ALBERT

Notizen: Abstract. Estimates of winter drainage, D, are available for 82 locations in England and Wales for each winter during the 35-year period, 1940/1 to 1974/5. At each location, D is approximately normally distributed. The variability, expressed as a coefficient of variation, is approximately inversely proportional to the average drainage; it is large, ranging from 20–30% in Wales and the uplands of northern and western England to 60–70% in eastern England. Assuming a normal distribution, the probability of exceeding a given amount of drainage is easily found.The proportion, f of solute initially in the soil that is leached each winter can be calculated using these estimates of D in a simple layer model. However, f is not normally distributed, but can be fitted by the Type-1 extreme-value distribution.If there are n years of data, and m is the rank of a value in order of decreasing size, the estimation of the probability, P, of exceeding the mth largest value, fm, is P(ffm) =m/(n+1), and the return period, t, is 1/P years. Using the transform, W= In[—In P], graphs of/against W yield families of lines that, for a given location and depth in the soil, depend only on soil type, and from which extreme values likely to be encountered in a given return period can be forecast. Results are discussed for Mildenhall, Suffolk (= 99 ± 68 mm), Cockle Park, Northumberland (±= 275 ± 125 mm), Welshpool, Powis (±= 373 ± 121 mm), Carmarthen, Dyfed (±= 764 ± 196 mm) and Ambleside, Cumbria (±= 1280 ± 276 mm).

Notizen: Abstract. During the four consecutive winters between 1984 and 1989 a computer simulation model was used to estimate the amounts of nitrogen in a cereal crop and available from soil to the crop after winter. The model does this by taking account of daily weather and by making simple assumptions about the starting conditions each autumn after the harvest of the previous crop. Some of the information which was given to farmers on viewdata systems is displayed, together with maps showing the average amounts of nitrogen in soil and crop in spring over 10 years in eastern England. This 10-year average is used as a baseline against which to judge the simulations in each of the four winters of our viewdata service.

Notizen: Abstract. In 1989–90 over 80% of the erosion on agricultural land in the South Downs was on ploughed or cultivated surfaces prepared for spring planting of cereals. This was in contrast to the pattern in previous years when most erosion was in winter cereal fields. An unusual late winter rainfall peak was the primary cause. Periods of erosion risk associated with other land uses on the South Downs are also discussed.

Notizen: Abstract. Linear, exponential and power function regressions were compared for rainfall, runoff and soil loss data. The power function performed better (R2= 0.77) than exponential or linear functions for estimating runoff from daily rainfall. However, this relationship was improved (R2= 0.96) by inclusion of a random component to the deterministic part of the function. A linear relationship between runoff and soil loss data performed better (R2= 0.77) than exponential or power functions. These relationships help in designing soil and water conservation works for supplemental irrigation in the area.

Notizen: Understanding soils — the experience of an adviser By N.H. Pizer

Notizen: Abstract. Various factors of soil erosion (erodibility of the soil, slope of the land and nature of the plant cover) were studied in a representative area of submontane Punjab. In the north-eastern part of the area, slope steepness, slope length, convexo-concave and concave slope patterns and sparse vegetation were the dominant factors governing erosion hazard. In the central and lower south-western part of the area, high soil credibility and sparse vegetation were the most important factors.Rill erosion was positively correlated (r= 0.87) with slope steepness. The erodibility of the soil was strongly correlated (r= 0.98) with amounts of silt + very fine sand.In the area with steeper slopes, the lower segments of transects were prone to more erosion because of high credibility. Slope shapes such as convexo-concave and concave could result in sloughing and greater erosion hazard if not properly protected. Slopes facing southwest were more prone to erosion than others because of more solar energy, greater aridity, less vegetation and concave shape.

Notizen: Abstract. In arid regions of India, cultivation of marginal areas and overgrazing of pastures have resulted in degradation of land. Accelerated wind erosion on sandy surfaces and water erosion on the shallow soils of piedmont areas are both common. Landsat Thematic Mapper sub-scenes have been used to map the type, extent and degree of degradation. In an area of over 5000 km2, 42% was affected by wind erosion and 50% by accelerated water erosion. A quarter of the whole area needs urgent attention for soil conservation.

Notizen: Abstract. The essential factors dependent on soil structure that influence plant growth are soil/root contact, adequate air and water, and low mechanical impedance. Bulk density, shear strength and texture arc interrelated closely and permit quantification of these factors. A general relationship between clay content and vane shear strength of soil at field capacity and non-limiting bulk density provides a rapid means of quantitatively estimating structure. We propose a procedure utilizing vane shear strength and a tactile assessment of clay content as criteria for judging soil structure in the field.

Notizen: Abstract. Despite a growing awareness that erosion on arable land in Britain is a potential hazard to long-term productivity, there is still only limited information on the rates involved, particularly long-term values. Use of the caesium-137 (137Cs) technique to study soil erosion within arable fields on various soil types at 13 locations in southern Britain has yielded retrospective measurements of the long-term (c. 30 years) rates of soil loss and the patterns of soil redistribution within the study fields. The range of long-term rates of net soil loss extends from 0.61 per hectare per year on clay soils in Bedfordshire to 10.5 t per hectare per year on brown sands in Nottinghamshire. The measured rates are compared with other published data for similar soil types and land use, and the implications for long-term productivity and potential environmental impacts are considered.

Notizen: Abstract. Field investigations on loamy sand soil showed that compaction by cattle trampling increased soil bulk density and cone penetrometer resistance. Trampling produced very dense zones at depths of 7–10.5 cm, which impeded drainage, despite the presence of large macropores. Soil structural and hydrological changes caused by hoof compaction can result in serious pasture management problems. Compaction simulation experiments on saturated turf indicated that most severe structural damage occurs on initial compaction.

Notizen: Abstract. Microbial biomass C and P were monitored in the Oh horizon of an afforested podzol in Mid-Wales before and after clearfelling. Measurements over a 2-year period indicated that soil moisture and temperature control the seasonal fluctuations in biomass C in this soil. Clearfelling significantly increased biomass P in the Oh horizon. This was probably caused in part by increased fluxes of organic and inorganic phosphorus from the felling debris and litter horizons of the forest floor.

Notizen: Abstract. A method is presented for compiling a manual for the estimation of crop residue cover in the field. The crop residue is a combination of standing stubble and the straw remaining on the ground after harvest. Field assessment of crop residue is important so that management decisions may be made in the field. Such decisions include selection of cultivation or sowing machinery, irrigation scheduling (for crusting materials), soil temperature control and grazing of crop residue. The manual consists of a graded set of colour photographs, taken from an overhead boom, and a sampling rate nomogram to determine the number of 1 m quadrats required in a given field to estimate the cover with a predetermined level of error. Two methods for calibration of the photographs are compared: (a) projection of slides onto a screen with manual counting, and (b) digital image analysis of the photographs. Image analysis is efficient, rapid and gives less error than counting from the projections because many more points are counted. The use of the manual in the field is described. It is an inexpensive piece of equipment for the field agronomist or farmer, and gives a reliable, rapid and semi-quantitative estimate of residue cover.

Notizen: Abstract. Crop growth on strongly weathered soils is often limited by soil compaction in addition to aluminium toxicity and/or calcium deficiency. This study examines the effects of subsoiling, lime and gypsum on penetrometer resistance, acidity, aluminium and calcium levels and cotton (Gossypium hirsutum L.) root growth on soils transitional between Cecil and Appling series (clayey, kaolinitic, thermic Typic Hapludults) in the Piedmont region of Georgia, USA. The main plots were subsoiled to depths of 0.35 or 0.80 m or untreated. Dolomitic limestone (0 or 4.03 t per hectare on subplots) and phosphogypsum (0 or 10 t per hectare on sub-subplots) were incorporated into the surface soil (0.15 m). Deep subsoiling (0.80 m depth) decreased penetrometer resistance at 0.3–0.5 m depth and increased yield in two of three years, but there was no response to shallow subsoiling (0.35 m depth). Lime increased yield when surface soil water pH prior to amendment was less than a Cate-Nelson critical value of 4.6. Gypsum moved downward much more rapidly than lime, increasing soil solution calcium ion activity to a depth of 0.8 m within 5 months of application. There were differences in clay content between replicate plots and calcium movement was faster where the clay content was less. Yield responses to gypsum in 1986 were attributed to increased root growth below 0.2 m resulting from the increased calcium ion activity. Yield response to gypsum in limed sub-subplots was significant only in 1986.

Notizen: Abstract. Concentrations of soil nitrate were measured in areas of different land use within a small drainage basin. From previous work on nitrate losses from subcatchments, soil nitrate levels were expected in the order arable 〉 grassland 〉 woodland. Although differences were detected, they were not consistent and seasonal variations in soil nitrate for the same land use were greater than those between land uses. Seasonal fluctuations in stream nitrate loads were not strongly related to the seasonal differences in soil nitrate levels but were more closely related to stream discharge and antecedent climatic conditions. Losses of nitrate from the catchment seemed to be transport limited and independent of variations in soil nitrate supply; the implication is that water quality control by land use manipulation will only be successful in supply limited situations when leaching losses are sensitive to variations in soil nitrate supply.

Notizen: Abstract. Geostatistics is basically a technology for estimating the local values of properties that vary in space from sample data. Research and development in the last 15 years has shown it to be eminently suited for soil and ripe for application in soil survey and land management. The basic technique, ordinary kriging, provides unbiased estimates with minimum and known variance. Data for related variables can be incorporated to improve estimates using cokriging. By more elaborate analysis using disjunctive kriging the probabilities of deficiency and excess can be estimated to aid decision.The variogram is crucial in all geostatistics; it must be estimated reliably from sufficient data at a sensible scale and modelled properly. Once obtained it can be used not only in the estimation itself but also to choose additional sampling sites, improve a monitoring network or design an optimal sampling scheme for a survey. It may also be used to control a multivariate classification so that the resulting classes are not too fragmented spatially to manage.

Notizen: Abstract. Experiments were conducted for one year on two different soil types. On a clay soil straw was either (a) burnt, (b) baled leaving the stubble, or (c) chopped and spread. The soil was tine cultivated to depths of 5, 10 or 15 cm or ploughed to 20 or 30 cm before winter wheat was sown conventionally. In addition, a direct-drilled crop was sown after each straw treatment. On a silt loam soil the direct-drilled, tine cultivated to 15 cm and ploughed to 30 cm treatments following burning or chopping and spreading straw were repeated.Tine cultivation incorporated less straw than ploughing, decreased plant establishment and early growth but did not decrease yield. Direct-drilling through chopped straw decreased yield on the silt loam but not on the clay soil. Short straw (〈 5 cm) was easier to incorporate than longer straw. Ploughing was the most efficient method of straw incorporation because it inverts soil. Early effects on crop growth and nutrient uptake following straw incorporation were transient and associated with large amounts of straw in the seeded layer of soil.

