bluuebunny/crossref_metadata_2025_split huggingface dataset:
SEED PRODUCTION STUDIES ON PERENNIAL RYEGRASS, TIMOTHY AND PRAIRIE GRASS
Authors: Hill M. J. , Watkin B. R. 
Published: April 2006

ABSTRACTA study over two years involving tiller identifica tion according to month of origin enabled the contribution of individual tillers of perennial rye grass Grasslands Ruanui, timothy Grasslands Kathu and a local New Zealand strain of prairie grass (Bromus unioloides) to be determined at seed harvest. In addition, the distribution of seed‐heads in different arbitrary emergence groups was detemined so as to allow analysis of individual seedhead components within each group.In all species, tillers formed during the first 4 months following an autumn sowing in the first year, and also in the immediate post‐harvest period and through the autumn in the second year, made a major contribution to seedhead numbers and seed yield at harvest. These tillers had a lower vegetative mortality rate than those formed in the spring.Primary tillers formed after sowing were highly persistent and became almost exclusively repro ductive. Many vegetative tillers died before har vest, behaving as annual tillers.Spring‐formed tillers made a major contribution to the vegetative growth of the plant over the summer and early autumn. These tillers generally died before the following winter. Tillers formed in winter and early spring by ryegrass and prairie grass showed a high mortality, particularly in the second year. In timothy, mortality was highest amongst tillers formed in late spring. The reduced contribution of spring‐formed tillers to the seed head population occurred as a result of fewer heads numerically compared with older tillers.In all species, most seedhead components varied according to time of ear emergence. Early emerged heads were generally longer, bore more spikelets and more florets per head and had a greater culm length than late‐emerged heads.The major trend in all species was a general depression in head length, spikelet and floret number and culm length with grazing. These effects were in most cases partly or completely overcome by N application. The major effect of applied N was to increase floret number per head.
Effects of fertilizers on the sulphur content of herbage
Authors: McLAREN R.G. 
Published: April 2006

AbstractThe sulphur concentrations in herbage samples from the plots of a long‐term fertilizer experiment have been examined in relation to levels of fertilizers applied. Sulphur applied as superphosphate increased herbage sulphiir concentrations whereas reduction in concentrations were observed with applications of nitrogen as ‘Nitro‐chalk’ and potassium as potassium chloride. Reduction in sulphur concentration occurred most likely as a result of increased dry matter production brought about by the added nitrogen and potassium, effectively diluting the sulphur content of the plant material. Potassium chloride may also have exerted an anion‐antagonistic effect on sulphate uptake by the plants. Levels of soil extractable sulphate were low in plots receiving no sulphur as fertilizer and high levels of nitrogen applied to these plots resulted in wide nitrogen: sulphur ratios in the herbage. Most of the sulphur applied to the soil in the spring was leached out of the topsoil by the end of the growing season.In some areas of Britain it seems possible that optimum utilization of applied nitrogen may only be obtained where sulphur is also added to the soil.
The effect of variety and fertilizer nitrogen level on red clover production
Authors: FRAME J. , HARKESS R. D. , HUNT I. V. 
Published: April 2006

AbstractEstablished swards of two diploid and two tetraploid red clover varieties sown pure received 0, 75, 150, 225 or 300 kg ha−1 N fertilizer and were cut three times in June, August and October 1971. The total yields of herbage DM for red clover varieties ranged from 8.01 to 11.32 t ha−1; swards sown with tetraploids Hungaropoly and Hera Pajbjerg were superior by 25% in DM yield and 23% in CP yield. The red clover contribution to these total yields of DM ranged from 6.05 to 10.69 t ha−1; tetraploid clovers outyielded diploids by 42% in DM yield and 39% in CP yield.The mean effect of N level on yield and on compositional attributes was slight. Total yields of herbage DM, averaged over all varieties, ranged from 9.50 to 10.22 t ha−1 and of total herbage CP from 1.76 to 1.91 t ha−1. The influence of N level on the red clover contribution was negligible. DM yields ranged from 8.54 to 8.72 t ha−1 and CP yields from 1.60 to 1.64 t ha−1.Superiority of tetraploid clovers over diploids was again confirmed. Red clover swards sown pure can give high yields without the application of fertilizer N.
The effect of a short‐persistence systemic insecticide on the yield of perennial ryegrass
Authors: HENDERSON I. F. , CLEMENTS R. O. 
Published: April 2006

