bluuebunny/crossref_metadata_2025_split huggingface dataset:
The effect of time of harvest on seed production of three red clover cultivars
Authors: PURI K. P. , LAIDLAW A. S. 
Published: April 2006

AbstractSmall plots of red clover cv. Sabtoron, S123 (diploids) and Hungaropoly (tetraploid) were harvested for seed production at two‐week intervals from 19 August to 17 October inclusive in 1981, inflorescence appearance rate, bee density and components of yield having been monitored throughout the summer. Inflorescence appearance rate reached a maximum at the end of July/early August for Hungaropoly and Sabtoron and during mid‐August for S123. Bee density followed a similar pattern. Florets and seeds per inflorescence and 1000‐seed weight decreased as flowering progressed except during the first three weeks in July. Potential seed yield was calculated from the components of yield for the harvests taken on 3 and 18 September. Losses in seed yield (difference between actual and potential) up to and during harvesting, threshing and cleaning were lower in the tetraploid cultivar (27–39%) than the diploid cultivars (35–l55%). Each cultivar had an optimum harvest time before which yield was affected by immature seeds and beyond which it was adversely affected by shedding of inflorescences and seeds and sprouting of seeds on the inflorescences. The optimum time to harvest Sabtoron was early September, Hungaropoly early to mid‐September and the late flowering cultivar S123 mid‐September when less than 4% of the inflorescences were still unripe. Seed yield and inflorescences per unit area were lower in the tetraploid cv, Hungaropoly (maximum 542 kg ha−1) than diploid cv. Sabtoron and S123 (864 and 897 kg ha−1 respectively) although the tetraptoid had heavier seeds. It is concluded that the optimum time to harvest red clover for seed production is about three or four weeks after the end of the period of rapid inflorescence production and that this coincides with the time when only a small proportion of unripe inflorescences remain.
A comparison of methods of establishing swedes following an early silage cut
Authors: EASSON D. L. 
Published: April 2006

AbstractExperiments were carried out over three seasons in which swedes were sown by precision drilling after ploughing and conventional cultivation or by direct drilling with two types of drill at two row widths with and without shallow cultivation. The swedes were sown in June or early July following a first silage cut and sward desiccation with paraquat. Precision drilling with inter‐row cultivation and singling gave a uniform weed‐free stand and had the highest mean yield of over 8 t DM ha−1 Where hoeing was omitted yields were reduced due to weed competition. Yields following direct drilling were lower than with precision drilling due to uneven plant establishment, weed competition and grass regrowth. A shallow rotavation prior to direct drilling improved uniformity and yields and reduced grass regrowth. Direct drilling produced high numbers of small roots. The highest root yields were associated with sowing in early June and harvesting in December or January. Overall yields from the silage cut plus direct drilled swedes and silage cut plus precision drilled swedes were 12 and 13 t DM ha−1respectively compared with about 14 t DM ha−1expected from a grass sward.
The nature of competition between perennial ryegrass and white clover
Authors: MARTIN M. P. L. D. , FIELD R. J. 
Published: April 2006

AbstractPerennial ryegrass and white clover were grown in boxes with either no competition, root competition only, shoot competition only, or both root and shoot competition between them, Boxes received either no nitrogen or 200 kg N ha−1 as a split application. The experiment was harvested at 8, 12, 16 and 20 weeks after sowing. Perennial ryegrass was more competitive than white clover throughout the experiment and its overall competitive ability increased with Lime. The effects of root competition were greater than those of shoot competition at the first harvest, with both forms of competition having similar affects at the second harvest, while at the third and final harvests shoot competition had greater effects than root competition. At the later harvests N application increased the overall competitive ability of perennial ryegrass, relative to white clover, mainly owing to the increase in its shoot competitive ability.
The effect of autumn fungicide application on spring dry matter accumulation in perennial ryegrass cv. S24
Authors: HAMPTON J. G. , HEBBLETHWAITE P. D. 
Published: April 2006

