bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of pesticides and fertilizer on invertebrate populations of grass and wheat plots in Kent in relation to productivity and yield
Authors: LINZELL BRIGITTE S. , MADGE D. S. 
Published: April 2006

AbstractAt a site in Kent, perennial ryegrass (Lolium perenne) variety S24 and Italian ryegrass (L. multiflorum) variety RVP, wheat varieties Armada and Norman, and the original mixed grass ley were grown in small plots during 1982–84. Two toxic pesticides (phorate and aldicarb) were applied to half the total number of plots three times each year to eliminate soil invertebrate populations. Fertilizer was also applied to most plots. The yields of the crops, grown with and without pesticide, and the effects of the fertilizer were compared. Grass herbage yield was measured on three occasions during the summers of 1983 and 1984. Wheat grain yields were also determined in 1983.During the first year significant differences were not apparent in grass dry matter yield between pesticide‐treated and non‐treated plots, but significant differences were found in the second year. The perennial ryegrass was more susceptible to pest damage than the Italian ryegrass or the grass ley. Grass yields varied between cuts and in relation to variety and pesticide treatment, yields tending to be greater in untreated plots. Fertilizer treatment greatly increased grass dry matter yields, particularly with the Italian ryegrass. The effects of pesticide treatment on both wheat varieties varied although some yield enhancement was evident.Invertebrate animal populations in pesticide and fertilizer‐treated plots were also assessed in autumn 1982, spring and autumn 1983 and spring 1984. In contrast to pesticide treatment, fertilizer treatment had little effect on soil invertebrate populations. Nematode populations were reduced at each sampling occasion by the pesticide treatment. Slug populations were initially unaffected but were subsequently reduced. Leatherjackets, by far the most abundant pest in both grass and wheat plots, were markedly affected by pesticides on all sampling occasions. Generally, fewer soil‐dwelling dipterous larvae were recovered in spring than in autumn. Stem‐boring dipterous larvae were virtually absent.
Effect of three clover varieties on growth, 15N uptake and fixation by ryegrass/white clover mixtures at three sites in Wales
Authors: GOODMAN P. J. , COLLISON M. 
Published: April 2006

AbstractGrass and clover production and nitrogen cycling were compared in 1983 and 1984 at three sites: an upland peaty gley and upland and lowland brown earths. The clover varieties Olwen and S184 were compared in 1983 and S100 and S184 in 1984. Ammonium and nitrate sources of 15N were used to measure nitrogen recovery from fertilizer and soil, nitrogen fixation and nitrogen transfer from clover to grass. Acetylene reduction was measured once, in 1983, but isotope dilution was used in both years.Olwen clover produced more dry matter and took up more 15N than S184. Olwen fixed more nitrogen than S184 over the whole season, as measured by 15N isotope dilution. Companion grass took up more soil nitrogen when growing with S184 than with Olwen. The clover variety S100, tested at the lowland site in 1984, caused no significant variations in dry matter accumulation or N fixation.In the dry 1984 season, grass dry matter accumulation and 15N uptake were less than in 1983, and plants actually lost total nitrogen from their roots to the soil. Fixation rate varied more in 1984 than in 1983. Nitrogen transfer from clover to grass was detected by isotope ratio differences in 1983, and by total N differences in 1984.Site differences were dominated by the greater dry matter accumulation of Olwen in the lowland in 1983, but in that year there was also increased dry matter accumulation and increased 15N fertilizer uptake, but less nitrogen fixed on the mineral upland site than on the peat soil.Whether 15N was given as ammonium or nitrate made little difference in these experiments.
Effect of fertilizers on the yield and chemical composition of pure sown white clover and on soil nutrient status
Authors: EVANS D. R. , THOMAS T. A. , WILLIAMS T. A. , DAVIES W. ELLIS 
Published: April 2006

