bluuebunny/crossref_metadata_2025_split huggingface dataset:
Residual N effect of grazed white clover (Trifolium repens)/ryegrass (Lolium perenne) swards on subsequent yields of spring barley
Authors: Evans D. R. , Williams T. A. , Mason S. A. 
Published: March 2009

SUMMARYResidual nitrogen from white clover/ryegrass swards and ryegrass monocultures was quantified in terms of the barley yield obtained after ploughing the swards. Clover/ryegrass swards based on small and medium-leaved cultivars of white clover and ryegrass monocultures were grazed continuously by sheep for 3 years (1984–87) at the Welsh Plant Breeding Station, Aberystwyth, ploughed in the following spring (1988) and then sown with the spring barley cultivar Doublet. Yield of barley obtained after clover/ryegrass mixtures was 50% greater than barley harvested after ryegrass monocultures. Barley yield was 1·6 t/ha more following the white clover cultivars Gwenda and SI84 with ryegrass than following ryegrass monocultures.
The contribution of the conceptus to weight change in pregnant Merino ewes at pasture
Authors: Wheeler J. L. , Reardon T. F. , Hedges D. A. , Rocks R. L. 
Published: March 2009

SUMMARYSeventy-nine pregnant Merino ewes grazing pasture at two intensities were slaughtered in groups at intervals from 60 days after conception to post-partum. Sixty-one nonpregnant ewes were also slaughtered. The weights of various organs including uteri and their contents were recorded and the energy content of each ewe was determined.The weight of uterine contents (conceptus) increased rectilinearly with increasing foetal age to 100 days: differences between singles and twins were not significant. From 100 days to term, the relationship was also rectilinear but the slope was greater: a more rapid increase occurred with twins than with singles (P < 0·05). The nutritional difference imposed did not affect the relationship.A regression of total energy reserve on live weight (less fleece and conceptus) was established. Differences between this relationship and those established separately for non-pregnant, pregnant and post-partum ewes were not significant.The contribution of changes in conceptus weight to live-weight changes in gravid ewes is discussed.
Recovery of 15N-labelled fertilizer applied in autumn to winter wheat at four sites in eastern England
Authors: Powlson D. S. , Hart P. B. S. , Pruden G. , Jenkinson D. S. 
Published: March 2009

SUMMARYThe recovery of autumn-applied labelled fertilizer N in winter wheat and in the soil and roots was measured in five experiments on three soil types in eastern England. In four of the experiments, crop recoveries of fertilizer N ranged from 11 to 34 % in years when drainage during winter and early spring was close to, or less than, the long-term average of about 200 mm. Crop recovery was higher (42 %) at a site where the soil was heavier and winter drainage was less. Total recoveries (in crop and soil, 0–50 cm) ranged from 22 to 61 %. Fertilizer N was at least risk to leaching when there was a large soil moisture deficit at the time of application. There was a linear relationship between fertilizer N lost and drainage (but not rainfall) between the time of N application and the end of March of the following year. Autumn-applied fertilizer N increased grain yield slightly in two of the experiments and decreased it in a third.
Effects of additional lighting to provide a summer photoperiod for winter-housed pregnant ewes on plasma prolactin, udder development and lamb birthweight
Authors: Bassett J. M. 
Published: March 2009

