bluuebunny/crossref_metadata_2025_split huggingface dataset:
Quantifying the effect of nitrogen fertilizer applications in spring on white clover content in perennial ryegrass‐white clover swards
Authors: LAIDLAW A. S. 
Published: April 2006

AbstractData are presented for the fourth (1979) and fifth (1980) harvest years of a trial in which four levels of N fertilizer (0, 30, 60 and 90 kg N ha−1) were applied each spring to swards with grass (perennial ryegrass cv. Barlenna) and each one of four cultivars of while clover (Blanca, Sabeda, Olwen and S100) or grass alone. Results from the first three years have been published.Dry matter (DM) harvested dropped from the fourth to fifth years over all swards by 1 −5 to 2 0 t ha−1 but response to N was maintained (17.4 and 24.4 kg DM (kgN)−l in response to 90 kg N ha−1 in 1979 and 1980 respectively) despite reductions in summer yields relative to unfertilized swards. Blanca swards produced significantly less DM harvested than all other cultivars in 1979 and all cultivars in 1980 except for Olwen. Clover DM harvested continued to fall from 1977, the mean for the unfertilized treatment in 1980 being 55% of that in 1979. Up to 1980 Sabeda swards produced more clover DM harvested than Blanca swards. Linear regressions between annual clover content at zero N and at each spring N level for each sward type over 5 harvest years were very highly significant. It is concluded that all cultivars used responded similarly to spring N. Further work to develop a method for predicting the effect of spring N on clover content of given swards is required.
The impact of low numbers of leatherjackets on grass yield
Authors: BLACKSHAW R. P. 
Published: April 2006

AbstractExperiments were carried out on seven sites in Fermanagh to investigate the yield loss caused by leatherjackets in grassland. Populations on the sites ranged from 65,000 to 865,000 ha−1 and significant damage was recorded from all sites except the least populated. Greater yield increases were obtained by controlling leatherjackets in September when compared with control in March. Regression models were fitted and it was found that 125,000 leatherjackets ha−1 in March caused a yield loss of 50 kg herbage dry matter (DM) ha−1 by mid‐May. Based on these figures the average yield loss to leatherjackets in Northern Ireland, from 1965 to 1982, was 208 kg DM ha−1. Controlling leatherjackets in September, rather than March, increased the potential avoidable yield loss by a factor of 2.72. The average yield loss at first silage cut is therefore 566 kg DM ha−1. On average, 100,000 ha grassland in Northern Ireland may be suffering an annual loss of 1t herbage DM ha−1.
The influence of soil wetness on utilized output from grassland on commercial farms
Authors: MATKIN ELIZABETH A. , PEEL S. , THOMASSON A. J. 
Published: April 2006

AbstractRecords of grassland productivity have been used for 93 farms in 1975–76 (a dry year) and 117 farms in 1977–78 (a wetter year). The samples were selected to contrast well‐drained and poorly/ badly drained farms and were further subdivided into dairy and beef. The number of farms in each of the four subsamples for each year was between 19 and 32. In addition the number of days on which the soil was at meteorological field capacity (field capacity days) on each farm was calculated.The mean utilized metabolizable energy (UME) output within the dairy sample was 45 GJ ha−1 on both well‐drained and poorly/badly drained farms. Within the beef sample the output was 41 GJ ha−1 on well‐drained farms and 37 GJ ha−1 on the poorly/badly drained farms.The correlation between fertilizer N and UME output was stronger on well‐drained farms than on the poorly/badly drained farms in the wetter year (r = 0.69 v. 0.16 on dairy farms; r = 0.56 v.− 0.12 on beef farms). In the drier year the converse was found (r=0.15 v. 0.49 on dairy farms; 0.13 v. 0.44 on beef farms). The effect of field capacity days on output was inconsistent; only within the dairy sample in the wetter year did increased wetness appear to reduce output.It is suggested that soil wetness may have only a small effect on utilized output from grassland on a whole‐farm basis because (i) most farms have at least some well‐drained land, (ii) much of the utilization damage occurs in relatively short periods in spring and autumn and (iii) despite having utilization problems, badly drained land is capable of growing large quantities of grass.
The winter hardiness of Festuca rubra, Holcus lanatus and Agrostis spp. in comparison with Lolium perenne
Authors: JONES P. K. , CHARLES A. H. 
Published: April 2006

