bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of herbage water‐soluble carbohydrate content and weather conditions at ensilage on the fermentation of grass silages made on commercial farms
Authors: HAIGH P. M. 
Published: April 2006

AbstractA total of 1009 samples of silage made in bunker silos on commercial farms between 1972 and 1978 was analysed to investigate the effect of herbage water‐soluble carbohydrate content (WSC) and weather conditions at ensilage on fermentation as measured by ammonia‐N concentration and pH of first‐cut grass silages.Silage dry matter (DM) content had the major effect on fermentation. Factors influencing silage DM were rainfall and hours of sunshine during silage making, and DM content of the grass cut. WSC content of herbage ensiled also had a significant effect on subsequent fermentation. The major influences on herbage WSC were hours of sunshine and rainfall during the growing season.The effect of chemical additives, albeit at poorly defined and often inadequate rates, was small in comparison to that of silage DM.The minimum DM necessary to produce well‐fermented silage without additive was approximately 260 g kg−1. Use of formic acid significantly reduced this requirement to 240 g kg−1and to 252 g kg−1for sulphuric add + formalin. The results indicate that the minimum herbage WSC necessary to prevent a clostridial fermentation developing in silage with a DM content of 230 g kg−1is approximately 37 g kg−1without additive and 30 g kg−1with formic acid.It is concluded that on commercial farms, weather conditions i.e. amount of rainfall and sunshine prior to and at ensilage, have a greater effect on subsequent silage fermentation than additive use.
Nutritive quality of little bluestem clones selected for phenotypic variability
Authors: KARN J. F. , TOBER D. A. 
Published: April 2006

AbstractLittle bluestem (Schizachyrium scoparium (Michaux) Nash), a perennial bunchgrass, is a potentially valuable species for use in restoring ground cover in shallow range sites that are subject to drought. However, there are no data on the nutritive quality of the diverse phenotypes of little bluestem found in the north central USA and south central Canada, and there are no cultivars of little bluestem that are adapted to these areas. The objectives of this study were to measure the nutritive quality of little bluestem clones sampled on different dates and to determine whether clones differed sufficiently to facilitate selection efforts to improve forage quality. Whole plant samples of little bluestem were clipped on 8 August and 8 September 1983 and 5 July and 6 August 1984 from a field nursery at Mandan, North Dakota, containing plants originating from Minnesota and North and South Dakota in the USA. Significant differences between sampling dates were found each year for in vitro digestible organic matter (IVDOM), crude protein, lignin, calcium, phosphorus (P) and potassium (K). In order to minimize the effects of maturity on chemical composition, data were statistically evaluated for clonal differences, using only the August sampling dates. Clones were further separated into north and southeast groups according to stage of maturity and latitude and moisture conditions where the clones originated. Clones were significantly different with respect to IVDOM and P in both the north and southeast groups for the August 1983–1984 data. IVDOM and P among clones averaged over years for the August sampling date ranged from 374to 521 g kg−1 and from O‐9to l‐6g kg−1, respectively, for the north group and from 456 to 538 g kg−1 and from 1–2 to 2–0 g kg−1, respectively, for the southeast group. The range in IVDOM and P suggests that selection to improve little bluestem quality components, especially later in the season, may be warranted. However, it is important that these results be corroborated under conditions where the effects of maturity are further diminished.
Comparison between isotope dilution and acetylene reduction methods to estimate N2 fixation rate of white clover in grass/clover swards
Authors: LAIDLAW A. S. , CHRISTIE P. , WITHERS J. A. 
Published: April 2006

