bluuebunny/crossref_metadata_2025_split huggingface dataset:
The effect of nitrogen and length of primary growth period on yield of leaf and stem components of perennial ryegrass
Authors: BARTHOLOMEW P. W. , CHESTNUTT D. M. B. 
Published: April 2006

AbstractThe influence of length of first growth period of the season and level of nitrogen application on yields of leaf and stem components of perennial ryegrass was estimated. Three primary growth periods of 21, 42 and 70 d were used in combination with nitrogen treatments allowing 0, 1.43, 2.86 and 429 kg N per ha per d of growth applied as a single dressing at the beginning of the growth period. Increases in level of nitrogen application and in growth time produced higher yields of both components, but particularly of stem. Mean leaf yield per tiller reached a maximum with a 42‐d growth period.Whilst the ratio of leaf: stem was altered markedly by longer growth periods it was apparently unaffected by nitrogen application.
The assessment of persistence and its application to the evaluation of mid‐season and late perennial ryegrass cultivars
Authors: CAMLIN M. S. , STEWART R. H. 
Published: April 2006

AbstractPersistence assessments on eight mid‐season and ten late cultivars of perennial ryegrass were made at the end of the second, third and fourth years after sowing. Botanical analyses were carried out on the herbage from plots cut in the fourth year and these results related lo the different persistence assessments. It was found that persistence assessments carried out at the end of the second year enabled predictions to be made about botanical composition of cuitivars in the fourth year. Little extra precision was gained by delaying assessment until the third or fourth years as the ranking order of cultivars with respect to persistence remained largely unchanged. All persistence assessments were positively correlated with yields of sown cultivars and negatively correlated with yields of unsown herbage species in the fourth year. However, only low correlation coefficients were obtained between persistence assessments and the total yield of sown cultivar and unsown species in the fourth year, due to yield substitution between these two components.In swards sown as monocultures low persistence in a cultivar is considered to be a lack of perenniality and tiller regeneration rather than poor competitive ability against volunteer species though in mixed swards competitive ability per se will have considerable influence upon the changes in botanical composition under different managements. Persistence and yield capacity are seen, however, as distinct characteristics of a cuitivar and long‐term yield potential is a joint function of these characteristics.
Effects of season and level of grazing on the utilization of heather by sheep 1. Responses of the sward
Authors: GRANT SHEILA A. , BARTHRAM G. T. , LAMB W. I. C. , MILNE J. A. 
Published: April 2006

AbstractThe effects of sheep grazing on the development and production of heather swards were studied over a period of 3 years in an experiment in which sheep numbers were adjusted to remove 0, 40% or 80% by weight of the current season's shoots in summer and in autumn.The number of shoots grazed increased with the level of grazing but not in direct proportion. The length of shoot grazed was greater at the 80% level of grazing. Heavy autumn grazing was associated with frequent uprooting and breaking off of shoots and with a high incidence of shoots grazed down to the previous season's wood. The siting of new season's shoots was influenced by the amount of shoot length grazed in the previous season. Grazing behaviour of sheep within a plot was affected by variation in heather cover with the sheep showing a tendency to graze near bare areas.After 3 years of grazing, standing crop was reduced by both levels of grazing whether in summer or autumn. New shoot production was unaffected on plots which had had the 40% level of shoot removal but was reduced by half on plots which had had the 80% level of shoot removal whether in summer or autumn.A clipping experiment was also carried out where 0, 40% or 80% of the length of current shoots was removed in May, early July and Septeinber. Standing crop was unaffected by May clipping but was reduced on plants with a history of 80% shoot removal in July or September. New shoot production was only reduced on clipped plants which had been subjected to 80% removal in September.The role of overwintering green shoots and carbohydrate reserves in the support of new shoot growth was considered.The implications of the results in relation to heather management are discussed.
A comparison of methods of recovering oesophageal extrusa from grazing sheep
Authors: HAMILTON B. A. , DENNEY G. D. 
Published: April 2006