AbstractPreliminary experiments were conducted to assess the winter hardiness of representative cultivars or populations of Festuca rubra, Holcus lanatus and Agrostis spp. in comparison with a hardy (Premo) and a susceptible (Grasslands Ruanui) cultivar of Lolium perenne. Two controlled‐environment tests and a field experiment including two cutting and two fertilizer managements are reported.Grasslands Ruanui andH lanatus suffered most damage in all tests. In the controlled‐environment experiments, Premo was at least as hardy as the F. rubra and Agrostis cultivars but in the field Premo was more susceptible. Spring growth of Premo was affected more by the cutting and fertilizer managements applied the previous summer and autumn than was spring growth of F. rubra or Agrostis spp.It was concluded that, whereas use off. F. rubra or Agrostis spp. should not be limited by fears of winter damage, poor winter hardiness may limit the value of H. lanatus for hill and upland reseeding.
Nitrate in silage
Authors: SPOELSTRA S. F. 
Published: April 2006

AbstractDue to intensive Fertilizer application most silage crops contain appreciable amounts of nitrate. During silage fermentation the nitrate is completely or partially degraded. End‐products are ammonia and nitrous oxide with nitrite and nitric oxide occurring as intermediates. Factors that influence nitrate degradation and the levels of end products and intermediates found in silages are reviewed. The role of plant nitrate reductase and of enterobacteria, Clostridia and lactobacilli in nitrate catabolism and the significance for silage quality are discussed. Attention is paid to silo‐filler's disease, an illness of farm workers that is caused by inhalation of oxides of nitrogen, and to the occurrence of nitrosamines in silages.
Comparative studies of the influence of sward conditions on the ingestive behaviour of cows and sheep
Authors: FORBES T. D. A. , HODGSON J. 
Published: April 2006

AbstractSeparate groups of non‐lactating cows and wether sheep grazed at similar herbage allowances for two successive 5‐d periods on swards that had previously been grazed frequently or infrequently with the intention of creating differences in canopy structure. Measurements were made of sward structure and composition, ingestive behaviour and diet composition. The preliminary treatments had little effect upon either sward conditions or animal behaviour.Herbage mass was reduced from 4020 kg dry matter (DM) ha−1 to 3290 kg DM ha−1 on average over a 5‐d grazing period as a consequence of the relatively low grazing pressure imposed. This resulted in a mean decline in intake per bite of 28%, and the changes for cattle and sheep did not differ significantly. However, there was a marked difference in the other behavioural responses of the two species; in the sheep biting rate fell and grazing time increased with declining herbage mass, particularly in the sward previously grazed infrequently, whereas the changes in the cattle were small.Differences in the botanical composition of the herbage eaten by cattle and sheep were minor, but there was a small but consistent advantage to the sheep in the digestibility of the herbage eaten.In the first of the two periods the variation in surface height after grazing was substantially greater for sheep‐grazed than for cattle‐grazed swards, indicating more patchy grazing by the sheep.Estimates of daily herbage organic matter (OM) intake calculated from ingestive behaviour variables were high (means 38 and 32 g (kg LW) −1 for cattle and sheep respectively) and usually declined substantially over a grazing period.
The use of a reflectance ratio meter to monitor grass establishment and herbicide damage
Authors: HAGGAR R. J. , ISAAC S. P. 
Published: April 2006

AbstractA sensor which detects the presence of green vegetation against a brown background was used to monitor the establishment of plots of Lolium perenne and Poa trivialis, either hand weeded or unweeded. The spectral assessments obtained by the meter were very closely related to the proportion of ground cover, assessed photographically, and harvested dry weight of the two species, at least up to 100 days (approx. 50% ground cover) from sowing, Such spectral assessments therefore provide a rapid, non‐destructive method of monitoring changes in green‐leaf biomass of establishing grasses. In a complementary investigation the meter provided accurate and objective assessments of scorch damage to grasses caused by various herbicides.
Slot‐seeding investigations. 4. Effect of phosphate fertilizer and grass suppressant on the establishment and growth of white clover in permanent pasture
Authors: WILLIAMS E. D. , HAYES M. J. , HAGGAR R. J. 
Published: April 2006

