bluuebunny/crossref_metadata_2025_split huggingface dataset:
Methods of analysing competition with special reference to herbage plants: I. Establishment
Authors: Hill J. , Shimamoto Y. 
Published: March 2009

SummaryA diallel arrangement, which incorporated the essential features of the de Wit density replacement series, was employed to study the effects of competition amongst five genotypes of perennial ryegrass (Lolium perenne). Of the five genotypes concerned two were derived from S·24, two were collected from natural populations in South Wales, while the remaining genotype originated from S· 23. These five genotypes were grown as monocultures and in all ten binary combinations. Within each combination there were three mixture proportions, namely 75:25, 50:50 and 25:75. All mixtures and monocultures were represented by two boxes, one of which was cut at 3-week intervals (frequent cutting) the other being cut at 6-week intervals (infrequent cutting). At each cut all plants within the appropriate mixtures and monocultures were harvested individually and their dry weight recorded.The results obtained over the first 18 weeks of the experiment (i. e. the first three complete growing periods) establish that competition is occurring in nine of the ten binary combinations. Within these nine combinations competition may be classified into one of three groups: first, it may be compensatory, in which the gains and losses incurred by the two components counterbalance; secondly, it may be positive complete complementation, where the advantage gained by the stronger component is such that the mixture performance matches that of the better monoculture, and thirdly, it may be positive over-complementation, where the yield of the better monoculture is surpassed by the mixture. Further tests disclose that a long-leaved S· 24 genotype is the strongest competitor, while a short-leaved, prostrate, indigenous genotype proves to be by far the weakest competitor.Estimates of the equilibrium proportions for each genotype combination suggest that most combinations are expected to become monocultures of the strongest component, with only the combination between the long-leaved indigenous and longleaved S· 23 genotypes remaining a mixture at equilibrium. None of these equilibria coincides with the proportions required to achieve maximum productivity from a particular combination. The results are considered in relation to the known characteristics of these five perennial ryegrass genotypes, while the wider agronomic implications are also discussed.
Effects of plant density, irrigation and potassium and sodium fertilizers on sugar beet: I. Yields and nutrient composition
Authors: Draycott A. P. , Durrant M. J. , Webb D. J. 
Published: March 2009

SummaryThree experiments (1970–2) on calcareous sandy loan tested all combinations of four plant densities (18500–124000 plants/ha), two amounts of potassium (0, 156 kg/K/ha) and sodium (0, 247 kg/Na/ha) fertilizer and two watering treatments on yield and chemical composition of sugar beet. The main effects of the treatments in all three experiments confirmed that at least 75000 plants/ha were needed for maximum sugar yield, that sodium fertilizer increased sugar yield more than potassium (+0.76 and +0.29 t/ha respectively) and that the crop responded to irrigation in some years (+1.35 t sugar/ha in 1970 and +1.67 t/ha in 1972).Analysis of the growth of the crop showed that increasing the plant density increased leaf growth per unit area from singling onwards and giving irrigation increased it from July; the effects persisted until harvest and were reflected in increased sugar yields. Fertilizer increased leaf growth early in the season but the effect disappeared later, although sugar yield was still increased. Interactions between plant density, fertilizer treatment and irrigation were small every year but there were some consistent effects on sugar yield. The results suggest that in commercial practice the optimum density is 75000 plants/ha; where irrigation is not practised, 247 kg/ha of sodium and 70 kg/ha of potassium fertilizer should be given. Where irrigation is applied, only 247 kg/ha of sodium needs to be given as the extra water increases the uptake of soil potassium.
The effect of potassium carbonate solution on the drying of lucerne: 2. Field studies
Authors: Tullberg J. N. , Minson D. J. 
Published: March 2009