AbstractIn two field experiments acetylene (C2H2) reduction by white clover in mixed swards was compared to N2‐fixed measured by 15N dilution. In both experiments, samples for C2H2 reduction were 7.5 cm diameter turves taken from plots within which microplots of 24 cm diameter were delimited and to which 15N was applied as ammonium sulphate (15NH4)2SO4). C2H2 reduction was assayed every 6–7 d. The rate of C2H2 reduction per unit length of stolon was applied to the estimated stolon length within the appropriate microplot at the time of assay, and the amount of C2H2 that would have been reduced within the microplot was estimated by integration.In experiment 1, turves taken from grass/clover swards to which 0, 1·5, 3·0, 4·5 or 6·0 g N m−2 had been applied were incubated in sealed chambers (10% C2H2, 90% air). The mean ratio of C2H2 reduced to N2 fixed during 5 weeks was 0.74:1. Application of N fertilizer lowered the proportion of assimilated N derived from N2 fixation from 95% in unfertilized swards to 83% in those receiving 6 g N m−2 (60 kg N ha−1). In experiment 2, clover roots and stolons from plots that previously had been grazed were dissected from turves and incubated in a stream of C2H2 and air (i.e. the open system). The maximum rate of ethylene (C2H4) produced during the first 12 min was taken as a measure of true nitrogenase activity. The relationship between C2H2 reduced and N2 fixed was significant (r=0.80**). The mole ratio was 0.55:1 for the 6 weeks duration of the experiment, the low ratio possibly being due to disturbance of the nodules adversely affecting acetylene reduction. Mole ratios from both experiments were well short of the theoretical 4·3:1. Using the open system does not, therefore, overcome the shortcomings of the acetylene reduction technique for measuring N2 fixation of white clover in mixed swards.
Competition between white clover (Trifolium repens L.) and subterranean clover (Trifolium subterraneum L.) in binary mixtures in the field
Authors: HILL M. J. , GLEESON A. C. 
Published: April 2006

AbstractWhite clover, (cv. Haifa) and subterranean clover (cv. Seaton Park) were grown in binary replacement series mixtures in the field at proportions of 100:0, 90:10, 50:50. 10:90 and 0:100, and cut every four weeks over three growing seasons from 1985 to 1987 at Scone, New South Wales (NSW) (32°S).Relatively low plant densities minimized competition in 1985, but in subsequent seasons Haifa and Seaton Park competed vigorously for the same resource;.; usually having relative crowding coefficients greater than 1.0, and relative yield totals greater than 1.0 in spring of 1986 and 1987, and autumn 1987. This over‐yielding appeared to be due to some complementarity of leaf morphology and canopy architecture.Haifa severely depressed seed production of Seaton Park in mixtures. Haifa regenerated as an annual in 1986, but as a perennial, from surviving stolons, in 1987 owing to lower maximum temperatures and better rainfall distribution in late summer and autumn of 1987.It is concluded that white clover can survive severe competition from subterranean clover as a seedling, and if moisture allows, may severely depress seed production from subterranean clover, regardless of whether plants are annual or perennial in origin. Spatial separation may minimize competition in average years but competition effects may be severe in seasons with sufficient summer rainfall for perennation of white clover, and seasonal autumn rainfall for germination of subterranean clover.
The effects of grazing with and without excretal returns on the accumulation of nitrogen by ryegrass in a continuously grazed upland sward
Authors: THOMAS R. J. , LOGAN K. A. B. , IRONSIDE A. D. , BOLTON G. R. 
Published: April 2006

AbstractRates of N accumulation were studied on sheep grazed grass swards maintained at a constant height of 5 cm for two growing seasons (1985 and 1986) and receiving no N fertilizer using a tiller tissue turnover technique. Grazing with normal excretal returns resulted in an 85‐105% increase in the estimated rates of N accumulation by laminae compared with similarly grazed swards where excretal returns were prevented. Generally, increases in tiller numbers in plots receiving excreta were mainly responsible for the increased rates of N accumulation, rather than increased rates of N accumulation per tiller. Rates of N remobilization from laminae and senescence (flux of N to standing‐dead litter pool) per tiller, and rates of leaf extension and leaf appearance/disappearance were unaffected by excretal returns, in urine patches increased tiller numbers and increased rates of accumulation per tiller both resulted in greater estimates of N accumulation compared with tillers not visibly affected by excreta. However, at any one time only about 11% of the plot area was affected by excreta and increases in N accumulation in excreta patches could not account for the overall plot increases in rates of N accumulation.The increased tillering in plots receiving excreta may have increased exploitation of the soil N. With an average stocking rate of 15 sheep ha−1, soil nitrate‐N, but not total N (Kjeldahl) nor bulk density, was increased during the winter of the second year as a result of excretal returns.
The effect of cutting systems on the yield of herbage from a small‐plot experiment
Authors: BINNIE R. C. , CHESTNUTT D. M. B. 
Published: April 2006