SummaryExposure of sheep to a long-day photoperiod during late pregnancy results in greatly increased plasma prolactin concentrations in both the ewe and her fetuses compared to values in animals experiencing short days. To investigate whether the endocrine changes resulting from provision of additional lighting might also influence the pre- and postnatal growth of lambs or udder development in winter-housed ewes, two experiments were carried out. In the first, a group of housed Mule ewes, lambing in early January 1989, were given additional lighting to provide a long-day photoperiod [16 h light: 8 h dark] from 6 weeks before delivery until 6 weeks after lambing. In the second experiment, 50 housed Mule ewes were given additional light for 7 weeks before delivery at the end of March 1990. In both experiments, comparable groups of housed Mule ewes experiencing only the natural shortday winter photoperiod served as controls.In both experiments, provision of the long-day photoperiod resulted, within 3 weeks, in highly significant increases in plasma prolactin concentrations in the ewes. Plasma prolactin concentrations in the lambs from ewes experiencing the long-day photoperiod were also increased at birth (8-fold) and throughout the suckling period (3–5-fold) compared to values in short-day control lambs.Despite these large differences in plasma prolactin concentrations, there was no significant effect of photoperiod on the birth weight of the lambs in either experiment. There was also no effect of photoperiod on the postnatal growth of lambs in Experiment 1.Provision of a long-day photoperiod resulted in some increase in the rate of growth of linear measurements of udder size in ewes during both experiments, but only resulted in a significant increase in estimated udder size at delivery in ewes with twins or larger numbers of fetuses in the first experiment. In both experiments the effect of a long-day photoperiod on udder size was similar to or less than the effect of one additional fetus.The results do not suggest that prenatal photoperiodic experience results in any major alteration in somatic development in lambs at birth or during early postnatal life. They do, however, give some support to other observations that ambient photoperiod may influence pre-partum udder development in the ewe.
The presence of indigenous glauconite in soils and its effect on soil fertility:I. Soils developed on sandy drift (Barming series)
Authors: McRae S. G. 
Published: March 2009

SUMMARYThe fertility, especially potassium status, of the Barming series in East Kent was studied by laboratory and pot test procedures to determine the effect of indigenous glauconite. Half of 12 otherwise similar soils contained appreciable glauconite.Glauconite contributed positively to the potassium status of the soils, especially the B horizons (45–65 cm), and was associated with higher values of exchangeable potassium, cation exchange capacity, nitric acid soluble potassium and intensity of potassium supply as measured by ΔḠ. More potassium was taken up and more released from initially non-exchangeable sources to ryegrass from the glauconitic soils. The available magnesium content of the soils was also positively correlated with glauconite content but available phosphate was not.
Total soluble solids content in relation to cytoplasmic diversity in sorghum
Authors: Kishan A. G. , Borikar S. T. , Choudhari S. D. 
Published: March 2009

SUMMARYA study of 76 F1 hybrids involving four sources of cytoplasmic male sterility and 19 male-fertility restorers indicated great diversity among the cytoplasms for total soluble solids. The exploitation of cytoplasms other than milo is recommended for breeding programmes aimed at high total soluble solids content. Most of the Indian restorers showed significant positive general combining ability (GCA) effects, whereas exotic restorers showed negative GCA effects for total soluble solids content.
The effects of omitting or reducing pesticide and other inputs on the disease incidence and yield components of winter wheat in Northern Ireland
Authors: Easson D. L. 
Published: March 2009

SUMMARYOmitting or changing various inputs to winter wheat, cv. Norman, were studied over the 1985/86, 1986/87 and 1987/88 crop years in Northern Ireland. Control plots received chemical inputs as commonly applied to intensively managed wheat, including herbicide, two broad spectrum fungicides and chlormequat and yielded 7·5, 9·3 and 6·3 t/ha in 1986, 1987 and 1988 respectively. Other treatments included no herbicide, no chlormequat, no late fungicide, no fungicide, no sprays, half seed rate, late sowing and late sowing with no sprays. Later sowing decreased take-all in 1986 and increased yield. All other treatments either reduced yield or had no effect. Omitting fungicide gave consistent and large decreases in yield by depressing the 1000-grain weight but the importance of early and late applications varied between years. The yield reductions from omitting fungicide were generally larger than those reported elsewhere. Lodging occurred in all years but chlormequat reduced it only in 1988 and gave a yield increase only in 1986, although the number of grains/ear was increased in all years. There was no evidence of any interactions between different pesticide inputs or with seed rate or sowing date.
Modelling the effects of vernalization on progress to final leaf appearance in winter wheat
Authors: Craigon J. , Atherton J. G. , Sweet N. 
Published: March 2009

