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  • 1
    Electronic Resource
    Electronic Resource
    Food-crop-based production systems as sustainable alternatives for Imperata grasslands? (1996)
    Springer
    Agroforestry systems 36 (1996), S. 55-82 
    Details
    ISSN: 1572-9680
    Keywords: erosion ; Imperata cylindrica ; Indonesia ; the Philippines ; rotational hedgerow intercropping ; sustainability criteria ; weed control
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Purely annual crop-based production systems have limited scope to be sustainable under upland conditions prone to infestation by Imperata cylindrica if animal or mechanical tillage is not available. Farmers who must rely on manual cultivation of grassland soils can achieve some success in suppressing Imperata for a number of years using intensive relay and intercropping systems that maintain a dense soil cover throughout the year, especially where leguminous cover crops are included in the crop cycle. However, labour investment increases and returns to labour tend to decrease in successive years as weed pressure intensifies and soil quality declines. Continuous crop production has been sustained in many Imperata-infested areas where farmers have access to animal or tractor draft power. Imperata control is not a major problem in such situations. Draft power drastically reduces the labour requirements in weed control. Sustained crop production is then dependent more solely upon soil fertility management. Mixed farming systems that include cattle may also benefit from manure application to the cropped area, and the use of non-cropped fallow areas for grazing. In extensive systems where Imperata infestation is tolerated, cassava or sugarcane are often the crops with the longest period of viable production as the land degrades. On sloping Imperata lands, conservation farming practices are necessary to sustain annual cropping. Pruned tree hedgerows have often been recommended for these situations. On soils that are not strongly acidic they may consistently improve yields. But labour is the scarcest resource on small farms and tree-pruning is usually too labour-intensive to be practical. Buffer strip systems that provide excellent soil conservation but minimize labour have proven much more popular with farmers. Prominent among these are natural vegetative strips, or strips of introduced fodder grasses. The value of Imperata to restore soil fertility is low, particularly compared with woody secondary growth or Compositae species such as Chromolaena odorata or Tithonia diversifolia. Therefore, fallow-rotation systems where farmers can intervene to shift the fallow vegetation toward such naturally-occurring species, or can manage introduced cover crop species such as Mucuna utilis cv. cochinchinensis, enable substantial gains in yields and sustainability. Tree fallows are used successfully to achieve sustained cropping by some upland communities. A variation of this is rotational hedgerow intercropping, where a period of cropping is followed by one or more years of tree growth to generate nutrient-rich biomass, rehabilitate the soil, and suppress Imperata. These options, which suit farmers in quite resource-poor situations, should receive more attention.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00142867
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  • 2
    Electronic Resource
    Electronic Resource
    Improving shifting cultivation in Southeast Asia by building on indigenous fallow management strategies (1999)
    Springer
    Agroforestry systems 47 (1999), S. 37-48 
    Details
    ISSN: 1572-9680
    Keywords: farming systems ; indigenous knowledge ; intensification ; slash-and-burn ; swidden ; uplands
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Shifting cultivation continues as the economic mainstay of upland communities in many countries in Southeast Asia. However, the conditions that historically underpinned the sustainability of rotations with long fallows have largely vanished. The imperative to evolve more permanent forms of land use has been exacerbated by rapid population growth, gazettement of remnant wildlands into protected areas, and state policies to sedentarize agriculture and discourage the use of fallows and fire. There are many compelling examples where shifting cultivators have successfully managed local resources to solve local problems. Technical approaches to stabilizing and improving productivity of shifting cultivation systems have not been notably successful. Farmer rejection of researcher-driven solutions has led to greater recognition of farmer constraints. This experience underlined the need for participatory, on-farm research approaches to identify solutions. The challenge is to document and evaluate indigenous strategies for intensification of shifting cultivation through a process of research and development. This process involves identification of promising indigenous practices, characterization of the practices, validation of the utility of the practice for other communities, extrapolation to other locations, verification with key farmers, and wide-scale extension.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006248104991