AbstractThe insecticide dimethoate was applied to a sward of S23 perennial ryegrass over a period of 2 years at three dose rates and at five frequencies of application. Annual DM yield was increased by up to 5% in the first year and by up to 17% in the second. The value of the additional yield is compared with the cost of obtaining it.
Estimation of herbage consumption by grazing cattle using measurements of eating behaviour
Authors: CHACON E. , STOBBS T. H. , SANDLAND R. L. 
Published: April 2006

AbstractFeed consumption (I). of a group of eight non‐lactating Jersey cows strip‐grazing oats at three stages of growth was estimated from number of eating bites (N) and bite size (5) measurements using the expression, I= N × S. N was measured with four non‐fistulated animals while S was determined independently with four oesophageal fistulated animals. These estimates were compared with herhage consumption estimates using a cutting technique (fourteen samples of both herbage offered and refused).Eating behaviour estimates of intake based on N and S were 29% higher than cutting estimates due to fistulated animals having a high number of mastication bites with the head up during sampling and a large diurnal variation in bite size. After allowing for these sources of error eating behaviour estimates were only 2% higher than cutting estimates.Sampling variability was similar for both cutting and eating behaviour techniques; on an individual plot basis the percentage coefficients of variation were 11.2 and 10.1 for cutting and eating behaviour techniques, respectively. Methods of reducing sample variability are discussed and tables of numbers of animals required to detect true differences in intake at various levels of precision are presented.It is concluded that herbage consumption by grazing ariimals can be obtained from measurements of eating behaviour.
The seasonal productivity, quality and response to nitrogen of four indigenous grasses compared with Lolium perenne
Authors: HAGGAR R. J. 
Published: April 2006

AbstractTo rectify the lack of comparative data on the productivity of some commonly occurring indigenous grasses, seasonal growth curves were obtained during the first year of a 3‐year study by harvesting monoculture plots of Holcus lanatus, Agrostis stolonifera, Festuca rubra, Poa trivialis and Lolium perenne (cv. S23) at monthly intervals in a staggered sequence. Under conditions of high soil fertility (40 kg ha−1 N per defoliation and frequent irrigation) the daily production of dry matter by P. trivialis followed the familiar two‐peaked pattern of L. perenne, albeit at a lower level after flowering. By comparison, F. rubra and A. stolonifera grew more uniformly throughout the year; H. lanatus, like F. rubra, was noticeable for its high productivity after midsummer. With monthly cutting all four indigenous grasses had a higher mean nitrogen content compared with L. perenne; mean digestibilities were also comparable with the exception of F. rubra.During the second year, when inputs of nitrogen and moisture were lower, primary spring growth was most rapid with H, lanatus and F. rubra but the high digestibility of L. perenne meant that harvesting could be delayed to obtain the most forage of a given D‐value. Regrowth, measured from cuts taken in early August and September, was greatest with A. stolonifera and F. rubra respectively.Dry‐matter responses to a total of 60 and 180 kg ha−1 N, applied in three applications on a split‐plot basis, were recorded during the last year. Apart from the early nitrogen application, the indigenous grasses responded well, except for A. stolonifera, especially after flowering. Though the response of L. perenne was consistently high throughout the summer, at least 20 kg DM per kg N, it yielded least of all the grasses at the low nitrogen level.The agricultural significance of these results are discussed. It is concluded that whereas L. perenne performs well at high levels of nitrogen and moisture, the other species do better than L. perenne, especially during mid‐season, when these factors are limiting.
The effect of cutting frequency and applied nitrogen on production and digestibility of perennial ryegrass
Authors: CHESTNUTT D. M. B. , MURDOCH J. C. , HARRINGTON F. J. , BINNIE R. C. 
Published: April 2006

