bluuebunny/crossref_metadata_2025_split huggingface dataset:
The effects of subsoil loosening and deep incorporation of nutrients on yield of broad beans, cabbage, leck, potatoes and red beet
Authors: Stone D. A. 
Published: March 2009

SUMMARYExperiments were made on a sandy clay loam soil with five crops to determine the effects of thorough loosening of the subsoil and deep incorporation of nutrients on yields during the subsequent 4 years.Loosening to 0·9 m increased fresh-weight yields by between nil and 95% depending on the crop and season. Responses were still considerable 4 years after the initial loosening and there was no evidence of any decline with time. Deep incorporation of nutrients did not improve yields.Loosening gave a durable increase in the volume of coarse pores and decreases in bulk density and penetrometer resistance. It also nearly doubled the rate of root extension when estimates were made for one crop, consistently increased water extraction from below 30 cm and, on occasion, reduced plant water stress.It is concluded that most of the benefits from deep loosening resulted from improvements i the rate at which plants could extract water rather than nutrients from the subsoil.
A study of mole drainage with simplified cultivation for autumn-sown crops on a clay soil
Authors: Harris G. L. , Goss M. J. , Dowdell R. J. , Howse K. R. , Morgan P. 
Published: March 2009

SummaryThe soil water regimes, flow paths of water and concentrations of nutrients in this water were measured for a clay soil growing winter wheat in 1978–9 and 1979–80. The soil was either drained with mole drains at 2 m spacing connected to plot drains 46 m apart or undrained. In the 1st year a compacted layer at about 20 cm depth caused a perched water table in the Ap horizon in both drainage treatments, and prevented the mole drains at 60 cm from affecting the water table. In 1979–80 after cultivation to disrupt the compacted layer, midway between the mole drains the depth to the winter water table was 20 cm greater than in undrained soil.Surface flow, interflow at the depth of the plough layer and deep drainflow from mole and pipe drains responded rapidly to winter rainfall events. During both winters the mole and tile system removed most of the rainfall on the drained plots and the peaky hydrographs were typical of a mole system in a clay soil. In the undrained plots only a small proportion of the winter rainfall was accounted for in flow from the top 30 cm, and up to 75% of the water was able to percolate downwards possibly to below the barriers that separated the plots. Long-term water-balance studies indicated that a proportion of the water moving to depth in the undrained plots was probably entering the deep drainage system of the drained plots. As a result, the mole and pipe drainage system often removed more water than the rainfall input less evapotranspiration. This problem did not affect the depth to the water tables.For each flow component concentrations of nitrate, ammonium, nitrous oxide, phosphorus, potassium and calcium were measured in the drainage water. Concentrations of nitrate-N from all drained plots were largest in autumn, being in the range 50–95 mg N/1, but then decreased to 1–5 mg N/1 by the end of March. Losses of nitrate-N were mainly through the mole drains and amounted to 43·6 and 59·7 kg N/ha in the 2 years. The quantities of nitrate-N lost in surface runoff or in flow in the cultivated layer were small on both treatments. Gaseous nitrous oxide, ammonium and phosphorus contents were very small. Potassium concentrations were somewhat larger, but not exceeding 3·5 mg/1. The calcium concentrations were in the range 40–210 mg/1. Concentrations of herbicides measured in November 1980 were negligible.In the 2nd year water was taken up from a greater depth in the drained than in the undrained plots from April onwards. These results are discussed in relation to water supply to the crops at this site.
The relative feeding value of kale (Brassica oleracea) containing normal and low concentrations of S-methyl-L-cysteine sulphoxide (SMCO)
Authors: Barry T. N. , Manley T. R. , Millar K. R. , Smith R. H. 
Published: March 2009

