputs of fertilizers, biological N2 fixation or recycled products from the human food system. Critical issues associated in particular with arable systems discussed in this paper include organic matter depletion and lack of synchronization between nitrogen (N) release from organic N pools (such as plant residues and green manures) and crop demand, leading to N losses and/or N deficiency. Further critical issues identified include efficient use of indigenous soil P and applied P fertilizers and, especially in organic systems, risk of depletion of P and K, which if realized reduce soil fertility and limit production. The risk of enrichment of trace elements to levels toxic to soil microbes, plants, animals or man is also discussed. Suggested measures for managing these critical issues include choice of crop rotation, residue and green manure management.
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    ISSN: 1475-2743
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract. The intensity of animal production around the world has increased substantially during the last half-century, which has led to large problems with the disposal of manures and waste waters. The focus of this paper is on the development of national policies to improve the nutrient management of concentrated animal feeding operations (CAFOs), where nutrients are invariably in surplus. To create proper nutrient management strategies for CAFOs, and to avoid environmental problems when surplus nutrients enter air, soil and water, we need to know the number of animals/birds in the unit, the quantity of manure/slurry produced, how this material is stored and handled and how much land is available for manure spreading. In this paper, we discuss the development of nutrient management strategies for CAFOs in Europe and North America, and the voluntary measures and environmental regulations related to this. For the planning of nutrient management to be comprehensive and efficient, we need expertise from several disciplines. This planning includes development of: animal diets that reduce the amounts of excreted nutrients; efficient storage and land application technologies; land application programmes to optimize yields and reduce nutrient losses; and strategies for use of excess manure outside the farm. Also, large-scale efforts involving many stakeholders (farmers, governments and private industry) are needed to solve problems with nutrient imbalances over the long term. Efforts along these lines include manure relocation, alternative uses of manures, nutrient trading, and a general extensification of animal agriculture. The overall guiding principle for policies and planning should be a balance of nutrients, on farms as well as at larger scales.
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    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract. To establish strategies for sustainable nutrient management, the priority of each identified element for different user groups and the issue of data transferability from one scale to the next need to be addressed. This is important to avoid developing policies and strategies using inaccurate data. This paper provides a thorough background on such issues and provides data from specific case studies to reflect the impact of scale on the usability and transferability of data. These data show that using information obtained in a laboratory setting for larger scales can generate major errors. Data are also provided regarding the spatial variability in total N and total P measured at different sub-watersheds within a large watershed. Results from this case study indicate that there is a definite spatial variability in N and P loadings, which makes it difficult to transfer and extrapolate from data measured at one sub-watershed to the entire watershed. Therefore, it can be concluded that using either measured or simulated data obtained at a small scale to respond to questions for larger scales may be erroneous. Such difficulty may be due to the inherent spatial variability in soils, nutrients, biology and other features of the landscape.
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    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract. This paper describes the development and application of a simple empirical model describing differences in water movement through a cracking clay soil at Brimstone Farm, Wiltshire, UK. An extended data set comprising readings of soil water tension has been collected from an area of 9 m2 instrumented with 4 nests each of 3 tensiometers. The cracks are responsible for considerable differences both in water pathway and flow magnitude. Variations in water flow suggested by changes in soil-water tension are described by a model developed using ‘ModelMaker’ and applied separately to each profile nest. The model envisages water flow to occur through three soil layers, and to be partitioned into matrix and macropore flow components. Water is lost via drainage to clay tile drains at 60 cm depth. Water flow between layers is described as a function of the hydraulic gradient using Darcy's Law, with additional drainage from structural voids within the soil. Differences in the effective hydraulic conductivity describing slow and rapid flow components equate to macro and matrix flow for each tensiometer profile. The results illustrate heterogeneous patterns of flow through a soil block and demonstrate that a comparatively simple model is able to represent satisfactorily water flow dynamics through a cracking clay soil.
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    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract. Fertilizer and manure application rate and timing are often based on the optimal nitrogen rate and not on potassium (K) requirements. This can lead to excess or shortage of K depending on the crop and rotation. In grass-dominated agricultural production, including many organic farming systems, K has become a critical element, especially in areas dominated by coarse-textured or organic soils. In this paper we review K management in relation to long-term sustainability of both the soil resource and the production of crops of high yield and quality. One question for the future is whether we can adopt management options that favour efficient use of K and secure a sustainable future for global K reserves. For example, is it possible to enhance the release rate of K from soil mineral sources so that we require less fertilizer K from K-bearing salt deposits? A reduction in external K inputs requires improved on-farm recycling of K in order to reduce losses. We also need a better understanding of soil processes and soil-plant interactions and decision-support tools to predict the potential K release from mineral weathering. Certain areas dominated by young, clay-rich soils can potentially supply enough K, whereas other areas with coarse sandy or organic soils have a very low weathering potential and would thus need external inputs of K.
