bluuebunny/crossref_metadata_2025_split huggingface dataset:
Slot‐seeding investigations. 1. Effect of level of nitrogen fertilizer and row spacing on establishment, herbage growth and quality of perennial ryegrass
Authors: HAGGAR R. J. , SQUIRES N. R. W. 
Published: April 2006

AbstractThree field experiments showed that perennial ryegrass can be successfully slot‐seeded into an existing Festuca‐Agrostis sward. Ryegrass survival was satisfactory in all cases but was improved on a low fertility site by the application of fertilizer N, P and K in the slot at sowing.The effect of varying inter‐row spacing from 37·2 to 15 cm was measured in a 3‐year experiment. In year one, involving seven cuts, slot‐seeding increased total herbage dry matter harvested by a mean value of 17%; inter‐row distances of 22·2‐30 cm gave the optimal combination of ryegrass + old sward herbage. Differences in yield between inter‐row spacings declined in the subsequent two years, as the rows of ryegrass thickened. Ryegrass digestibility (measured only in year two, from six cuts) was higher than that of the old sward; total metabolizable energy harvested from 15‐cm rows was 20% higher than that from unsown controls. Increasing N input from 200 to 400 kg ha‐1, starting in year two, only produced a significant increase in total herbage harvested in year three but proved effective in increasing the ryegrass contribution from the wider spaced rows.
The management of Brassica for winter forage in the sub‐tropics
Authors: KALMBACHER R. S. , EVERETT P. H. , MARTIN F. G. , JUNG G. A. 
Published: April 2006

AbstractIn subtropical latitudes temperate crops can be grown during the cool months but the growing season is restricted by the termination and beginning of hot weather. Postponing sowing date in south Florida from October to November to January resulted in 150, 130 and 110‐d growing seasons respectively. Dry matter (DM) yields of turnip, swede, rape and kale were lowered by each later sowing date and shorter growing season, and crude protein (CP) concentration was the same as for, or was increased by late sowing. In vitro organic matter digestibility (IVOMD) of turnip, swede and rape leaves was not affected by sowing date, but roots of turnip and swede from the earlier sowings and longer growing seasons were more digestible. Yield of the four species depended on harvest management as well as date of sowing and length of growing season. Total yield of turnip and swede were unaffected by harvest management but multiple cutting resulted in greater leaf yields and smaller root yields, whereas stockpiling resulted in smaller leaf yields and larger root yields. Kale produced more DM when harvested once at the end of the winter growing season but rape produced the greatest DM yield when sown in October and harvested
Leaf surface expansion on the main axes of white and red clovers
Authors: ARNOTT R. A. , RYLE G. J. A. 
Published: April 2006

AbstractPlants of white clover (Trifolium repens L.) cv. Blanca and red clover (T. pratense L.) cv. Hungaropoly were grown singly in controlled environments. The effects of eight treatments on the two species were examined: 16‐ and 8‐h photo‐periods × 20/15 and 15/10°C day/night temperatures ×Rhizobium‐free plants receiving nitrate N and inoculated plants receiving no combined N. Twice weekly measurements of the main axis leaf size, petiole length, rate of leaf production and the time period between the appearance of a leaf and its final size were carried out for 8 weeks after sowing.Increasing the day/night temperature from 15/10 to 20/15°C, or doubling the daylength from 8 to 16 h (doubling the daylength increased temperature by 1·2°C) accelerated the rate of leaf production and expansion and increased petiole length and the final area of leaves. Most aspects of main axis leaf growth were reduced in the inoculated plants dependent on their own N fixation compared with the nodule‐free plants receiving abundant nitrate N. The results suggest that the temperature above which white clover exhibits appreciable leaf growth in the field could be relatively high compared with grasses. Further research is required to define these differences and relate them to seasonal changes in the environment.
Frequency and severity of defoliation of grass and clover by sheep at different stocking rates
Authors: CURLL M. L. , WILKINS R. J. 
Published: April 2006