AbstractFungicide applied to plots of perennial ryegrass cv. S24 in the autumn of 1981 significantly increased tiller number and total dry matter accumulation in February and March of 1982. However, fungicide application in the autumn of 1982 failed to increase tiller number or dry matter accumulation in the spring of 1983. It is suggested that fungicide application in autumn 1981 prevented the death of tillers caused by fungal attack after snow covered the plots in December 1981.
Herbage losses from tiller pulling in a continuously grazed perennial ryegrass sward
Authors: TALLOWIN J.R.B. 
Published: April 2006

AbstractTiller pulling was studied in a perennial ryegrass sward that was continuously grazed by cattle. The treatments included severe (sward height after grazing 25 mm), medium (50 mm) or lenient (75 mm) grazing from turn‐out in April to 1 June, followed by grazing to 50 mm in the remainder of the season. Tiller pulling was confined to the midsummer‐autumn period of the grazing season. The losses were most severe in swards that had been leniently grazed to a mean height of 75 mm during the spring and least severe in swards grazed to a height of 25 mm. The lenient grazing treatment allowed both the true stem development and aerial tillering whereas in the more tightly grazed swards true stem development was significantly less and aerial tillering was virtually absent. The pulled organic matter in the lenient treatment was equivalent to about 5·3% of the total harvested yield. In the severely grazed swards, pulling losses were equivalent to about 1·7% of the total harvested yield. A high rate of turnover of the pulled herbage was found in all the treatments with between 69 and 78% of the freshly pulled herbage disappearing within a week of being pulled. Tiller pulling was found to have no effect on either the subsequent autumn‐winter tiller density or yields of cuts taken in the following year.
The effect on annual dry matter yield of using a hand‐controlled mower or a plot harvester for cutting herbage on small‐plot trials
Authors: SHELDRICK R. D. , LAVENDER R. H. , TEWSON V. J. , COBBY J. M. 
Published: April 2006

AbstractA sward of S24 perennial ryegrass was sampled at 4‐weekly intervals over two seasons with either a Haldrup 1500 plot harvester or a hand‐controlled mower fitted with a fixed reciprocating cutter bar. Plot dimensions were adjusted to the width of the machines'cutter bars (1.5 m and 1.0 m respectively) so that there were no discard areas to require removal. Plots were cut either once, or twice in opposite directions. After cutting, residual stubble heights and the proportion of ground surface covered by leaf laminae were recorded.Mean annual dry matter (DM) yields recorded in ten harvests made each year showed no overall significant difference between the machines. However, previous practice had been to sample plots with one pass of the hand‐controlled mower and to trim the sampled area while removing the usual discard strips. The comparison of annual DM yields from one cut taken with the Haldrup or from two cuts taken with the mower, but with the yield at the second cut excluded, showed a mean advantage of 1.55 t DM ha−1 a−1 for the Haldrup technique or a 14.6% increase over previous practice.Cutting twice significantly (P<0.001) reduced herbage production by a mean of 0.85 t DM ha−1 a−1, mean residual stubble height by 9.8 mm and the proportion of ground covered by leaf laminae by 9.8%. Provided that judgment is exercised when planning treatments and layout of trials, it is concluded that the Haldrup 1500 plot harvester is a valuable labour‐saving tool. However, DM yields from trials cut frequently with this machine are likely to exceed those from similar trials cut with a hand‐controlled mower, following the usual G.R.I. Staff (1961) technique.
The effects of stocking rate and nitrogen fertilizer on a perennial ryegrass‐white clover sward
Authors: CURLL M L. , WILKINS R. J. , SNAYDON R. W. , SHANMUGALINGAM V. S. 
Published: April 2006