Notizen: Abstract. Soil has a finite strength to resist permanent volume change and permanent shear deformation. When the stresses imposed on the soil are of a sufficient magnitude to overcome the strength, then the deformation falls into one of two regimes. At low stress ratios (ratio of normal stress to maximum past stress) the soil expands when sheared and at high stress ratios it compresses. The maximum past stress in a field soil is the pre-consolidation stress. The pre-consolidation stress is the compressive stress greater than which compression is considerable and permanent.These regimes of soil deformation behaviour are consistent and predictable under a wide range of conditions. They are described by the critical state concept, which can usefully be applied to soil management. Management decisions can be based on whether the stresses imposed by a particular operation result in high or low stress ratios. This governs whether the soil will deform permanently or not (for compaction damage), expand on shear (tillage) or compress on shear (preparation of rice paddy soils). The change in permeability and structure can also be predicted from the deformation regime.

Notizen: Abstract. The influence of three urease inhibitors, hydroquinone (HQ), phenyl phosphorodiamidate (PPDA) and N-(n-butyl) phosphorothioic triamide (NBPT) on denitrification of nitrate in soil was studied in an incubation experiment under waterlogged conditions, at 25°C and in the presence of increasing amounts (0.0, 0.1 and 1 %) of ground barley straw. Two hundred milligrams of nitrate-N (as potassium nitrate) was added with the respective urease inhibitors.Addition of barley straw increased the denitrification rate in the soil. Within 2 days the added nitrate-N was completely reduced. This result was confirmed by the measurement of nitrous oxide. HQ decreased gaseous nitrogen loss by decreasing the activity of the denitrifiers in the soil. The inhibitory effect was increased by adding increasing amounts of HQ. Because denitrification is stimulated by readily decomposable organic matter, the retardation seems to be a short-term effect. The other urease inhibitors, PPDA and NBPT, had no significant influence on the denitrification process when they were applied at the rate of 4 mg per kilogram of soil.

Notizen: Abstract. Current methods of agricultural land evaluation in Queensland and other parts of Australia have been criticized for their inflexibility and lack of attention to costs (both private and social) associated with particular land uses. These deficiencies can limit the usefulness of land evaluation procedures in defining land capability and suitability for farm and regional land use planning. This paper outlines a new method based on soil potential ratings, that incorporates biophysical crop simulation modelling, expert systems and risk analysis. The technique is able to integrate biophysical and economic data in a measure which can be readily computed, updated and communicated to land managers.

Notizen: Abstract. A 2-year field experiment assessed the effectiveness of fertilizer, surface applied and injected liquid digested sewage sludge in increasing yields from reclaimed but regressing pasture on colliery spoil. At the first harvest, surface applications of sewage sludge gave the largest yields, although only a third of total fertilizer nitrogen (N) had been applied at this stage of the experiment. The greatest yields in the first year were given by fertilizer treatments which included the highest level of applied N, and large surface applications of sludge.Surface applications of sludge on plots that were ripped gave the largest residual yields in the second year of the experiment. The percentage cover of clover was inversely related to the amount of nitrogen applied. A study of plant roots indicated that soil injection supplies sludge at too great a depth to benefit grass.Taken overall the results confirm that the regression of pastures established on reclaimed colliery spoil is primarily caused by lack of nitrogen and phosphorus. But the effect of compaction in decreasing root growth, and therefore the ability of the grass to take up nutrients, is also apparent.

Notizen: World Map of the Status of Human-Induced Soil Degradation. Global Assessment of Soil Degradation (GLASOD) By L.R. Oldeman, R.T.A. Hakkeling & W.G. SombroekEvaluation of Land Resources in Scotland Edited by J.S. Bibby & M.F. Thomas.

Notizen: Abstract. A basic task of national soil survey organizations should be to monitor changes in soil properties. The objectives would be to establish which land-use systems, on which soil types, are causing decline in fertility, and to keep track of the effects of pollution. Unless data are obtained at national level, attempts to monitor global soil changes cannot succeed.

Notizen: Abstract. Soil provides an environment for all forms of life, from viruses and bacteria to trees, and these soil inhabitants play many important roles in soil development and in the maintenance of soil fertility. Policies for protection of soil should therefore include criteria for the biological quality of soil. The establishment of such criteria can only be based on an understanding of the function of the different groups of soil organisms, including the interactions between these groups which give rise to such processes as mineralization of organic matter. However, we are only beginning to understand this most complex of ecosystems. Current information is reviewed and the problems of establishing biological standards for soil are considered. Much of the discussion on assessment of pesticide side effects is relevant to this topic, and the future need to quantify risk associated with the introduction of genetically-engineered organisms into soils is likely to stimulate further debate on this topic.

Notizen: Abstract. The methods of soil handling used by Greenham Construction Materials Ltd (Greenham) have been designed to avoid damage to restored soils and the need for subsequent curative work. The systems used to plan restoration, move soil and install drainage are described. The quality of restored land and its cropping potential are described with reference to Greenham's Laleham Farm site at Shepperton Pit in Middlesex. Materials Ltd, to avoid soil damage in the course of extract-

Notizen: Abstract. Runoff and erosion rates on loamy sand soils were measured at the Hilton experimental site, Shropshire. Little runoff and no erosion occurred on a steep runoff plot inserted into permanent grassland. Most precipitation infiltrated into the soil and was transmitted down slope as interflow within the Ah horizon. In contrast, considerable amounts of runoff and erosion occurred on the bare arable plots. These results suggest that incorporation of strips of permanent grassland into arable systems could assist soil and water conservation. Considering the high erosion rates on bare steep plots, conversion of slopes 〉 12° to permanent grassland seems appropriate.

Notizen: Abstract. Protection of soil against common threats to its function are discussed in relation to UK forestry practice. British forestry uses very little fertilizer and pesticides, so the effect of their use on forest soil is minimal. Some soil acidification often accompanies forestry, but there is as yet no evidence that UK forest condition or yield have suffered as a consequence. Proper management of forest operations can control the severity of soil compaction and erosion, and though there is no evidence that either is widespread, more information is required on their occurrence.

Notizen: Abstract. Although there is a need to protect soils against future pollution, many sites are already badly contaminated by past activity. The paper describes some of the contaminants which affect soils, and the policies for acceptable levels adopted by national governments. Various appropriate clean-up policies are discussed.

Notizen: Abstract. Soil clean-up policies have been a major focus of environmental concern in the Federal Republic of Germany. With the unification of the two Germanies there is an increased need for these policies. The paper briefly describes the nature of the soil contamination problem, and the development of a soil clean-up programme. Clean-up policies are evaluated by comparison with practices in the USA.

Notizen: Abstract. The paper introduces the need for soil protection policies and the importance of standardized soil analytical and descriptive procedures, using examples from The Netherlands and the international Labex programme. The structure and concerns of the International Organization for Standardization Technical Committee on Soil Quality (TC 190) are outlined.

Notizen: Abstract. LEACHN is a deterministic model for simulating nitrogen dynamics in soil. Transport processes are based upon numerical solutions to the Richards equation for water flow and the convection-dispersion equation for solute transport. Transformations of urea, ammonium, nitrate and three organic pools are included, and the influence of water content and temperature can be reflected. Lack of measured input data sometimes limits the more general use of models such as these. Approaches to estimating data values using soil survey information and a limited number of measured data are discussed. Simple model sensitivity studies and a limited number of field measurements can guide the choice of input data values and lead to simulations that reflect the main features of the field soil nitrogen regime. Such an approach provides initial values for a modelling exercise, and improves intuition regarding the relative importance of processes and interactions in the field nitrogen cycle.

Notizen: Abstract. The ability of the SOIL-SOILN models to predict nitrate leaching rates from arable land under different fertilizer inputs is tested. The SOIL model predicts water and temperature conditions in a layered soil profile and provides driving variables for the SOILN model which describes nitrogen inputs, transformations and losses. SOILN model predictions were compared with measurements of nitrate leaching at application rates of zero, 100 and 200 kg N per hectare (NO, N100 and N200) in a long-term field experiment in south-west Sweden. Large discrepancies between model predictions and measurements of nitrate leaching were found in some years (up to 100%) and were attributed to important soil processes which are either not included in the model (macropore How) or are difficult to model satisfactorily (partitioning between surface runoff and infiltration during snowmelt periods, crop nitrogen uptake). Nevertheless, long-term mean yearly leaching losses at the different nitrogen application rates (3, 6 and 46 kg per hectare at NO, N100 and N200, respectively) were reasonably well estimated by the model.

Notizen: Abstract. The model described divides the soil into layers and considers two categories of water, mobile and immobile, in each layer. It has two main parameters, one a measure of the soil's capacity to hold water and thence to retain solutes against leaching, and the other a measure of the ease with which water can pass through the soil and carry solutes with it. These are, in effect, capacity and rate parameters, and the model is unusual in having both. They can be estimated from the percentages of clay and other soil components. The rate parameter varied appreciably between plots in the field but in a consistent manner. The model has been validated against field experiments following the vertical movement of solute applied to the soil surface and allowed to leach, and the paper includes one such test.

Notizen: Abstract. Techniques for determining the probability density function (pdf) of travel times of solute molecules through a defined volume of soil, following a pulse or step-change input to the soil surface, are described. A stochastic transfer function model (TFM) based on the pdf of nitrate travel times works satisfactorily when the nitrate originates from a pulse input of soluble fertilizer to the soil surface. However, a TFM based on the pdf of a surface-applied tracer, such as chloride or tritiated water, is less satisfactory for simulating the leaching of indigenous soil nitrate. The main problems seem to be the difficulty of estimating mean nitrate concentrations because of the spatial variability of nitrate in field soils, accounting for denitrification during leaching, and the uncertain reproducibility of the soil's transport characteristics, as embodied in its operationally defined fractional transport volume, θst, Nevertheless, for many practical applications, a simplified empirical model which treats the soil's transport volume as a well mixed reactor of average initial concentration C, can provide satisfactory predictions of the quantity of nitrogen leached over extended periods. Irrespective of which model is used, a comprehensive treatment of nitrate leaching, particularly for soil generated nitrate, requires a detailed knowledge of transfers of labile nitrogen within the transport volume, and across its boundaries other than those monitored at the input and output surfaces.