AbstractThe frequency and severity of defoliation of individual grass tillers and clover plant units was studied in Lolium perenne‐Trifolium repens swards grazed by sheep at stocking rates ranging from 25 to 55 sheep ha‐1 and either receiving no N fertilizer or 200 kg N ha‐1. On average, sheep at the highest stocking rate defoliated individual tillers once every 4·2 d compared with once every 9·2 d at the lowest stocking rate with the removal of 58% and 47% of the leaf length of each tiller leaf at these stocking rates. Clover plant units were defoliated once every 4·2 d at the highest stocking rate and once every 7·2 d at the lowest stocking rate with the removal of 51% of its leaves and 12% of its stolon at the high stocking rate and 42% and 4% respectively at the low stocking rate. Differences in frequency and severity of defoliation between N fertilizer treatments were smaller than between stocking rates. Grass tillers and clover plant units were both defoliated less frequently and less severely in swards fertilized with N, though the difference in defoliation frequency between fertilizer treatments decreased as stocking rate increased. Defoliation frequency was related to the length of grass leaf per tiller or number of clover leaves per plant unit, and to the number of these tillers and the herbage on offer.
A survey of ryegrass swards for the presence of fungal pathogens in relation to management
Authors: LAM ANNIE 
Published: April 2006

AbstractSurveys of perennial and Italian ryegrass swards (Lolium perenne L. and L. multiflorum Lam.) at regular intervals in 1977 and 1978 in Berkshire, Wales and Devon confirmed that leaf infection by Drechslera spp. was the most frequently occurring foliar fungal disease. Rhynchosporium spp. and Puccinia coronata Corda were also recorded but in contrast to Drechslera spp., which caused damage throughout the year, attacks by these two fungi were only sporadic.The incidence of Drechslera was greater in 1977 than in 1978 and was greater in Berkshire where most fields were infected in both years than in Wales and Devon. Both perennial and Italian ryegrasses were infected. The number of leaves damaged increased with leaf age. Damage was greater on fields managed for conservation than those which were grazed. Infection increased from February onwards and was greatest in autumn. It is concluded that Drechslera might be controlled by removing infected herbage in autumn by cutting. Rhynchosporium spp. were prevalent only in Berkshire and more Italian ryegrass fields (ca, 50%) were infected than perennial ryegrass fields (ca, 10%). Infection was confined to the period March to May. This pathogen caused more leaf area damage than Drechslera. Puccinia coronata occurred only once in Devon and Wales. In Berkshire incidence was confined to 1978 and was common from September to November, when 60–70% of both Italian and perennial ryegrass fields were infected. Some difference between perennial ryegrass cultivars was observed.
The effects of Rumex obtusifolius on the seasonal yield of two mainly perennial ryegrass swards
Authors: OSWALD A. K. , HAGGAR R. J. 
Published: April 2006

AbstractA preliminary field experiment on a sward cut six times during 1978 indicated that total grass herbage harvested was negatively related to the number of Rumex obtusifolius plants present; densities of five to ten plants m−2 resulted in reductions of up to 30%, although the total quantity of herbage harvested (including Rumex) may have remained constant. However, R. obtusifolius densities did not significantly affect grass yield during the first half of the growing season. A negative relationship between R. obtusifolius ground cover and grass yield, particularly from late July onwards, was shown in a second field experiment during 1979 and 1980 using a 3‐cut management. It was estimated that to produce a 20% reduction in grass growth in July‐August and October, R. obtusifolius ground covers of 30% and 20% respectively were needed. Sixty per cent of the total herbage harvested in 1980 consisted of R. obtusifolius. These results indicate the damage that can be caused by this species and suggest that control measures should be taken before early summer.
Factors influencing seed movement and dormancy in grass seeds
Authors: SCHÖNFELD M. A. , CHANCELLOR R. J. 
Published: April 2006

AbstractAwned seeds of four grasses were submitted to humidity changes on dry and damp soil to see how far the awns assisted in distribution and seed burial. The results indicate that awns on their own are probably of limited importance. In another study, seeds of seven species were soaked in water with high or low oxygen levels to determine whether dormancy could be induced. Waterlogging delayed germination briefly but did not induce dormancy except in Avena fatua. Oxygen level proved unimportant. The effect of temperature on germination and dormancy was examined in seeds of Agrostis capillars. Seeds of this species germinated best at fluctuating temperatures with a minimum difference of 10°C between day and night temperatures. Constant or slightly fluctuating temperatures over 20°C or under 10°C induced dormancy in a small percentage of seeds.
An economic assessment of the potential benefits of replacing grass by grass‐clover mixtures for 18‐month beef systems
Authors: DOYLE C. J. , MORRISON J. 
Published: April 2006