AbstractExtrusa samples were collected from two groups of oesophageally fistulated sheep grazing together. One group had foam plastic oesophageal plugs fitted below the fistula to assist in the complete collection of extrusa; the second group grazed without plugs. The extrusa were collected in four periods chosen to cover as wide a range of herbage conditions as possible varying from herbage with a high proportion of green leaves to predominantly dry material with a high proportion of dead leaves and stems. The plant components of the extrusa were determined and there was no evidence that stems or any other plant component preferentially by‐pass the fistula in grazing sheep. It was concluded that it is not necessary to insert foam plastic plugs in the oesophagus of grazing sheep to obtain representative samples of ingested herbage.
Effects of season and level of grazing on the utilization of heather by sheep. 2. Diet selection and intake
Authors: MILNE J. A. , BAGLEY L. , GRANT SHEILA A. 
Published: April 2006

AbstractThe effect of level of removal of current season's shoots of heather (0,40 and 80% of the dry matter of the shoots) in the summer and autumn on the intake and diet selection by grazing Scottish Blackface wether sheep was examined in an experiment conducted over two years in which all combinations of level and season of grazing were provided. The treatment plots were grazed for 5 weeks at any one time and measurements made of intake and diet selection in weeks 2 and 5.In both the summer and autumn grazing periods level of removal in week 2 had little effect on the quality of the diet selected. In week 5, digestibility of organic matter was higher for the 40% than the 80% level of removal in the summer (0·543 vs 0·508) and particularly in the autumn (0·503 vs 0·449). Digestibility of the diet selected was higher in week 2 than in week 5 in both the summer (0·555 vs 0·525) and in the autumn (0·511 vs 0·476). Mechanisms of diet selection are discussed.In the summer grazing period only small differences existed in intake of organic matter between levels of removal but in the autumn intakes were higher at the 40% than the 80% level of removal. In a clipping experiment in which 0, 40 or 80% of the length of current season's shoots was removed in May, July and September in 3 consecutive years the nitrogen content of clippings in May and July was higher and the cell wall constituent lower at the 40% level in comparison to the 80% level of removal. Higher levels of removal at the previous clipping increased the nitrogen content of the clippings in May, July and September and reduced the cell wall constituent content in September.
The influence of climatic factors on physiological development in perennial ryegrass
Authors: KEATINGE J. D. H , CAMLIN M. S. , STEWART R. H. 
Published: April 2006

AbstractDates of initiation of reproductive development and of ear emergence were determined for four cultivars of perennial ryegrass (Lolium perenne) representing a range in maturity from early to late in a single trial in 1977. The influence of climatic factors upon the reproductive development was investigated and it was found that, while day‐length largely influenced the dates of initiation, subsequent growth and development towards ear emergence was influenced mainly by temperature. The data indicated that cultivars may have similar requirements in terms of accumulated temperature between the physiological growth stage of initiation and the agronomically significant growth stage of ear emergence. The possibility of achieving greater accuracy in forecasting ear emergence dates by relating meteorological data to the physiological development of the individual cultivars is suggested.
Regrowth of ryegrass swards subject to different cutting regimes and stocking densities
Authors: KING J. , LAMB W. I. C. , McGregor M. T. 
Published: April 2006

AbstractA cutting experiment was carried out on a sward of S23 perennial ryegrass to study the effect of different defoliation regimes on regrowth and the factors affecting regrowth. The defoliation frequencies and intensities encompassed the range commonly found on continuously stocked pastures. The defoliation regimes produced swards of contrasting growth form with regrowth characteristics which differed in respect of senescence loss, fall in water‐soluble carbohydrate concentration, residual leaf area index, photosynthesis per unit leaf area index and photosynthesis per unit area of land. Regrowth was most closely related to the latter. These results were used to interpret data for net canopy photosynthesis of continuously grazed pastures.
Effects of grazing by lambs in autumn on a red clover‐perennial ryegrass sward
Authors: LAIDLAW A. S. 
Published: April 2006

