bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of cutting height on the productivity and composition of perennial ryegrass–white clover swards
Authors: Acuña G. H. P. , Wilman D. 
Published: March 2009

SUMMARYAll combinations of five cutting heights (2, 4, 6, 8 and 10 cm), two rates of P application (0 and 100 kg P/ha per year) and two irrigation treatments (0 and maximum soil water deficit 35 mm) were compared on field plots sown with a mixture of perennial ryegrass (Lolium perenne L.) and white clover (Trifolium repens L.) in Wales. The cutting and P treatments were applied for 4½ years (1986–90) and the irrigation treatments for 2 years (1987 and 1988). The plots were cut at 4-week intervals from April to October each year.Applied P and irrigation had only a small effect on the productivity and composition of the swards. The proportion of white clover in the sward was inversely related to the height of cutting, so that clover was almost eliminated by 3 years of 10 cm cutting. This reduction in clover content led to a 50% reduction in herbage yield. Close cutting increased the tiller density of ryegrass in May and June of the first harvest year, but this effect was subsequently reversed as clover competed more strongly with ryegrass under close cutting. The proportion of unsown species, predominantly Agrostis tenuis, was much higher in the third and fourth than in the first and second harvest years and was positively related to the height of cutting. Close cutting depleted soil K and soil water.
Winter cover crops to minimize nitrate losses in intensive lettuce production
Authors: Jackson L. E. , Wyland L. J. , Stivers L. J. 
Published: March 2009

SUMMARYA 2-year study conducted in Salinas, California in 1989–91 showed that soil nitrate (NO3–N) concentrations were reduced by cover crops during a short winter fallow period and that this practice can be compatible with year-round vegetable crop production schedules by planting and incorporating cover crops directly on the beds into which the lettuce crop will be direct seeded in the early spring. Cover crops grown the first year were oilseed radish (Raphanus sativus cv. Renova), white senf mustard (Brassica hirta cv. Martigena), white mustard (Brassica alba), Phacelia (Phacelia tanacetifolia cv. Phaci), rye (Secale cereale cv. Merced) and annual ryegrass (Lolium multiflorum). Only phacelia and Merced rye were included in the second year. In both years, all of the cover crops depleted soil NO3-N and soil moisture relative to the fallow control. Estimates of cover crop root length, based on core sampling to 60 cm soil depth, averaged 18800 m/m2 after 17 weeks of growth the first year and 12500 m/m2 after 13 weeks of growth the second year. Above-ground dry matter production averaged 449 g/m2 (12·8 g N/m2) the first year and 161 g/m2 (61 g N/m2) during a shorter growing period and under the more adverse growing conditions of the second year. Following cover crop incorporation with a rotary tiller, soil ammonium (NH4-N), N03-N and net mineralizable N (anaerobic incubation) peaked after c. 1 week, then gradually declined for 1 month. Cover-cropped plots sustained higher net mineralizable N levels than the fallow control after incorporation. Nitrate concentrations after spring rains were lower in soils left fallow during winter. The subsequent lettuce crop was not affected by cover crop treatment.
Whole body metabolism of cysteine and glutathione and their utilization in the skin of Romney sheep: consequences for wool growth
Authors: Lee J. , Harris P. M. , Sinclair B. R. , Treloar B. P. 
Published: March 2009