SummaryKale of normal and low S-methyl-L-cysteine sulphoxide (SMCO) content was produced by growing the same cultivar in soils of normal (20–30 mg/kg) and low (5–10 mg/ kg) soil sulphate-S concentration. Compared with normal S plots, kale grown in low S plots showed little or no reduction in D.M. yield or total N content, but contained lower concentrations of inorganic sulphate, SMCO and glucosinolates.Replicated plots of normal and low SMCO kale were grazed by lambs for 12-week periods in two consecutive years, using a fixed crop allowance of 2·5 kg D.M./animal/ day. All animals were given injections of copper and iodine, and oral supplements of selenium, to ensure that effects upon animal performance could largely be attributed to differences in kale SMCO concentration.SMCO concentration in the diet consumed by lambs grazing normal and low SMCO kale was respectively 0·60 and 0·35% D.M. Following the onset of kale feeding, all animals developed subclinical haemolytic anaemia which stabilized by week 6, and was more marked during weeks 1–6 than during weeks 7–12. Animals grazing low SMCO kale showed a less severe anaemia than those grazing normal SMCO kale, which was associated with lower blood concentrations of dimethyl disulphide and Heinz bodies, and higher reduced glutathione (GSH) and packed cell volume (PCV) levels. Liveweight gain and wool growth were greater for lambs grazing low than normal SMCO kale during weeks 1–6, corresponding to the period of most severe haemolytic anaemia, but during weeks 7–12 there were no differences between the two groups.It was concluded that SMCO content depressed kale feeding value, with most of the depression occurring in the first 6 weeks of grazing, and that in these experiments the lambs were able to adapt to kale containing 0·6% D.M. as SMCO after 6 weeks of feeding. Endocrine factors involved in this adaptation are discussed.
Changes in amino acid compounds of wheat plants during ensiling and aerobic exposure: the influence of propionic acid and urea phosphate-calcium propionate
Authors: Ashbell G. , Theune H. H. , Sklan D. 
Published: March 2009

SummaryChanges in distribution of amino acid nitrogen of chopped wheat plants ensiled at shooting and flowering when wilted, and at the milk and dough stages as fresh material, were determined as affected by addition of 0·8% propionic acid (PrA) or 2·2% urea phosphate-calcium propionate (UP-CaPr). Analyses were carried out after an ensiling period of 90 days and after a further aerobic exposure period (AE) of 7 days.Total amino acid (TAA) contents in the dry matter (D.M.) during the fermentation period and in the AE were stable in untreated material (UM) and treated material. Concentration of essential amino acids decreased during fermentation, this decrease being higher in the UM. The free amino acids were low in the fresh material (18·6% of TAA) but increased in the ensiled material to ca. 71 % of the TAA in the silage. In the AE this level was 63% in UM and 69% in treated material. The ammonia-N contents increased during fermentation in UM and especially in the UP-CaPr treatments, while the opposite occurred in the PrA treatments.The concentrations of and changes in 21 amino acids (AAs) are given. The highest AA concentrations recorded in the fresh material were those of arginine, lysine, glutamic acid, alanine, leucine, proline and glycine. The most marked increments in AAs as a result of fermentation were those of ornithine, γ-amino butyric acid, threonine and methionine. Marked decreases were observed in glutamine, arginine and glutamic acid. PrA increased mainly arginine, asparagine and glutamine, whereas γ-amino butyric acid decreased; UP-CaPr increased arginine, asparagine, lysine and glutamic acid (in silage only) and reduced γ-amino butyric acid and glutamine (in AE only).
The availability of nitrogen in liquid sewage sludges applied to grassland
Authors: Hutchings N. J. 
Published: March 2009

SummaryThe availability to grass of the nitrogen in liquid anaerobically digested sludge (LDS) and liquid aerobic sludge (LAS) was investigated in a 2-year field trial. The mean availability of the nitrogen in the LDS over the 2 years was 44% on a freely drained sandy soil and 34% on a poorly drained clay soil. The corresponding values for the LAS were 56 and 44%. A greater inhibition or organic-matter decomposition by clay particles or a greater loss of nitrogen by either ammonia volatilization or denitrification were all possible reasons for the lower availability of the sludges on the clay soil. Investigation of the magnitude of gaseous losses of nitrogen from sludge-amended grassland under U.K. conditions is required. Current models of the availability of the nitrogen in liquid sludges may not be realistic if these losses are significant.
Field trials assessing the effect of inoculating agricultural soils with endomycorrhizal fungi
Authors: Hall I. R. 
Published: March 2009