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  • 90
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    Soil use and management 21 (2005), S. 0 
    ISSN: 1475-2743
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract. Changes in agricultural subsidies in Europe and the ready availability of fertilizers have allowed a spatial decoupling of livestock and crop production. This has increased the flow of nutrients that occurs between farms compared to within individual farms. In terms of nutrient cycling, mixed farms provide the opportunity to re-integrate aspects of agricultural production. The degree of integration between crop and livestock production is denned by the reliance on the use of home-produced feed compared to imported feed, and is independent of intensity. Management of inputs and/or internal flows offers the scope to improve nutrient use efficiency (NUE) on mixed farms. Greatest uncertainties in calculating NUE are associated with variation in yield and composition of home-produced feed, and consequent manure composition. Three key areas are addressed to highlight the interchange of nutrients (and risks for losses) between crop and livestock production; (i) the role of livestock diet in manipulating the amount and availability of manure nutrients; (ii) the impact of manure management on nutrient losses; and (iii) nutrient management through the integration of crops and livestock in rotations. While not all the associated issues are unique to mixed farming, these three areas all influence NUE.
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  • 91
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    Oxford, UK : Blackwell Publishing Ltd
    Soil use and management 21 (2005), S. 0 
    ISSN: 1475-2743
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract. This paper highlights the principal problems related to the recycling of municipal wastes to arable land and outlines future solutions. History reveals that transport of sewage with water was introduced early (2500 bc), but only some Asian societies, which did not utilize sewage flushing, redistributed toilet wastes to arable land effectively. Nutrient flow analyses in developed countries indicate a withdrawal of 20 kg N and 3kgP ha−1 yr−1 from arable land because of non-return of organic human wastes. Limited reuse of municipal organic wastes in agriculture in several European countries is often seen as a question of waste quality. However, we believe that despite acceptable quality levels only minor progress in recycling has been achieved. Higher water contents in organic wastes than in harvested crops and, consequently, high costs for drying or transportation of wastes, often in combination with non-optimal plant nutrient composition, will remain the bottleneck which restricts the recycling of nutrients in wastes. One solution is to extract nutrients out of organic wastes and thereby derive concentrated compounds similar to those in inorganic fertilizers that can be redistributed and applied to soil. The challenge for modern sewage treatment systems is to shift perspective from removal to recovery of nutrients.
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  • 92
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    Oxford, UK : Blackwell Publishing Ltd
    Soil use and management 21 (2005), S. 0 
    ISSN: 1475-2743
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract. The Pan-European Soil Erosion Risk Assessment (pesera) model was evaluated using existing soil erosion data collected under various types of climate, vegetation, landscape and soil conditions. The data used represent a variety of typical Mediterranean land uses such as winter wheat, vines, olives and bare, stony land prevailing in hilly areas. Using this data, the model was calibrated for sediment transport by overland flow and results compared to measured soil erosion values from runoff plots and a watershed on a monthly basis. The performance of the model was assessed statistically, showing that it can be satisfactorily used for predicting soil erosion rates under the conditions included in the study. The overall model estimate including all the available experimental data was 0.69 t ha−1 yr−1 with a maximum error of 1.49 t ha−1 yr−1. After validation, the model was applied to a small watershed (60 ha) of great ecological importance for the sea turtle Caretta caretta. For this purpose, soil and vegetation maps were compiled from all the necessary data for applying the model. The model was run for three years using daily data from an existing nearby meteorological station. The predicted and measured soil erosion rates for a 7-month period were 0.31 t and 0.18 t, respectively. Application of the model to each mapping unit showed the over-riding importance of land use for sediment generation under the given climatic conditions. Bare land, occupying 5.5% of the watershed area, generated up to 69% of the total sediments estimated for the watershed. It is concluded that the pesera model can be used as a regional diagnostic tool under a range of soil, topographic and climatic conditions for identifying the best land use type and vegetation cover to protect hilly areas from soil erosion. The calculated overall root mean square error for the model is 0.06 t ha−1 yr−1, compared to a soil erosion rate of 0.04 t ha−1 yr−1, which can be tolerated for protecting the area for the sea turtle.
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  • 93
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    Oxford, UK : Blackwell Publishing Ltd
    Soil use and management 21 (2005), S. 0 
    ISSN: 1475-2743
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract. Total concentrations of heavy metals in soils were measured before and after the catastrophic floods of 1997, which devastated most districts within the commune of Racibórz in southern Poland. The assays covered lead, zinc, cadmium, chromium, nickel and copper. Analyses on soil samples taken in 2002, after the floods, were compared with those of 1992, taken as part of regular monitoring. There was an increase in the mean concentrations of heavy metals as a consequence of the flooding. Only a small part of this increase may be due to changes in the method of analysis between the two dates. The mean concentrations of heavy metals after flooding did not exceed the permissible levels for Polish soils. Permission was therefore granted to continue using much of the flooded land for farming. However, the investigations located a number of places where heavy metals were above permissible levels. Some of these were a consequence of the floods, but others were considered to be due to contamination from previous industry. Where high concentrations were found, land was excluded from agricultural use.