AbstractA mathematical model which simulates the potential production and utilization of herbage on perennial ryegrass and grass‐white clover swards in the context of an 18‐month beef enterprise is described. Using the model the potential costs and benefits of replacing grass by grass‐clover mixtures have been determined. Potentially grass‐clover swards receiving no fertilizer N are shown to have annual DM yields equivalent to ryegrass swards receiving at least 300 kg N ha −1. Apart from the benefits of reduced fertilizer N usage there appear to be indirect benefits related to a lower concentrate requirement per head. In consequence, from an economic viewpoint grass‐clover swards potentially compare very favourably with heavily fertilized grass swards, even if account is taken of the opportunity costs of lower stocking rates associated with grass‐clover systems. However, this conclusion awaits experimental confirmation.
The productivity of May‐lambing ewes grazed at three stocking rates on lowland grass
Authors: NEWTON J. E. , BETTS J. E. , WILDE R. M. 
Published: April 2006

AbstractFor the 2 years 1977 and 1978 Masham ewes grazed a perennial ryegrass (Lolium perenne cv. S24) pasture from the beginning of April until the end of September each year. Twelve ewes were allocated to each of the three stocking rate treatments, 12 (L), 16 (M) and 20 (H) ewes per ha. Each treatment was rotationally grazed around six paddocks with a forward creep for the lambs. Conservation cuts were taken from each treatment in late May and were generally sufficient to cover a 3‐month winter feeding period for treatments L and M but were always insufficient for treatment H. Lambing took place at pasture during the second half of May. No concentrates were fed to the ewes during late pregnancy or lactation but lamb birth weights (4–8 kg) and lamb growth rates over the first 4 weeks (240 g d−l) were satisfactory. Organic matter intakes (OMI)of grass by the pregnant ewes(1816,1844 g OMI ewe−1) were not affected by the stocking rate. Intake of grass by the lactating ewes was affected by year and by stocking rate. The overall growth rate of lambs was higher on treatment L than either M or H but decreased on all treatments during the latter half of the grazing season, resulting in 43% of L and only 3% of M and H lambs being fit for slaughter by the end of September. The main features of this time of lambing are low costs and the production of predominantly store lambs.
The digestion by cattle of grass silages made with no additive or with the application of formic acid or formic acid and formaldehyde
Authors: ROOKE J. A. , GREIFE H. A. , ARMSTRONG D. G. 
Published: April 2006

AbstractThe aim of the experiment was to assess the effect of applying, at commercially recommended rates, formic acid or formic acid/formaldehyde at ensilage upon the subsequent digestion of the silages by cattle. Three wilted grass silages were made from perennial ryegrass ensiled at a DM concentration of 206 g kg−1 after a poor wilting period of 49 h without additive application and with application of 2.5 litres t−1 of formic acid or of 4.5 litres t−1 of a mixture of (gkg−1) 500 formic acid, 200 sulphuric acid and 200 formatin giving an application rate of 15 g formaldehyde kg−1 herbage crude protein (N × 6.25).The silages were fed to cattle equipped with rumen cannulae and duodenal re‐entrant cannulae. Results from analyses of silage composition and from the digestion of organic matter and N showed no major differences between silages. The efficiency of rumen microbial N synthesis, the rumen degradability of silage N (determined in vivo or in sacco) and in vivo digestion of individual amino acids were also unaffected by additive treatment. These results indicate that poor wilting conditions before ensilage restricted the effectiveness of additive treatment; the ineffectiveness of formaldehyde in reducing the rumen degradability of silage N may also have been related to the low rate of formaldehyde application.
Grazing by sheep and the distribution of species through the canopy of a red clover‐perennial ryegrass sward
Authors: LAIDLAW A. S. 
Published: April 2006