AbstractThe effects of three levels of potash, phosphate and lime fertilizers on the yield and mineral content of white clover (Trifolium repens) and on soil nutrient levels were studied in a field experiment over 7 years. The aim of the experiment was to define an optimum fertilizer programme for breeding nurseries and experimental fields.Potash was the main factor limiting production: clover yield was negligible after 2 years where no potassium was applied. Phosphate increased yields after the third year, while liming had no significant effect on clover yield.The soil potassium status improved with the repeated application of potash over the 7–year period, but no consistent pattern was discernible for the phosphate treatments. There was a slight increase in soil pH with liming.Application of phosphate increased the phosphorous content of herbage, but had no effect on other plant constituents for the first 2 years. Subsequent applications increased the calcium and sodium contents. Potash reduced the content of all constituents other than potassium as the treatment levels increased. Lime had little effect on plant constituents other than calcium.
Coefficients for the dry‐weight rank method of botanical analysis of pasture
Authors: SCOTT D. 
Published: April 2006

AbstractThe coefficients of the dry‐weight‐rank (DWR) method ('t Mannetje & Haydock, 1963) can be predicted from the general occurrence of the geometric series relationship between abundance and rank of species in a pasture using either an estimate of the percentage contribution of the first ranked species, or from the ratio of the contribution of two species.
Lime and major nutrient fertilizers required to establish a perennial ryegrass/white clover pasture on a non‐calcareous gley in the Scottish uplands
Authors: RANGELEY ANNE , BOLTON R. 
Published: April 2006

AbstractA field experiment with mixed swards of perennial ryegrass and while clover carded out in 1982–83 using small cut plots is described. With perennial ryegrass, lime slightly decreased annual dry matter (DM) production in 1982 (the sowing year) but increased it in 1983 (the first harvest year) by about 1 t ha‐1. Applications of N and P produced small increases in DM in 1982 and greater increases in 1983. In the latter season annual DM production varied from an average of 3·5 to about 10 t ha‐1 with 0 or 480 kg N ha‐1 applied in three equal‐sized dressings throughout the growing season. Application of 40 kg P ha‐1 in 1982 increased DM production by about 2·5 t ha‐1 in 1983 but higher rates had little effect. Fifteen mg extractable P kg‐1 soil seemed sufficient to support levels of production normally expected from ryegrass pastures in upland Scotland, Applications of K did not affect DM production. N increased tiller weight and sward height of ryegrass; lime and P tended to increase tiller weight but this effect was not statistically significant. Leaf appearance and tiller number were not affected by treatments.The white clover content of the pasture was decreased 10‐fold by application of N and increased by lime and P (1·45 and 1·46‐fold. respectively). The DM response to P was most apparent in limed soil and was also affected by the siting of the plots in the experimental area. Effects of lime and P on growth of white clover were to increase the number of stolon growing points and root nodule numbers per unit area.The results emphasize the importance of lime and P fertilizer for establishment and growth of pasture in this soil and the differences between white clover and ryegrass in their responses to these.
Effect of stocking rate in early season on dairy cow performance and sward characteristics
Authors: BAKER ANNE‐MARIE C. , LEAVER J. D. 
Published: April 2006

AbstractA comparison was made of stocking rates of 4·7, 5·6 and 6·4 cows ha‐1 during the first 7 weeks (period 1) of the grazing season. Each group of British Friesian cows was continuously stocked on a day and a night field. In the subsequent periods 2 and 3 (each lasting 7 weeks) the three groups were maintained at the same stocking rate within periods (4·2 and 31 cows ha‐1, respectively). The differential stocking rates were achieved by the addition and removal of cows.The stocking rates applied in period I had no significant effects on milk yield, milk composition, liveweight change or condition score, in any period. Milk production ha‐1 over the three periods totalled 12390,13 978 and 14986 kg, and the estimated utilized metabolizable energy totalled 773, 81·5 and 86·6 GJ ha‐1 for low, medium and high stocking rates, respectively.Increased stocking rate in period I was associated with a decrease in sward height in periods 1 and 2. This led to an increase in herbage metabolizable energy, and crude protein contents, and to an increase in tiller population density. The lowest stocking rate gave greater live individual tiller weights throughout the experiment and a longer interval between defoliation of individual tillers in period 1.The results indicate that high stocking rates in the spring are not necessarily detrimental to overall summer performance of spring calving dairy cows. However, high stocking rates in the early season ensure a high level of herbage utilization and milk output ha‐1 in that period. Although this practice leads to a reduced sward height in mid season, the sward has less rejected area, a higher tiller population density and a higher digestibility than swards stocked at a lower level.
Growth of white clover in eight grass species and the effects of propyzamide, a grass‐suppressing herbicide
Authors: WILLIAMS E. D. , HAYES M. J. 
Published: April 2006