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  • 94
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    Soil use and management 21 (2005), S. 0 
    ISSN: 1475-2743
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract. We examined the use of soil quality (SQ) assessment to predict soil productivity and stability as a component of site potential for rangelands. Two minimum sets of data were compared for the SQ assessment within an area of relatively uniform climate. Data set 1 consisted of total soil N, topsoil depth, effective profile depth (EPD), and grade of structure, thus incorporating only soil chemical and physical properties. Data set 2 included exchangeable soil potassium, EPD, soil water retention capacity at wilting point, a soil slake test, and a nutrient cycling index. The interrelationships between soil properties and plant growth characteristics (i.e. total and herbage yield) were investigated and interpreted by statistical analysis and expert knowledge. By performing multiple regressions for each data set against the plant growth characteristics, we identified the contribution of each data set variable to the variability in plant characteristics and, thus, the predictive potential of each variable and data set. Within data set 1, EPD was important and in data set 2 the nutrient cycling index, which is a landscape function index derived from soil surface attributes, played the most important role in predicting potential. Principal component analysis was used to provide weighting factors for each indicator. We then transformed and combined observed indicator values for each data set using weighting factors and scoring functions into an additive soil quality index (SQI) varying in value from 0 to 1. The SQIs, with values greater than 0.8, provide optimum conditions for high yield.
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  • 95
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    Soil use and management 21 (2005), S. 0 
    ISSN: 1475-2743
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract. The favoured temperature range for soyabean seed germination is 25–30 °C and the crop is sensitive to water stress. In northern India, the crop is sown in the hot-dry months of May–June. Straw mulching can alter the soil's hydrothermal regime by lowering the temperature and reducing evaporation losses. A field experiment was conducted from 1999 to 2002 at the Research Farm of Punjab Agricultural University, Ludhiana on a loamy sand soil to evaluate the effect of wheat straw mulch on soil temperature, soyabean seed yield and crop growth. Maximum soil temperatures at sowing depth, recorded during the 1-month period after sowing (seed germination to seedling establishment stage), were high under no-mulch, ranging from 30.6 to 48.6 °C, while mulching substantially reduced these temperatures by 1.4 to 12.7 °C. Mulching increased soyabean seed yield by 4.4 to 68.3% in different cropping seasons; it also increased plant biomass by 17 to 122% and nodule mass by 8 to 220%. Leaf area index, chlorophyll content of leaves and number of pods per plant were all increased. Seed yield improvement under mulch was negatively correlated with rainfall distribution (number of rainy days) and amount during the whole cropping season. The percentage increase in seed yield with mulching was regressed against the total number of rainy days and total rainfall in millimetres in the cropping season. Thereby 93% of the variation in response to mulching in different cropping seasons was explained by the distribution and amount of rainfall.
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  • 96
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    Soil use and management 21 (2005), S. 0 
    ISSN: 1475-2743
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Forecasting crop nitrogen (N) demand is important for maximizing productivity and minimizing losses to the environment, and includes taking into account residual effects. The residual N effect was estimated in a dairy crop rotation (spring barley undersown with grass-clover, first and second year ley, spring barleylpeas undersown with ryegrass, oats undersown with ryegrass and fodder beet) with different management (grazed or cut) and manure type (slurry or deep litter) by anaerobic incubation and plant N-uptake in a pot experiment and in the field. For comparison a 10-year-old grass-clover ley was included. Type of animal manure did not affect the residual N effect. Crop rotations with grazed grassland had a residual N effect that on average was 13% higher than the same rotation without grazing. Ploughing of grassland clearly increased residual N effects for several years, but age of grassland at ploughing was of little importance. Thus, the residual N effect of 10-year-old grass-clover ley only marginally exceeded that of undersown grass-clover, despite considerable difference in estimated N-surplus. The results indicate that organic N is easier to mineralize the more recently it has been formed. Good correlations existed between soil inorganic N in the spring, N released during anaerobic incubation, and plant-available N. However, chemical analyses may be difficult to implement in practical farming due to difficulty of achieving representative samples in systems characterized by huge spatial variability.