SummaryIn two field studies it was found that lucerne hay swaths sprayed with 3000 1/ha of 2% (w/w) aqueous potassium carbonate solution after cutting dried more rapidly than mechanically conditioned or control swaths; the ratio of drying rates being 2·17:1·43:1·00 respectively. Hay yields were increased in one of the two studies by the use of potassium carbonate.The effect of different application rates was studied in a third trial using 200, 500 and 875 1/ha potassium carbonate solution, compared with mechanically conditioned and control swaths. After only 29 h of field exposure all swaths treated with potassium carbonate had dried to moisture contents below that required for baling (moisture: dry matter ratio < 0·3).
Relationship between lodging, morphological characters and yield of varieties of maize (Zea mays L.)
Authors: Remison S. U. , Akinleye Dele 
Published: March 2009

SummaryField experiments were carried out in the early and late growing seasons in the rainforest zone of Nigeria to find out the relationship between lodging, morphological characters and yield of maize.Morphological characters associated with lodging were plant height, ear height and length of basal internode. There was a negative correlation between lodging and yield. Much of the lodging recorded, especially in the early growing season, was due to weak stems. Earliness, diameter of stem and leaf area had no relationship with lodging.
The effects of the date of defoliation of the seed potato crop and the storage temperature of the seed on subsequent growth: 1. Sprout growth
Authors: Wurr D. C. E. 
Published: March 2009

SummarySeven experiments carried out over 3 years investigated the effects of the date of defoliation of the seed crop and the storage temperature of the seed on subsequent sprout growth.The time of defoliation of the seed crop had a small, variable effect on the number of sprouts but with all varieties in every year, early defoliation gave the greatest total sprout length. The effect of later defoliation on sprout length varied according to the variety and the year. Most of the variation in total sprout length per tuber appeared to be attributable to differences in the date of dormancy break of the seed tuber.Storage throughout the winter at 15 °C gave fewer sprouts but a greater total sprout length per tuber than storage at 9 °C. A linear relationship between total sprout length per tuber and accumulated day degrees above 0 °C from dormancy break accounted for most of the variation in sprout length occurring in Désirée, Pentland Crown and Majestic as a result of storage at 9 °C and 15 °C for different periods of time.
A consideration of the techniques for estimation of milk yield by suckled sheep and a comparison of estimates obtained by two methods in relation to the effect of breed, level of production and stage of lactation
Authors: Doney J. M. , Peart J. N. , Smith W. F. , Louda F. 
Published: March 2009

SummaryThree techniques, lamb-suckling and test-weighing, hand- or machine-milking following administration of oxytocin, and measurements of body-water turnover, used for the estimation of milk yield in suckled sheep are discussed in relation to sources of error and comparability of estimates.Results are presented from an experiment in which the lamb-suckling and the oxytocin techniques were compared. The mean daily milk production of Scottish Blackface and East Friesland × Scottish Blackface ewes suckling single and twin lambs was measured by both methods at weekly intervals for 6 weeks. All ewes were well nourished to ensure full expression of milking capacity. Additional information from a similar experiment on Merino ewes is also presented.The oxytocin method gave higher estimates of mean daily milk yield in the first week of lactation, especially in the groups of ewes rearing single lambs and in the Blackface breed. By the second week in most groups and the third week in all groups there were no significant differences between estimates made by the two methods and the relative values of the estimates were not affected by level of milk production, number of lambs suckled or genotype of ewe and lamb.
The effect of the dry period on the subsequent lactation in three half-sib groups of British Friesians
Authors: Wood P. D. P. 
Published: March 2009