AbstractSeedlings of white clover (cv. Grasslands Huia) were introduced as spaced plants into 3‐year‐old monoculture plots of eight grass species (Agrostis capillaris, Agrostis stolonifera, Dactylis glomerata, Festuca rubra, Holcus lanatus, Lolium perenne, Phleum pratense and Poa pratensis) during June 1984. In mid‐April 1985 plots were split for application of propyzamide at the following concentrations: 0, 0·2, 0·4, 0·6 kg a.i. ha‐1.During 1984 differences between clover seedling growth in the different grass species became apparent within 2 weeks; growth was greatest in F. rubra, P. pratensis and H. lanatus and smallest in D. glomerata, L. perenne and P. pratense. During 1985, when more N fertilizer was given, H. lanatus and D. glomerata, were equally competitive and clover contributed only 16–18% of the total herbage yield of 10·4 t ha‐1 in them, compared with 33–50% of yields ranging from 9·6 to 119 t ha‐1 in the other six species. Propyzamide decreased grass growth in mid‐season by more than 50% but there was little overall persistent benefit to clover yield, except for A. stolonifera and P. pratense with 0·4 and 0·6 kg ha‐1 treatments. Dactylis glomerata and perenne were least and H. lanatus, F. rubra and P. pratensis most suppressed by the herbicide.Possible reasons for the overall large clover contribution from a very sparse seedling population and the relatively small effects of propyzamide are discussed as well as future work required to improve the predictability of effects of grass suppression.
The influence of forage quality and concentrate level on dry matter intake and milk production of British Friesian heifers
Authors: PHIPPS R. H. , WELLER R. F. , BINES J. A. 
Published: April 2006

AbstractThirty‐six British Friesian heifers were divided into two groups during weeks 3‐26 of lactation and received ad libitum either good (G) or average (A) quality grass silage. The in vitro digestible organic matter in the DM was 680 and 600 g kg‐1 for silages G and A, respectively. In addition, the heifers in each group were offered concentrate at either a low (4.3 kg DM d‐1), medium (64 kg DM d‐1) or high (8.4 kg DM d‐1) level. The concentrate contained 180 g (kg DM)‐1 of crude protein and had a calculated metabolizable energy concentration of 12.9 MJ (kg DM)‐1.Increasing concentrate level significantly increased milk yield (P < 0.01), milk protein concentration (P < 0.05), and yield of both milk protein depressed milk fat concentration (P < 0.001) and silage intake (P < 0.001).Although the overall effect of silage quality on milk yield was not significant, the milk yields for silage G at each concentrate level were higher, significantly so for low level, than the corresponding values for silage A. An improvement in silage quality did not affect milk fat concentration but significantly increased the concentration of milk protein (P < 005) and yields of both milk fat (P < 005) and protein (P < 0001). The response of silage DM intake to improved silage quality was 0 06 kg DM per 10 g rise in vitro DOMD value. Each additional kg concentrate DM depressed intake of silages G and A by 0‐63 and 0‐27 kg DM, respectively. Substitution rate was also significantly related to stage of lactation.With both silages, the digestibility coefficients determined in vivo for acid detergent fibre (ADF) decreased significantly (P < 0.001) when concentrate level was increased from low to high. Differences for DM, OM and total N digestibility coefficients between treatments were not established as significant at the 5% level.Estimates of mean efficiency of utilization of ME for lactation, made on a weekly basis, were 049 and 052 for the heifers given silages G and A. respectively, and 048, 052 and 052 for those given the low, medium and high levels of concentrate. Energy balances were calculated on a mean weekly basis.
The effect of cutting and grazing managements on dry matter yield of white clover varieties (Trifolium repens) when grown with S23 perennial ryegrass
Authors: EVANS D. R. , WILLIAMS T. A. 
Published: April 2006