Notizen: Book reviewed in this article.Policy and Practice in the Management of Tropical Watersheds By H.C. PereiraSoils and their Management: a Sino-European Perspective Edited by E. Maltby and T. Wollersen.

Notizen: Abstract. The leaching of spring-applied fertilizer nitrogen was measured by soil sampling on three soils widely used for spring cropping: a loamy sand, a sandy loam and a sandy silt loam. Soils were fallow during the experiment. Results were compared with simulations obtained with a computer leaching model. The model differentiated well between soil types, and predicted mineral nitrogen remaining in the top 30, 60 or 90 cm with reasonable precision. It tended to over-estimate the rate of nitrification of ammonium from ammonium nitrate fertilizers. The causes of occasional large discrepancies between sampling and measurement are discussed.

Notizen: Abstract. The modelling of leaching of nitrate and other solutes in artificially drained soils is complicated by the need to consider both unsaturated and saturated components of the system. This work is an attempt to couple together an unsaturated zone transport model (Addiscott & Whitmore, 1991) with a steady state travel- time model (Ernst, 1973) for the saturated zone. The model was tested using chloride leaching data from eight hydrologically isolated plots on a pipe-drained clay loam soil. Approaches to parameter estimation are discussed. Results were variable, for on some plots saturated zone travel time could be virtually neglected, whereas on other plots this component was apparently important.

Notizen: Abstract. Leaching losses of nitrate-nitrogen were measured from a set of eight hydrologically isolated plots on a clay loam soil over the period from September 1987 to February 1990. Variable drainflow recovery from the plots hampered accurate estimation of nitrate loading, but results suggest that, when inorganic nitrogen fertilizer is applied up to the recommended amount, there is little influence of the amount applied on the amount leached. We did, however, observe the following effects on nitrate leaching: leguminous green manure incorporated in autumn increased leaching of nitrate-nitrogen by 10–15 kg per hectare during the winter; autumn cultivation caused some increase in leaching compared with no cultivation in one year; some systematic variations in nitrate leaching occurred between years and between plots, but were unrelated to treatments.From the results we conclude that green manuring does not provide sufficient nitrogen for organically grown crops on this soil but contributes significantly to nitrate leaching, and that growing spring cereals, with the land remaining in stubble as long as possible in autumn, may be the best strategy to minimize nitrate leaching.

Notizen: Abstract. A Land Evaluation System for rainfed agriculture has been developed in Zambia. It is intended for use in reconnaissance and semi-detailed land evaluation studies, and works with 74 subqualities, 40 crops and four input levels. The subqualities are rated and converted into constraint classes per input level. The most limiting constraints determine the final suitability class. Expected yields per suitability class and input level are then estimated. The system was calibrated by a field study at four locations. Comparisons were made between expected and actual yields and expected and actual constraints. The range of actual yields was wider than that expected, probably because of variation in management between farmers. The average actual and expected yields were strongly correlated, but chi-squared tests showed that they were significantly different. The system generally works well in assessing land suitability for crops commonly grown in Zambia.

Notizen: Abstract. Experiments were started in 1967 to investigate the effects of soil mixing on fen peat soil. Peaty topsoil was mixed with mineral subsoil to a maximum depth of 80 cm at two sites, one with a clay subsoil, the other sand. Mixing was done on a commercial scale with a range of implements. After initial increases, yields of arable crops on both mixed soils were subsequently similar to those on unmixed soil. Residual herbicide activity was enhanced on mixed soils, and evidence of peat conservation was obtained at one site. The practice has not been taken up commercially because of the high capital cost of mixing and lack of serious problems which had been predicted following peat wastage.

Notizen: Abstract. Relationships between soil colour patterns and depth and duration of water tables were studied using piezometers in three soil hydrosequences. A colour index was developed to quantify matrix colour, size and colour of mottles, and continuity and colour of clay films. It correlated well with duration of saturation when above 5°C (r= 0.88) and with duration of total saturation (r= 0.87). The colour index is useful to evaluate soils for various land uses.

Notizen: A cultivar of Italian ryegrass (Bb 2067), specifically bred for high magnesium content, was assessed for its efficacy in alleviating the incidence of hypomagnesaemia in lactating ewes. Pasture and animal management was regulated to maximize the potential for the development of hypomagnesaemia. The incidence of clinical hypomagnesaemia in ewes grazing the control pasture (cv. RvP) was 21% within the first 10 days and this was accompanied by a significant fall of 35% in serum magnesium concentration. The incidence in ewes grazing the high magnesium cultivar was only 2·5% and there was no significant change in the serum magnesium concentration.The mean magnesium content of Bb 2067 herbage (1·45 gkg DM-1) was 48% higher than cv. RvP (0·93 g kg DM-1) while calcium and phosphorus were 15% and 30% higher. The mean dry matter intake of ewes grazing Bb 2067 was higher than that of ewes grazing RvP, and although the difference was not statistically significant there were significantly increased intakes of magnesium, calcium and phosphorus for ewes grazing Bb 2067 compared with RvP. Ewes grazing Bb 2067 ingested more than the recommended allowance of magnesium and were close to sufficiency for calcium and phosphorus, while those grazing RvP were in serious deficit for all three minerals.There was no significant difference in the ewe body weight loss between the treatments but lamb liveweight gain was significantly greater on the Bb 2067 pastures compared with those on cv. RvP.It was concluded that the high magnesium grass provided an effective means of controlling hypomagnesaemia under grazing despite the extreme predisposing conditions imposed in this trial.

Notizen: The effects of a combined pesticide and fungicide (P + F) treatment on the proportion of white clover in an established perennial ryegrass/white clover sward were assessed on six occasions during 1988 and 1989, under two cutting frequencies (2- or 6-week intervals) and with or without N fertilizer (120 kg ha-1 per annum). In 1988 P + F treatment significantly increased the proportion of clover in August and October, with an increase at the latter harvest being much greater where N was also applied. There was no significant interaction between P + F treatment and cutting frequency, although less frequent cutting increased significantly the proportion of clover in October where N was not applied.In 1989, drought prevented the proportion of clover from exceeding 1% throughout, regardless of management factors. P + F treatment significantly increased the proportion of clover in August, and significantly reduced populations of slugs, foliar-feeding insects (mainly Collembola; Sminthuridae) and the area of clover leaf damaged by pests. No marked effect of P + F treatment on populations of plant parasitic nematodes was detected. No appreciable incidence of fungal diseases was observed in either year.

Notizen: Five pasture treatments were applied to three semi-natural hill grassland communities. The pasture treatments were: (1) controlled grazing, (2) controlled grazing + lime, (3) controlled grazing + lime + phosphate, (4) controlled grazing + lime + phosphate + oversown white clover and (5) controlled grazing + lime + phosphate + oversown white clover + oversown perennial ryegrass. The communities were dominated by Agrostis/Festuca (site 1), Molinia (site 2) and Nardus (site 3). The Nardus at site 3 was substantially reduced by herbicide before treatments were applied. All treatments were grazed simultaneously by mature wether sheep on three occasions each year to a residual herbage mass of 560 kg DM ha−1. There were two grazing periods, each of 4 weeks duration, beginning in mid-May and mid-July respectively and a further grazing period of 3 weeks duration beginning in mid-October. The number of sheep grazing days and liveweight gain of sheep were recorded during each grazing period for 13 years at each site. Organic matter intake (OMI) and digestibility (OMD) of ingested herbage were measured in years 2, 5 and 13.Mean daily OMI per head ranged from 1290 g for treatment 1 to over 1400 g for treatments 4 and 5. OMI values were higher for the Agrostis/Festuca site (mean OMI 1450 g) than for the Molinia and Nardus sites (1310 g and 1370 g respectively) largely owing to differences in the values for treatments 1, 2 and 3. OMI values for each treatment decreased by around 300 g between May and October.Mean OMD values from treatments 1, 2 and 3 were higher for the Agrostis/Festuca site (0·66) than for the Molinia and Nardus sites (0·63 and 0·64 respectively). The OMD values for treatments 1, 2 and 3 at the Molinia and Nardus sites declined by between 0·05 and 0·02 between years 2 and 13 and also showed the greatest decrease between May and October (0·08). OMD values for treatments 4 and 5 (0·67 and 0·69 respectively) were higher than for treatments 1, 2 and 3 at all sites and levels were maintained over 13 years.Individual liveweight gains of sheep increased from treatment 1 (−18 g d−1) to treatment 5 (82 g d−1), but they decreased over time on all treatments.The Agrostis/Festuca site gave 17% more annual sheep grazing days than the Molinia site and 33% more than the Nardus site. The mean number of annual sheep grazing days for each treatment ranged from 2250 for treatment 1 to 3640 for treatment 5. Annual sheep grazing days increased over 13 years by between 35 and 45% for treatment 1 and 55 and 70% for treatment 5.The results are described in relation to the changes in pasture composition and herbage accumulation.

Notizen: The experiment aimed to examine the effects of sodium chloride (NaCl) application to pasture on dairy cow production, distinguishing the effects of Na supply on pasture production from the direct effects on animal production, and also to examine the preference of dairy cows for sodium-fertilized pasture. Twenty-four dairy cows were grazed in six treatment areas with three fertilizer levels—all (A), one-half (H) or none (N) of the area fertilized with 50 kg NaCl ha−1, and with or without 50 g cow−1 day−1 NaCl supplementation (+, −) offered in concentrate feed. The experiment was a changeover design with four 3-week periods. NaCl fertilization increased herbage growth rate and Na, Cl and calcium (Ca) contents and reduced K content. Milk yield and liveweight gain were increased by NaCl application to pasture but not by direct supplementation. Milk fat content was increased with increasing Na concentration in the diet. Grazing time was increased by NaCl application to pasture, but only cows not receiving direct NaCl supplementation preferred NaCl-fertilized pasture. Ruminating time was increased both by NaCl application to pasture and by direct supplementation. It is concluded that in the warm, dry conditions of this experiment, increasing Na supply to natrophilic herbage increased both pasture and animal production, and that within the range 3–8 g Na kg−1 dietary DM, increasing Na supply to the cow increased milk fat content.