AbstractIn 1976, 1977 and 1978 a red clover‐perennial ryegrass sward was cut twice for silage, and in the autumn of 1976 and 1977 it was either grazed at low and high stocking rates, i.e. seventeen and thirty‐four lambs per ha respectively, or was cut with a forage harvester. The effects of grazing on yield in the following year were examined.Herbage growth in the grazing period was slow and did not differ significantly between the treatments. The yield of silage dry matter taken in May and July was highest in ungrazed plots (9·8 and 8·1 t ha‐1 in 1977 and 1978 respectively) and lowest in plots stocked at the high rate (5·9 and 5·7 t ha‐1 in 1977 and 1978 respectively). The aftermath yield for grazing in 1977 was slightly but significantly greater on treatments grazed in the previous year compared with ungrazed treatments.Red clover content decreased markedly during grazing, the high stocking rate treatment containing 2·4% clover and the ungrazed treatment 57·3% clover. The high stocking rate treatment also had the lowest red clover content in the first silage cut. Red clover content in grazed plots increased to a level similar to that in ungrazed plots by the start of the grazing period in the subsequent harvest year.Animal performance was higher at the low than at the high stocking rate but herbage consumption per head did not differ significantly between the two grazing treatments.Possible reasons for the adverse effect of grazing on the red clover are defoliation and treading. It is concluded that such experiments can form the basis of an economic assessment of red clover and help the farmer decide whether or not he should integrate the crop into his system.
The effect of some pre‐treatments on proteolysis during the ensiling of herbage
Authors: CARPINTERO C. M. , HENDERSON A. R. , McDONALD P. 
Published: April 2006

AbstractTwo experiments were carried out to examine the nitrogenous changes occurring in herbage during harvesting and ensiling. In the first, ryegrass‐clover was wilted rapidly in the laboratory (6 h) and in the field under good (48 h) and poor (48 h and 144 h) weather conditions. Protein breakdown and ammonia formation were negligible in herbage wilted rapidly and it was only when the crop was exposed to a prolonged wilt in humid conditions that appreciable proteolysis occurred. In the second experiment ryegrass‐clover was ensiled in laboratory silos after treatment with varying levels of formic and sulphuric acids. An additional treatment included herbage inoculated with a mixture of lactic acid bacteria and glucose. The silos were opened after 4 and 50 d and samples were analysed for protein‐N, ammonia‐N, water‐soluble carbohydrates and organic acids. There was a high negative correlation between level of addition of either acid and the degree of proteolysis and deamination. Even at the highest levels of formic acid (7·7 g per kg) and sulphuric acid (4·0 g per kg) additions, however, about 45% of the original herbage protein was degraded after 50 d in the silo. The inoculum treatment was also effective in reducing proteolysis, the effect after 50 d being comparable with formic acid applied at a rate of 4·1 g per kg.
The effects of density, date of inflorescence emergence, date of harvesting and temperature upon seed quality in tetraploid hybrid ryegrasses
Authors: AKPAN E. E. J. , BEAN E. W. 
Published: April 2006

AbstractThousand‐seed weight, germination and seedling dry weight were measured in some tetraploid hybrid ryegrasses to study variations in seed quality. In cv. Sabrina, seed from spaced plants had a higher 1000‐seed weight and seedling dry weight, and a slower germination rate than seed from narrow drills. Seed from later emerging groups of inflorescences had a low 1000‐seed weight and seedling dry weight, but a high germination rate. Seeds of cv. Sabrina, Leri and Augusta harvested at between 10 and 25 d after peak anthesis had low 1000‐seed weights, low germination rates and low seedling dry weights. Air temperatures between inflorescence emergence and seed maturity also affected seed quality; an increase in temperature from a 15°/10°C regime to a constant 25°C environment reduced 1000‐seed weight and seedling dry weight, but increased germination rate. It is concluded that year‐to‐year variation in seed characters will occur because of temperature and other climatic changes, but seed quality can also be influenced by the time at which the seed is harvested. If combine harvesting is carried out at a moisture concentration of about 400 g kg‐1 (≡40%) then maximum yields of seed of a high quality should be obtained.
Herbage measurement in situ by electronics. 3. Calibration, characterization and field application of the earth‐plate forage capacitance meter: a prototype
Authors: TOLEDO J. M. , BURNS J. C. , LUCAS H. L. , ANGELONE A. 
Published: April 2006