AbstractWhite clover (cv. Grasslands Huia) was slot‐seeded in April 1982 into plots of permanent pasture of differing botanical composition and reserves of soil phosphate. In one investigation the short‐term effects of placing different amounts of phosphate (P2O5) in different positions in relation to the slot were investigated. In another, emphasis was given to effects of a grass‐suppressing herbicide, propyzamide, on herbage growth and clover contributon during the second year.Fewer seedlings established on plots with a high initial P status and abundant in Holcus lanatus and Alopecurus pratensis than on plots deficient in P2O5 and dominated by Agrostis capillaris and Festuca rubra. P2O5decreased numbers of establishing clover seedlings when applied in the slots but not when placed beneath them. Growth was increased most when placement was beneath the slot. Application of P2O5to plots previously supplied with it resulted in 7.2 g total above ground and 1.7 g stolon dry weight (m row)−1compared to 1.3 and 0.1 g respectively in plots with low reserves and DO applied P2O5.Propyzamide greatly increased the yield and the contribution of clover in the presence of high initial P status and applied P2O5. Without propyzamide, clover made only a small contribution until July, averaging 7% for the whole season with little benefit from residual P. Clover growth in late summer was increased from 41 to 292 kg DM ha−1 where P2O5 was applied to P‐deficient plots sprayed with propyzamide in the previous autumn. The large increases in clover contribution following propyzamide application were accompanied by small decreases in total seasonal yield of grass. The proportions of H. lanatus and. F. rubra. were decreased and of A. capillaris, increased.Spread of clover from the slots was slow during the first year but was encouraged by both P2O5 and propyzamide during the second year. Factors requiring further investigation are discussed.
South‐west England grassland survey 1983. 2. Trends in cropping pattern, reseeding and sward composition 1970–83
Authors: PEEL S. , MATKIN ELIZABETH A. , ELLIS JULIA A. , HOPKINS A. 
Published: April 2006

AbstractSeventy‐eight farms in south‐west England, originally visited in 1970–72, were revisited in 1983 in order to identify changes in land use and re‐seeding over the c. 12‐year period; changes in sward composition were assessed on fifty‐nine of these farms. The results were also compared with Ministry of Agriculture, Fisheries and Food (MAFF) Census results and MAFF Seeds Branch data.The proportion of tillage had declined from 29 to 24%. This was in agreement with census results for the south‐western counties, but contrasted with those for England and Wales as a whole, which showed an increase from 38.8 to 41.7% tillage. It is indicative of grass becoming more predominant in south‐west England as east England has become more dominated by tillage cropping.There had also been a decline in the amount of short‐term grassland. In 1970–72 17% of the grassland was intended to last from 1 to 4 years; in 1983 the proportion was only 10%. That these intentions were being carried out was confirmed by the fact that in 1983 there was more grassland in each of the age categories 5·8,9·20 and over 20 years. The trend towards older grassland confirms that shown by regional and national census data, and the trend away from short‐term swards is in line with deliveries of herbage seed which indicate reduced use of Italian ryegrass (Lolium multiflorum).Botanical composition had changed appreciably, with the proportion of Lolium perenne having increased in swards of all ages, e.g. from 35 to 51% in swards 5–8 years old and from 17 to 31% in those aged over 20 years. Other sown species, predominantly Dactylis glomerata and Phleum pratense, had declined markedly in swards over 4 years old. The proportions of Agrostis spp., Festuca spp. and Poa trivialis had fallen, but Holcus lanatus had increased slightly. There had been a marked reduction in infestations of perennial broad‐leaved weeds, particularly Ranunculus, but also Rumex and Cirsium spp.
The effect of system of silage harvesting and feeding on milk production
Authors: Gordon F. J. 
Published: April 2006