Notizen: The potential drying rate of cut forage grasses and legumes, following treatment with a 2% potassium carbonate (K2CO3) solution, were compared with those of untreated crops under laboratory conditions. Material was fully exposed to a flow of conditioned air (20°C; 50% relative humidity). Treatment with K2CO3 had little effect on the drying rate of a range of cultivated grass species. The drying of legume species, particularly lucerne was accelerated. The average reduction in lucerne drying time, following K2CO3 treatment, was 63% and was similar for a range of varieties. The differential drying of lucerne leaf and stem fractions was reduced following treatment, and reduced further by selective treatment of the stem. Potassium carbonate treatment was superior to traditional mechanical conditioning for accelerating water loss from cut lucerne. The practical implications are discussed.

Notizen: A factorial pot-experiment was carried out to investigate the effect of burial of stolons (stolons unburied or buried to a depth of 0·5–1 cm at day 0), with and without defoliation (plants uncut or all unfolded laminae removed at weekly intervals) on the growth of two varieties of white clover (cv. Kent or cv. Milkanova) harvested on three dates (14 d, 28 d and 42 d after burial). The soil used was a 3:2:1 mixture of clay loam:peat:sand, and there were three replicates of each variety for each treatment at each harvest date.Burial of stolons in the absence of defoliation had no effect on stolon extension, leaf appearance, or the concentration of water-soluble carbohydrate in the stolons. The number of axillary buds developing (new branches plus flowers) was increased on the new surface-growing tips of primary stolons but was reduced on branch (i.e. secondary) stolons. The proportion of branches to flowers was largely unaffected by burial.Defoliation caused substantial reductions in the concentration of water-soluble carbohydrates in stolons and stolon extension growth, a reduction in number of axillary buds developing, and in the proportion of buds which were floral, but had only a small effect in reducing leaf appearance.The combination of stolon burial and defoliation resulted in the death of secondary stolons; 42% of all secondary stolons had died by day 42, and stolon extension, leaf appearance and numbers of axillary buds developing on secondary stolons were severely reduced. The numbers of axillary buds developing on primary stolons was increased owing to more buds developing on the resurfaced stolon tips, but the increase was inadequate to compensate for the reduced growth, and death of secondary stolons.Differences between clover varieties in response to treatments were small. In general, the smaller variety, cv. Kent, was more adversely affected by burial than the larger variety, cv. Milkanova. A variety x defoliation interaction occurred for senescence of leaves; petiole senescence of cut leaves was reduced or similar to that of intact leaves for cv. Kent, but was increased for cv. Milkanova.The results are discussed in relation to treatment effects on carbon sources and sinks, and in relation to climate-soil interactions.

Notizen: Eight grass silages were made from two contrasting varieties of perennial ryegrass, four silages each from a late-cut early-maturing (high dry matter, HDM) variety and from an early-cut, late-maturing (low dry matter, LDM) variety. The grass was ensiled without additive (untreated), or with formic acid, or with one of two enzyme mixtures of hemicellulases and cellulases (enzyme 1 and enzyme 2) for a period of 130 d.Formic acid-treated silage had lower levels of lactic acid at both levels of dry matter than the other silages. Enzyme treatment of grass prior to ensilage resulted in reduced levels of cellulose, acid-detergent fibre and neutral-detergent fibre in LDM silages and lower acid-detergent fibre and neutral-detergent fibre in the HDM silages compared with the corresponding untreated and formic acid-treated silages. Voluntary intakes (g DM d−1) of untreated and enzyme-treated silages were significantly (P〈0·01) lower at both digestibilities compared with formic acid-treated silages (LDM: untreated, 982; formic, 1069; enzyme 1, 868; enzyme 2, 937; HDM: untreated, 931; formic, 1027; enzyme 1, 943; enzyme 2, 914). The organic matter, carbohydrate and nitrogen digestibility coefficients of LDM silages were significantly (P〈0·001) higher than those of HDM silages. There were no significant differences in any component digestibility related to silage additive.Comparison of digestibility coefficients for constituents of the LDM silages fed to sheep or steers showed no differences between species.

Notizen: A series of experiments was undertaken to determine population statistics for in vitro organic matter digestibility (in vitro OMD) data and to examine the effects of basal diet, donor animal and precollection fasting interval on the activity and specificity of rumen fluid inoculum. The experiments utilized wether sheep, a diverse set of pasture grass and legume feeds prominent in the Australian subtropics and the Tilley and Terry in vitro digestibility procedure running under the operating pressure of a practicing feeds evaluation laboratory.The standard errors of in vitro OMD estimates for within and between batch runs were ±0·88 × 10−2 and 0·62 × 10−2, respectively. These error terms were used to develop protocols to accept, reject or scale raw in vitro OMD data. Differences between donor animals in the activity of rumen fluid were highly significant. Extending the precollection fasting interval beyond 16 h was associated with a substantial decline in inoculum activity.An in vitro-in vivo calibration relationship based on fifteen test feeds and using lucerne (Medicago sativa) as basal diet was described by the linear model y = 1·3 x-0·195±4·9 × 10−2r= 0·79 (y =in vivo OMD, x =in vitro OMD). Despite large effects of basal diet on both the absolute values and relative ranking of test feeds, neither the RSD nor r values were improved using alternative diets to Lucerne chaff.The results highlight the need to formally standardize the analytical and biological components of the in vitro digestibility procedure to safeguard the integrity of data.

Notizen: Perennial ryegrass/white clover pastures were grazed at different times in the winter to study the effect of time of grazing on subsequent plant growth. In 1983–84, 1984–85, and 1985–86, pastures were grazed to a residual of 400 kg dry matter ha-1 by sheep once in early December (D), January (J), February (F), March (M), or April (A) and compared with an ungrazed control (C). Rates of herbage accumulation on C in the winter were low, averaging 6, -9, and 2 kg dry matter ha-1 in December, January, and February, respectively. Little forage production occurred during the month immediately following winter grazing. Herbage accumulation rate then increased sufficiently to replace the forage removed from winter-grazed paddocks by early spring. By May, herbage mass on grazed treatments was similar to C except for D and A which averaged 20 and 47% less forage than C, respectively (P〈0·01). Herbage accumulation rates of D were unique among winter grazing treatments in never exceeding those of C. By May 1986, D yielded less perennial ryegrass compared with C (P〈0·05). Grazing reduced the number of leaves per ryegrass tiller for 1 to 2 months following grazing. By May, J, F and M had numerically more tillers m-2 and more leaves per tiller than C. Similar May yields of J, F, M, and C resulted from fewer but larger and slightly less leafy tillers of ungrazed compared with winter grazed plants.

Notizen: Over three grazing seasons (1984-1986) a sward of perennial ryegrass, cv. Talbot, which received a total of 336 kg N ha-1 each season, was cut or grazed with ewes at 3- or 4-week intervals on a rotational basis.Sward productivity was higher under cutting than under grazing irrespective of the interval between defoliations. Under cutting, mean herbage organic matter (OM) yields over both intervals were 8·66, 9·62 and 8·17 t ha-1 in 1984, 1985 and 1986 respectively while under grazing the corresponding yields were 7·65, 8·63 and 7·50 t ha-1. The mean annual yield of herbage defoliated at 3-week intervals was 7·50, 8·64 and 7 ·20 t OM ha-1 compared with 8·80, 9·60 and 8·46 t OM ha-1 for swards defoliated at 4-week intervals in the three years respectively.The nitrogen (N) content of both the available and the residual herbage was consistently higher under grazing than under cutting. Available herbage contained 31·3 and 27·7 g N kg OM-1 and residual herbage 26·1 and 22·7 g N kg OM-1 under grazing and cutting respectively.The mean yield of N under cutting was 284 kg ha-1 compared with 304 kg ha-1 under grazing. Defoliation interval had no effect on N yield, the overall mean yield being 294 kg ha-1 under both 3- and 4-week defoliation intervals. The effect of the treatments on tiller population was slight and inconclusive.The process of grazing reduced yield probably as a result of damage to the sward through trampling; the positive effect of excretal N on yield was minimal on account of the short grazing periods.

Notizen: Four grass silages were made from perennial ryegrass ensiled after a 1h wilt in 2-t silos without additive application, with application of formic acid or with one of two enzyme mixtures of hemicellulases and cellulases (enzyme 1 and enzyme 2). Effluent losses were monitored over the ensiling period (130 d).Analyses of the silage showed that formic acid-treated silage had lower concentrations of lactic acid than the other silages. Both enzyme-treated silages had lower levels of cellulose, acid detergent fibre (ADF) and neutral-detergent fibre (NDF) than the untreated and formic acid treated silages. Effluent production was highest with enzyme-treated silages.The silages were subsequently fed to growing steers equipped with rumen cannulae and T-piece duodenal cannulae. Apparent whole-tract digestibilities of organic matter constituents were significantly lower (P 〈 0·05) with both enzyme-treated silages (untreated; 0·736, formic acid; 0·722, enzyme 1; 0·694, enzyme 2; 0·703). Both untreated and enzyme 2-treated silages sustained higher nitrogen digestibilities (g g−1 intake) (untreated; 0·675, formic acid; 0·636, enzyme 1; 0·630, enzyme 2; 0·662) and N retentions (g d−1) untreated; 16·0, formic acid; 14·0, enzyme 1; 11·6, enzyme 2; 16·6), but none of these differences was significant. When formic acid-treated silage was offered, there was a greater amount of organic matter apparently digested in the rumen (ADOMR). Non-ammonia nitrogen and microbial nitrogen flows at the duodenum were similar on all diets. The efficiency of microbial protein synthesis was highest with enzyme 2-treated silage and lowest with formic acid-treated silage (untreated, 35·4; formic acid, 25·2; enzyme 1, 30·4; enzyme 2, 39·4), but none of these differences were significant.

Notizen: Five experiments were carried out to investigate the effects of glucose oxidase (GO) on the preservation of grass silage in the absence of micro-organisms. In the first experiment, GO was tested in a 3% glucose solution. At the level of 1190 U GO l-1 the pH value decreased to 3·94 in 1 h and to 3·02 in 24 h. At the level of 11·9 U l-1 the pH decreased to 3·45 in 24 h.The second experiment was performed by packing chopped grass into glass jars, sterilizing in an autoclave and adding GO. One day later the pH value had decreased to 4·65; 1·60% gluconic acid was found in the dry matter.In the other three experiments grass was sealed in polythene bags and sterilized by gamma-irradiation. GO was found to cause a faster decrease in pH. Removing air from the silage by compaction decreased the GO activity. The addition of cellulase delayed the GO functioning for one day. Lactobacillus inoculant had no effect. Evidence was obtained that GO may affect the profile or activity of the original microflora of grass silage.