AbstractPlots of an established perennial ryegrass sward (cv. Talbot) fertilized with 100 or 300 kg N ha−1 were harvested with one of three plot mowers; an Agria with 38‐mm finger spacing and an Allen Mayfield with 38‐mm finger spacing or 78‐mm finger spacing. The choice of mower was arranged factorially with four post‐harvest treatments: no post treatment; a second (cleaning) cut using the same mower and cutting in the same direction as the first (sampling) cut; a cleaning cut using the same mower, but in the opposite direction to the sampling cut; and a cleaning cut using a rotary mower. Sward productivity as organic matter (OM) was measured over four harvests at 6‐ to 7‐week intervals. The Agria mower resulted in 12·3 and 15‐9% more OM yield than the Allen Mayfield fitted either with knife‐bars at a similar spacing, or with wider‐spaced fingers, respectively. Yield of OM in the subsequent cut was reduced when a cleaning cut was taken; particularly when it was taken in the opposite direction to the sampling cut or when using a rotary mower.
An ultrasonic rangefinder for measuring the undisturbed surface height of continuously grazed grass swards
Authors: HUTCHINGS N. J. , PHILLIPS A. H. , DOBSON RUTH C. 
Published: April 2006

AbstractAn ultrasonic rangefinder (sonic sward stick) was developed for rapidly measuring and recording the undisturbed surface height of swards. HFRO and ultrasonic sward stick measurements of undisturbed sward height over continuously grazed pasture were closely related. The measurements obtained with both instruments were related to the sward mass; the distribution of that mass between leaf, stem and dead material had little effect.
Inorganic phosphorus and DNA concentrations in the leaf tissue of some forage species
Authors: HART A. L. , COLLIER W. A. 
Published: April 2006

AbstractRyegrass, some white clover cultivars (Grasslands Huia, Trifo, Barbian and Luclair) and lotus were grown in the presence of mineral nitrogen and at a range of phosphorus (P) supply. Ryegrass had the highest leaf inorganic P concentrations on a dry weight basis, and lotus the lowest. In the clovers and lotus shoot yield was correlated with inorganic P concentration; it was not correlated in ryegrass, although this was possibly a result of the stage of development of ryegrass when it was harvested. Ryegrass was always more efficient than the legumes in acquiring P and growing rapidly. When inorganic P concentration was expressed on the basis of DNA, lotus had concentrations intermediate between that of ryegrass and the clovers, i.e. lotus had at least as much inorganic P per unit of DNA as white clover. It is suggested that although lotus is more efficient than white clover in terms of the concentration of inorganic P on a dry weight basis, the amount of inorganic P required per ‘module of metabolism’ (or cell), is similar. Lotus also has larger cells than white clover and the relatively greater efficiency of lotus may lie at least partly in its ability to achieve an equivalent leaf area or weight with fewer cells, i.e. cytology contributes to efficiency.
Spatial analysis of forage parameters using geographic information system and image‐analysis techniques
Authors: SMITH S. M. , SCHREIER H. E. , BROWN S. 
Published: April 2006

AbstractIn efficient agricultural systems high production and high quality is expected throughout the year, but spatial and seasonal variation of biophysical variables can have a significant impact on the yield and quality of production. The yield and quality component of a forage field was monitored using statistical and Geographical Information System (GIS) techniques. The display of yield and forage quality in a spatial context proved to be very useful to the farmer since it allowed him to determine where in the field he obtained the best and worst production and whether such performance was consistent over the entire growing season. GIS is considered a new management tool that allows the spatial evaluation and presentation of production information in a new and innovative manner. Examples are provided to assist farmers in production accounting, to determine cause and effect relationships between management and production, to forecast production and to modify management to account for differences within the field.
Supplementary forage for grazing sheep. 1. Effects on lactating ewes and lambs
Authors: MARTIN J. H. , PHILLIPS C. J. C. , ALCOCK M. B. 
Published: April 2006

AbstractIn two experiments, ewes in weeks 1–20 of lactation received either pasture only or pasture plus ad libitum conserved forage. Herbage height was maintained at 3·3–3·4 cm on both treatments by manipulation of stocking rate in the 24 plots (twelve per treatment) used for the experiment with additional ewes and lambs. In experiment 1, silage, which was of lower metabolizable energy (ME) and crude protein (CP) contents than the grazed herbage, was consumed at an average of 375 g dry matter (DM) ewe−1 d−1. In experiment 2 a strawmix, containing (g kg −1 freshweight) 480 g barley straw, 300 g concentrate and 220 g molasses, again with a lower ME and CP content than the grazed herbage, was consumed at an average of 165 g DM ewe −1 d −1. In both experiments ewes not receiving forage lost weight whereas those with forage gained weight and tended to have increased body condition scores. Offering silage or strawmix did not affect lamb liveweight gain or stocking rate.
The effects of sodium chloride application to pasture, or its direct supplementation, on dairy cow production and grazing preference
Authors: CHIY C. P. , PHILLIPS C. J. C. 
Published: April 2006