SummaryFour field experiments were established to gauge the effect of inoculating white clover with selected strains of vesicular-arbuscular mycorrhizal (VAM) fungi. The four sites chosen ranged in fertility from undeveloped, phosphorus-impoverished tussock grassland to high fertility alluvial flats. As far as practicable conventional agronomic practices were followed prior to and during sowing. The soils were otherwise untreated and contained the normal complement of indigenous VAM fungi. Infested soil pellets were used to introduce the fungi into the soils as this was considered more appropriate to pastoral farming than for example transplanting infected seedlings.Initially the introduced fungi tended to have little or no effect on dry-matter yields but by the end of the first season there were significant responses to Gigaspora margarita, Glomus mosseae, Glomus macrocarpum or a mixed inoculum of Glomus pallidum and Glomus tenue. In the second season, dry-matter yields were increased on the two tussock grassland sites by up to 760 kg D.M./ha (ca. 30%), 825 kg D.M./ha on the moderately fertile site (14%) and 640 kg D.M./ha (5%) on the high fertility site. The growth responses tended to decrease with time probably owing to the spread of fungi from the inoculated to the control plots though growth responses were still present at the end of the 3rd year on two of the sites. Within each experiment the application of up to 50 kg P/ha per year did not reduce the size of the responses to inoculation. This and herbage chemical analyses suggested that a more efficient use of phosphatic fertilizers may have been only part of the reason for the responses to inoculation.
A winter wheat crop simulation model without water or nutrient limitations
Authors: Weir A. H. , Bragg P. L. , Porter J. R. , Rayner J. H. 
Published: March 2009

SummaryA whole crop computer simulation model of winter wheat has been written in FORTRAN and used to simulate the growth of September- and October-sown crops of Hustler wheat at Rothamsted for the years 1978–9, 1979–80 and 1980–1. Results of the simulations, which are for crops with adequate water and nutrients, are compared with observations from experiments at Rothamsted. The model uses daily maximum and minimum temperatures and daylength to calculate the dates of emergence, double ridge, anthesis and maturity of the crops and the growth and senescence of tillers and leaves. In the simulations, the canopy intercepts daily radiation and produces dry matter that is partitioned between roots, shoots, leaves, ears and grain. Partial simulations, using observed LAI values, produced dry matter in close agreement with observations of late-sown crops, but consistently overestimated the total dry-matter production of the early-sown crops. Full simulation described satisfactorily the average difference in dry-matter production to be expected with changes in time of sowing, but did not give as close correspondence for individual crops. A grain growth submodel, that linked maximum grain weight to average temperatures during the grain growth period, correctly simulated the observed growth of individual grains in the 1981 crop. The benefits to be obtained by combining whole crop modelling with detailed crop observations are discussed.
A model of canopy development in winter wheat
Authors: Porter J. R. 
Published: March 2009

SummaryA computer simulation model of canopy development in a crop of winter wheat is described. The principal features of the model are the simulation of the emergence, growth and senescence of individual leaves and the production of tiller groups (cohorts) during a defined phenological period, with their survival depending on cohort age and shoot population density.Comparison is made between the model output and early- and late-sown crops from three seasons. The behaviour of the model in response to changes in leaf senescence and tiller production is discussed for crops sown in 1978.
Desalinization of a salt-affected soil in plots of various sizes under two modes of water application
Authors: Dahiya I. S. , Grewal K. S. , Anlauf R. , Richter J. 
Published: March 2009

SummaryLeaching in a salt-affected, permeable, sandy loam soil was evaluated under continuous and intermittent ponding conditions in 2 × 2 m (S1), 4 × 4 m (S2) and 6 × 6 m (S3) plots. The soil contained large amounts of soluble salts throughout the profile to the water table, chiefly chlorides and sulphates of sodium, calcium and magnesium. The leaching curves did not differ significantly between Slf Sa and S3 plots under continuous ponding but did under intermittent ponding. The leaching efficiency decreased sharply with increased plot size. The leaching efficiency in Sj plots was significantly greater with intermittent than with continuous ponding, but the reverse was true in S3 plots. The displacement of the resident soil solution in S1 plots under intermittent ponding was nearly piston-like. With increased plot size, it tended to deviate from this behaviour. The leaching curves from S3 plots (this size being reasonable in farmers' fields) were compared with those obtained from numerical solution of a simplified steady-state salt transport model. The model also included a source term, solubility rate constant, for the slightly soluble salts present in the experimental soil. The pore water velocity was estimated from field capacity and time-averaged infiltration rate. The effective dispersion coefficient and solubility rate constant were estimated by a least-squares minimization technique. A reasonably good agreement was obtained between simulated and experimental leaching curves. For practical purposes, this simple model may be adequate to predict leaching in salt-affected soils similar to the one under consideration.
Detection and estimation of components of genetic variation and genotype × environment interaction in three wheat crosses
Authors: Singh S. , Dahiya M. S. 
Published: March 2009