AbstractFour stocking rates (25–55 sheep ha −1) and two N fertilizer treatments (nil or 200 kg N ha−1) were imposed on swards containing perennial ryegrass (Lolium perenne) and white clover (Trifolium repens) which were continuously stocked throughout one grazing season. These treatments gave swards that varied greatly in their content of white clover. The effects of these treatments on pasture and animal performance in the following season were examined when all plots were continuously‐stocked with 25 yearling sheep ha−1 and received no N fertilizer. There was slight regeneration of clover in the second year. Herbage growth ranged from 5.4 to 11.0 t dry matter (DM) ha−1, was closely correlated with the clover content of the swards and was higher on swards that had previously received 0 rather than 200 kg Nha−1.The liveweight gain and wool production of sheep in the second grazing season closely reflected the herbage growth and clover content of the swards. As a result, animal production was greatest from swards which had previously been stocked at the lowest rate and had received no N fertilizer and least from swards which had been stocked at the lowest rate but had received N fertilizer.The results show that the adverse effects of over‐grazing and N fertilizer application in one season may be partially rectified by lower stocking rates and by withholding N fertilizer in the following season.
Relationships between growth and measured weather factors among contrasting varieties of Lolium, Dactylis and Festuca species
Authors: NORRIS I. B. 
Published: April 2006

AbstractItalian, perennial, hybrid ryegrass, tall fescue and cocksfoot were used to determine the influence of the weather upon grass growth. Throughout the spring and summer months of 1975 and 1976, weather conditions were monitored. Crop growth rate, leaf extension rate, leaf appearance rate and tillering were recorded. Natural (control), covered and irrigated treatments were applied. In spring, crop growth rates were correlated with solar radiation and temperature, but growth rates were greatest at high levels of insolation. Leaf extension rate was associated with temperature during spring. But during summer this association between temperature and leaf extension became confused as soil water deficit increased. Leaf extension rate in the tall fescue variety SI 70 was the slowest of all for a given temperature. In 1975 leaf growth was very sensitive to temperature; the rate of leaf appearance increased as temperature increased. In 1976 water deficit reduced crop growth rate in spring, and was the major factor influencing crop growth rates in all varieties during summer. Leaf extension and leaf appearance rates were both reduced by increasing soil water deficit. The ryegrasses appeared most sensitive to drought and poor recovery growth was found in the Italian RvP and the hybrid Snowdon.
A von Liebig response function to nitrogen and phosphorus for hay production from irrigated pastures
Authors: PARIS Q. , PARIS P. 
Published: April 2006

AbstractPermanent pasture in the Po Valley of Italy was the site of a pluriannual experiment (1975–81) to observe the effects on hay production of N and P fertilizer applications well above those normally recommended. A split‐plot design with a randomized complete block arrangement of the whole‐plot factor with 5 levels of N and the subplot factor with 3 levels of P was chosen for the experiment. The maximum rate of N application was 800 kg ha−1 while the corresponding rate for P was 87.3 kg ha−1. Principal species in the sward were orchard grass (Dactylis glomerata L.), perennial ryegrass (Lolium perenne L.), common velvetgrass (Holcus lanatus L.) and white clover (Trifolium repens L.).This field was irrigated according to customary techniques during summer months and cut five limes each year. Yields were analysed by means of a response function of the linear and plateau type which incorporates von Liebig's Law of the Minimum, it was found that this function represents the hay response very well with respect to N. In fact, beyond 390 kg ha −1 applied N the response is negligible up to 800 kg ha−1, the maximum rate tested in this experiment. The optimal rate of applied N decreased consistently over the years from 390 to 260 kg ha−1. At these unusually high levels of fertilization hay production increased about 60–80% compared with normal practices.The estimation of the von Liebig response function requires mathematical programming knowledge. The estimates obtained are maximum likelihood estimates. The practical importance of estimating and using this response function lies in its ability to achieve the maximum response with the minimum amount of fertilizers among all other admissible response functions. Hence, its adoption for making fertilizer recommendations would save farmers money and limit chemical pollution to the environment.
A comparison of insecticide treatments for the control of frit fly in seedling ryegrass
Authors: MOWAT D. J. , JESS S. 
Published: April 2006