AbstractThe experiment aimed to examine the effects of sodium chloride (NaCl) application to pasture on dairy cow production, distinguishing the effects of Na supply on pasture production from the direct effects on animal production, and also to examine the preference of dairy cows for sodium‐fertilized pasture. Twenty‐four dairy cows were grazed in six treatment areas with three fertilizer levels—all (A), one‐half (H) or none (N) of the area fertilized with 50 kg NaCl ha−1, and with or without 50 g cow−1 day−1 NaCl supplementation (+, −) offered in concentrate feed. The experiment was a changeover design with four 3‐week periods. NaCl fertilization increased herbage growth rate and Na, Cl and calcium (Ca) contents and reduced K content. Milk yield and liveweight gain were increased by NaCl application to pasture but not by direct supplementation. Milk fat content was increased with increasing Na concentration in the diet. Grazing time was increased by NaCl application to pasture, but only cows not receiving direct NaCl supplementation preferred NaCl‐fertilized pasture. Ruminating time was increased both by NaCl application to pasture and by direct supplementation. It is concluded that in the warm, dry conditions of this experiment, increasing Na supply to natrophilic herbage increased both pasture and animal production, and that within the range 3–8 g Na kg−1 dietary DM, increasing Na supply to the cow increased milk fat content.
The effect of adding surface water to herbage on its digestion by ruminants
Authors: PHILLIPS C. J. C. , MARGERISON J. K. , AZAZI S. , CHAMBERLAIN A. G. , OMED H. 
Published: April 2006

AbstractIn two experiments the effects of adding surface water to herbage on its digestion by ruminants were examined. In experiment 1, with sheep, adding water to silage reduced DM intake and the diet DM digestibility. Offering a high DM alternative forage, hay, increased DM digestibility with the wetted silage, but tended to decrease it with the dry silage. More hay was eaten with the wetted than dry silage. In experiment 2, with steers, adding water to fresh herbage reduced DM intake but had no effect on rumen pH or ammonia levels. Adding water to the herbage reduced the rate of DM disappearance from nylon bags placed in the rumen and the proportion of rumen liquor particles of low specific gravity. The proportion of very short and very long particles in the rumen liquor was also reduced by adding water to the herbage.
The effect of heat‐treatment and gamma radiation on the composition of unwilted and wilted lucerne silages
Authors: CHARMLEY E. , VEIRA D. M. 
Published: April 2006

AbstractThree unwilted and three wilted silages were prepared from lucerne. Unwilted and wilted material was ensiled either without treatment (UWC and WC), after gamma irradiation (UWI and WI), or following heat‐treatment and inoculation with Lactobacillus plantarum (UWH and WH). Gamma radiation was from a cobalt 60 source. The UWH material was heat‐treated using steam, and WH material was treated with dry heat. At ensiling, irradiated material was considered to be sterile, and heat‐treated material had lost 80% of its original protease activity. Fifteen 1‐litre silos were prepared for each treatment (90 in total), and three from each treatment were opened after 1, 4, 14, 70 or 200 d ensiling. In irradiated silages, there was no accumulation of organic acids, but water soluble carbohydrate (WSC) concentration was almost double (116 g kg‐1dry matter) that at ensiling. This indicated extensive liberation of WSC from more complex carbohydrates during ensiling. The extent of silage fermentation in heated silages was similar to control silages. The WH silage had a higher proportion of the organic acids as lactic acid relative to the other treatments, possibly as a result of inoculation with L. plantarum. Proteolysis was unaffected by irradiation. However, heat‐treatment markedly reduced the extent of proteolysis, particularly in the first four days post‐ensiling. Deamination appeared to be related to the type of microbial fermentation rather than to the extent of proteolysis.
Interactions between pesticide treatment, cutting frequency and rate of N fertilizer on white clover grown in mixture with perennial ryegrass
Authors: LEWIS G. C. 
Published: April 2006