SUMMARYA simple model of vernalization, originally developed to quantify the vernalization response of fieldgrown carrots, was fitted to previously published experimental results for winter wheat cv. Norin 27. The optimum temperature for vernalization indicated by the model wasc.5·2 °C, as this induced the fastest progress to final leaf appearance, expressed as the reciprocal of number of days from sowing to final leaf. This rate decreased linearly with temperature rise or fall on either side of the optimum, extrapolating to zero at –4·8 °C (Tmin) and 26·6 °C (Tmax). When all the treatment temperatures and durations were expressed as vernalizing degree days > –4·8 °C (V °C d), there was a linear increase in post-treatment development rate with increasing vernalization up toc.275 V °C d. Ending the effective treatment duration for vernalization at the estimated time of initiation of the final leaf primordia brought many of the data points closer to the linear trend which described the rest of the data.Effects of using leaf number, which is linearly related to thermal time, instead of days as the unit of time to compensate for temperature differences in the original experiment were examined. Unvernalized plants had the potential to produce 18 leaves before flowering and therefore rates were expressed as the fraction of the potential total leaf number that each new leaf represented. All plants were assumed to have an initial development rate of 1/18 per leaf. This rate was assumed to increase linearly with time during the vernalizing treatment periods and then remain constant after treatment until the final leaf appeared. Leaf numbers reported from the original experiment were used with these assumptions to estimate the rate at the end of each treatment. The relationship between these rates and treatment temperatures was similar to that for rates based on post-treatment durations. There was an optimum temperaturec.5·5 °C andTminandTmaxof –5·1 and 18·8 °C estimated by extrapolating the decreasing linear trends to the base rate of 1/18. When plotted against V °C d calculated from these temperatures, the rates from the full data set were well represented by the model line which had been fitted to the data from just one treatment duration.
Yields of crop dry matter and nitrogen in long-term barley rotation trials at two sites in northern Syria
Authors: Jones M. J. , Singh M. 
Published: March 2009

SUMMARYTrials were established at two sites in 1982 to compare six 2-course rotations, in which barley alternated with feed legumes (pure or mixed with barley), fallow or barley, in partial factorial combination with different N and P fertilizer regimes. This paper summarizes data from the second to the seventh cropping seasons.Barley yielded most after fallow and more after legumes than after barley; but, on the basis of total dry matter production over both courses, barley-legume rotations outyielded barley-fallow and barley-barley rotations. In terms of net nitrogen offtake, which may be taken as a rough measure of feed value, barley-legumes surpassed the other rotations by c. 100% at both sites, whether the comparison was made on values obtained from plots with or without added fertilizer. Of the legumes, Lathyrus sativus was slightly more productive than Vicia saliva, and this carried over into the rotational yield of both dry matter and nitrogen. Rotations involving pure legumes were slightly more productive than those involving legume/barley mixtures.Yields of all crops and rotations varied greatly from year to year depending on rainfall. Those of the barley-fallow rotation were much less variable than those of the barley-barley rotation at the wetter site (323±103 mm), with the barley-legume rotation intermediate; but variability was much greater at the drier site (250±79 mm), with much less difference between rotations. Nevertheless, fertilizer use and rotations including legumes gave a significant yield advantage under the driest conditions.
Influence of sowing rate on dry matter yield, plant density and survival of lucerne (Medicago sativa) under dryland and irrigated conditions
Authors: Thompson D. J. , Stout D. G. 
Published: March 2009