Notizen: Three unwilted and three wilted silages were prepared from lucerne. Unwilted and wilted material was ensiled either without treatment (UWC and WC), after gamma irradiation (UWI and WI), or following heat-treatment and inoculation with Lactobacillus plantarum (UWH and WH). Gamma radiation was from a cobalt 60 source. The UWH material was heat-treated using steam, and WH material was treated with dry heat. At ensiling, irradiated material was considered to be sterile, and heat-treated material had lost 80% of its original protease activity. Fifteen 1-litre silos were prepared for each treatment (90 in total), and three from each treatment were opened after 1, 4, 14, 70 or 200 d ensiling. In irradiated silages, there was no accumulation of organic acids, but water soluble carbohydrate (WSC) concentration was almost double (116 g kg-1dry matter) that at ensiling. This indicated extensive liberation of WSC from more complex carbohydrates during ensiling. The extent of silage fermentation in heated silages was similar to control silages. The WH silage had a higher proportion of the organic acids as lactic acid relative to the other treatments, possibly as a result of inoculation with L. plantarum. Proteolysis was unaffected by irradiation. However, heat-treatment markedly reduced the extent of proteolysis, particularly in the first four days post-ensiling. Deamination appeared to be related to the type of microbial fermentation rather than to the extent of proteolysis.

Notizen: The herbage production and quality of swards of three grass species, prairie grass (Bromus willdenowii Kunth), reed canary-grass (Phalaris arundinacea L.) and phalaris (Phalaris tuberosa L.) were compared with perennial ryegrass (Lolium perenne L.) and hybrid ryegrass (L. perenne L. ×L. muitiflorum Lam.) under 6–cut (experiment 1) and 4–cut (experiment 2) regimes over 3 years at Ayr; annually, 360 kg ha-1 fertilizer N were applied. At Edinburgh prairie grass was compared with Italian ryegrass (L. multiflorum Lam.), timothy (Phleum pratense L.) and cocksfoot (Dactylis glomerata L.) under an annual 4–cut regime for 3 years (experiment 3); fertilizer N application totalled 350 kg ha-1 annually.Prairie grass gave the highest annual dry matter (DM) production at Ayr, averaging 11·99 t ha-1 in experiment 1 and 15·62 t ha-1 in experiment 2. Reed canary-grass was much less productive whilst phalaris did not persist after harvest year 1. On average, prairie grass gave 8–10% more DM than the three ryegrasses in the 6-cut system but its advantage was much less under the 4-cut regime. In experiment 3, the DM production of prairie grass and Italian ryegrass were similar in year 1, but following winter damage prairie grass gave the lowest production in subsequent harvest years.Prairie grass had digestibility (OMD) values lower than the ryegrass but higher than reed canary-grass, timothy and cocksfoot. The water soluble carbohydrate (WSC) concentrations in prairie grass were markedly higher than in timothy and cocksfoot but lower than those in Italian ryegrass. Prairie grass had relatively low P and Mg concentrations. Reed canary-grass had relatively low OMD and Ca, but high N, P, K and Mg contents.It is concluded that prairie grass may have potential in the UK as a special-purpose species for conservation management but mainly in the milder climatic areas. The Phalaris species evaluated had disappointing agronomic potential.

Notizen: In two experiments, ewes in weeks 1–20 of lactation received either pasture only or pasture plus ad libitum conserved forage. Herbage height was maintained at 3·3–3·4 cm on both treatments by manipulation of stocking rate in the 24 plots (twelve per treatment) used for the experiment with additional ewes and lambs. In experiment 1, silage, which was of lower metabolizable energy (ME) and crude protein (CP) contents than the grazed herbage, was consumed at an average of 375 g dry matter (DM) ewe−1 d−1. In experiment 2 a strawmix, containing (g kg −1 freshweight) 480 g barley straw, 300 g concentrate and 220 g molasses, again with a lower ME and CP content than the grazed herbage, was consumed at an average of 165 g DM ewe −1 d −1. In both experiments ewes not receiving forage lost weight whereas those with forage gained weight and tended to have increased body condition scores. Offering silage or strawmix did not affect lamb liveweight gain or stocking rate.

Notizen: Lamina wettability, assessed using water droplet contact-angle and surface water-retention measurements on excised leaves, was examined in Lolium perenne cv. Melle, cv. Condesa and an indigenous population from an old pasture, Holcus lanatus, Poa trivialis and Agrostis stolonifera. The species fell into two significantly distinct categories, those with unwettable laminae, namely H. lanatus and A. stolonifera, and those with highly wettable laminae, P. trivialis and the three L. perenne populations. There was no significant difference between the L. perenne populations, which had the most wettable laminae overall. The possible implication of these differences in lamina wettability on animal production is discussed.

Notizen: Measurements of undisturbed sward surface height (sward height) were made using the HFRO and sonic sward sticks at 20 cm intervals along 100 m transects laid across paddocks grazed by either sheep, cattle or goats. Measurements of sward height were also made at 5 cm intervals along 10 m transects laid across the same paddocks using the HFRO sward stick alone. The variance of the measurements from each transect was partitioned across the range of spatial scales of roughness present using spectral analysis. The variance of the sward surface height appeared to be dominated by variation with spatial scales of less than 1 to 2 m. The variances of measurements made with the two sward sticks were similar despite the greater sampling area of the sonic sward stick. This was due to the presence of variation at spatial scales much larger than the sampling area of either instrument and to a greater contribution from non-spatially related sources to the variance of the sonic sward stick measurements. The use of weighted disc meters for obtaining the mean height of continuously grazed sward deserves re-examination, while automation of the sonic sward stick may be worthwhile if the spatial distribution of herbage is to be described.

Notizen: Prairie grass (Bromus willdenowii Kunth) and a tetraploid Westerwolds ryegrass (Lolium multiflorum Lam.) were established in a field trial in April 1987 and grown for a 3-month period of undisturbed growth. During this period the biomass partitioning and forage quality of each plant component was compared for the two species. Leaf, tiller and plant populations were assessed on ten occasions while accumulation of herbage and roots, chemical composition, leaf area and light interception were determined on six occasions. Herbage was divided into leaf lamina, inflorescence, vegetative and reproductive pseudostem. Nitrogen, water-soluble carbohydrates, ash, cell wall and in vitro digestibilities were determined.Prairie grass had lower plant, tiller and leaf populations but larger tillers and more live leaves per tiller than Westerwolds ryegrass. Both species had similar light interception and leaf area index. Roots were distributed more evenly and to greater soil depths in prairie grass. Leaf lamina made major contributions to herbage DM accumulation and accumulation of the various chemical components, but as reproductive development occurred, reproductive pseudostem became a major component of the total sward. Harvesting herbage to gain optimum quantities of DM, herbage quality and regrowth is discussed. It is concluded that prairie grass is a high-yielding, high-quality forage grass, comparable with Westerworlds ryegrass.

Notizen: Plots of white clover (Trifolium repens) and perennial ryegrass (Lolium perenne) white clover were sown with and without fungicide seed treatment, seed treatment with Cytozyme (a proprietary growth-promoting agent) and pesticide granules (carbofuran or carbosulfan) mixed with the seed. Sowings were made in April/May at Hurley (1986 and 1987), Dorchester (1987) and Bronydd Mawr (1987). Only treatments containing pesticide significantly improved seedling emergence or herbage yield in the 1986 sowing. In 1987, pesticide greatly increased seedling emergence of ryegrass and clover at Hurley and Dorchester, but had no effect at Bronydd Mawr. At Hurley, herbage yield and the proportion of clover were more than doubled for up to a year, by chemical treatment after sowing in 1986.Populations of plant parasitic nematodes were recorded at all sites and it is suggested that at Hurley and Dorchester seedlings with nematode damage were unable to survive the dry soil conditions that prevailed. In a subsequent pot experiment, pesticide granules controlled root endoparasitic nematodes and significantly increased seedling emergence of white clover in dry soil but had no effect in moist soil.

Notizen: The productivity of ten grasses was measured under six cuts per annum for 3 years and three cuts for a fourth harvest year in comparison with a perennial ryegrass (Lolium perenne) control. The grasses were Yorkshire fog (Holcus lanatus), two red fescues (Festuca rubra), creeping bent (Agrostis stolonifera), bent (Agrostis castellana), bent (Agrostis capillaris), smooth meadow-grass (Poa pratensis), crested dogstail (Cynosurus cristatus), sweet vernal (Anthoxanthum odoratum) and timothy (Phleum bertolonii). Another grass sown, rough meadow-grass (Poa trivialis), did not persist after the first harvest year. Annual N rates were 0, 120, 240, 360 and 480 kg ha−1.Classified by DM production, the grasses grouped into: high (perennial ryegrass, Yorkshire fog and red fescue), intermediate (creeping bent, bent (A. castellana), crested dogstail and smooth meadow-grass) and low (bent (A. capillaris), sweet vernal and timothy. With frequent cutting, production ranking interacted with N rate: Yorkshire fog. red fescue and creeping bent were more productive than ryegrass at the 0 N and 120 N rates but not at higher N rates; crested dogstail and sweet vernal outperformed ryegrass at 0 N; ryegrass and smooth meadow-grass performed relatively better at moderate to high N. DM production of ryegrass was matched or exceeded by some of the other grasses during different parts of the season particularly at low N rates. Notable features from the 3-cut regime were the outstanding DM production of Yorkshire fog at all N rates and the poor production of bent (A. capillaris) and crested dogstail. High DM response to applied N in both cutting regimes was given by perennial ryegrass. smooth meadow-grass, red fescue cv. Boreal, timothy, crested dogstail and Yorkshire fog.N concentrations were highest in less productive grasses such as the bents and lowest in highly productive ryegrass and Yorkshire fog. Ryegrass was superior in digestibility to the other grasses, but especially to the red fescues, bents and smooth meadow-grass. The other grasses, especially Yorkshire fog and bent (A. capillaris) were superior to ryegrass in P, K and Mg concentrations, but not Ca.It is concluded that the annual and/or seasonal production of some of the secondary grasses at low to moderate N rates, e.g. the performance of Yorkshire fog and red fescue, warrant a reconsideration of their poor reputation, particularly within the context of increasing grassland extensification. Breeding to improve selected characteristics, such as digestibility in red fescue, seems justified. Assessment of the grazing and ensiling qualities of secondary grasses require further study.