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  • 3
    Electronic Resource
    Electronic Resource
    Relationships between crop temperature, grain yield, evapotranspiration and phenological development in two hybrids of moisture stressed sorghum (1981)
    Springer
    Irrigation science 2 (1981), S. 213-224 
    Details
    ISSN: 1432-1319
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Recent studies have shown that the grain yields of corn (Zea mays L.) and wheat (Triticum aestivum L.) are related to the degree of water stress they undergo. The purpose of the study reported here was to establish relationships between crop temperature and the grain yields, phenological development, evapotranspiration rates (ET) and leaf water potential (ψ l ) of two hybrids of grain sorghum (Sorghum bicolor L. Moench) subjected to varying levels of plant water stress. The study was conducted at the University of Nebraska Sandhills Agricultural Laboratory in 1978 on a Typic Ustipsamment (Valentine fine sand) soil. The sorghum hybrids used were RS 626 and NB 505. Four irrigation treatments were applied in order to subject the crops to varying levels of water stress during each of three major growth stages. Soil moisture was monitored with a neutron probe. ET was estimated with the water balance technique. Crop temperature was measured with an IR thermometer and leaf water potential was measured with a Scholander pressure bomb. Grain yields were reduced by water stress occuring at anytime during the growing season. Yield reductions were largest when stress occurred during only the grainfill period and were least when stress occurred during the entire growing season. The percentage reduction in sorghum grain yield can be described by an index involving the seasonal accumulation of the daily mid-day temperature differences between well-watered and stressed crops (Σ TSD). As Σ TSD values increased, ET decreased. However, the correlation of ET with Σ TSD was relatively low (R2 = 0.60) probably due to the limited amount of data available for analysis and inaccuracies in the soil water balance method used to estimate ET. The mid-day temperature of well-watered rows ranged between 18.0 and 32.8 °C with a mid-day temperature range of about 0.5 °C between the well-watered rows in various plots for several days following an irrigation. However, in certain instances, the mid-day temperature range increased to 1–2 °C for a few days before irrigation. This suggests that certain of the rows experienced water stress and should have been irrigated earlier. Yield data support that conclusion. Range in crop temperature within a field appeared to be a sensitive indicator of crop water stress in sorghum. No significant difference in the phenological development of sorghum resulted from water stress except in one NB 505 plot in which plants were stressed throughout the entire season. In that plot, the stressed plants lagged in development behind non-stressed plants by approximately ten days. The differences in mid-day leaf water potentials (Δψ l ) and crop temperatures (ΔT) between stressed and non-stressed vegetation were examined. As ΔT increased up to about 4 °C, Δψ l , also increased. Beyond that point, Δψ l decreased while ΔT continued to increase. This behavior was attributed to stomatal closure which permitted an increase in ψ l of the stressed plants (hence reducing Δψ l ) even as ΔT continued to increase.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00258375
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  • 4
    Electronic Resource
    Electronic Resource
    Grain crop response to contour hedgerow systems on sloping Oxisols (1998)
    Springer
    Agroforestry systems 42 (1998), S. 107-120 
    Details
    ISSN: 1572-9680
    Keywords: erosion ; Gliricidia sepium ; Oryza sativa ; Paspalum conjugatum ; Penisetum purpureum ; Zea mays
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Farming systems that minimize the rate of soil degradation and optimize food crop yields are needed to sustain soil productivity on sloping, acid, infertile soils in the humid tropics. Research was conducted on two Oxisols with slopes ranging from 22 to 30% to evaluate the performance of several contour hedgerow systems, with and without the addition of 60 kg N ha−1 per crop, on rice (Oryza sativa) and maize (Zea mays L.) production. Contour hedgerows were double rows of the tree legume Gliricidia sepium (G); Gliricidia and the native grass Paspalum conjugatum (GPas); Gliricidia and an exotic fodder grass Penisetum purpureum (GPen); double rows of Penisetum (Pen); and a conventional open field (C) farming system without hedgerows. Gliricidia prunings and all crop residues were applied to the soil surface in the alleys, but Penisetum was harvested. Food crop yields in all hedgerow treatments tended to be less than the Control for the first two years, presumably due to the displacement of land planted to the food crop. In the third and the fourth years, the rice and maize yields of Treatments G and GPas exceeded the Control, most consistently when N was not applied. Penisetum reduced food crop yields regardless of N application presumably due to nutrient removal in the fodder. The results indicate that Gliricidia in a contour hedgerow increases food crop yield on strongly acid Oxisols by recycling nutrients and partially supplementing the N demand by the food crops.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006020319918