SUMMARYLucerne (Medicago sativa L.) sowing rates were evaluated to determine how environmental conditions affect seedling establishment and plant survival. Lucerne (cv. Peace) was sown during 1988 at rates ranging from 2·8 to 11·2 kg ha-1 at one irrigated and two dryland sites (a forest and a mid-elevation grassland site) near Kamloops, British Columbia, Canada. Dry matter (DM) yield was measured for 3 years, and plants were counted to estimate seedling establishment and plant survival. Sowing year DM yield increased linearly with sowing rate at the irrigated and forest sites, but at the mid-elevation grassland site it decreased at sowing rates > 5·6 kg ha-1. In the first full-production year, DM yield levelled off at sowing rates > 8·4 kg ha-1 at the irrigated site and was not affected by sowing rate at the forest site. At the grassland site, first full-production year DM yield decreased at sowing rates > 2·8 kg ha-1. In the second full-production year, there was a linear effect of sowing rate on DM yield at the irrigated site, but it did not affect DM yield at the two dryland sites. At all sites, the percentage of seedlings that survived to the end of the second growing season decreased curvilinearly as seedling density increased. Survival was less at the irrigated site than at the dryland sites. Higher sowing rates are required at irrigated sites than at dryland sites to obtain maximum yield or a required plant population density.
Effects of recurrent selection on populations of various generations in wheat by using the Tai Gu single dominant male-sterile gene
Authors: Wang X. W. , Lap J. R. , Fan L , Zhang R. B. 
Published: March 2009

SUMMARYMass selection (MS) and bulk selection of a single character (CS) were used for the improvement of a base population, Bl, which was composed of Tai Gu male-sterile progenies of ten high protein content and four high yielding parental lines of wheat (Triticum aestivum L.), transferred by 6–10 backcrossing generations, with equal numbers of plants from each line. Backcross mass selection (BS) was used for the improvement of a second base population, B2, which was formed by Tai Gu malesterile plants of four high yielding parental lines, again with equal numbers of plants from each line. Three cycles of selection were conducted for both population Bl and B2. Direct genetic advances of sterile plants for six traits were studied. The results indicated that use of the Tai Gu male-sterile single dominant gene is effective for recurrent selection of wheat. For improvement of a single character, CS was the most effective method, of which the selective effect in the first cycle (Cl) was greater than in the second (C2) and the third cycle (C3), although multivariate analysis snowed that the CS method was not conducive to the maintenance of variation in a population. The greatest response to selection was found in C2 with the MS method. Multivariate analysis also indicated that both the MS and BS methods increased the variation in the population, but MS was found to be the best selective method as judged by the mean response over three cycles of selection.
The yield of potato plants as affected by stem canker (Rhizoctonia solani), blackleg (Erwinia carotovora subsp. atroseptica) and by neighbouring plants
Authors: Hide G. A. , Welham S. J. , Read P. J. , Ainsley A. E. 
Published: March 2009

SUMMARYPotato seed tubers inoculated with Rhizoctonia solani and Erwinia carotovora subsp. atroseptica, to induce stem canker and blackleg respectively, were planted with uninoculated seed tubers in field experiments designed to measure the effects of the diseases and of neighbouring plants on tuber yield. Gaps were also included. The plant variables total and ware (> 150 g) yields and tuber numbers were affected by disease, and also by competition from the two plants on either side in the same row (first neighbours), and increased as competition from neighbouring plants decreased. Plants adjacent to the first neighbours also influenced yields of plants with stem canker but those in adjacent rows did not have a significant effect with either disease. Both diseases altered the tuber size distributions, which were also modified by neighbouring plants. The data were used to predict total and ware yields for crops containing different proportions of healthy, diseased and missing plants.
General adaptability of potato genotypes selected in the UK for the Mediterranean region
Authors: Brown J. , Dale M. F. B. , Mackay G. R. 
Published: March 2009