AbstractThe effects of three defoliation treatments upon the performance of eight white clover varieties when grown with S23 perennial ryegrass were investigated. These treatments included a cutting only regime as used in National List trials and rotational and continuous sheep grazing.There were significant (P<0·001) differences between treatments, and the ranking of clover varieties also differed between the three treatments. The significance of this finding is discussed in relation to the evaluation of breeding material and varieties prior to recommendation to farmers.Clover yields were less under grazing than cutting. This was due mainly to the selective grazing and removal of stolon material which occurred in the former treatments. Differences in the grass/clover balance resulting from the three treatments are discussed in relation to the degree of protection afforded to the clover stolons by the grass component.
Silage intake and milk production in cows given barley supplements of reduced ruminal degradability
Authors: KASSEM M. M. , THOMAS P. C. , CHAMBERLAIN D. G. , ROBERTSON S. 
Published: April 2006

AbstractThree change‐over experiments were conducted to determine the effect on ad libitum silage intake and milk production in dairy cows of treatment of barley supplements with an acid‐formaldehyde reagent designed to reduce the rate of starch and protein digestion in the rumen. In Experiment 1 there were six dietary treatments consisting of silage with supplements of 4·0,6·5 and 9·0 kg d‐1 of barley given untreated or treated with formaldehyde reagent (8·1 t‐1). In Experiment 2 there were four dietary treatments consisting of silage with supplements of barley (7·0 kg d‐1) or barley and fishmeal (6·0 kg d‐1 plus 1·0 kg d‐1), with the barley untreated or treated with formaldehyde reagent (15·1t‐1). In Experiment 3 there were four dietary treatments consisting of silage given alone or with supplements of barley (9·0 kg d‐1). Treated barley (15·1 t‐1, 9·0 kg d‐1) and barley plus sodium bicarbonate (9·0 kg d‐1 plus 25·0 g d‐1).Treatment of the barley supplement with formaldehyde reagent had no effect on silage intake or milk production in Experiment 1 where the rate of application of the reagent was low and the basal silage‐barley diet was limiting in rumendegradable nitrogen. However, in Experiments 2 and 3 treated barley supplements were associated with improvements in silage intake and milk production. As compared with corresponding control diets containing untreated barley, increases in silage intake ranged from 0 to 0·16 of the control value, whilst associated increases in the yields of milk, milk fat, milk protein and lactose were 0·077–0·089, 0·016–0·026, 0·092–0·118 and 0·080–0·092 of the control value. These responses are discussed in relation to the increases in silage intake and milk production observed with fishmeal supplementation of the diet in Experiment 2 and inclusion of sodium bicarbonate in Experiment 3.
The effect of herbage surface water and the provision of supplementary forage on the intake and feeding behaviour of cattle
Authors: BUTRIS G.Y. , PHILLIPS C.J.C. 
Published: April 2006

AbstractHigh rainfall and the corresponding low herbage DM content has been shown to adversely affect cattle intakes and production. This could arise from physical restrictions on intake or digestion rate, or other behavioural limitations such as reduced palatability. A knowledge of the reason for the intake reduction would assist in determining the optimum supplement to feed. Eight steers were offered four diets in a changeover design. The diets were: A, cut herbage; B, cut herbage with added surface water; C, as B but with a low dry matter (DM) forage supplement (silage); and D, as B but with a high DM forage supplement (hay). The addition of surface water to herbage reduced DM intake and feeding time but had no effect on biting rate or rate of intake. Neither hay nor silage was eaten in sufficient quantities to restore DM intake, even though the silage was of similar nutrient composition to the herbage.
The effect of nitrogen in spring on shoot number and leaf area of white clover in mixtures
Authors: DENNIS W. D. , WOLEDGE JANE 
Published: April 2006

AbstractSwards of perennial ryegrass/white clover were cut to 3 cm in March and allowed to regrow for approximately thirteen weeks. Half the swards received nitrogenous fertilizer at the time of cutting (+N treatment) while the other half received none (—N treatment).About four weeks after the application of treatments, the number of clover shoots in the — N treatment was significantly higher than that in the +N; at this stage total leaf area index on both treatments was low, but significantly greater in the + N. After 30 days, more light was reaching ground level in the — N treatments, and about 40 days after cutting there was between 17 and 50% more clover in the — N treatment than the +N.It is suggested that the inhibition of stolon branching with a consequent restriction in the rate of increase of clover leaf area is a major factor in the adverse effect of N fertilizer on clover.
The effect of strategic nitrogen application and defoliation systems on the productivity of a perennial ryegrass/white clover sward
Authors: FRAME J. , PATERSON D. J. 
Published: April 2006