AbstractLaboratory experiments gave useful indications of the effectiveness of insecticide treatments to control larvae of frit fly (Oscinella frit L.). Lightly infested field experiments provided confirmatory evidence. Several seed treatments, insecticide granules combine‐drilled with the seed and post‐emergence sprays were very effective. The feasibility of delivering granules with seed must be confirmed for each granular formulation. Post‐emergence sprays were most effective if applied at approximately the time of oviposition but several also gave a strong residual effect if applied earlier and a remedial effect if applied after larval establishment in the seedlings. More detailed conclusions are discussed.
An investigation into the use of ranked set sampling on grass and grass‐clover swards
Authors: COBBY J. M. , RIDOUT M. S. , BASSETT P. J. , LARGE R. V. 
Published: April 2006

AbstractFour experiments were conducted to assess the performance of ranked set sampling relative to random sampling for the estimation of herbage mass and clover content in grazed swards. The expected theoretical efficiencies were not observed due to the method of selection of quadrats and the nature of the distribution of herbage mass. Nevertheless there should be worthwhile improvement in precision over random sampling, provided that the quadrats within a set are as well spaced as possible, allowing, if necessary, for visual comparison.
Comparison of the relative performance of perennial ryegrass varieties under upland and lowland conditions
Authors: DAVIES D. A. , JONES E. L. , MORGAN T. E. H. 
Published: April 2006

AbstractProductivity, seasonal growth and persistence of 10 perennial ryegrass (Lolium perenne L.) varieties were assessed al an upland (305 m) and lowland (30 m) site in mid‐Wales. Averaged over 3 harvest years (1979–81), mean dry matter (DM) production at 8.8 t ha−1 was 22% lower in the upland environment, with spring (April and May) growth showing greatest contrast varying from only 6% of that in the lowland in 1979, after a severe winter, to 113% in 1981.Relative ranking of varieties differed considerably between the two environments and no correlation was found between DM production at the two sites (r= 0.5945). Early heading varieties performed better in the spring than late types at the upland site. A comparison of the results with those published from official variety testing trials gave a positive relationship under lowland conditions (r= 0.7162*) but no correlation with those from the upland centre (r= 0.1969).The findings of the study show that relative productivity of varieties, but not persistency, differs between upland and lowland environments.
South‐west England grassland survey 1983
Authors: HOPKINS A. , MATKIN ELIZABETH A. , ELLIS JULIA A. , PEEL S. 
Published: April 2006

AbstractA survey of grassland on 127 farms in south‐west England was conducted in order to investigate the cutting and grazing management of grassland, botanical composition and the use of fertilizer N, and to quantify recent trends in reseeding and the age structure of swards. Twenty‐six percent of the grassland surveyed was classified as arable grassland (in rotation with crops) and 74% as permanent grassland. Only 37% of the established grassland on dairy farms was aged over 20 years compared with 53% on livestock farms. Mowing was practised on 52% of the grassland, two‐thirds of it every year, and virtually all grassland was grazed for part of the year. The average fertilizer N input was 168 kg ha−1with considerable variation with sward age (average 113 kg ha−1for over‐20‐year‐old swards) and between dairy farms (average 217 kg ha−1) and livestock farms (100 kg ha−1)‐ The average proportion of sown species (mainlyLolium perenne)ranged from 90% in young swards to 36% in swards aged over 20 years, with considerable variation within age groups.L. perennewas associated with high inputs of fertilizer N, good drainage, sheep grazing and organic manures, e.g. among swards aged over 20 years it contributed 38% on average where >250 kg N ha−1were applied, but only 12% where no fertilizer N was applied. A continuous network ofTrifolium repensoccurred in 27% of the grassland–this was associated with low inputs of fertilizer N, good drainage and sheep grazing.Agrostisspp. were the most abundant unsown species andCirsium arvense, Ranunculusspp. andRumexspp. the most common broad‐leaved weeds. Features of the sample are compared with those in the south‐west England region and in England and Wales as a whole.
Effects of grass defoliation on the establishment and growth of slot‐seeded white clover
Authors: BOATMAN N. D. , HAGGAR R. J. 
Published: April 2006