Notizen: Early reproductive development in Lolium perenne L. has been widely used for defining growth stages in spring, and this has been useful in managing seed crops and in trials involving the use of growth retardants.A numerical scale for apical development based on morphological criteria, has been successfully used in research. The scale identifies eleven clearly recognizable stages of apical development, from the vegetative apex through to the immature, but completely-formed spike. It is intended that the key should be used to identify consistantly precise stages in apical development.

Notizen: Five white clover populations of Swiss origin and three bred varieties were grown in binary mixtures with two perennial ryegrass varieties, Aurora and S23. The seasonal yields of clover and grass plus clover were measured under a cutting regime during the second and third years after establishment. A series of destructive detailed sward measurements was made during the late autumn to spring period preceding each harvest year. In this way changes in the amounts of stolon, leaf plus petiole and numbers of growing points were monitored during the winter.There were large differences in clover yield between populations in both years. These were evident from the first (spring) harvest in each year. Higher-yielding clovers in spring tended to produce higher annual clover yields. No grass × clover interaction was evident at any harvest. Large differences between clovers were also apparent in the morphological characteristics measured, with the Swiss material generally having greater amounts of stolon, leaf plus petiole and numbers of growing points present in early spring. It is proposed that these factors contribute to the high spring yield in the Swiss populations. Loss of stolon length over each winter was less in the Swiss material, indicating that its good spring growth was not obtained at the expense of winter hardiness. Annual clover yield was found to be significantly positively correlated with the amount of stolon present in spring, exemplifying the importance of stolon survival over the winter.

Notizen: Procedures used to determine chemical composition and digestible organic matter in dry matter (DOMD) are slow and expensive. The possibility of using near-infrared reflectance spectroscopy (NIRS) as an alternative procedure was investigated with annual legumes. Material from cultivars of Medicago murex, Trifolium balansae, T. resupinatum and T. subterraneum was harvested soon after plants had matured. Samples were sorted into stem, leaf and burr fractions and analysed chemically and by NIRS. Data were then sorted into two similar sets, one of which was for calibration and the other for validation. Data for each chemical fraction, in samples used for calibration, were regressed sequentially against the corresponding reflectance spectral data, the log of there reciprocal of which was transformed to first or second derivatives. Equations of best fit were then used to predict the composition of samples in the validation set.Standard errors of calibration and validation respectively, expressed as percentages of the mean, were 0·5 and 0·6 for dry matter (DM), 2·0 and 2·6 for organic matter (OM), 4·8 and 4·3 for DOMD, 6·0 and 7·2 for crude protein, 4·1 and 4·4 for acid-detergent fibre (ADF), 2·5 and 3·1 for neutral-detergent fibre (NDF) and 8·9 and 10·9 for lignin.

Notizen: A chemical hybridizing agent (CHA: WL 84811, azetidine-carboxylic acid. Shell Chemical) was applied to annual ryegrass (Lolium rigidum Gaud. cv. Wimmera) at four levels: 0, 1·6, 2·4 and 3·2 kg active ingredient (a.i.) ha−1, at booting and at anthesis with a view to reducing seed set and increasing the proportion of cell solubles in the senescing and dead plants. The CHA treatments reduced stem elongation by up to 40% and reduced the proportion of pollinated florets progressively according to the concentration of CHA. At 3·2 kg (a.i.) ha−1 only 14% of florets were fertilized compared with 86% on the zero (control) treatment.The CHA treatments also resulted in progressive increases in the number of secondary tillers. Since there was no increase in the amount of neutral-detergent solubles associated with increased CHA application, it was concluded that storage carbohydrates, which might otherwise have been directed towards seed development, were partitioned towards increased tillering. There was no effect, therefore, on the proportion of neutral-detergent soluble material in senescing and dead plants.

Notizen: The growth of a timothy sward, a timothy/white clover mixture and a multi-grass/white clover mixture were compared and related to climatic factors at two sites of different altitudes.Temperature and radiation had a greater effect on sward growth than did species composition or management. If the reproductive and vegetative growth periods were studied separately, then more than 90% of the variation in yield could be explained by temperature and radiation. During spring reproductive growth, yields per unit increment of temperature or radiation were 2–3 times higher than during summer vegetative growth. Spring growth was affected more by temperature than by radiation and the lower yields at the higher altitude were also related to lower temperatures.

Notizen: Five pasture treatments: (1) controlled grazing, (2) controlled grazing + lime, (3) controlled grazing + lime + phosphate, (4) controlled grazing + lime + phosphate + oversown white clover and (5) controlled grazing + lime + phosphate + oversown white clover + oversown perennial ryegrass were applied to three semi-natural hill grassland communities. The communities were those dominated by Agrostis/Festuca, Molinia and Nardus. The proportion of Nardus at the Nardus-dominant site was substantially reduced by herbicide before treatments were applied. All treatments were grazed simultaneously by mature wether sheep on three occasions each year. There were two grazing periods each of 4 weeks duration between mid-May and mid-August with a further grazing period of 3 weeks starting mid-October. During each grazing period stock numbers were set so that a residual herbage mass of 560 kg DM ha −1 remained at the end of the grazing period. Measurements of net herbage accumulation (NHA) were made annually over a period of 13 years at each site. The green:dead ratio of grasses, species composition of the pasture and the pH of the soil were measured at intervals during the experiment.Estimates of mean annual NHA ranged from 3860 kg DM ha−1 for treatment 1 (controlled grazing) to 5170 kg DM ha−1 for treatment 5 (oversown white clover and perennial ryegrass). The application of lime and phosphate increased annual NHA by 300–350 kg DM ha−1 with a further increase of around 400 kg DM ha−1 when white clover was sown. Increases in NHA between year 1 and year 13 ranged from 30% for treatment 1 to around 55% for treatment 5. Although there was no difference in the mean NHA between sites, the herbage from the Agrostis/Festuca site contained a higher proportion of green grass and white clover than that from the other sites. The highest levels of green grass and white clover were found on the oversown treatments at each site.The grazing pressure exerted produced relatively little change in the botanical composition at the Agrostis/Festuca site. At the Molinia-dominant site the Molinia was largely replaced by Nardus during the first 6 years and Nardus also increased in cover at the Nardus site. Application of lime and phosphate generally increased the proportion of Poa pratensis, Festuca rubra and Agrotis tenuis but did not halt the spread of Nardus at the Molinia and Nardus sites. White clover and perennial ryegrass were successfully introduced by oversowing and proportions remained high throughout the 13 years. The cover by bryophyte spp. increased at all sites with the greatest increases occurring in each case on the less comprehensive pasture treatments.These results suggest that on Agrostis/Festuca-dominant pastures herbage biomass production can be increased with relatively low-cost pasture treatments while maintaining Species diversity. However, Nardus and Molinia dominant pastures are likely to require more comprehensive pasture treatments involving sown grasses and white clover to provide herbage of acceptable quality and avoid an increase in Nardus and bryophytes in the sward. With a regime of episodic summer grazing and the addition of fertilizers oversown pastures can be maintained over long periods of time.

Notizen: A simulation model of yeast and mould growth in aerobically deteriorating silage was tested and analysed. The model predictions of aerobic stability were compared with actual stability data from published experiments and were accurate when maize silage composition and initial yeast and mould counts were known. The time-course of deterioration was simulated for various initial temperatures and yeast and mould concentrations and exhibited primary, secondary, and tertiary heating in some cases; however, the model was limited in its ability to predict temperature history during deterioration because of the simplified treatment of heat transfer. In simulations, the relative importance of yeasts and moulds depended mainly on initial fungal concentrations, whereas the relative importance of mesophiles and thermophiles depended primarily on initial temperature. The model predicted that the period of silage aerobic stability ends when fungal concentrations reach approximately 0·001 g g−1 silage. Temperature, water-soluble carbohydrate concentration, fungal populations, and fermentation product concentrations in interaction with pH had the greatest direct effects on predicted aerobic stability. The model results suggest that aerobic stability is greatest when the pre-ensiling forage is highly buffered, of low dry matter content, and contains sufficient water-soluble carbohydrates to allow fermentation to the lowest possible pH with no residual water-soluble carbohydrates.

Notizen: A mosaic of short, frequently grazed areas and tall, infrequently grazed areas is a characteristic of swards continuously stocked with cattle. Inclined point quadrat measurements were used to compare sward structure on the frequently and infrequently grazed areas in an experiment on mixed grass/clover swards with beef cattle, in which the swards were maintained at overall mean rising-plate target heights of 3·0, 5·5 or 7·0 cm. The results demonstrate large within treatment differences in the vertical distribution of plant parts between the frequently and infrequently grazed areas, and smaller differences within these areas between treatments. The consequences of these observations and the need for greater effort in recording the detailed structure within these areas in grazing experiments is noted.

Notizen: Ryegrass and white clover were sown singly or in combination at various seeding rates by direct drilling into plots in which a range of slug densities had been established by molluscicide baiting. For both ryegrass and white clover, weights of individual seedlings and numbers and yields of seedlings per metre of drill row were significantly affected by slug density, ryegrass seed rate, clover seed rate and interactions of these factors. Plant losses increased asymptomatically with slug density, indicating higher rates of seedling destruction per slug at low slug densities.

Notizen: A field study was conducted from 1983 through 1986 to ascertain the effect of endophyte (Acremonium coenophialum), nitrogen fertility and tall fescue (Festuca arundiancea) genotype upon the soluble carbohydrate content of tall fescue from grazed paddocks. Non-grazed paddock exclosures were evaluated for 1984 and 1985. Plant tissues were extracted with 0·1 mol 1−1 H2SO4 to obtain acid-extractable carbohydrate (AEC). The AEC concentration and yield (concentration × dry matter) varied among and within years, generally was not influenced by endophyte, and was influenced by N fertility and cultivar. The AEC concentration from non-grazed exclosures was inversely related to AEC yield. Grazed paddock AEC concentration and yield were not significantly correlated. Grazed paddock AEC concentration remained fairly constant over the growing season, whereas AEC yield was greatest during periods of ample rainfall. The cultivar Johnstone generally had the greatest AEC concentration when compared with AU Triumph and KY-31. Even though endophyte is a carbohydrate sink, sward scale effects on AEC, as influenced by endophyte, were virtually undetected, suggesting that presence of endophyte is not detrimental to the fescue host. Grazed and non-grazed tall fescue AEC concentration and yield patterns differ and indicate the need to interpret non-grazed quality and management data carefully.