SummaryThe data obtained from 360 progeny families produced by crossing 40 F2 plants from each of three wheat crosses HD 2009 × HD 1949, Raj 821 × WH 147 and NP 876 × HD 1949, to three testers (the testers being the two parents of each original cross and their F1 in each case) were subjected to triple test cross analysis for detecting and estimating additive, dominance and epistatic components of genetic variation and interaction of these components with environment for plant height, spike length, number of tillers per plant, number of spikelets per spike, number of grains per spike, 1000-grain weight, number of days from sowing to heading and to maturity, grain yield per plant and grain yield/above ground dry matter ratio (harvest index). Epistasis was an important element for plant height, number of tillers per plant, number of grains per spike and grain yield per plant in all three crosses. Both the i type and j and l type epistasis were equally important. In general, the magnitude of additive component was larger than that of dominance component. The additive gene effects were more sensitive to environmental change than the dominance gene effects. Similarly, j and l type epistasis was relatively more sensitive to environment than the i type epistasis.
Evaluation of overseas pig breeds using imported semen 1. Growth and carcass performance
Authors: Sutherland R. A. , Webb A. J. , King J. W. B. 
Published: March 2009

SummaryAlthough a given foreign breed may offer worthwhile genetic improvement, the cost of importing purebred stock makes its evaluation difficult. An experiment was performed in which the breeds compared were represented instead by semen from boars standing at national artificial insemination stations in their native countries. Contemporary groups of Large White × Norwegian Landrace females were inseminated, some with British Large White (LW) semen, and some with semen from Canadian Yorkshire (CY), Danish Landrace (DL), Norwegian Landrace (NL), or United States (American) Duroc (AD) or Yorkshire (AY). One pair (male castrate and gilt) from each litter was performance tested from 27 to 82 kg live weight fed ad libitum (AL), another pairwas tested over the same weight range but fed to a time-based scale (TS). The number of LW, CY, DL, AD, AY and NL sires used was 51, 12, 21, 7, 6 and 23 respectively; a total of 401 litterswas evaluated. The differences between the progeny of LW sires and those of CY, DL, AD, AY and NL were, respectively: in daily live-weight gain (g), AL, –30, 40, –80, –50, –40 (maximum s.E. 16) with no significant differences for TS; in food conversion ratio, AL,0·02, – 0·13, 0·03, –0·05, 0·00 and TS, 000, – 0·14, 0·05, –0·03, –0·06 (maximum S.E. 0·049 for both feeding regimens); in percentage of lean by weight in the rumpback joint, AL, –2·1, –1·9, –1·8, 2·3, –0·7 and TS, – 0·1, –0·9, –1·9, 3·0, – 1·4 (maximum s.E. 1·28 for both); in overall economic worth (pence per pig sired), AL, – 150, 50, – 170, 110, – 40 and TS, – 10, 100, – 200, 190, 30 (maximum s.E. 83 for both). The U.S. Yorkshire and Danish Landrace seem unlikely to be of use commercially in the U.K., while the most promising breeds, U.S. Duroc and Canadian Yorkshire, have not yet been evaluated with sufficient precision to reduce the risk involved in their use to an acceptable level.
Effect of row arrangement on light interception and yield in sorghum-pigeonpea intercropping
Authors: Natarajan M. , Willey R. W. 
Published: March 2009