AbstractA trial was carried out to investigate whether or not sheep grazing at stocking rates of 22 (low) and 44 (high) ha−1 select red clover from a red clover‐perennial ryegrass sward, The distribution of botanical and morphological components was assessed in consecutive 5‐cm layers through the canopy inside and outside exclosure cages moved every 2 weeks for 6 weeks. The difference between inside and outside cages for a given layer was an indication of the amount of each component consumed from that position in the sward, and the corresponding difference for clover content was considered an indication of selection.Evidence of selection was observed over the third and fourth weeks of grazing, especially in the high stocking rate treatment. Laminae of red clover were selected in preference to other plant parts and were grazed throughout the depth of the canopy in contrast to grass. The basal layer at the high stocking rate during weeks 5 and 6 was not grazed suggesting that the crown of red clover may be protected from severe overgrazing by accumulation of dead matter.It was concluded that the low herbage density of red clover‐grass swards allowed the occurrence of selection which was most pronounced when the sward was being grazed down relatively quickly.
Photosynthetic rate and carbon balance of grazed ryegrass pastures
Authors: KING J. , SIM E. M. , GRANT S. A. 
Published: April 2006

AbstractThe relationship between net canopy photosynthesis (Pnc) measured at 400 J m−2 s‐1 and leaf area index (LAI) was determined on ryegrass‐dominant swards over a range of her bage masses in five grazing experiments. In three experiments the swards were continuously stocked either by sheep or by cattle to maintain a number of herbage heights and hence LAI values. In two experiments the swards were intermittently grazed with 21 ‐d regrowth intervals. On the continuously stocked swards measurements were made over nine periods each of 7 to 21 d in length. On the intermittently grazed swards measurements were made over six periods while the herbage was being grazed down from a high to a low LAI and over three periods during the regrowth phase.On all the swards where measurements were made while grazing was in progress, the relation of Pnc to LAI was linear. The photosynthetic rate was greater on the continuously grazed than on the intermittently grazed swards up to LAI 35 and in two experiments to LAI 5. The relationship of Pnc to LAI of swards in the regrowth phase was predominantly curvilinear and such that over much of the LAI range they had a greater photosynthetic potential than the same swards being grazed down from high to low mass. Daily rates of CO2 uptake and growth in the field were calculated for one continuously stocked experiment. Both were linearly related to LAI in the range LAI 2–4·5. The agronomic implications of the results are discussed.
The reproducibility of in vivo estimates of digestibility and voluntary digestible organic matter intake of grass varieties by sheep
Authors: EVANS E. M. , POTTER J. F. 
Published: April 2006

AbstractFour cocksfoot varieties were harvested at three different growth stages and offered ad libitum to yearling Clun wethers in three 24‐d feeding trials indoors over a 4‐month period. A further cocksfoot variety conserved in bulk was offered concurrently as a control feed.The concentration of digestible organic matter in the dry matter (DOMD) and voluntary intake were measured in each feeding period. There was no significant change in the measured DOMD values between the different feeding periods. Voluntary intake of digestible organic matter (DOMI) increased over the 4‐month period for all four varieties and for the control feed. The increase in intake was greatest for the most digestible material, i.e. first‐cut harvests. Differences in DOMI were statistically significant between feeding periods for all varieties but the differences could be eliminated by correcting intakes with values from the control feed. It is concluded that comparisons of grass varieties involving intake measurements must either be made in the same feeding period or a control feed included and results corrected according to the control response.
The utilized metabolizable energy output of grassland on hill farms in Northern Ireland
Authors: McADAM J. H. 
Published: April 2006

AbstractForty hill farms in Northern Ireland were surveyed to obtain information on stocking rates and output and to identify factors affecting output. The mean farm area of 194 ha was composed of 155 ha hill land and 39 ha inbye land with a mean stocking rate of 0–7 cow‐equivalents ha−1.On the average farm most of the grassland (88%) was over 20 years old. The preferred species content of the swards averaged 22% over the whole farm and 42% in cut swards. This latter result may be attributed to the relatively high level of fertilizer N applied to these swards (131 kg ha−1) compared to the mean application rate over the whole farm of only 29 kg N ha−1 and 93 kg ha−1 applied to the inbye land.Output data calculated as utilized metabolizable energy (UME) per unit area for the whole farm and separately for hill and inbye components showed that although only 21% of the farm area was inbye land almost half the annual total metabolizable energy requirements of stock had to be met by grazing inbye. The capacity of herbage to meet stock energy demands was much lower on the hill with supplementary feed having to be provided over the winter.Calculated output from inbye land was 39 GJ ha−1 compared to 7 GJ ha−1 from the hill and 15 GJ ha−1 from the whole farm. UME output of the whole farm was negatively correlated with farm size (r=−0 55) and positively correlated with stocking rate (r = 0 89), applied N level (r = 0 63)
The distribution of opaline silica bodies in the leaf sheaths of two perennial ryegrass cultivars differing in their susceptibility to attack by dipterous stem‐borers
Authors: MOORE D. 
Published: April 2006