Notizen: In efficient agricultural systems high production and high quality is expected throughout the year, but spatial and seasonal variation of biophysical variables can have a significant impact on the yield and quality of production. The yield and quality component of a forage field was monitored using statistical and Geographical Information System (GIS) techniques. The display of yield and forage quality in a spatial context proved to be very useful to the farmer since it allowed him to determine where in the field he obtained the best and worst production and whether such performance was consistent over the entire growing season. GIS is considered a new management tool that allows the spatial evaluation and presentation of production information in a new and innovative manner. Examples are provided to assist farmers in production accounting, to determine cause and effect relationships between management and production, to forecast production and to modify management to account for differences within the field.

Notizen: Perennial ryegrass pastures were maintained at sward surface heights (SSH) of 30, 60, 90 and 120 mm by continuous variable stocking using lactating ewes and their twin lambs in spring and non-lactating (dry) ewes in autumn.The effects of SSH on ingestive behaviour, herbage intake, animal performance and sward structure and production were measured in spring, and again in autumn, when an additional SSH of 20 mm was also established.In spring, differences in sward structure were quickly established with mean tiller numbers of 41 000, 30 000, 21 000 and 19 000 m−2 and leaf area indices (LAI) of 1·5, 2·2, 3·3 and 4·1 at SSH of 30 to 120, respectively. By autumn the mean tiller numbers had fallen to 26 000, 26 000, 23 000, 18 000 and 13 000 m−2 and LAI to 1·0, 1·1, 1·5. 2·0 and 1·5 for treatments 20 to 120.The mean stocking rates for the ewes in spring were 27, 20, 22, and 19 ewes ha−1 and growth rates of their lambs were 208, 275, 250 and 263 g d−1 for treatments 30 to 120. In autumn the stocking rates maintained for dry ewes were 22, 15, 9, 4 and 0 for treatments 20 to 120.In spring, both grazing times (GT) and prehension biting rate (BR) were negatively correlated with SSH, while bite mass (BM) was positively correlated with SSH. However, mean daily intakes of organic matter (OM), were reduced only for animals grazing the 30 mm sward.In autumn, intake rate was lower only for the animals grazing the 20mm sward and GT and BR were not significantly affected by SSH.Relationships between SSH and, components of ingestive behaviour and intake, are presented and the control mechanisms involved are discussed. The results showed that the optimum sward surface height for continuously stocked swards, grazed by sheep, Was between 30 mm and 60 mm.

Notizen: Seventeen grass or oats swards, displaying a wide and largely independent variation in surface height and bulk density, were produced using different seed rates at sowing and different cutting or grazing pre-treatments. Four sheep confined in cages were allowed to take twenty bites from small patches of each sward, and measurements of bite weight and the physical dimensions of the average bite in the sward (bite depth, area and volume) were related to a range of sward structural characteristics.Mean bite weight per sward ranged from 40 to 330 mg dry matter (DM). It was positively related to surface height (range 6–55 cm), which acted primarily upon bite depth and hence bite volume, and to the bulk density of the grazed stratum (range 0·1–2·0 mg DM cm −3) which influenced bite weight directly. The effects of surface height and grazed stratum bulk density were independent and additive, resulting in a planar response surface.The influence of sward variables on bite area was less clear than on bite depth, but within a given grass species the effect of surface height appeared to be positive and that of the population density of grazed leaves and stems negative. These findings are considered in relation to a theory concerning grazing mechanics.The merits of the grazing cage technique are discussed and suggestions made for further work.

Notizen: The bottleneck restricting introgression of useful genes directly from diploid into hexaploid wheats is the low number of BC1F1 seeds obtained. In crosses between hexaploid wheat (Triticum aestivum L.; AABBDD) and Aegilops squarrosa L. (DD) or T. urartu Thum. (AA), this bottleneck may be overcome simply by pollinating a sufficient number of F1 spikes. However, hybrids between hexaploid wheat cultivars (T. aestivum) and T. monococcum L. (AA) generally are highly female-sterile, often having no pistils. One T. monococcum accession, PI 355520, when crossed with T. aestivum, produced hybrids with female fertility in the same range as that of T. aestivum/A. squarrosa or T. aestivum/T. urartu hybrids, ca. 0.5 to 1.0 backcross seed per spike. We found that female fertility was controlled by two duplicate genes in PI 355520, and that this accession can be used as a bridging parent to introgress genes from other T. monococcum accessions into hexaploid wheat. Pairing of homologous chromosomes was less frequent and weaker in such crosses than in T. aestivum/A. squarrosa crosses, but homoeologous bivalents occurred at a rate of almost 0.5 II per cell. Restitution division was detected in crosses involving all three diploid species and was confirmed cytologically in crosses with PI 355520. Chromosome numbers of BC1F1 plants ranged from 35 to 67; plants with 49 or more chromosomes occurred at frequencies of 0.09 to 0.21 among progeny of A. squarrosa and T. urartu and 0.29 in progeny of T. aestivum/T. monococcum crosses involving PI 355520. These results are consistent with those of previous studies, demonstrating the potential of direct Hexaploid/diploid crosses for rapidly introgressing useful genes into Hexaploid wheat with minimum disturbance of the background genotype.

Notizen: Genetic markers are most useful in plant breeding but so far only a few morphological and isozyme markers are known in Beta vulgaris. In this paper, the isozyme systems aconitase (AGO), NADH-:dihydrolipoamiddehydrogenase (DIA), esterase (EST), fructose-1,6-bisphosphatase (FDP), and hexokinase (HK) were genetically analysed. Isoelectric focussing (IEF), vertical polyacrylamide gel electrophoresis (PAGE) and starch gel electrophoresis (SGE) were used to separate the isozymes. A total of eight loci could be identified. The allelic forms of Aco-1, Dia-1, Est-1, Est-5 and Hk-1 are active monomers. The gene products of Est-3 and Fdp-2 are active as dimers. Est-2 also showed allelic forms without activity; null-alleles.

Notizen: The effect of in vitro cold treatment (+6°C, 90 days) on selection of low-temperature tolerant (LTT) mutants was investigated using X-irradiated (15 Gy and 20 Gy) and non-irradiated cell suspensions of Chrysanthemum morifolium cv. ‘Parliament’. Low temperature reduced significantly the number of regenerating calli, especially in the irradiated cultures. After the end of the cold stress 684, 197 and 54 plants were obtained from the 0 Gy, 15 Gy and 20 Gy treated cultures, respectively. Testing these plants in the greenhouse (+12 °C, winter low-light) most of the early flowering variants were selected from the 15 Gy population.

Notizen: Confidence intervals for heritability and expected genetic advance of seven agronomic traits in two populations of perennial ryegrass have been computed in two ways (a = bootstrap method; b = parametric method) for five different combinations of selection. Two conclusions can be drawn from our results:〈list xml:id="l1" style="custom"〉—Superiority of individual selection over family or every combination of selection.—Usefulness of methods based on resampling to estimate confidence intervals for genetic parameters without particular statistical hypotheses.

Notizen: One hundred variants of Chrysanthemum morifolium cv. ‘Parliament’, selected on a single plant basis for early flowering at low temperature, were tested on a clonal basis. These variants originated from irradiated or non-irradiated microcalli subjected to a one-step greenhouse selection procedure, or, a two-step selection procedure (preselection in vitro at 6°C followed by selection in the greenhouse). Clones originating from irradiated calli flowered significantly earlier than the controls. Most of the low-temperature tolerant (LTT) mutants were found among plants obtained by the one-step selection procedure. Variants originating from slowly regenerating calli yielded more LTT mutants as compared to those of fast(er) regenerating calli. We therefore conclude that, irradiation and subsequent selection of plants from slowly regenerating calli considerably increases the efficiency of selecting LTT mutants. The expected advantage of a preselection in vitro at low-temperature could not be confirmed.

Notizen: Ten varieties of quinoa with origins ranging from latitude 39° S to 12° S and from sea level to an altitude of 3,800 m were grown on two soil types in two years in Cambridgeshire, England, in order to assess the extent and nature of genotype × environment (G × E) interactions and identify genotypes suited for cultivation at temperate latitudes. There was evidence that varieties differed in their susceptibility to water logging during germination. Plant height was strongly influenced by competition with weeds, and varieties differed in their susceptibility to this. The number of days to anthesis and to maturity were strongly dependent on the variety, but these periods were generally longer following an earlier sowing. The grain yield was also strongly dependent on the variety, but weed competition, a micronutrient deficiency and bird damage affected the varieties differently. Varieties originating at high latitudes gave the highest yields, about 5,000 kg/ha. Earliness and yield were strongly associated at the level of variety means, but the pattern of G × E interaction differed among the variables measured.

Notizen: The germplasm of the potato (S. tuberosum ssp. tuberosum) has been modified since the beginning of this century by breeders who introgressed important agronomic traits, for example disease resistance genes, from several wild and cultivated Solanum species of the Americas. In this paper we show that the Rflp analysis of potato-breeding material can be used to detect chromosomal regions descended from more-distantly related Solanum species. The Rflp patterns of individuals of ten Solanum species, ten breeding lines of S. tuberosum ssp. tuberosum and the cultivated variety ‘Bintje’ were analyzed. Rflp data for each of eight single loci of known genomic position were used for the computation of locus-specific phenograms by distance matrix methods. Several of the potato-breeding lines deviated clearly from the clustered species S. tuberosum, S. stenotomum and S. canasense for one or more of the loci considered. These deviations indicated the presence of “exotic” germplasm at a particular locus. The possibility of detecting such germplasm has implications for mapping the agronomic traits for which the wild species were introgressed and which may still be linked to “foreign” chromosome fragments.

Notizen: The quantitative-genetic basis of sprouting resistance in winter rye (Secale cereale L.) was investigated in order to facilitate breeding for improved baking quality. Crosses within and between the Petkus and Carsten gene pools were tested along with the parental lines over two locations, two years, and two harvest dates. Heritabilities of approximately 0.6 were found for falling number (FN), a-amylase activity, dormancy, and amylograph curve characters. FN showed moderate heterosis that reached 35%. High genetic variation for FN was observed in most genetic materials, and error variances were generally small. Considerable genotype × year interactions occurred. Genotypes with high FN showed more instability for FN over environments. General combining ability was the main source of genetic variation for FN (80%) and was correlated with line per se performance in the Carsten gene pool (r = 0.66). FN showed moderate to strong correlations with slowness of development, but only loose ones or none with other agronomic traits. We conclude that improving sprouting resistance by selecting for FN should be highly effective and would not cause unfavourable side effects with regard to yielding performance.