AbstractGrass swards were cut at intervals of 2, 3, 4, 5, 6 and 8 weeks and received 336 or 673 kg ha−1 nitrogen the higher level being applied as a single or as split dressings. Reducing cutting interval from 8 to 2 weeks reduced mean DM yield by 37% from 14·2 to 9·0 t ha−1 and digestible DM yield by 24% from 9·4 to 7·2 t ha−1. The response to the extra N at the highest level of application was greatest under the most frequent cutting regimes. Application of N did not affect the digestibility of DM. Results are discussed in relation to the comparative effects of frequency of cutting at different seasons of the year and at different levels of N.
Nitrogen studies in Lolium perenne grown for seed I. Level of application
Authors: HEBBLETHWAITE P. D. , IVINS J. D. 
Published: April 2006

AbstractIn field trials in 1971–73, perennial ryegrass cv. S23 and S24 were given up to 200 kg ha−1 nitrogen (N) and dry weight, seed yields and seed yield components measured. Optimum levels of applied N ranged from 80 kg ha−1, where livestock had grazed the crop in the establishment year or where residual N levels were about 70 kg ha−1, to 120 kg ha−1 where residual N was low. Application of more than 120 kg ha−1 did not increase yields further because of increased lodging and increased production of vegetative tillers. Seed set was 37–55% in S24 and 25–29% in S23 and was decreased by lodging.
The effect of silage chop length on the voluntary intake and rumination behaviour of sheep
Authors: DESWYSEN A. , VANBELLE M. , FOCANT M. 
Published: April 2006

AbstractTwo experiments were conducted with sheep to investigate the effect of silage chop length on voluntary intake and eating and ruminating behaviour. The silages, made from Italian rye‐grass, either received no additive or formic acid at a rate of 4 g kg−1 and were chopped to lengths of 5.3 cm (long), 1.8 cm (short) before ensiling or 1.8 cm (long/short) before feeding. The addition of the additive and short chopping improved the fermentation characteristics of the silage. Voluntary intake of silage dry matter and organic matter was higher with the short than with the long silage. Differences in silage digestibilities and cellulolytic activity did not explain the increase in silage intake. Sheep on the long silage had a lower rate of intake and a shorter ruminating time than on short silage, and thus the effective breakdown of the silage in the rumen was delayed, i.e. an increased latency time. Pseudo‐rumination was significantly higher on the long than on the short silage.
Seed development and seed shedding in North Italian ecotypes of Lolium multiflorum
Authors: HARUN R. M. RAJA , BEAN E. W. 
Published: April 2006

AbstractSeed development and seed shedding were studied in seven populations of Lolium multiflorum. Five of these populations were from the North Italian Plains, two from the Piedmont area and three from the Lombardy region. The remaining populations were Delecta, a variety derived from ecotypes from the Lombardy Plain, and RvP Lemtal. Seed shedding was greatest in the three ecotypes from the Lombardy Plain and lowest in RvP Lemtal. The two ecotypes from the Piedmont Plain, and Delecta, gave intermediate values. Moisture loss during ripening was greatest in the Lombardy ecotypes but there were no differences in the time taken to reach maximum 1000‐seed weight. Germination values had reached a maximum 27 d after anthesis in all populations. It is suggested that the North Italian ecotypes, or varieties derived from them, should be harvested by direct combining at a moisture concentration of 450 g kg‐1 (≡45%) to obtain the maximum weight of germinable seed.
Effects of defoliation and fertilizers on root competition between Dactylis glomerata and Lolium perenne
Authors: REMISON S. U. , SNAYDON R. W. 
Published: April 2006

Abstract Dactylis glomerata and Lolium perenne were grown in single‐species stands and in mixed‐species stands in boxes for 1 year. Plants were grown in paired rows in each box with full competition below ground, but aerial partitions prevented shoot competition. The rows were cut either frequently (six cuts) or infrequently (three cuts).In single‐species stands, frequent defoliation reduced the root competitive ability of D. glomerata plants, when growing with infrequently defoliated plants, though this occurred only if no N fertilizer was applied. Frequent defoliation did not affect the root competitive ability of L. perenne plants, in single‐species stands, whether or not N fertilizer was applied.In mixed‐species stands, the root competitive ability of D. glomerata was always greater than that of L. perenne, though N fertilizer applications and frequent cutting both reduced the root competitive ability of D. glomerata relative to L. perenne.Mixtures of frequently cut and infrequently cut plants, in unfertilized single‐species stands, always yielded more than the mean of the uniformly treated stands (frequently or infrequently cut); they usually yielded more than the highest‐yielding uniformly treated stand. Mixtures of frequently and infrequently cut plants, in fertilized single‐species stands, always yielded less than the mean of uniformly treated stands.Mixed‐species stands usually yielded more than the mean yield of the component species, and sometimes yielded significantly more than the highest yielding component. This effect generally increased with time.Relative yield totals (RYT) were consistently greater than 1·0, in both single‐species and mixed‐species stands, when no N fertilizer was applied. RYT were greatest (1·2–1·6) when neither N nor P fertilizer was applied, and generally increased with time.The results are discussed in relation to the effects of cutting on root competition and the probable value of mixed‐species stands.
A critical review of remote sensing and other methods for non‐destructive estimation of standing crop biomass
Authors: TUCKER COMPTON J. 
Published: April 2006

