bluuebunny/crossref_metadata_2025_split huggingface dataset:
Water use and water‐use efficiency of perennial ryegrass swards as affected by the height and frequency of cutting and seed rate
Authors: COX RUTH , PARR T. W. , PLANT R. A. 
Published: April 2006

AbstractThe effects of cutting height (20 and 44 mm), frequency (once every 2 weeks April‐September inclusive and twice a year) and seed rate (250 and 20 kg ha‐1) on the water use and herbage yield of perennial ryegrass swards, for 3 years after sowing, were compared.Frequent cutting and a low cutting height reduced water use in the first year only. In later years infrequent cutting led to higher yields and higher water‐use efficiencies, but did not affect total water use or the shape of the soil water profile. Seed rate influenced sward composition and the pattern of water use, but not total water use. The swards from the low seed rate had a lower stubble biomass and tiller density, and extracted relatively more water at depths of 75 and 85 cm and less at depths of 15 and 35 cm, than the swards derived from the high seed rate.The ratio of actual: potential evapotranspiration was reduced as the soil water deficit increased and was lowest in the summer after a dry spring. Cutting height and frequency during summer were shown not to be effective methods of either conserving water or manipulating the effective rooting depth of an established sward.
A comparison of nitrogen fertilizers for spring and summer grass production
Authors: SWIFT G. , CLELAND A. T. , FRANKLIN M. F. 
Published: April 2006

AbstractThree experiments were carried out in 1983‐85 to compare split dressings of ammonium nitrate and urea with a single injection of aqueous ammonia for seasonal and total annual dry matter (DM) production. Total annual fertilizer nitrogen (N) applied was 360 kg ha1 for a six‐cut management. The solid fertilizers were applied in spring at different dates for the first cut and then after cuts 1 —4in the pattern 90,90,60,60,60 kg N ha1. A winter injection of aqueous ammonia in the first year was replaced thereafter by early and late spring injections, the latter at 300 kg N ha1 with 60 kg N ha 1 as ammonium nitrate. Injection was to a depth of 100 mm at 30 cm spacing using a commercial applicator. The experiments were carried out on farms in a low rainfall area; the soils were sandy loams.Urea gave 3% less total DM production than ammonium nitrate (0middot;32±0middot;153 t ha‐1) and produced on average 7% less DM in the spring, and 12% less in dry conditions in early autumn of 1984. Lower production was associated with reduced uptake of N, which occurred at most cuts. From these experiments it is concluded that urea can be a suitable alternative to ammonium nitrate, and when used in spring must be about 20% cheaper per kg N. The performance of aqueous ammonia was variable. In the dry summer of 1984, when applied in early April with 60 kg N ha‐1 as ammonium nitrate it equalled the ammonium nitrate treatment in both spring and total production and was better (P< 0 −05) in early autumn. In the same year, an early March injection was inferior (P < 0 05) in total DM production to ammonium nitrate. This early injection was also lower, but not significantly (P>005) in 1985, mainly because of lower spring production. A delayed, mid‐April injection, plus ammonium nitrate, in 1985, gave even less spring growth and lower total production. A January injection, in 1983, showed poor persistency and is not recommended for sandy loam soils.
Particle size reduction of the leaves of a tropical and a temperate grass by cattle
Authors: WILSON J. R. , AKIN D. E. , McLEOD M. N. , MINSON D. J. 
Published: April 2006