SUMMARYInfusion of [35S]-labelled cysteine into the jugular of Romney sheep of different ages was used to estimate the extent of combined cysteine and cystine (cyst(e)ine) and glutathione (GSH) interchange in various tissues, including skin, and to measure whole body irreversible loss rates (1LR) for cyst(e)ine. The studies were undertaken at Palmerston North, New Zealand during 1990 and 1991.Reverse phase HPLC using a fluorigenic reagent, 7-fluoro-2,1,3-benzoxadiazole-4-sulphonate (SBD-F) was used for the simultaneous determination of thiols (cysteine and GSH) in whole blood (bound and free fractions), liver, kidney, small intestine, muscle, pancreas and skin. The appearance of [35S]-label in thiol compounds and their oxidation products was determined by ion-exchange HPLC. Specific radioactivities (SRA) for cyst(e)ine and GSH derived from this data showed equivalence for cysteine and GSH SRAs in all tissues, except for whole blood, indicating rapid withintissue interconversion between these thiols. In whole blood, however, the very low SRA for GSH (< 4 DPM/nmol) compared to cyst(e)ine (250 DPM/nmol) indicated markedly slower or negligible exchange with red blood cell GSH, and hence little inter-organ transport of [35S]-label as GSH.Close infusion of [35S] cysteine into a defined patch of skin and collection of the venous outflow permitted directin vivomeasurement of the proportional uptake of cysteine by the skin. Results indicated considerable variation in the uptake of cysteineper se(20–40%) but no, or very little, oxidation of cysteine in the skin and no net export of GSH.The combination of whole body, tissue and skin specific studies of [35S]-labelled cysteine metabolism quantitatively confirmed the very high proportion of circulating cyst(e)ine in sheep which is directed to skin and wool protein synthesis alone, and highlighted those aspects of this metabolism which are of most importance to wool production.
Wool follicles initiate, develop and produce wool fibres in ovine fetal skin grafts
Authors: McCloghry C. E. , Hollis D. E. , Raphael K. A. , Marshall R. C. , Foldes A. , Kennedy J. P. , Wynn P. C. 
Published: March 2009

SUMMARYResearch into the mechanisms that control the initiation and development of wool follicles has been severely hampered by the inaccessibility of fetal skin in utero. The aims of this study were to determine whether ovine fetal skin, when grafted onto the athymic nude mouse (nu/nu), could be maintained outside the uterine environment and, if so, whether it would retain its ability to initiate and develop wool follicles capable of producing wool fibres.Skin was removed from the mid-side region of ovine fetuses on days 45, 55, 65, 75, 85 and 95 of gestation, and transferred to graft beds prepared on anaesthetized nude mice. After developing for 20 days on the recipients, the grafts were excised for histological examination. Control ovine fetal skin was also obtained at the above times and from fetuses on days 105 and 115, and similarly processed for histological examination.Fetal skin at all ages was successfully grafted onto nude mice; 90% of all grafts were accepted and maintained by the recipients. Follicle initiation and/or development occurred in all grafts, including those formed from day 45 fetal skin, collected and grafted prior to follicle initiation in vivo. The number of follicles in grafted skin was reduced compared to that in control fetal skin of equivalent age; however, follicle development was generally accelerated. Follicle initiation and development occurred predominantly in the peripheral zone of the grafts. Some of the follicles present in the skin at grafting were lost due to the grafting procedure, while others continued to develop and produce wool fibres. Follicle development varied considerably between grafts. All grafted skin exhibited premature loss of the periderm layer and cornification of the epidermis, probably in response to the exposure of the skin surface to the atmosphere. There was a notable absence of both arrector pili muscles and sweat glands associated with graft follicles, and a retardation of sebaceous gland development.The grafting technique developed in this study has enabled ovine fetal skin to be maintained outside the uterine environment for extended periods of time and may provide an improved means for future investigation of wool follicle initiation and development.
Experiments with upland rice in southern Belize: fertilizer application, weed control, plant spacing, sowing rate and variety
Authors: Johnson D. E. , Lee P. G. , Wilman D. 
Published: March 2009

SUMMARYAgronomic research was carried out on upland rice in Toledo District, Belize, in 1979–86, with the objective of improving returns from the traditional system of shifting cultivation and of examining the potential for reducing the demand for new land by cropping for more than one season. The rice was grown in the wet season on land cleared from forest by slash and burn, using a traditional planting technique, placing seed in holes made with a pointed stick.In a series of fertilizer experiments, in which rice was grown for up to 7 consecutive years, urea and triple superphosphate both increased grain yield, whereas muriate of potash had no effect. Mean yield in the fifth year was 85 % of that in the first. Urea and triple superphosphate both increased the number of full grains/panicle.A slash and mulch weed control treatment before sowing resulted in low yields of grain in the third year; yield after the use of propanil and 2,4-D (after sowing) was, on average, 77% of the yield after hand weeding; omitting weed control after sowing led to very low yields, particularly in the second and third years.In the varieties Bluebonnet and C22, grain yield was increased by reducing the distance between stations, particularly where 6, rather than 15, seeds were sown per station. Reducing the distance between stations increased the leaf area index during crop development and the number of panicles/m2, which more than counterbalanced reductions in the number and area of leaf blades per plant, the number of panicles per plant and the number of full grains per panicle. However, the yield/kg of seed sown and per hour spent planting was greatest at the widest spacing. C22 produced more panicles per plant and a greater weight of grain per plant and per hectare than Bluebonnet.It was concluded that returns from the traditional system can be improved and the demand for new land reduced.
Performance and yield of sunflower (Helianthus annuus) cultivars under rainfed and irrigated conditions in Sudan
Authors: Amir H. A. , Khalifa F. M. 
Published: March 2009