AbstractTwo silages were produced by harvesting grass either unwilted, using a direct cutting flail forage harvester (flail‐direct), or wilted following precut‐ting and being picked up using a meter‐chop harvester (precision‐wilted). Formic acid was applied at the rates of 2·45 and 2·9 1 t‐1 for the flail‐direct and precision‐wilted silages, respectively. Weather conditions were difficult, both before and during harvesting with a total of 27 mm rainfall falling on the wilted herbage before ensiling.The in‐silo dry matter losses were 199 and 68 g kg‐1 for the flail‐direct and precision‐wilted silages, respectively. The resulting silages had mean particle lengths of 49 and 24 mm, dry matter contents of 186 and 276 g kg‐‐1 and D‐values of 068 and 062 for the flail‐direct and precision‐wilted silages, respectively.During a 141‐day feeding period commencing on 19 November, the two silages were offered to 88 British Friesian cows with a mean calving date of 21 January and divided into four groups in a 2×2 factorial design experiment. The silos were divided longitudinally and two groups of cows were self‐fed the silages in situ, one for each silage type, while the other two groups were easy‐fed the same silages along a feed fence.There were no significant interactions between system of silage harvesting and feeding on any of the measurements of animal performance. Animals on the flail‐direct silage consumed 16% less silage dry matter and produced 10% more milk per cow than those on the precision‐wilted silage treatment. The overall effect was a 12% greater milk output for each unit of grass dry matter ensiled with the flail‐direct than with the precision‐wilted harvesting system.System of silage feeding did not significantly influence silage intake or milk output, with the mean milk yields during the final 21 days of the study being 234 and 236 kg d‐1 (±0.30) for the self‐ and easy‐feed systems, respectively.The effects of the treatments on milk composition, liveweight change, body condition score and total ration digestibility are also reported.
Potential seed yield of white clover varieties
Authors: EVANS D. R. , WILLIAMS T. A. , DAVIES W. ELLIS 
Published: April 2006

AbstractFifteen varieties of white clover were sown in order to assess the seed yielding ability of new and potential varieties and to examine those plant factors which affect seed yield. Counts were made on number of inflorescences m‐2, proportion of ripe inflorescences and other inflorescence and seed characters. The data were used to compute potential seed yields.Average potential seed yields were 276 and 76 kg ha‐1 in the first and second year, respectively. The decrease in the second year seed yields underlines the overriding effect of adverse weather conditions during the critical June to August period. The major effect was a reduction in the number of inflorescences produced, the number of florets per inflorescence and seeds per floret.Some of the new listed varieties have a significantly higher seed potential than SI00, e.g. Menna (+ 38%) and Olwen (+28%), and this should facilitate the production of adequate seed supplies of British bred varieties.
Organic and inorganic fertilization compared in a natural Mediterranean grassland
Authors: LIACOS L. G. , PAPANASTASIS V. P. 
Published: April 2006

AbstractThe effect of goat slurry on species composition and herbage production as compared to inorganic fertilizer was studied in a natural grassland dominated by warm and cool season perennial grasses in Macedonia, Greece. Goat slurry was applied in early spring every 1 or 2 years at a rate of 40 t ha‐1 being equivalent to about 160 kg N ha‐1 and 100 kg, P2O5 ha‐1. Inorganic fertilizer was also broadcast in early spring at a rate of 80 kg N ha‐1 and 100 kg P2O5 ha‐1 every 2 years. Measurements of the basal cover of the dominant species or groups of species and herbage yields were taken for 6 years at the end of the growing period in June, while in the seventh year the experiment was grazed with goats. It was found that goat slurry improved species composition more than the inorganic fertilizer by depressing the less palatable warm season grasses and favouring the subdominant cool season grasses and legumes. Goat slurry significantly increased herbage yields in most of the years. It is suggested that the optimum rate of goat slurry is 40 t ha‐1 every 2 years as this encourages plants most preferred by goats.
Effect of cultivar and seed rate of perennial ryegrass and strategic fertilizer nitrogen on the productivity of grass/white clover swards
Authors: FRAME J. , BOYD A. G 
Published: April 2006