AbstractTo investigate links between the anatomy of grass leaves and their resistance to breakdown in the rumen, leaf blades of the tropical grass, green panic (Panicum maximum var, trichoglume), and the temperate grass, Italian ryegrass (Lolium multiflorum), were chopped into 50 mm lengths and fed fresh to cattle. Particle size reduction of the chewed feed was studied immediately after eating and after digestion in nylon bags in the rumen for 6, 12, 24, 48, 96 h and 3 weeks. The lengths of fibre elements, separated into groups of different diameters, were measured on samples digested for 96 h. The process of tissue breakdown was studied using light and electron microscopy.Green panic leaves had twice the cross‐sectional area of thick‐walled tissues, a higher vascular bundle frequency per unit leaf width, and less, but more densely packed mesophyll, than did the ryegrass leaves. Despite the contribution of these characteristics to greater leaf rigidity, green panic was broken down to a greater degree by chewing than was ryegrass.During digestion, width reduction of the chewed leaf particles was faster in ryegrass than in green panic because of two anatomical features: (i) the straight‐walled intercostal cells of the epidermis in ryegrass were easily separated allowing the epidermis to split, whereas the sinuous walls in green panic were resistant to splitting, and (ii) the epidermis of ryegrass was linked to the vascular bundles by thin‐walled mesophyll cells and was shed when these were digested, whereas in green panic the linkage was via thick‐walled bundle sheath cells causing the epidermis to remain attached for much longer. Ryegrass leaf was reduced to isolated fibres within 24 h digestion; this process took >48 h in green panic. These fibres all had a high resistance to length reduction by digestion irrespective of their anatomical or species origin. Even after 3 weeks in the rumen there was little digestive disruption to the longitudinal walls of these fibres.The isolated vascular fibres of ryegrass were smooth‐surfaced in contrast to those of green panic which were rough owing to attached undigested bundle sheath cells and jagged, broken sections of epidermis; this could influence ease of separation of particles from the digesta mass and flow from the rumen.Anatomical differences between these grasses were, therefore, important in the rate of width reduction of leaf particles during digestion and for the characteristics of the isolated fibre, but not for length reduction of particles during digestion
Chemical Composition, in vitro digestibility and in vitro VTA concentrations of New Mexico native forages
Authors: HOLECHEK J. L. , ESTELL R. E. , GALYEAN M. L. , RICHARDS W. 
Published: April 2006

AbstractComparative chemical composition, in vitro digestibility, and in vitro volatile fatty acid (VFA) concentration and molar proportions of current year's growth of twelve important native New Mexico forage species were evaluated. Volatile fatty acid data were collected on forage samples subjected to 12‐h in vitro digestion using two different inoculum sources. Forbs and shrubs had higher (P<0·05) total nitrogen and total available‐ nitrogen concentrations than grasses; however available nitrogen as a percentage of total nitrogen did not differ (P>0·05) among grasses forbs and shrubs. in vitro organic matter digestibility (IVOMD) was higher (PKOOS) for forbs and shrubs than grasses for all incubation periods (24, 48, 72 hours). Lucerne hay and prairie grass hay inocula gave similar IVOMD results. Based on 24‐h IVOMD divided by 72‐h IVOMD, forbs were digested more rapidly than grasses (P<0·05). Total VFA concentration and molar proportion differences among grasses, forbs and shrubs were small
Yield of white clover populations in mixture with contrasting perennial ryegrasses
Authors: COLLINS ROSEMARY P. , RHODES IAN 
Published: April 2006

AbstractA field experiment was established in May 1986 in which four white‐clover populations originating in Switzerland, and a bred variety, Menna, were grown in binary mixtures with their ‘co‐existing’ perennial ryegrasses and three other bred ryegrasses— Aurora, Talbot and Melle. The productivity of both components of the mixtures was measured by cutting samples in October 1986 (after establishment) and on five occasions during the growing season in 1987, Substantial differences were observed between clover yields in different mixtures, and the yield ranking of clover was found to vary with companion grass. It was concluded that the interaction between grass and clover populations originated at an early stage in sward development, being evident in both the 1986 establishment cut and the spring cut of the following year. The implications of these results for the formulation of breeding objectives and the evaluation of breeding material are briefly discussed.
The effect of some invertebrate species on persistence of white clover in ryegrass swards
Authors: MOWAT D. J. , SHAKEEL M. A. 
Published: April 2006

AbstractIn two experiments in established swards of perennial ryegrass and white clover, plots were treated with pesticides to control slugs, leather‐jackets, weevil larvae and lucerne flea as selectively as possible. Other plots were treated to control ail of these pests.Chlorpyrifos application in early summer (to control weevil larvae) and methiocarb pellets (to control slugs) also gave partial control of leather‐jackets. Other effects on non‐target species were considered to be unimportant, as pest status could not be attributed to the species. A high level of control of lucerne flea by methiocarb pellets, noted previously, was confirmed.At both sites combined treatment against insect pests and slugs produced large increases in clover content and yield over a 3‐year period, in comparison with untreated plots, although clover tended to decline In alt plots. At one site, where the clover content of untreated plots reached 33% at one stage, specialist clover herbivores such as weevils and lucerne flea were more common. Treatments directed against weevils and slugs gave the highest clover yields, and leatherjacket control may also have contributed, particularly when the population reached 0.9 m ha−1 in the final year. At the other site, where the clover content was low (ultimately 01.1–6%), leather‐jacket populations reached 2.1 m ha−1 and slug numbers were also relatively high. Control of these species contributed most to the relative increase in clover content and yield.
Nitrogen in the detergent fibre fractions of temperate legumes and grasses†
Authors: SANDERSON M. A. , WEDIN W. F. 
Published: April 2006