SUMMARYA trial of open-pollinated (OP) cultivars and hybrids of different origins was conducted in 1986–1988 at two sites in the central clay plains of Sudan, rainfed at one site and under supplementary irrigation at the other. Throughout this study, the patterns of growth of the OP cultivars differed greatly from those of the hybrids, despite differences amongst cultivars within each group. Differences in seed yield between OP cultivars and hybrids under irrigation were not significant; but, under rainfed conditions, the hybrids gave higher yields than the OP cultivars. Partitioning efficiency (PE; reproductive mass: total biomass) increased more rapidly during flowering and seed filling in the hybrids than in the OP cultivars; differences in PE between the two groups were significant. The higher leaf area index, leaf area duration and crop growth rate of the OP cultivars were compensated to some extent by the higher PE and leaf efficiency values of the hybrids, resulting in similar seed yields of all cultivars under irrigation. Overall, irrigation increased seed yield by 0·6–1·9 t/ha and increased oil content by 8–15%.
Urinary excretion of allantoin and allantoin precursors by sheep after different rates of purine infusion into the duodenum
Authors: Balcells J. , Guada J. A. , Castrillo C. , Gasa J. 
Published: March 2009

SUMMARYTwo experiments were carried out to determine endogenous losses and the response of urinary purine derivatives to increased duodenal inputs of purine bases. Four ewes each fitted with a re-entrant cannula at the proximal duodenum, and conventionally fed, were subjected to full replacement of duodenal digesta followed by the administration of a solution either free of purines (Expt 1) or enriched with increasing amounts of purines, to supply 0·48–21·27 mmol/animal per day (Expt 2). Basal daily urinary excretions of allantoin, uric acid, hypoxanthine and xanthine were 11·5 ± 0·94, 9·9 ± 0·67, 6·9 ± 0·46 and 1·2 ±0·16 mg/kg W0·75. Allantoin was the only purine derivative which increased in response to incremental inputs of duodenal purines. The relationship between allantoin excretion and infused purines showed a urinary recovery of 0·8 for purines infused at > 220 μmol/kg W0·76. Lower rates of infusion did not alter allantoin excretion. The results show urinary allantoin to be a useful index to estimate duodenal input of purines when animals are fed close to or above their energy maintenance requirements.
Vigour differences in brassica seed and their significance to emergence and seedling variability
Authors: Powell A. A. , Thornton J. M. , Mitchell J. A. 
Published: March 2009

SUMMARYSeeds of the Brussels sprout cultivar Asmer Aries having low vigour as a result of ageing emerged more slowly when sown in module trays and had slightly lower final emergences than seeds which had not undergone ageing and were of high vigour. Low seed vigour also resulted in the production of seedlings which were shorter and more variable in height at the first-leaf stage. Once the seedlings reached the transplanting stage there was greater variability in the fresh and dry weights of seedlings produced from seeds having low vigour, although the mean seedling weights differed little from those produced by high-vigour seeds. Similar observations were made for samples of commercial seed of cauliflower, Brussels sprouts, Dutch cabbage, red cabbage and calabrese provided by vegetable transplant propagators and in use in 1988. Low-vigour seeds again emerged more slowly with low final emergence and produced smaller and more-variable seedlings. The implications of these observations for the production of vegetable seedlings for transplanting are discussed.
Comparative energy and protein utilization in kids and lambs
Authors: Alam M. R. , Poppi D. P. , Sykes A. R. 
Published: March 2009