AbstractFour cultivars of perennial ryegrass (intermediate diploid cv. Talbot and tetraploid cv. Barlatra, and late diploid cv. Parcour and tetraploid cv. Petra) were each sown at 10,20 and 30 kg ha‐1, all with 3 kg ha‐1 of white clover cv. Donna. Herbage productivity was measured over 3 harvest years, 1982–84. under two annual rates of fertilizer N (0 and 150 kg ha‐1); the 150 kg ha‐1 rate was split equally between March and August applications.Fertilizer N increased total herbage DM production; the 3‐year means for the 0 and 150 kg ha‐1 N rates were 8·04 and 8·91 t ha‐1, respectively. In successive years, total herbage responses to N (kg DM (kg N applied)‐1) were 6·6, 35 and 72 (overall mean, 58). Mean white clover DM production over the 3 years was reduced from 4·48 t ha‐1 at nil N to 2·82 t ha‐1 at the 150 kg ha‐1 rate, a fall of 37%. Grass seed rate did not influence total herbage production or white clover performance. The two intermediate perennial ryegrass cultivars had a marginal advantage in total herbage production over the two late cultivars, but white clover content and production were higher with tetraploids than diploids.It is concluded that the value of increased herbage production from strategic use of fertilizer N has to be weighed against its depressive effect on white clover performance; application of 75 kg ha ha‐1 N in both spring and autumn was excessively high if maintenance of a good white clover content in the sward is an objective. There is considerable flexibility in the grass: clover seed ratio in seeds mixtures. Modern highly‐productive perennial ryegrass varieties do not differ substantially in compatibility with white clover but tetraploids permit better clover performance than diploids.
Growth of naturally occurring Listeria spp. in silage: a comparative study of laboratory and farm ensiled grass
Authors: FENLON D. R. 
Published: April 2006

AbstractA laboratory method for ensiling grass in bags, which simulates the aerobic deterioration found in big bale silage, is described. These conditions selectively encouraged the multiplication of naturally occurring listeria. All grasses ensiled in this way gave detectable numbers of listeria, usually L. monocytogenes, indicating that these bacteria are a normal part of the microflora of grass. The results from the laboratory silage were comparable to those found in the same grass ensiled in big bales on the farm.
The estimation of dry green biomass in hayfields from canopy spectroreflectance measurements
Authors: BÉDARD J. , LAPOINTE G. 
Published: April 2006

AbstractSpectral reflectance measurements were found useful in estimating the dry green biomass (DGB) in hayfields in eastern Québec, Canada. The calibrated measurements of reflectance obtained in the 650 and 800 nm bands (respectively defined as the RED and NIR indices), the NIR/RED ratio, and the ratio (NIR‐RED)/(NIR + RED) were used to generate various regression models which explained between 74 and 90% of the variance in DGB. The proportion of legumes, grasses and herbs in the canopy had no apparent influence on the reflectance measurements or on the value of the models.
The effect of fertilizer nitrogen rate, white clover variety and closeness of cutting on herbage productivity from perennial ryegrass/white clover swards
Authors: FRAME J. , BOYD A. G. 
Published: April 2006

AbstractFour varieties of white clover (small‐leaved cv. Aberystwyth S184. medium‐leaved cv. Grasslands Huia and large‐leaved cvs Linda and Olwen) were sown at 3 kg ha‐1 together with 10 kg ha‐1 perennial ryegrass cv. Talbot. Herbage productivity was measured for three harvest years, 1979‐81, over four annual rates of fertilizer N (0,120,240 and 360 kg ha‐1) and two closeness of cutting treatments (80 and 40 mm from ground level). A simulated grazing regime of six cuts per year at 3‐ to 6‐week intervals was used.Production of total herbage DM was increased by increasing N rate; mean annual DM production ranged from 783 1 ha‐1 with no N to 11701 ha‐1 at 360 kg ha‐1 N. Mean herbage response to N (kg DM per kg N applied) was 73,90 and 108 for the three successive N increments relative to no N. Mean white clover DM production was reduced from 4 14t ha‐1 with no N to 051 t ha‐1 at 360 kg ha‐1 N.The large‐leaved clover varieties were more productive than the small‐ or medium‐leaved varieties at all N rates. Close cutting increased total herbage and white clover by a mean annual 16% and 31%. respectively. White clover varieties did not interact with either N rate or closeness of cutting.It is concluded that repetitive N application over the growing season is incompatible with white clover persistence and production, even with large‐leaved clover varieties or with close cutting, two factors which improved clover performance in the experimental swards.