Notizen: Previous studies have indicated a relationship between genome size and cold tolerance in plants. Many species adapted to growth in cool environments have large genome sizes. These studies are based on interspecific DNA content variation. In this study, the nuclear DNA content of eight maize populations was determined. These populations were obtained from the University of Nebraska and represent populations selected for cold tolerance and their respective unselected original populations. Intraspecific DNA content variation was observed between the selected and unselected populations. Upon assessing the data based solely on cold tolerance, no clear relationship between genome size and cold tolerance was apparent. When both freeze tolerance and cold tolerance were considered, populations which were cold tolerant and exhibited a certain degree of freeze tolerance were observed to have significantly larger genomes relative to the unselected populations. Thus, it appears that the relationship between intraspecific genome size variation and cold tolerance is similar to the relationship between interspecific genome size variation and growth at cooler temperatures in plants.

Notizen: By interspecific hybridization within the genus Brassica, trigenomic haploids were produced and back-crossed four times with B. napus, variety ‘Andor’. From this material, monosomic B-genome chromosome addition lines were selected with the extra chromosome derived from three different B-genome sources, i.e., B. nigra (BB), B. carinata (BBCC), and B. juncea (AABB). After selfing and/or microspore culture, disomic addition lines were obtained. Meiotic behavior was studied of the trigenomic hybrids, the pentaploid BC1 plants, and the monosomic addition lines. The addition lines were shown to possess cytological stability and good fertility.

Notizen: Chloroplast (cp) and mitochondrial (mt) DNA restriction profiles of a cytoplasmic male sterile (CMS) line of Brassica juncea and its maintainer line were compared and found to be markedly different. Comparison of cpDNA restriction profiles of fifty different species of genus Brassica and some allied genera showed that the cpDNA profiles of CMS lines were similar to that of B. tournefortii for twenty different restriction endonucleases. This CMS system is thus not of spontaneous origin as reported earlier, but is alloplasmic in nature. Comparison of restriction profiles of mtDNA of B. tournefortii and CMS lines revealed some differences which might either be due to changes in DNA pattern during the transfer, or, due to the cytoplasm coming from a B. tournefortii line different from the one used in this study.

Notizen: The quantity of N2 fixed in common bean (Phaseolus vulgaris L.) is a quantitatively inherited trait that shows sufficient genetic variability for improvement through breeding, but there is little information on gain from selection for 15N-determined N2 fixation ability. The objective was to determine whether intrapopulation recombination and selection could be used to improve N2 fixation. Four agronomically acceptable lines were selected, based on their acetylene reduction-determined N2 fixation ability, from an inbred backcross (IB) line population created from a cross between the high N2-fixing donor parent ‘Puebla 152’ and a commercial, low N2-fixing recurrent parent ‘Sanilac’. These four IB lines were intercrossed, advanced to the F3, and the six resulting F3 populations with 25 F3 families per population were evaluated for N2 fixation in a low-N field using 15N-depleted (NH4)2SO4. The six F3 population means differed significantly and were superior to ‘Sanilac’ for N2 fixation ability and yield, indicating significant improvement over ‘Sanilac’. Four F3 population means were similar to ‘Puebla 152’, indicating selection advance towards high N2 fixation while retaining favorable agronomic characteristics. Fifty percent of the F3 families were superior to ‘Sanilac’ for N2 fixation and one family exceeded ‘Puebla 152’, indicating that intrapopulation recombination produced improvement of 15N-determined N2 fixation.

Notizen: Several methods for determining yield reduction resulting from Septoria nodorum blotch have appeared in the literature during the past decade. These methods varied from the measurement of effects of disease on components of yield to calculation of area of symptoms on certain leaves at different growth stages. We analyzed data from a uniform group of wheat entries in the USDA Septoria nursery that had been grown in seven locations in North America and Europe during the years 1982–1987. Symptom severity and height of symptom on the plant were compared to kernel number and kernel weight. Location, year-within-location and genotype were also considered. In the context of this study, we concluded that location, and year-within-location are the most important factors determining yield reduction (as measured by relative kernel weight). Selection directly for components of yield is quite effective, but selection by means of disease symptoms is often not correlated with yield. We also conclude that specific methods for relating symptoms to yield reduction that are applicable to a particular location are probably useful and appropriate for that location only.

Notizen: Interspecific hybridization between the grasspea, Lathyrus sativus, and 15 wild species in Section Lathyrus is reported. Only two species, L. amphicarpos and L. cicera produced viable F1 hybrids with low fertility when crossed with L. sativus as male parent. Crosses with six other species produced pods following pollination when L. sativus was the male, but seedlings were inviable, seeds did not germinate or pods were empty or had totally shrivelled seeds. When L. sativus was the female parent, only one cross with L. gorgoni produced an F1, but the seedling was inviable. The germplasm resources of the grasspea are identified, with L. amphicarpos and L. cicera placed in the secondary gene pool and the other species in the tertiary gene pool. The definition of these germplasm resources is discussed in terms of grasspea improvement through plant breeding.

Notizen: Estimates of N2 fixation in segregating populations of bean plants based on 15N-isotope methods are technically demanding and expensive; therefore, indirect measures based on related traits including total seed N were used to select for improved N2 fixation and yield. In 1985, six populations of F2-derived F3 families resulting from six parental lines crossed to a common tester were grown in field trials on a low-N soil. In 1986, 25 selected half-sib families and two populations of full-sib F4 families were grown under similar conditions. Parents and a non-nodulating soybean line were included both years. Narrow sense (HNS) heritability estimates based on parent-offspring regressions ranged from 0.57 for total seed N to 0.39 for shoot biomass in one population, but were near zero for all measured traits in a second population. Among the criteria used to identify parental lines with superior potential for producing progenies with high total seed N, testcross population means combined with estimates of realized heritability were the most reliable. Selection of the best F3 families for total seed N resulted in F4 families with increased total seed N and higher seed yields, while seed protein percentage was unchanged. When plants are grown on low-N soils, selection for total seed N offers a useful alternative to selection for increased N2 fixation based on 15N-isotopic or total-N-difference method.

Notizen: Two double-cross populations were used to evaluate the efficiency of independent, alternate, and simultaneous selection practiced from the F2 to F8 for resistance to anthracnose and angular leaf spot of common bean (Phaseolus vulgaris L.). Seven resistant and high-yielding lines were selected from each of the four environments used during this study. These lines and the seven parents involved in two populations were evaluated in an 8 × 8 lattice design with three replications in two cropping seasons. Pathogen inoculum was used to create the three test environments: anthracnose alone, angular leaf spot alone, and anthracnose and angular leaf spot together. All entries were also evaluated in a fourth, disease-free environment. Selection for resistance to anthracnose and angular leaf spot was effective in both populations. Mean disease scores of all selected lines for anthracnose were lower than that of angular leaf spot irrespective of selection environment. Among the three stress environments, yields were higher in the anthracnose environment. However, lines selected alternately for anthracnose and angular leaf spot were usually higher yielding, and the highest yielding line in both populations originated from this selection environment. The mean yield of selected lines was higher and the highest yielding line originated from the population involving a parent (G 1805) belonging to the Mexican highland race ‘Jalisco’. Positive association existed between seed yield of protected and pathogen-inoculated environments. No association was found between resistance to anthracnose and angular leaf spot.

Notizen: Inheritance of resistance to Yellow Mosaic Virus (YMV) was studied in crosses of mungbean, black-gram and their interspecific crosses with Vigna sub-lobata. Resistance to YMV was recessive in the three Vigna species. The segregation ratios in F2 and back crosses indicated that the resistance was digenic recessive in the crosses of mungbean and in interspecific crosses of mungbean with blackgram and Vigna subiobata but YMV resistance was monogenic recessive in blackgram crosses.

Notizen: After mutagenic treatment with NMU (nitroso-methylurea) flower buds and flower-bud pedicels of broccoli were cultivated in vitro. Among regenerated MJ plants, one male sterile, but female fertile mutant was found, for which a monogenic dominant inheritance of male sterility was demonstrated. A scheme to utilize dominant controlled genie male sterility in Brassica oleracea for hybrid breeding is discussed.

Notizen: This research is aimed at quantitative genetic analysis of several avocado traits and cultivars. The experimental material consists of our avocado breeding project in which data were collected from several crosses as well as selfings of cultivars. Parenthood was determined by isozymes and the seedling progenies were assessed for eight traits. A biometrical genetic approach for analysis of this breeding project is presented. Genetic profiles of the traits and cultivars were detailed by several characteristics: level of heterozygosity and dominance deviation, dominance of alleles, dominance direction, general evaluation of additive and non-additive genetic variance, maternal inheritance, and allelic differences among the various cultivars in major genes controlling the same quantitative trait. Five avocado cultivars: ‘Fuerte’, ‘Hass’, ‘Ettinger’, ‘Tova’, and ‘Rosh-Hanikra’, were characterized separately for each trait. Practical conclusions for the breeder regarding economically important quantitative traits are discussed.

Notizen: A total of 329 chickpea lines, comprising 130 kabiili and 199 desi types, originating from six regions, viz., Indian sub-continent, Middle East, North Africa, America, Europe and USSR, were sown in augmented design. The data recorded on agronomic characters on all entries from each region were evaluated in terms of group (region) means. Among the six regions, greater plant height and lateness in flowering were specific to USSR entries. Group means of USSR accessions, both desi and kabuli, differed significantly from those of Indian varieties for a majority of the characters. These observations indicate that the degree of expression of certain characters could be ascribed to specific areas, which led to area-specific adaptations. Furthermore, type-specific differentiating characters, differing in degree of expression, were observed in desi and kabuli types. For example, high mean values of characters, like branches, pods, grain yield and harvest index, were associated with desi types, and 100-seed weight with kabulis. History of cultivation and selection for specific purpose has been cited as cause for area-specific adaptations and type-specific differentiating characters.

Notizen: Book reviewed in this article: Wagner, F., und G. Prediger, Der Feldversuch: Durchführung und Technik.