SUMMARYTwenty-eight male castrate kids and 28 male castrate lambs were assigned to a comparative slaughter experiment to compare energy and protein utilization. The experiment was conducted from January to March at Lincoln, New Zealand. Ten animals of each species comprised the initial slaughter group while the remaining 18 animals were randomly allocated to five feeding regimes. Animals were offered high-quality meadow hay for 13 weeks and then slaughtered. The energy retained in the body was regressed against metabolizable energy intake (MEI) to obtain estimates of maintenance energy requirement (MEm) and efficiency of energy utilization for growth (kg).Kids tended to have a higher MEm (0·44 v. 0·37 MJ ME/kg W0·75 per day in kids and lambs, respectively) and a higher kg (0·28v. 0·22) though these differences were not significant. There was no difference between the species in the composition of gain of the fleece or hair-free body with a protein energy to gross energy ratio in the gain of 0·20. The fleece or hair-free body composition was similar for both species (initial 0·51v. 0·48; final 0·36 v. 0·32; protein energy:gross energy, kids and lambs, respectively). Overall, the values for kg in both species were low and could not be explained solely by the composition of the gain.The efficiency of use of apparently absorbed amino acid (AA) for fleece or hair-free body protein deposition was higher for kids (0·52 v. 0·29) and, when the fleece or hair was included, the value increased markedly for lambs (0·50 v. 0·41, kids v. lambs, respectively). The protein energy apparently absorbed in the small intestine/MEI was not high or different between species (mean 0·18). The efficiency values for both species are low and not explained by the supply of protein relative to energy, which was not high.It was concluded that, with high-quality forage used to promote live weight gain, there was little difference between kids and lambs in the utilization of forage energy, and that the efficiency of utilization of absorbed protein for protein deposition was lower than expected in both species.
Interactions between applications of gypsum and zinc sulphate on the yield and chemical composition of rice grown on an alkali soil
Authors: Singh M. V. , Chhabra R. , Abrol I. P. 
Published: March 2009

SummaryA field experiment on an alkali soil (ESP 94) studied the effect of gypsum applied at 0, 2·5, 5 and 10t/ha and zinc sulphate applied at 0, 10, 20, 30 and 40 kg/ha on the growth, yield and chemical composition of rice. The effects of gypsum and zinc applications were additive. Optimum response of rice was to 10 kg zinc sulphate/ha at the 5 and 10 t/ha gypsum levels. At low levels of gypsum, plant growth was poor owing to toxicity of Na and/or deficiency of Ca, and higher levels of zinc sulphate gave a yield response. Zinc-deficient plants had significantly lower Zn concentration but higher concentrations of Fe, Mn, Cu, Ca and Mg than the healthy plants. Application of gypsum decreased the concentration of Na, Fe and Zn in rice plants and increased the concentration of Ca, K, Mn and Cu. in plots not treated with gypsum, the Zn concentration of plants was higher but grain yield was lower than that of gypsum-treated plots. Application of zinc increased the DTPA-extractable Zn but gypsum decreased the soil sodicity and DTPA-extractable Zn in alkali soils.
Measurement on slaughter weight, side weight, carcass joints and their association with carcass composition of two types of Sudan Desert sheep
Authors: Karim A. I. A. El , Owen J. B. , Whitaker C. J. 
Published: March 2009

SummaryRelationships between slaughter weight, side weight, linear carcass measurements, carcass joints, carcass composition, and prediction equations for carcass composition have been established for Sudan Desert lambs.Of the carcass linear measurements, chest depth had the highest coefficient of correlation with slaughter weight (r = 0·62) and side weight (r = 0·64) followed by the circumference of the buttocks with correlation coefficients of 0·49 and 0·63 respectively.Correlation coefficients between percentage tissue in the side and percentage tissue in the different joints showed that percentage lean in middle neck and shoulder, leg and best end, in this order were strongly associated with percentage lean in side (P < 0·001). Percentage bone in middle neck and shoulder, leg and loin was positively associated with percentage bone in the side. Fat in leg and best end neck gave a significant correlation (P < 0·001) with percentage fat in the side.Trivariate regression equations for prediction of carcass composition were calculated for both sexes in the two breed types and the best end neck joint was found to be the best practical predictor with R2a (adjusted coefficient of determination) of 0·81–0·98 for lean prediction and 0·70–0·92 for fat prediction.
Response of white clover and grass to applications of potassium and nitrogen on a potassium-deficient hill soil
Authors: Simpson D. , Wilman D. , Adams W. A. 
Published: March 2009