SUMMARYThe recombinant genotypes generated with a potato breeding scheme cannot always be evaluated over the range of environments for which cultivar development is aimed. At the Scottish Crop Research Institute, the cultivar breeding programme aims to develop genotypes which perform well in one or more environments in the UK and/or countries around the Mediterranean basin. In each of three years (1984, 1985 and 1986) between 40 and 50 potato genotypes were selected solely on their phenotypic performance in an environment just south of Edinburgh in Scotland. These were then trialled at sites in four environments in the typical ware-producing regions of England and four environments around the Mediterranean region. Despite significant genotype x environment interactions for many traits, the superior genotypes tended to perform well over a wide range of environments.
The effect of cover crops on the establishment and yield of vining peas and on nitrate leaching
Authors: Knott C. M. 
Published: March 2009

SUMMARYExperiments were designed to assess the effects of cover crops, compared with bare stubble, on the establishment and yield of a following crop of vining peas sown in March. The cover crops of winter wheat (to simulate self-sown wheat) or winter rye, and bare stubble, were ploughed in on different dates: 1 December, 1 February or 1 March. Cover crops were destroyed with or without the use of herbicide. The three experiments in 1990/91, 1991/92 and 1992/93 were sited on a free-draining, sandy loam soil at Thornhaugh, Cambridgeshire.The cover crops, sown as soon as possible in September following a winter wheat crop, had low dry matter (DM) production and nitrogen uptake in the dry autumns of 1990 and 1991, but in the third experiment (1992/93), autumn rainfall was higher than the long-term average and DM production and N uptake were greater. Cover crops reduced the overwinter soil mineral nitrogen (SMN) content in all 3 years compared with bare stubble. However, in spring, SMN increased where cover crops had been incorporated, due to the mineralization of the cover crop residues. Rye captured more nitrogen than wheat.Vining pea vigour and maturity at quick-freezing harvest stage were not affected by cover crop, destruction date or method in any of the three seasons.On the light soil, satisfactory seedbeds were achieved after ploughing at all three timings for experiments in 1990/91 and 1992/93 and vining pea yields were not reduced by cover crops or by destruction date or method. However, delayed ploughing in February and March in the 1991/92 experiment resulted in lower vining pea yields compared with ploughing in December. This was due to poor seedbeds after late ploughing rather than cover crop, stubble treatment or method of destruction.
Response of Mediterranean grassland to phosphate and stocking rates: biomass production and botanical composition
Authors: Osman A. E. , Cocks P. S. , Russi L. , Pagnotta M. A. 
Published: March 2009

SUMMARYThree rates of phosphate (0, 25, and 60 kg/ha P2O5) were applied to phosphorus-deficient native grassland at Tel Hadya, in northern Syria, and biomass productivity, botanical composition and number of legume seeds in the soil were monitored for five seasons (1984/85–1988/89). The experiment was grazed at low (0·8 sheep/ha per year) and high (1·7 sheep/ha per year) stocking rates from the second to the fourth seasons of the experiment; in the fifth season, the low and high stocking rates were increased to 1·1 and 2·3 sheep/ha per year, respectively. The experimental site was typical of native grassland within the cereal zone of west Asia, where cropping is not possible because of shallow, stony soils and steep slopes.The results showed that annual applications of phosphorus, even as low as 25 kg P2O5/ha, alleviated the deficiency in soil P and resulted in improved pasture production, even in dry years. Legume production showed the greatest response to P, increasing by 0·3–3 times the production of the control treatments. By the fifth season, legume seed mass had increased threefold and number of seeds sixfold in the P-treated plots, compared with the first season, while in the control plots there was little change. Rain-use efficiency on the P-treated plots was more than double that of the controls by the fourth and fifth seasons.Practical application of the results depends on whether (i) legumes are as frequent in native grasslands, as a whole, as they are at Tel Hadya, (ii) the P deficiency observed at Tel Hadya is widespread, and (iii) grazing of communally owned grasslands can be controlled. It is suggested that all three criteria will often be fulfilled and, therefore, that grassland productivity in west Asia could be substantially increased. Furthermore, the results suggest that above-ground cover and soil organic matter will also increase after P application, both of which will help to reduce soil erosion and thereby increase the sustainability of livestock production in west Asia.