AbstractThe productivity of a mixed sward comprising perennial ryegrass cv. Fantoom and white clover cv. Aran was measured under eight defoliation management systems and two fertilizer N rates (0 and 75 kg ha‐1) applied in spring. The defoliations involved a basic six‐harvest simulated grazing system together with the interposition of silage cuts once or twice at varying times during the growing season; evaluation was made over three harvest years, 1983‐85.Mean annual production of total herbage DM over the three years was 8.351 tha‐1 without N and 9.49 tha‐1 with 75 kg N ha‐1, a mean response of 15.2 kg DM per kg applied N. The responses for individual treatments occurred mainly at the first cuts, whether for simulated grazing (a mean of 12 9 kg DM) or for silage (a mean of 259 kg DM); however, this influence of spring N was not sustained at other cuts over the season. Mean annual white clover DM production was 4.19 t ha‐1 with no N and 3.32 t ha‐1 with 75 kg ha‐1 N, but the reduction due to N was not significant in any year. The mean amount of clover stolon DM present post harvest over all management systems was 1.33 t ha‐1 with no N and 1.03 t ha‐1 with 75 kg ha‐1 N.Mean annual DM production of total herbage from the six‐harvest system was 8.11 t ha‐1 Compared with 8 88 t ha‐1 (a 9% increase) from the systems with one silage cut and 9.241 ha‐1 (a 14% increase) from the systems with two silage cuts. Corresponding white clover DM production was 4.02, 3 87 and 3 53 t ha‐1, respectively, and mean stolon DM amounts post harvest, 1 12,1.15 and 1‐23 t ha‐1, respectively.It is concluded that grass/white clover swards are suitable for management systems which involve cutting for conservation. Spring N application did not greatly reduce white clover production in this experiment where white clover was at higher levels than are likely in farming practice and the swards were not grazed. More knowledge of spring N rates, and indeed of N application rates generally, would be advantageous in future assessment of silage cutting systems.
Redistribution of nitrogen and phosphorus on Palace Leas meadow hay plots as a result of aftermath grazing
Authors: SHIEL R. S. , BATTEN J. C. 
Published: April 2006

AbstractAftermath grass growth on Palace Leas meadow hay plots at Cockle Park Experimental Farm, Northumberland, is well correlated with hay yield, but there is variation in grazing intensity and dunging pattern between plots leading to a redistribution of nutrients. Plots which are low in nutrients, as a result of treatments applied since 1897, receive inputs from the surrounding plots but these have not prevented the development of large differences in flora, hay yield and soil properties between plots. Variation in grazing intensity between plots may have contributed to an increase in soil organic matter content on some of the more acid plots.
Productivity and persistence of prairie grass (Bromus willdenowii Kunth)
Authors: FALLOON R. E. , HUME D. E. 
Published: April 2006

AbstractA field trial measured effects of the head smut fungus Ustilago bullata Berk, on forage productivity of prairie grass (Bromus willdenowii Kunth). Simulated swards containing different proportions of U. bullata infected and non infected plants were established in the autumn, and sward and plant parameters were measured over the following 15 months. Total herbage produced from swards containing only non‐infected plants was 27.3 t ha−1, while that from totally infected swards was 14.6 t ha−1. Infected plants produced fewer and lighter tillers than non‐infected plants when both were growing together in swards. Almost all the U. bullata infected plants died during an epidemic of bacterial wilt disease (caused by Xanthomonas campestris pv. graminis (Egli, Goto and Schmidt) Dye), while most of the‘non‐infected plants survived. The deleterious effects of U. bullata on individual plant productivity affected sward productivity only when the proportion of infected plants in swards was greater than 50%. Plants not infected with U. bullata compensated for low productivity and death of infected plants by producing large numbers of tillers.