AbstractSeveral different techniques for the non‐destructive estimation of pasture or range biomass are critically reviewed and compared to remote sensing methods. Similarities and differences between the visual estimation procedure, β‐attentuation, capacitance meters, weighted disc, and spectral methods are discussed in terms of accuracy, time, ease of operation, operational constraints and calibration procedures. No one technique has been shown to be superior across the board to the other techniques reviewed for ground‐based biomass estimation. A discussion of the strengths and weaknesses of each non‐destructive method allows for the selection of the technique most suited to a particular application.
Grass production studies in the uplands of north‐east Scotland 2. The effects of fertilizer treatment
Authors: RILEY H. C. F. , MACLEOD D. A. 
Published: April 2006

AbstractThe effects of fertilizer treatment were studied over two seasons on a 2 × 2 factorial arrangement of altitude and major soil group. The soil groups were brown earths and podzols and the altitudinal zones were 260–320 m and 380–440 m. Major responses were found to N only and these were generally linear in terms of overall dry matter yield up to the highest treatment level of 176 kg ha‐1. Productivity on brown earths was significantly higher than on podzols and differences between soil groups were not removed by increasing fertilizer input. In most instances 88–132 kg ha‐1N would have to be added to podzols to achieve the same yields as on brown earths with no N input. Apparent fertilizer recoveries and responses per unit of fertilizer input did not, however, differ markedly between soil groups. Overall yields were comparable with those from lowland situations at similar levels of N input, but the growing season was short and 60–80% of production was obtained by early July.
Components of regrowth in grazed and cut Lolium perenne swards
Authors: GRANT SHEILA A. , BARTHRAM G.T. , TORVELL LYNNE 
Published: April 2006

AbstractGrowth measurements were made on Lolium perenne‐dominant vegetative swards during 4‐week regrowth periods following grazing or cutting.In the grazing study, the ryegrass (Lolium perenne) swards were grazed for 12‐d periods with stock numbers set according to initial herbage allowances per animal of 16, 32 and 64 kg organic matter per sheep. One area was grazed in summer and another area in the autumn.In the cutting experiment four ryegrass swards growing in boxes were prepared by cutting to either 2 or 6 cm at either 14‐ or 28‐d intervals. The swards were cut back in autumn to 2 or 6 cm. During the regrowth period half the boxes were retained in full light and half shaded to 48% of incident light.Herbage weight, rates of leaf extension, senescence, leaf appearance and tillering, water soluble carbohydrate reserve levels in tiller bases and, in the cutting experiment, sheath tube lengths and lamina lengths of leaves which had grown through the sheath tube were measured at intervals during the regrowth period.Final herbage weights reflected management history but net herbage accumulation over the four‐week regrowth period, though affected by season, pretreatment and light level, was similar on swards subjected to different grazing or cutting treatments.This result was partially explained by changes in the balance between growth and senescence per tiller as herbage weight increased with time during regrowth, and partially by the reduced production per tiller in harder‐grazed swards being offset by a rapid increase in tiller numbers.There was a positive curvilinear relationship between lamina length and the length of the sheath tubes through which the laminae emerged.Carbohydrate reserve levels declined rapidly after grazing or cutting, the extent of the decline being related lo the severity of the defoliation. Recovery commenced after four days in summer and was complete within 3 weeks but reserve levels remained low in plants grazed or cut in autumn.The need is discussed for more detailed descriptions of sward states in management studies and for more information on component processes of growth, the factors affecting them and how these interact with different kinds of management systems.
Presence ofDrechsleraspecies in certified ryegrass seed‐lots
Authors: LAM A. 
Published: April 2006