AbstractCalibration of an earth‐plate forage capacitance meter was conducted on pure stands of Festuca arundinacea Schreb., Medicago sativa L., Cynodon dactylon (L.) Pers. and Trifolium repens L. and a mixture of Trifolium repens and Dactylis glomerata L. Dry weight (DW) prediction equations were developed using the instrument capacitance reading modified by visual estimates of height, stand density and species percentage. In general, meter readings (MR) correlated better with DW than with fresh weight or weight of water and especially when the area harvested exceeded 0·537 m2. Correlation between MR and DW improved with increasing top plate area and with decreasing distance between the top plate (suspended sheet of aluminium) and the earth‐plate ground. The use of a plastic shield to suppress the forage to a uniform height caused a reduction in the correlation between MR and DW.The use of MR to predict DW from selected settings, their linear and curvilinear relationships and several auxiliary observations gave results with R2 values ranging from 0·94 to 0·99, depending on species and mixture.
The effect of a cereal supplement during early lactation on the performance and intake of ewes grazing perennial ryegrass at three stocking rates
Authors: YOUNG N. E. , NEWTON J. E. , ORR R. J. 
Published: April 2006

AbstractA comparison was made of the effect of a cereal supplement during early lactation on the performance and intake of ewes suckling two lambs while rotationally grazing pasture at stocking rates of 20, 17 or 14 ewes per ha. Supplement (S) at the high (H) and medium (M) stocking rates resulted in higher organic matter (OM) intakes (grass + supplement) of 2040 and 2500 g d‐1 respectively, compared with the herbage OM intakes of unsupplemented (U) ewes of 1750 and 2040 g d‐1 respectively. At the low (L) stocking rate the total OM intake of supplemented ewes and the herbage OM intake of unsupplemented ewes was similar at 2250 and 2210 g d‐1 respectively.Lamb growth rate (g d‐1) to 12 weeks of age was significantly lower on treatment UH (229) compared with those on UM (253) and UL (262). Growth rates on S treatments were similar (SH 248; SM 261; SL 272) and there were no significant differences between S and U within stocking rates. Unsupplemented ewes lost significantly more weight during the period of intake measurement than those receiving supplement. The speed of rotation was faster where supplement was not fed at the medium and high stocking rates and herbage accumulation under UH was less than under SH. Only at the high stocking rate did feeding a supplement give a higher financial output.
An improved electronic capacitance meter for estimating herbage mass
Authors: VICKERY P. J. , BENNETT I. L. , NICOL G. R. 
Published: April 2006

AbstractAn improved electronic capacitance pasture meter is described, and data on its calibration and use in a grazing trial are presented. The instrument is light (1·4 kg) and portable, and uses integrated circuits to record the readings from a number of sampled sites. It has a digital display and can be constructed for a modest cost. The meter is mainly responsive to the surface area of the herbage and hence it is less sensitive to variations in moisture content of the pasture than previous meters. Thus it can be calibrated to measure the mass of herbage dry matter to ground level and reduces the need to collect and dry herbage samples for frequent recalibration of the instrument.
Effect of spring grazing on the yield and quality of perennial ryegrass (Lolium perenne) and cocksfoot (Dactylis glomerata) cut for conservation
Authors: SWIFT G. , EDWARDS R. A. 
Published: April 2006

AbstractTwo early perennial ryegrass varieties (Cropper and RvP Hay Pasture), an intermediate perennial ryegrass (Talbot) and an early cocksfoot (Roskilde) were grazed fortnightly by sheep, mown to simulate grazing or left undefoliated from January to May. The effects of spring management on ear emergence, D‐value (in vitro) and conservation yields were assessed in each of the 2 years 1976 and 1977. Grazing and mowing had a similar effect on date of first (5%) and 50% ear emergence of the ryegrass varieties; the effect was an average delay of 2 d in both stages of growth over the 2 years. Defoliations significantly (P<0·001) delayed the fall in D‐value with no significant differences between grazing and mowing in the ryegrass varieties, nor in cocksfoot in 1977. The occurrence of a D‐value of 67 was delayed by between 3 and 8 d for the ryegrasses and 9 and 11 d for the cocksfoot. The early ryegrasses produced stemmy regrowths and fell to 67 D‐value about 4 weeks after the final defoliations in 1976 and after 5–6 weeks in 1977. The fall in D‐value took 7–14 d longer in the intermediate ryegrass. Yields were significantly (P < 0·001) reduced by grazing and mowing, particularly in 1976. The DM yield reductions in mid June averaged 25% for the ryegrasses and 41% for the cocksfoot.The results indicate that either first or 50% ear emergence may be used to indicate times when a D‐value of 67 will be reached in grazed or ungrazed swards but further work is required to determine the effect of weather conditions on the accuracy of this prediction. An early fall in D‐value of early perennials after spring grazing, and a marked reduction in yield of cocksfoot, suggests that these grasses should be used sparingly where spring grazing of fields set aside for conservation is a feature of the farming system.
Further experiences of beef production on permanent pasture in 1976–78
Authors: ELLIOTT J. G. , DALE R. J. 
Published: April 2006