AbstractData are few on concentrations of nitrogen (N) in the cell wall and lignocellulose (neutral‐ and acid‐detergent fibre (NDF and ADF), respectively) of herbage. Herbage N can be partitioned into neutral‐ and acid‐detergent soluble and insoluble N to crudely estimate rapidly degradable (N soluble in neutral detergent), slowly degradable (neutral‐detergent fibre N (NDFN) minus acid‐detergent fibre N (ADFN), herein termed available fibre N (AFN)), and indigestible N (ADFN) in the rumen. Our objective was to examine the effects of herbage species, maturity stage, and plant part on N in the NDF and ADF of lucerne (Medicago sativa L.), red clover (Trifolium pratense L.), timothy (Phleum pratense L.), and smooth bromegrass (Bromus inermis Leyss.). Herbage was harvested at four 2‐week intervals during spring of 1984 and 1985. Leaves, stems and total herbage were analysed for total N, and N in NDF and ADF. Concentrations of N in ADF in leaves, stems, and total herbage of lucerne and clover were twice that of grass ADF. This may be due to greater lignin concentrations generally reported in legumes. Concentrations of NDFN in leaves of lucerne, clover, timothy, and bromegrass were 9–8, 26.4, 8.6, and 6.4 g kg−1 of NDF, respectively, averaged over harvests and years, whereas stem concentrations were 4.2, 4.6, 32, and 2.4 g kg−1 of NDF, respectively. Leaf concentrations of ADFN in lucerne, clover, timothy, and bromegrass were 4.6, 5.3, 20, and 1.6 g kg−1 of ADF, respectively, averaged over harvests and years, whereas stem concentrations were 3.4, 33, 14, and 14 g kg‐’of ADF, respectively. As a proportion of the total N, NDFN and ADFN increased with plant maturity in leaves, stems, and herbage. In stems, 49% of NDFN was ADFN, whereas in leaves only 21% of the NDFN was ADFN. The larger portion of ADFN in stems probably reflects the larger proportion of lignified xylem and other structural tissues, which have a greater proportion of lignified secondary cell walls, whereas the greater proportion of NDFN in leaves may mirror the greater amount of mesophyll cells with primary cell walls. More than 80% of the total N in leaves, stems, and herbage was in the cell solubles, which may be rapidly ruminally degradable.
A correction for the influence of changes in lamina weight per unit length in grasses on measurements of the weight of lamina removed by grazing
Authors: Tallowin J. R. B. , TCACENCO F. , PATEFIELD M. , BROOKMAN S. K. E. 
Published: April 2006

AbstractChanges in the weight per unit length along the first and second fully‐expanded laminae of Lolium perenne, Agrostis stolonifera, Holcus lanatus and Poa trivialis were experienced in tillers harvested in April and June 1987 from a permanent pasture under contrasting nitrogen treatments. Schematic models representing the weight distribution along the laminae of the different species are presented. From these models, predictions of the weight of any given proportion of the lamina length have been calculated. The weight of segments of lamina have been estimated, using the appropriate lamina model for a species, and these estimates provided consistently greater precision than estimates of lamina weight when no correction for lamina shape was considered, the length of a segment of lamina simply being multiplied by the mean overall weight per unit length of the lamina.
A further study on the evaluation through lactating cattle of a bacterial inoculant as an additive for grass silage
Authors: GORDON F. J. 
Published: April 2006

AbstractAn experiment is described in which three silages were prepared from herbage treated with either a bacterial inoculant (Ecosyl, Imperial Chemical Industries plc) at 2‐71 t−1, formic acid (850 g kg−1, Add‐F, BP Chemicals International Ltd.) at 2‐21 t−1, or no additive (control). The herbage (second regrowth from perennial ryegrass swards), was ensiled unwilted, and had mean dry matter (DM) and water‐soluble carbohydrate concentrations at ensiling of 186 and 34‐1 g kg−1 respectively. The resulting silages were all well preserved and had only minor chemical differences.Thirty lactating British Friesian cows were subjected to a 21 d standardization period and were then offered the three silages for 21 d in a randomized‐block design experiment. The animals were stalled individually, offered the silages ad libitum and in addition received 5 kg d−1 of a supplement containing 198 g crude protein kg DM−1. The mean silage DM intake, milk yields and milk fat concentrations during the final 7 d on treatment were 8‐44, 8‐62 and 887 kg d−1; 238, 230 and 25‐1 kg d−1; and 368, 400 and 366 g kg−1 for the control, formic acid‐ and inoculant‐treated silages respectively.Following the feeding trial, six cows per treatment were subdivided to provide three animals which were offered silage alone, and three offered silage plus 5 kg d‐’supplement. Rumen samples taken after 21 d on these treatments indicated no effect of the inoculant on ruman volatile fatty acid proportions, whereas the use of formic acid resulted in increases in both acetate and butyrate concentrations.The results from this study support that of the earlier work that this particular inoculant, when used at ensiling, can considerably improve animal performance over that achieved with both untreated and formic acid‐treated silages.
Dry matter yield and nutritive value of four summer annual crops in north‐west Spain (Galicia)
Authors: LLOVERAS JAIME 
Published: April 2006