AbstractThe effects of a combined pesticide and fungicide (P + F) treatment on the proportion of white clover in an established perennial ryegrass/white clover sward were assessed on six occasions during 1988 and 1989, under two cutting frequencies (2‐ or 6‐week intervals) and with or without N fertilizer (120 kg ha‐1 per annum). In 1988 P + F treatment significantly increased the proportion of clover in August and October, with an increase at the latter harvest being much greater where N was also applied. There was no significant interaction between P + F treatment and cutting frequency, although less frequent cutting increased significantly the proportion of clover in October where N was not applied.In 1989, drought prevented the proportion of clover from exceeding 1% throughout, regardless of management factors. P + F treatment significantly increased the proportion of clover in August, and significantly reduced populations of slugs, foliar‐feeding insects (mainly Collembola; Sminthuridae) and the area of clover leaf damaged by pests. No marked effect of P + F treatment on populations of plant parasitic nematodes was detected. No appreciable incidence of fungal diseases was observed in either year.
Herbage productivity of prairie grass, reed canary‐grass and phalaris
Authors: FRAME J. , MORRISON M. W. 
Published: April 2006

AbstractThe herbage production and quality of swards of three grass species, prairie grass (Bromus willdenowii Kunth), reed canary‐grass (Phalaris arundinacea L.) and phalaris (Phalaris tuberosa L.) were compared with perennial ryegrass (Lolium perenne L.) and hybrid ryegrass (L. perenne L. ×L. muitiflorum Lam.) under 6–cut (experiment 1) and 4–cut (experiment 2) regimes over 3 years at Ayr; annually, 360 kg ha‐1 fertilizer N were applied. At Edinburgh prairie grass was compared with Italian ryegrass (L. multiflorum Lam.), timothy (Phleum pratense L.) and cocksfoot (Dactylis glomerata L.) under an annual 4–cut regime for 3 years (experiment 3); fertilizer N application totalled 350 kg ha‐1 annually.Prairie grass gave the highest annual dry matter (DM) production at Ayr, averaging 11·99 t ha‐1 in experiment 1 and 15·62 t ha‐1 in experiment 2. Reed canary‐grass was much less productive whilst phalaris did not persist after harvest year 1. On average, prairie grass gave 8–10% more DM than the three ryegrasses in the 6‐cut system but its advantage was much less under the 4‐cut regime. In experiment 3, the DM production of prairie grass and Italian ryegrass were similar in year 1, but following winter damage prairie grass gave the lowest production in subsequent harvest years.Prairie grass had digestibility (OMD) values lower than the ryegrass but higher than reed canary‐grass, timothy and cocksfoot. The water soluble carbohydrate (WSC) concentrations in prairie grass were markedly higher than in timothy and cocksfoot but lower than those in Italian ryegrass. Prairie grass had relatively low P and Mg concentrations. Reed canary‐grass had relatively low OMD and Ca, but high N, P, K and Mg contents.It is concluded that prairie grass may have potential in the UK as a special‐purpose species for conservation management but mainly in the milder climatic areas. The Phalaris species evaluated had disappointing agronomic potential.
Net production of herbage from a continuously stocked Lolium perenne‐dominated sward in late autumn
Authors: GUNN R. G. , SMITH W. F. , AGNEW R. D. M. , SMITH A. D. M. , SIM D. A. 
Published: April 2006

AbstractPreliminary studies were carried out on the effect of stocking rate during late autumn on a continuously stocked Lolium perenne‐dominated sward at an upland site in central Scotland. Measurements were made of L. perenne tiller population density on 29 September and 2 November and of L. perenne net production, mean sward height and total herbage mass in early and late October and early and late November. Stocking rates were 12 ewes per ha during October and 8 and 16 ewes per ha during November. Sward height and herbage mass declined with time and more rapidly at the higher stocking rate. L. perenne growth per tiller and per unit area was influenced by time but not by stocking rate and was closely related to the 5·5°C soil temperature at 10 cm depth. Tiller senescence was greatly reduced at the higher stocking rate and/or the consequentially lower sward height and herbage mass. Tiller net production was therefore sustained at a positive level on the higher stocked sward throughout November while on the lower stocked sward it fell below zero early in November.