AbstractLeaf sheaths of two cultivars of perennial ryegrass were prepared by chemical oxidation so that the silica bodies in the tissues could be studied. The cultivar Fortis, which is relatively resistant to stem‐borer attack, contained many‐intercostal silica bodies in the leaf sheath but the more susceptible cultivar S24 contained few. If the pattern of silica bodies affects levels of stem‐borer infestation, it may be possible to breed for this characteristic.
Defoliation of ryegrass‐dominated swards by sheep
Authors: BARTHRAM G. T. , GRANT SHEILA A. 
Published: April 2006

AbstractPatterns of defoliation in perennial ryegrass‐dominated swards were examined in two experiments. In Experiment I measurements were made on four swards after a single overnight grazing. In Experiment 2 observations were made repeatedly on marked tillers in two continuously stocked swards which were grazed down over a 24‐d period. In both experiments the chance of defoliation was related to lamina height both within and between age classes. Lamina angle was measured in Experiment 2 and within age classes the chance of defoliation was also independent of lamina angle. In Experiment 1 tillers most frequently had both of the two youngest laminae grazed; in Experiment 2 tillers with only lamina 1 grazed occurred most frequently, but defoliation of the two youngest laminae was again common.The different frequencies of grazing of the different classes of laminae is interpreted as being a function of their frequency of occurrence within the grazed layer at the top of the sward. The pseudostem apparently restricted the depth of the grazed layer in the very short swards of Experiment 2.Grazing behaviour in relation to sward structure and the patterns of defoliation and their implications for herbage production are discussed.
Orchardgrass and perennial ryegrass with applied nitrogen and in mixtures with legumes
Authors: SOLLENBERGER L. E. , TEMPLETON W. C. , HILL R. R. 
Published: April 2006

AbstractBotanical composition of swards can markedly affect their productivity, forage quality, and acceptance by animals. The objective of this research was to determine the amounts of dry matter (DM) and N harvested in the different botanical components of swards where perennial ryegrass and orchardgrass were sown alone and fertilized with N, or sown in mixture with legumes.Broadcast sowings were made on conventionally prepared seedbeds in August 1979 and May 1980 on a Hagerstown silt loam soil (fine, mixed mesic Typic Hapludalf). When seeded alone, orchardgrass cv. Pennlate and perennial ryegrass cv. Reveille received rates of N ranging from 0 to 448 kg ha−1 a−1. The grasses were also grown in mixtures with alfalfa cv. Arc, red clover cv. Arlington, or birdsfoot trefoil cv. Viking. The same legumes were sown alone. Four legume seed rates were used in both the pure legume and mixed stands.Legume DM harvests were greater in mixtures with perennial ryegrass than in legume‐orchard‐grass swards. An exception occurred in the first year as birdsfoot trefoil harvested DM was lower in trefoil‐ryegrass swards than in trefoil orchardgrass mixtures, probably owing to vigorous competition from ryegrass in the seedling stage. As legume seed rates were increased, both the legume and grass components of mixed swards produced more DM and N. Grass DM and N harvested in orchardgrass mixtures exceeded those of ryegrass mixtures for the 3‐year period.Sward weediness, most prevalent in pure legume stands planted at low seed rates, was sharply reduced by including either grass with the legumes. Volunteer legumes contributed to DM harvested only when the grasses were sown alone and not fertilized with N.Species differences in crude protein (CP) concentration were significant. Birdsfoot trefoil had the highest CP of the legumes, averaging 241 g (kg DM)−1. Alfalfa and red clover averaged 219 and 208 g CP (kg DM)−1 respectively. Perennial ryegrass herbage had a higher CP concentration than that of orchardgrass in both pure and mixed swards. Grass CP increased significantly in response to fertilizer N and to higher legume seed rates.