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  • 97
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    Soil use and management 21 (2005), S. 0 
    ISSN: 1475-2743
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract. Recent work has demonstrated that the Olsen test for phosphorus (P) is an unreliable predictor of plant-available P in soils derived from basalt parent material in Northern Ireland. The present study was conducted to develop a more reliable soil-P test for these soils by regressing P fractions removed from soil by various chemical extractants against herbage P indices calculated from plant tissue test data using a diagnosis and recommendation integrated system. The degree of P saturation of the soil P sorption capacity, based on ammonium oxalate extractable P, Al and Fe, provided a better prediction of P available to swards on basaltic soils than either the Olsen test or a number of other well-known soil-P test procedures. The superiority of the degree of P saturation test on basaltic soils was attributed to the fact that it simultaneously takes account of both P quantity and P buffering capacity factors in predicting P availability. The Olsen-P test, which accounts for the P quantity factor alone, was only reliable for non-basaltic soils. Re-classifying the P fertility status of basaltic soils according to the degree of P saturation test could result in considerably less P being recommended for these soils with possible consequential benefits to water quality.
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  • 98
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    Oxford, UK : Blackwell Publishing Ltd
    Soil use and management 21 (2005), S. 0 
    ISSN: 1475-2743
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract. A model of the impact of land management changes upon soil organic carbon (SOC) was constructed, and the total amount of topsoil organic carbon was estimated for the arable area of England from 1940 to 2000. The largest influence on the overall mean SOC in arable topsoils proved to be a decline in the area of both permanent and temporary grassland. SOC declined over a prolonged period (60 years), but has now reached a plateau. Modelling changes in mean values enabled a statistical evaluation to be made between a measured decline in the number of sites with ‘high’ SOC levels between 1980 and 1995, and the decline predicted by the model. The SOC content of arable soils in England was measured at National Soil Inventory sites twice in recent decades: in 1980 and 1995. The proportion of fine textured soils in the lowest SOC class (〈2.3%) rose from just over 40% to about 50% over the same period. There was a significant difference between the observed values of 1995 and those expected from modelling the decline from 1980 values, in the category of ‘low SOC’ fine textured soils. The variation in the fine textured soils represents a significant and widespread decline in topsoil organic carbon concentrations, which was greater than the underlying long-term trend.
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  • 99
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    Oxford, UK : Blackwell Publishing Ltd
    Soil use and management 21 (2005), S. 0 
    ISSN: 1475-2743
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract. The success of organic cropping systems depends on symbiotic N2 fixation by leguminous crops, and it is important to explore new management systems to improve the nitrogen input through N2 fixation. During two growing seasons the possible advantage of growing fababean (Vicia faba L.) in ridges was studied in comparison to the traditional method on flat soil. Differences in soil physical parameters resulted in a significantly greater microbial activity and a deeper root system at the flowering stage when grown in the ridge than on the flat. Consequently, the amount of fixed N at flowering was significantly greater in ridges than in flat soil. However, during the period from flowering until harvest, when the major part of the N uptake and N2 fixation took place, the differences between the treatments disappeared. Average values for the growing season of fluorescein diacetate hydrolysis, arylamidase activity and arylsulphatase activity were significantly greater in the ridge than on the flat, and the microbial biomass-C, derived from substrate induced respiration (SIR), was on average 232 and 223 μg C g−1 soil in the ridge and on the flat, respectively. Measured total-N uptake, including root N (0–30 cm depth), ranged from 206 to 247 kg N ha−1, of which 182–201 kg N ha−1 was fixed N. From 154 to 173 kg N ha−1 was removed in grain resulting in a soil-N balance of +28 kg N ha−1 in both years. However, by including estimates of total root N and rhizodeposition-N the soil-N balance ranged from +52 to +62 kg N ha−1.
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  • 100
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    Oxford, UK : Blackwell Publishing Ltd
    Soil use and management 21 (2005), S. 0 
    ISSN: 1475-2743
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract. Soil samples from a 32-year grassland field experiment were taken from 0–5, 5–10, and 10–15 cm soil depths in February 2002. Plots received annual treatments of unamended control, mineral fertilizer, three rates of pig slurry and three rates of cow slurry, each with six replicates. Samples were analysed for cation exchange capacity (CEC), exchangeable cations (Na+, K+, Ca2+, Mg2+), pH and Olsen P. Exchangeable sodium percentage (ESP) was calculated as a sodicity indicator. Mean ESP was generally greater for slurry treatments than the control, with a trend of increasing ESP with application rate. This was particularly marked for cow slurry. At 0–5 cm depth ESP increased from 1.18 in the control to 1.75 at the highest rate of pig slurry and 5.60 at the highest rate of cow slurry. Similar trends were shown for CEC, exchangeable Na+, K+ and Mg2+, Ca2+ and Olsen P. The build-up of soil P due to slurry applications, together with this combination of physical and chemical factors, may increase the risk of P loss to surface waters, particularly from soils receiving high rates of cow slurry.
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