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  • 5
    Electronic Resource
    Electronic Resource
    Soil property changes in contour hedgerow systems on sloping land in the Philippines (1999)
    Springer
    Agroforestry systems 46 (1999), S. 251-272 
    Details
    ISSN: 1572-9680
    Keywords: acid soil ; alley cropping ; hedge-crop competition ; nutrient dynamics ; soil fertility ; sustainability
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The impact of contour hedgerow systems on soil sustainability under acidic conditions has been widely criticized. A study was undertaken to determine the effects of management and hedgerow species on soil properties. Cassia spectabilis (a non-N-fixing tree legume), Gliricidia sepium (an N-fixing tree legume), Pennisetum purpureum (a forage grass), and Stylosanthes guyanensis (a forage legume) contour barriers were compared with an open field (non-hedgerow treatment) over 1 cowpea and 2 rice seasons. Three types of management viz.: prunings applied + N0P0K0, prunings applied + N50P20K20 and prunings removed + N50P20K20 were used as subplot treatments. The soils were strongly acidic (pH 4.5) and classified as clay Orthoxic Palehumult. Cassia performed better than the other species in terms of pruning biomass, N and P contributions over a period of 20 months. There was a combined positive effect of pruning biomass and fertilizers on rice and cowpea yields in Pennisetum and Gliricidia systems, while a tendency towards a positive effect of pruning biomass on rice was found in the Cassia system. The pruning biomass and/or fertilizer application did not significantly influence the top soil organic C, N and available P in the hedgerow systems. Soil bulk density was significantly reduced by the application of Cassia prunings after 12 months. Organic C, N and P dynamics indicated that in situ pruning biomass was not sufficient to maintain their level in the soil. But the cassia systems with prunings applied + N50P20K20 experienced the lowest degradation in soil organic C (2.1 t ha−1) followed by the Gliricidia systems (4.1 t ha−1). The overall results imply that the application of pruning and inorganic fertilizer is imperative to conserve soil resources, and non- N-fixing tree species can exert a significant advantage in biomass and thereby in soil N-recycling under acidic soil.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006049711801
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  • 6
    Electronic Resource
    Electronic Resource
    Nitrogen fixation capacity in the component species of contour hedgerows: how important? (1994)
    Springer
    Agroforestry systems 27 (1994), S. 241-258 
    Details
    ISSN: 1572-9680
    Keywords: Gliricidia sepium ; Senna spectabilis ; Cassia spectabilis ; Pennisetum purpureum ; tree legume ; alley cropping
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The choice of an appropriate hedgerow species is one of the most critical decisions in exploiting the value of a contour hedgerow system. The implications of hedgerow species with nitrogen (N)-fixation capacity on hedgerow-crop competition and crop productivity have been widely debated. We examined the agronomic significance of N-fixation by comparing the performance of species representing three classes of hedgerow vegetation: A nitrogen-fixing tree legumeGliricidia sepium), a non-nitrogen fixing tree (Senna spectabilis syn.Cassia spectabilis), and a forage grass (Pennisetum purpureum). The 4-year study investigated the hedgerow biomass and nutrient yields, and their relative effects on the performance of two annual crops commonly grown in alley farming systems, with emphasis on hedgerow-crop interference. The work was done on an Ultic Haplorthox (pH 4.8, organic C 1.9%, total N 0.18%).Senna produced 46% more pruning biomass on an annual basis than didGliricidia; N supplied to the alley crops was similar toGliricidia in the first year of observation, but 20–30% higher in the succeeding years. Upland rice and maize grain yields and total dry matter were unaffected by tree species, but the nitrogen-fixing tree exerted less competitive effects on the annual crops growing in adjacent rows. Grass hedgerows reduced maize yields 86% by the second year, indicating an unsustainable drawdown of nutrients and water. We conclude that hedgerow systems composed of a nitrogen-fixing tree did not exert significant advantages compared to a non-fixing tree species, and that factors other than N-fixation were more important determinants for the choice of hedgerow species.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00705059
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  • 7
    Electronic Resource
    Electronic Resource
    Preface (1996)
    Springer
    Agroforestry systems 36 (1996), S. v 
    Details
    ISSN: 1572-9680