SummaryAll combinations of four levels of potassium and two of nitrogen were applied in each of 2 years to a hill sward on a brown podzolic soil with an 8 cm peaty surface horizon anda very low level of extractable K. The sward had been surface-sown 11 years before with white clover (Trifolium repens L.) and perennial ryegrass (Lolium perenne L.). During the course of the experiment, harvesting was by cutting, with an average interval between cuts of 5 weeks. The previous management had been sheep grazing.The proportion of clover in harvested herbage was increased by applied K and reduced by applied N. The clover grew strongly in the 1st year of cutting management where K, but no N, was applied, but there was much less clover in the 2nd year on all plots. The concentration of K in both clover and grass was greatly increased by applied K, but only the clover responded strongly in terms of extra herbage produced. This suggests that grass growth was N-limited, whereas the clover had sufficient N from symbiotic fixation.Applied K increased the size and weight of clover leaves, the rate of extension of the stolon main axis, and the number and length of stolon branches, but did not affect the rate of emergence of leaves on the stolon main axis. Applied N had a generally negative effect on the aspects of clover growth and morphology which were measured. The length and weight per ryegrass leaf blade were generally slightly increased by both applied K and applied N.
The growth and development of Corchorus olitorius (L.) grown alone and intercropped with tomato (Lycopersicon esculentum (Mill.))
Authors: Ojeifo I. M. , Lucas E. O. 
Published: March 2009

SummaryTwo experiments were conducted on two varieties of Corchorus olitorius(‘NHCo 6’ and ‘NHCo 7’). The first one was on the effect of density of planting on their growth and development whilst the second was on the best planting ratio for Corchorus-tomato intercropping.There was no significant difference in morphological characters of the two varieties. The maximum value of leaf area index for the two varieties was around 3. Maximum marketable and edible yields were obtained for the two varieties at 30 × 5 cm (666600 plants/ha) and the best time for harvesting was 44 days after sowing.The best planting ratio for Corchorus-tomato intercrop was 2 rows of Corchorus and 1 row of tomato for maximum edible yield of Corchorus but for maximum economic returns, the best ratio was 1 row of Corchorus to 2 rows of tomato.
The effect of a slant-legged subsoiler on soil compaction and the growth of direct-drilled winter wheat
Authors: Hipps N. A. , Hodgson D. R. 
Published: March 2009

SummaryThe effect of a slant-legged subsoiler (Trade name, ‘Paraplow’) on the growth of two crops of winter wheat following an intensively grazed grass-clover ley was investigated in 1981–2 and 1982–3. The treatments for the first crop were direct drilling, loosening the soil by shallow cultivation before drilling, loosening by ‘Paraplow’, and a combination of ‘Paraplow’ and shallow cultivation. For the second crop these treatments were repeated and a fifth added, loosening by ‘Paraplow’ after drilling. Seed was sown with a triple disk direct drill and all treatments received the same quantity of fertilizer.Soil compaction was measured with a cone penetrometer in the autumn of 1982 and spring 1983; root axes were counted and dry-matter weights of shoot, grain yield and components of yield obtained.Loosening soil by ‘Paraplow’ did not increase significantly the number of roots nor was the uptake of water by the crop in dry periods affected, even though soil strength, measured as cone resistance, was considerably reduced.Shallow cultivation increased grain yield in the first wheat by 0·34 t/ha (P< 0·05) but had no effect on the second wheat. The ‘Paraplow’ did not increase yield of the first crop but the mean response of 0·65 t/ha in the second crop was significant (P < 0·05). Using the ‘Paraplow’ before or after drilling gave similar yields. Increases in yield were produced by more grains per unit area, not increased 1000-grain weights.It is concluded that the apparently compacted soil did not restrict the growth of wheat and that the beneficial effect of the ‘Paraplow’ in the second crop was probably due to better drainage in the wet spring.