AbstractWhite clover was slot‐seeded into a low‐fertility permanent pasture in May 1979. The effects of cutting interval (1, 2 and 4 weeks) and cutting height (3 and 7 cm), in the presence and absence of above‐ground partitions, were recorded in terms of clover establishment and growth up to 15 weeks. The partitions resulted in a considerable increase in growth, stolon production and survival of clover plants, especially from 6 weeks after sowing, indicating a large effect of shoot competition from the surrounding sward. However, the effectiveness of defoliation in reducing grass competition appeared limited; close cutting did give some benefit to establishing clover but cutting frequency had little effect. In view of the limited success in reducing grass competition by cutting, further attempts at alleviating root competition are needed, possibly involving fertilizer placement and the use of grass‐suppressing herbicides.
Comparison of management techniques for evaluating Italian and hybrid ryegrass cultivars
Authors: JONES E. L. , ROBERTS J. E. 
Published: April 2006

AbstractThe effect of management on dry matter yield and persistence of eight cultivars was assessed over a 3‐year period (1978–80) under integration of sheep grazing and simulated sheep grazing with cutting for conservation, and the two cutting frequencies used in the National List trials. A high correlation was obtained in the first and second harvest years between managements in respect of annual production, the ranking order of yield being similar for the range of cultivars. In the third harvest year yield correlation and persistence between sheep grazing and simulated sheep grazing was high and similar to previous years, but all other yield and persistence correlations were considerably reduced. A major effect of frequent cutting management used in the National List trials was the increase in the proportion of unsown grasses (mainly Poa spp.) in the swards.
Voluntary intake and in vivo digestibility by sheep of five lilies of Cenchrus ciliaris selected on the basis of preference rating
Authors: MINSON D. J. , BRAY R. A. 
Published: April 2006

AbstractA study is reported on the voluntary intake and digestibility by sheep of five lines of Cenchrus ciliaris when grown as swards and cut at six different stages of growth. Previous studies with C. ciliaris grown in small rows had shown large differences between these lines in grazing preference by cattle. The ranking order for preference wasline31>10 = 23>30 = 36.When offered singly to sheep in pens the five lines could be divided into three groups according to their voluntary intakes. Lines 10 and 30 had the highest mean daily intakes of 56·1 and 57·6 g (kg W)‐0·75 compared with lines 23 and 36 with low mean intakes of 48·5 and 48·6 g (kg W)‐0·75. Line 31 was intermediate with a mean intake of 543 g (kg W)‐0·.Mean dry matter digestibility of the five lines ranged from 0·577 to 0·597%. Lines 10 and 30 had the lowest digestibility. The difference in intake between the five lines was positively correlated with their proportion of leaf (r= 0·97). Low‐intake lines (23 and 36) also had the highest proportion of seed head.It was concluded that selection of C. ciliaris on the basis of preference by cattle in a cafeteria study provided no useful guide to voluntary intake when the different lines were grown, cut, dried, chopped and fed separately to sheep.
Supplementary feeding of forage to grazing dairy cows, 3. The effect of three daytime stocking rates on the performance of cows offered grass silage overnight
Authors: ROBERTS D. J. , LEAVER J. D. 
Published: April 2006

AbstractOver a 24‐week period, three groups of dairy cows were continuously stocked at 8, 10 or 12 cows ha‐1 between morning and afternoon milkings, and overnight were housed and offered grass silage ad libitum. Due to a prolonged drought, sward heights only averaged 4·1 cm.The increase in daytime stocking rate led to a decline in herbage intake, and increases in silage intake. At the highest stocking rate (12 cows ha‐1), the silage intake failed to compensate for the reduced herbage intake. Consequently the total dry matter and estimated metabolizable energy intakes were lower than for the 8 and 10 cows ha‐1 treatments. Milk yields and milk composition were not significantly affected by treatment but the 12 cows ha‐1 stocking rate gave the lowest milk and milk solids yields.The utilized metabolizable energy (UME) on the grazed swards was greatest for the 10 cows ha‐1 treatment. The sward cut to provide the silage had a UME level (GJ ha‐1) 32% greater on average than the grazed swards during the same growth period. The total areas utilized for grazing and silage production for 8, 10 and 12 cows ha‐1 were 0·240, 0·224 and 0·215 ha respectively. Fat and protein yields per unit area were greatest for the 10 cows ha‐1 group.