AbstractBetween 1976 and 1978 a further 154 beef animals were grazed in separate groups on Alberts and Far field at Begbroke Hill, the former being a paddock system and the latter being set‐stocked. Each year part of Alberts received complete fertilizer (147–180 kg ha‐1 N) and part did not. All of Far field received complete fertilizer (140–190 kg ha‐1 N). Drought caused a reduction in output in 1976, but in 1977 and 1978 total production of live weight was 9·07 and 8·74 t respectively from 11·65 ha grassland. Calculations of corrected outputs show that maxima of 829 kg ha‐1 in Alberts and 908 kg ha‐1 in Far field were achieved from fertilized grass. The highest output in Alberts represented 929 livestock unit grazing days per ha or 87·9 GJ ha‐1 in 1978.
Copper and other minerals in herbage species and varieties on copper‐deficient soils
Authors: FORBES J. C. , GELMAN A. L. 
Published: April 2006

AbstractThe mineral composition of Lolium perenne, Dactylis glomerata, Trifolium repens, Lotus corniculatus and six non‐leguminous broadleaved herbs was determined at two sites on copper‐deficient soils with and without soil‐applied copper sulphate at 2 kg Cu ha‐1. D. glomerata was richer than Lolium perenne in P, Mn and Cu, and T. repens was richer than either grass species in Ca, P, Mg and Cu. D. glomerata cultivars differed in Ca, P, Na and Mg concentrations, and L. perenne cultivars in Ca concentration. Lotus corniculatus contained less Ca, P, Na and Mn but more Zn than T. repens. Achillea millefolium was rich in K, Cichorium intybus in K, Mg and Zn, Petroselinum crispum in Na and Zn, Rumex acetosa in K, P, Mg and Zn and Taraxacum officinale in Na, Mg and Zn. Rumex was low in Na and Plantago lanceolata in Na and Mn. None of these herbs was richer than T. repens in Cu. Copper sulphate application raised the Cu concentration of the herbage only slightly, species or varieties differing little in their response to applied Cu. It is concluded that adjustment of botanical composition, with or without copper sulphate application, will not help to prevent hypocupraemia in grazing stock.
Herbicides and seed production by two perennial ryegrass cultivars grown in weed‐free conditions
Authors: OSWALD A. K. 
Published: April 2006

AbstractThe effects of five herbicides on seed yield and viability of perennial ryegrass cv. S24 were tested at two sites. Benzoylprop‐ethyl, chlorfenpropmethyl, difenzoquat, ethofumesate and flam‐prop‐isopropyl were safe to use at doses recommended for use in other crops. When applied at three times the recommended dose, only difenzoquat reduced the yield and germination of seed and benzoylprop‐ethyl reduced seed germination. The recommended doses of difenzoquat and ethofumesate were safe when applied on cv. Barlenna at different growth stages. Difenzoquat reduced seed yield only after three times the recommended dose was applied to tillered plants. Ethofumesate, even at three times the recommended dose, did not affect seed yield but plant numbers were reduced by early treatment. The results suggest that the herbicides tested may be safe to use in perennial ryegrass seed crops at the recommended doses but more work is needed on the safety of difenzoquat in relation to crop growth stage.
Varying the time of spraying with paraquat or glyphosate before direct drilling of grass and clover seeds with and without calcium peroxide
Authors: DAVIES W. I. C. , DAVIES J. 
Published: April 2006

AbstractThe practise of sward desiccation using glyphosate or paraquat followed by direct drilling of seed gave an environment which increasingly inhibited germination and establishment when the interval between spraying and drilling was decreased from 21 days to nil. Burning or removal of old sward improved establishment. Calcium peroxide used as a seed dressing improved seedling establishment in most treatments.