SUMMARYReserve energy accumulated before calving may make a contribution to total lactation yield. Random samples of cows which produced their first two lactations in the same herds were drawn from the progeny groups of three British Friesian sires whose milk yield proofs differed by a very significant amount. Regression of second lactation yield on first lactation, intervening dry period and length of lactation showed that the effect of the dry period was different in the three groups. Daughters of sire A with a contemporary comparison of + 374 ± 20 kgshowed a regression of 21·6 ± 7·8kg/day of dry period; sire B+174 ± 24 kg, 9·0 ± 5·2 kg/day; and sire C -174 ± 87 kg, 5·5 ±3·0 kg/day. If the dry period can be regarded as an opportunity for the cow to accumulate body reserves, a standard 60-day dry period could have made a contribution to total yield in group A of 25·5%, in group B of 12·2% and in group C of 8·1%. The argument for regarding these figures as approximate measures of the relative response to steaming up of the cows in the three groups is developed.
Comparison of sulphur-coated urea and ammonium sulphate amended with N-Serve as sources of nitrogen for sugarcane
Authors: Dalal R. C. , Prasad M. 
Published: March 2009

SUMMARYA comparison of ammonium sulphate (AS) with and without N-Serve and sulphurcoated urea (SCU) as N sources for sugarcane, studied in a pot experiment, showed that although the tillering, the leaf N concentration and cane yield were increased by adding fertilizer N there were no significant differences between N sources. However, AS and AS + N-Serve depressed the soil pH, especially that of acidic soils, much more than SCU. In a field experiment where AS, urea and SCU were compared on a calcareous soil, it was observed that urea gave significantly lower cane and sucrose yields than AS and SCU when N was applied on the surface, possibly due to greater volatiliization losses from urea. Subsurface application increased the efficiency of urea, although the method of placement had no significant effect on the N efficiency of AS and SCU. AS was as effective as SCU. Thus the coating of urea by sulphur increased its efficiency for sugarcane only when applied on the surface of a calcareous soil.
The nutrition of the early weaned lamb:III. The effect of ad libitum intake of diets varying in protein concentration on performance and on body composition at different live weights
Authors: Ørskov E. R. , McDonald I. , Fraser C. , Corse Elizabeth L. 
Published: March 2009

SUMMARY1. Fifty lambs weaned at about 5 weeks of age were fed ad libitum on mixtures of barley and fish meal containing either 11·0, 15·7 or 19·4% crude protein in dry matter. Male and female lambs on each diet were killed at intervals, starting after they had been on the diets for 3 weeks. The last to be killed had attained a live weight of about 55 kg.2. The mean rate of voluntary feed consumption was less at all live weights for the lambs on the diet containing 11·0% crude protein than for those on the other diets and the difference was statistically significant at live weights of 30 and 35 kg. Mean rates of live-weight gain on the low, medium and high protein diets were respectively 191, 270 and 330 g per day for the male lambs and 177, 225 and 301 g per day for the females, the increase with protein concentration being highly significant. Feed conversion rate (kg feed/kg gain) over the whole experiment increased with increasing weight at slaughter. After adjustment for this effect the mean values showed significant dietary effects, and were least on the highest protein concentration.3. The percentages (y) of nitrogen or of ether extract in the dry matter of the carcass or of the whole empty body were found to be related non-linearly to the empty-body weight (x) at time of slaughter. The relationships were satisfactorily described by equations of the form y = A + Be-Cx, where A, B and C were fitted constants. The relationships for males and females had to be fitted separately, but a common value of A could be used with each of the three groups of male lambs and similarly for the three female groups.4. These relationships were used to obtain estimates of the nitrogen, ether extract and energy content of empty-body gain per unit live-weight gain. The estimated percentages of energy retained as fat were of the order of 76–83%, in agreement with ARC estimates (1965), except for male lambs between 14 and 20 kg live weight on medium or high-protein diets, for which the estimates were only 62 and 63%.5. The implications of these relationships are discussed with particular reference to the finding of dietary effects on body composition during the growth period of the lambs and to the tendency for these differences in body composition to diminish as mature live weight was approached. The differences in body composition between male and female lambs showed no such tendency to diminish.
The effect of benomyl systemic fungicide and the growth regulator CCC on eyespot disease of barley
Authors: Davies J. M. L. , Jones D. Gareth 
Published: March 2009