AbstractSamples of 39 perennial ryegrass (Lolium perenneL.) and 24 Italian ryegrass (Lolium multiflorumLam.) commercial seed‐lots used at the Grassland Research Institute between 1974 and 1978 were examined for the presence of seed‐borneDrechsleraspecies. The five species ofDrechsleraisolated from the seeds wereD. andersenii, D. siccans, D. nobleae, D. sorokinianaand an unidentifiedDrechslerasp.A high proportion of the seed‐lots were infected but levels of infection were low except in the perennial ryegrass cv. S24. Infection was located more commonly inside the caryopses than externally on the lemmas and paleae, and about 12% of the seedlings growing from infected seeds were infected. The species recovered in the seedlings were the same as those observed on the seeds.There was no relationship between level of seed infection and level of damage observed in the field in the autumn of the first harvest year.
Effects of formic acid on silage fermentation, digestibility, intake and performance of young cattle
Authors: PARKER J. W. G. , CRAWSHAW R. 
Published: April 2006

AbstractData from twenty‐two comparisons carried out at ADAS Experimental Husbandary Farms are used to compare untreated and formic acid‐treated silages. Additive treatment led to an improved fermentation in some crops, particularly those of low DM concentration (<262 g kg‐1). Where this occurred there were associated benefits in silage digestibility (+0·234 units), intake (+16%) and the growth rate of young cattle (+0·28 kg d‐1). Where the fermentation of the untreated silage was good, both digestibility and animal performance associated with treated and untreated silages were similar. It is suggested that the justification for using formic acid in a commercial situation is thus restricted to occasions where the untreated crop would be liable to develop a clostridial fermentation. These may be when crops contain less than 35 g water‐soluble carbohydrate kg‐1.
The effects of degree of chopping grass for silage and method of concentrate allocation on the performance of dairy cows
Authors: GORDON F. J. 
Published: April 2006

AbstractThree silages were produced from the same swards by harvesting grass using either a double‐chop harvester (DC) or a precision‐chop harvester adjusted to produce a long staple length (PL) or a short staple length (PS). The mean particle lengths were 47, 52 and 14 mm respectively.Of each material 250 t was ensiled unwilted and with formic acid additive at the mean rate of 2‐4 litres t‐1 of grass. All three silages were well preserved and degree of chopping had no effect on fermentation as indicated by either pH, ammonia N or organic acid concentration.The silages were offered ad libitum to seventy‐two British Friesian cows with a mean calving date of 28 January which were in their second or later lactation, in a randomized‐block experiment from day 8 of lactation until 12 April. In addition twelve animals on each silage received a uniform daily concentrate allowance of 7·2 kg while twelve were offered concentrates according to their individual milk yields but with a mean concentrate allowance over the twelve cows of 7·2 kg d‐1. Degree of chopping had no significant effect on either silage dry matter intake or milk yield with mean intakes during the final 21 d of the experimental period of 9·2, 9·2 and 9·2 kg d‐1 and mean milk yields of 25·2, 25·2 and 25·2 kg d‐1 for the DC, PL and PS silages respectively. Method of concentrate allocation did not affect either the total yield of milk during the experimental period, 1717 and 1697 kg, or the total lactation yield, 5635 and 5711 kg, for the uniform and yield‐related allocation methods respectively. The butterfat and protein concentrations of the milk were not significantly affected by either the degree of silage chopping or the method of concentrate allocation.
The fertility of heifers consuming red clover silage
Authors: AUSTIN A. R. , ASTON K. , DRANE HILARY M. , SABA N. 
Published: April 2006

AbstractThe fertility of forty‐two heifers offered either red clover silage or grass silage prior to and during the period of insemination was compared. Pregnancy rate to first service was significantly higher (P < 0·25) on red clover silage at 76% compared with 43% on grass silage. Pregnancy rates from a mating period covering three oestrus cycles were similar on the two silage diets. The ratio of services to pregnancies was lower on red clover silage (1·2) than on grass silage (2·2). In a subsidiary trial with twenty‐three heifers, pregnancy rate to first service on red clover silage was 78%.There was no evidence to indicate that herd fertility is depressed by red clover silage.