SummaryTwo experiments examined the effect of improving the distribution of the pigeonpea plants in sorghum-pigeonpea intercropping by having an alternate row arrangement of the two orops (SP) instead of the two sorghum: 1 pigeonpea row arrangement (SSP) that was studied earlier. One experiment was under conditions of good moisture supply (a deep Vertisol site in the high rainfall year of 1978) but the other experienced early moisture stress and had much lower end-of-season soil moisture storage (an Alfisol site in 1979). In 1978 the proportional sorghum yield was not affected by row arrangement (86 and 85% of the sole crop yield for the SSP and SP treatments respectively). Under the drier Alfisol conditions of 1979, the proportional sorghum yield was lower, probably because of the increased competitive ability of the drought resistant pigeonpea, and it was adversely affected by the alternate row arrangement (72% for SSP and 60% for SP).Compared with the SSP arrangement, the SP arrangement increased the level of light interception by the intercropped pigeonpea immediately after the sorghum harvest from 30 to 48 % in 1978 and from 44 to 60 % in 1979; the total energy intercepted during the whole post-sorghum period was increased by 23 and 12 % in the 2 years, respectively. However, these improvements in canopy cover were associated with only small increases in total dry matter of the intercropped pigeonpea at final harvest, from 69 to 74 % of the sole crop in 1978 and from 60 to 65 % in 1979. The increase in seed yield was even less than that in total dry matter in 1978 (from 90 to 93% of the sole crop) but similar in 1979 (71 to 76%); the value of this increase in 1979 was insufficient to offset the decrease in sorghum yield. None of the increases in total dry matter or seed yield of pigeonpea reached significance. It is concluded that with a good moisture supply alternate rows could be an alternative to the 2 sorghum: 1 pigeonpea arrangement, though it offers no additional yield advantage. With poorer moisture supply, alternate rows are not a worthwhile option because of the risk of reducing sorghum yield to an extent that cannot be offset by the small increase in pigeonpea yield.
The effects of carbohydrate supplements on ruminal concentrations of ammonia in animals given diets of grass silage
Authors: Chamberlain D. G. , Thomas P. C. , Wilson Wilma , Newbold C. J. , Macdonald J. C. 
Published: March 2009

SummaryA total of 15 rumen-cannulated sheep and four rumen-cannulated goats (Expt 3) were used in five latin square experiments designed to investigate the effects of carbohydrate supplements on ruminal ammonia concentration in animals given grass silage diets. In Expt 1 barley supplements were given at the same time, 1 h before or 2 h before a meal of silage. The treatments were designed to alter the synchronization between energy release from fermentation of barley and ammonia release from the degradation of silage N compounds. As compared with the unsupplemented control diet, barley supplements reduced (P < 0–05) rumen ammonia concentration and increased (P < 0–01) the number of total protozoa, but the time at which barley was given was without effect. In Expt 2 animals receiving silage or silage-barley diets were defaunated chemically. This treatment led to a 20–25 % reduction in rumen ammonia concentration. In Expt 3 supplements of maize starch, glucose and sucrose were compared. Mean ammonia concentrations were 231 mg/1 for the control unsupplemented diet and 205, 155 and 160 mg/1 (S.E. 21) for the starch, glucose and sucrose treatments. Corresponding numbers of protozoa were 7–7, 15–1, 6–1 and 6–3 x 10s/ml (S.E. 1–8). In Expt 4 the diets were unsupplemented silage or the same diet plus supplements of sucrose or xylose. Xylose reduced ammonia concentration more than sucrose, the values (mg/1) being 236 (control), 206 (sucrose) and 125 (xylose) (S.E. 19). There was no difference between the supplements in numbers of protozoa. Xylose induced a smaller reduction in pH, a higher (P < 0–05) proportion of acetate and a lower (P < 0–05) proportion of butyrate in rumen fluid than did sucrose. Effects of rumen pH were examined in Expt 5 where supplements of sucrose were given alone or together with NaHCO3. Rumen pH values were 6–38 for the control unsupplemented diet and 5–99, 6–28 and 6–55 (S.E. 0–06) for the diets supplemented with sucrose, sucrose plus 50 g NaHC03 and sucrose plus 100 g NaHCO3. Corresponding values for ruminal ammonia were 193, 151, 93 and 41 mg/1 (S.E. 10). Differences in VFA proportions between sucrose treatments were small and significant (P < 0–05) only for butyrate. It is concluded that there are important differences between carbohydrate sources in their effects on nitrogen metabolism in the rumen. Differences between starch and sugars appear to relate to the influence of the carbohydrates on the microbial population of the rumen, as was indicated by the differential effects of the carbohydrate sources on the number of total protozoa; differences between sugars appear to depend in part on the rates of sugar fermentation and the associated reduction in rumen pH.