SUMMARYThe systemic fungicide benomyl was used as a seed dressing and as a spray at two concentrations, 250 and 500 ppm, on the winter barley variety Pella. An additional treatment was a spray application of CCC at 500 ppm. All spray treatments were applied at growth stage 3–4. Without fungicide treatment, total yield in the inoculated plots was approximately 40% of that in the uninoculated plots. The 500 ppm fungicide-spray treatment significantly decreased incidence and severity scores of eyespot, the seed dressing being significant only for the latter. The seed dressing and 500 ppm spray treatments significantly increased mean yield/head, fertile tiller number and 1000 grain weight. All the fungicide treatments significantly increased total yield in the inoculated plots. There were no significant effects of CCC upon disease or upon yield, neither was there any interaction between benomyl and CCC.
The effect of sowing date and season on the development and yield of Navy beans (Phaseolus vulgaris) in south-east England
Authors: Scarisbrick D. H. , Carr M. K. V. , Wilkes J. M. 
Published: March 2009

SUMMARYThe results of experiments in which Navy beans (cv. Purley King) were precision drilled at the beginning, middle and end of May in 1972, 1973 and 1974 suggest that the optimum time to sow is mid-May when soil temperatures at 10 cm depth have reached 12–13 °C. Earlier sowing usually led to a reduced plant stand and low yields whilst in 1972 and 1974, two exceptionally cool years, later sowing resulted in lower yields following a reduction in 1000-seed weight.Despite contrasting weather conditions acceptable yields of seed were obtained in all 3 years from mid-May sowings although cool wet conditions in the autumn of 1974 curtailed drying of the seeds below 30% moisture content. Accumulated temperatures (Ontario units) were successfully used to predict stages in crop development and the data used to demarcate the areas in England most suitable for Navy-bean production.
An assessment of the influence on net herbage accumulation, herbage consumption and individual animal performance of two lengths of grazing rotation and three herbage allowances for grazing beef cattle
Authors: Bartholomew P. W. , McLauchlan W. , Chestnutt D. M. B. 
Published: March 2009

SUMMARYOver three grazing seasons a sward of perennial ryegrass, cv. Gremie, was grazed on a rotational paddock system by growing beef cattle weighing on average 185·5 kg when turned out to grass in April. Six grazing treatments were compared: grazing at 20- or 35-day intervals at each of three herbage allowances of 5·3, 4·3 and 3·3 kg grass D.M./100 kg live weight (4·0, 3·2 and 2·4 kg D.M./IOO kg live weight in the 1st year).Measurements of net herbage accumulation and herbage consumption throughout each grazing season were made by taking grass sampling clips to ground level before and after grazing. Animal live-weight gain was assessed by regression on weighings of stock taken either every 7 or every 4 days depending on regrowth interval treatment. Adjustment of allocation treatment was made by varying the weight of stock grazing on a fixed paddock area.In no year did annual net herbage organic-matter accumulation (NHA) differ significantly according to length of grazing interval. NHA showed a 4·7 % advantage for the longer interval in the first 2 years which changed to a deficit of 4·1 % in the final year of the experiment. Herbage allowance treatment produced no significant effect on NHA in any year. The interaction effect of herbage allowance and grazing interval was not significant.Herbage consumption was greater in 2 years out of three under the 20-day regrowth period than with the 35-day treatment, although average degree of defoliation was slightly greater (44·0 v. 38·4%) with the longer interval.Animal live-weight gain was significantly (P < 0·05) affected by herbage allowance in all 3 years; decreasing herbage allowance generally resulted in reduced live-weight gain. Only in 1 year was there a significant difference (P < 0·001) in live-weight gain with the different rotation length treatments.
Comparative effect of six cultivars at four rates of nitrogen on the grain yield and grain quality of spring-sown malting barley in Ireland
Authors: Conry M. J. 
Published: March 2009