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00142864
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  • 8
    Electronic Resource
    Electronic Resource
    The Imperata grasslands of tropical Asia: area, distribution, and typology (1996)
    Springer
    Agroforestry systems 36 (1996), S. 3-29 
    Details
    ISSN: 1572-9680
    Keywords: alang-alang ; area estimates ; cogon ; degraded lands ; Imperata cylindrica (L.) ; uplands
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The rehabilitation or intensified use of Imperata grasslands will require a much better understanding of their area, distribution, and characteristics. We generated estimates of the area of Imperata grasslands in tropical Asia, and suggested a typology of Imperata grasslands that may be useful to define the pathways toward appropriate land use intensification. We conclude that the area of Imperata grasslands in Asia is about 35 million ha. This about 4% of the total land area. The countries with the largest area of Imperata grasslands are Indonesia (8.5 million ha) and India (8.0 million ha). Those with the largest proportion of their surface area covered with Imperata are Sri Lanka (23%), the Philippines (17%), and Vietnam (9%). Laos, Thailand, Myanmar, and Bangladesh evidently all have similar proportions of their land area infested with Imperata (about 3 to 4%). Malaysia (〈 1%), Cambodia (1%), and the southern part of China (2%) have but a minor proportion of their total land area in Imperata. The species was found widely distributed on the full range of soil orders. It occupied both fertile (e.g. some of the Inceptisols and Andisols) and infertile soils (Ultisols and Oxisols) across a wide range of climates and elevations. Imperata lands fall into four mapping scale-related categories: Mega-grasslands, itmacro-grasslands, meso-grasslands, and micro-grasslands. The mega-grasslands are often referred to as ‘sheet Imperata’. They are the large contiguous areas of Imperata that would appear on small-scale maps of say 1:1,000,000. We propose that this basic typology be supplemented with a number of additional components that have a key influence on intensification pathways: land quality, market access, and the source of power for tillage. The typology was applied in a case study of Indonesian villages in the vicinity of Imperata grasslands. We propose an international initiative to map and derive a more complete and uniform picture of the area of the Imperata grasslands. This should include selected studies to understand conditions at the local level. These are critical to build the appreciation of change agents for the indigenous systems of resource exploitation, and how they relate to local needs, values and constraints.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00142865
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  • 9
    Electronic Resource
    Electronic Resource
    Agroforestry innovations for Imperata grassland rehabilitation: workshop recommendations (1996)
    Springer
    Agroforestry systems 36 (1996), S. 263-274 
    Details
    ISSN: 1572-9680
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00142877
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  • 10
    Electronic Resource
    Electronic Resource
    Root pulling resistance in rice: Inheritance and association with drought tolerance (1985)
    Springer
    Euphytica 34 (1985), S. 905-913 
    Details
    ISSN: 1573-5060
    Keywords: Orvza sativa L. ; rice ; drought tolerance ; genetics ; leaf water potential ; root pulling resistance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Avoidance of drought stress is commonly associated with root system characteristics and root development. The inheritance of root pulling resistance in rice (Oryza sativa L.) was investigated and its relationship with visual field scores for drought tolerance was studied. Transgressive segregation for high root pulling resistance was observed in 3 crosses (high x high, low x high, and intermediate x intermediate). Both dominant and additive genes control the variation. F1 superiority for high root pulling resistance was observed and could be exploited in an F1 hybrid breeding program. F2 distribution curves indicated that plants highly resistant to root pulling can be obtained not only from low x high and high x high crosses, but also from intermediate x intermediate crosses. Root pulling resistance in rice has a low heritability (39 to 47%). Thus, breeding for a high root pulling resistance may best be accomplished by selection based on line means rather than individual plant selection. Field screening showed significant differences in leaf water potential among random F3 lines. F3 lines with higher leaf water potential had better visual scores for drought tolerance. Visual drought tolerance scores were correlated with root pulling resistance. Plants with high root pulling resistance had the ability to maintain higher leaf water potentials under severe drought stress. The usefulness of the root pulling technique in selecting drought tolerant genotypes was confirmed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00035430
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