SUMMARYNine experiments were conducted in the south-east of Ireland on three contrasting soils over a 3-year period (1988–90) to test the effect of six cultivars at four rates of nitrogen on the grain yield and quality (ex-farm) of spring-sown malting barley.Blenheim gave the greatest grain yield and lowest protein on average. Blenheim and Prisma had similar low protein values but Prisma gave significantly lower (P <0·05) mean grain yields than Blenheim at all three sites. Corniche gave significantly lower (P <0·05 to 0·01) grain yields than Blenheim in all nine experiments. Choice of cultivar had a considerable effect (<16%) on the yield and protein content of malting barley but season and soil type had a much larger effect (2–3 times greater).The application of increasing increments of fertilizer nitrogen generally increased grain protein and screenings significantly (P <0·05 to 0·01) in all nine experiments but it did not always give increased grain yields. The levels at which nitrogen gave significant grain yield increases depended on season and soil type. Season and soil type had a much larger effect on grain yield and quality than nitrogen rate.It was not possible to relate grain yield to specific climatic factors except on the light textured soil in 1990 when severe moisture stress in the early part of the growing season reduced grain yield by 32·5% compared with the previous 2-year average.
Planting pattern of two pigeonpea (Cajanus cajan) cultivars when intercropped with groundnut (Arachis hypogaea)
Authors: Rao L. J. , Mittra B. N. 
Published: March 2009

SUMMARYField experiments were conducted during the two monsoon seasons of 1985 and 1986 at Kharagpur, West Bengal, to investigate the effect of pigeonpea cultivars and their planting pattern on the performance of a groundnut–pigeonpea intercrop. In intercropping the crops were also sown at 100% population of their sole crops. Groundnut plant growth and development was affected by intercropping with pigeonpea and the decline in pod yield ranged from 7 to 50% of the sole crop yield. The compact, short-statured and short duration pigeonpea cultivar, ICPL87, intercepted only 50% of the incoming solar radiation as against the 70% intercepted by LRG30 at the peak vegetative stage. The significantly higher groundnut yield (48%) obtained from the intercrop with the former pigeonpea cultivar as compared to the latter justifies the belief that the performance of the groundnut was light-related. This was further confirmed when the light interception by pigeonpea was reduced by increasing the row spacing from 90 to 150 cm and there was a consequent increase in groundnut yield. The cultivar and row arrangement of pigeonpea that allowed equal utilization of light by both crops gave increased productivity.
Interpopulational and intervarietal F1 hybrids in Lolium perenne: heterosis under simulated-sward conditions
Authors: Foster C. A. 
Published: March 2009

SUMMARYThe performance of a series of intervarietal F1 hybrid populations was determined in simulated swards in a range of environmental conditions. On average the hybrids were more stable in performance than their parental varieties, but they showed no general yield advantage. Several hybrids were markedly heterotic at the higher-parental level, however. More heterosis was exhibited in high productivity conditions than in less favourable environments. A generally poor correlation between parental and F1 hybrid performance under competitive simulated-sward conditions and performance in noncompetitive spaced-plant conditions was found.
Development of the testis and epididymis of the Clun Forest ram
Authors: Colyer R. J. 
Published: March 2009

SUMMARYObservations were made on the development of the testes and epididymides of thirty-two Clun Forest ram lambs. There were no significant differences between the weights and volumes of the left and right testes and epididymides.The rate of increase in testicular and epididymal weights was linear up to a body weight of 46 lb (20·9 kg) followed subsequently by a significantly greater rate of increase at higher body weights. Similar patterns of growth occurred in relation to age, although at a given age there was a wide range of testicular and epididymal weights. There was a close relationship between the development of the testis and the epididymis at body weights greater than 46 lb (20·9 kg).There were two distinct phases in the dimensional growth of the testis. Increases in testicular length and breadth proceeded at much the same rate at testis weights of below 20 g. During the subsequent phase testicular length increased at a significantly greater rate than testis breadth.