AbstractForage production based on summer annual crops is a common agricultural practice in many areas of the world where the growing season is favourable.0An investigation was conducted over 3 years to compare the dry matter (DM) yield and quality of four annual crops; maize (Zea mays L.), sunflower (Helianthus annus L.), sudangrass (Sorghum bicolor L. Moensch) and sorghum (Sorghum bicolor L. Moensch) x sudangrass; in two rainfed locations with different summer temperatures in north‐west Spain (Galicia). The crops were compared at three harvest dates; first weeks of August and September and, except for sunflower, at a later silage stage.The comparative forage yields of each crop varied depending on location and harvesting date, reflecting their suitability for the climate of the location.At Mabegondo, with relatively mild summer temperatures (16.5 °C), maize throughout summer and sunflower until September produced higher DM yields than sudangrass and sorghum × sundangrass. At this location the silage DM yields for maize, sorghum × sudangrass and sundangrass were respectively 15.2, 9.92 and 7.79 t ha−1. At Puebla de Brollón, where the average temperature from June to September was about 2 °C higher than at Mabegondo, the DM production of the sudan‐type crops were similar to maize, while sunflower was significantly lower at the September harvest. The silage DM yields were: maize 14.07 t ha−1 sorghum x sudangrass, 14.05 t ha−1, sudangrass 12–26 t ha−1.The in vitro dry matter digestibility (IVDMD) of maize was always higher than that of the other crops, with an average value of 700 g kg−1.It is concluded that, in north‐west Spain, maize is the most suitable summer crop for maximum yield of good quality forage from the first week of August through to the normal silage stage in October.
Effects of spring defoliation and fertilizer nitrogen on the growth of white clover in ryegrass/clover swards
Authors: DAVIES ALISON , EVANS M. ELEANOR 
Published: April 2006

AbstractAn examination was made of the effects of different spring treatments on the growth of white clover in a ryegrass/white clover sward. Plots were either cut once (in February, March or April) or twice (in February and April) or left uncut. Nitrogen was applied to half of the plots in each instance. The clover was sampled at intervals of approximately 3 weeks from February to June to determine numbers of leaves and growing points and weights of plant parts. Rates of leaf appearance were also observed and estimates were made of total herbage mass from ground‐level cuts.Percentages of white clover in the herbage were higher in unfertilized than in fertilized plots and in defoliated than in undefoliated plots. The percentage increases that followed defoliation were usually maintained into later regrowth, showing that clover content was not automatically reduced as herbage mass increased. Increases in growing points were recorded after the beginning of April in defoliated unfertilized plots but not in undefoliated fertilized plots or in plots fertilized and defoliated twice during the spring period, in which numbers fell substantially.Inverse relationships were found between rates of leaf appearance, or the number of green leaves retained per stolon, and herbage mass, whereas heights of clover and grass leaves and the percentage of dry matter allocated to petiole rather than leaf in the clover increased with increasing herbage mass.We suggest that the observed differences between spring treatments in clover percentage result primarily from their differential effects on the formation and death of tillers and growing points in the early stages of regrowth.
Growth of prairie grass (Bromus willdenowii Kunth) and Westerwolds ryegrass (Lolium multiflorum Lam.) at Wageningen, The Netherlands
Authors: HUME D. E. 
Published: April 2006

AbstractHerbage quality, yields, tiller and plant populations of ‘Grasslands Matua’ prairie grass and ‘Caramba’ tetraploid Westerwolds ryegrass were investigated in a 2‐year field trial on a sandy soil. Plots were either harvested frequently (five to six cuts per year) or infrequently (four cuts). During the first year, herbage was separated into leaf, vegetative and reproductive pseudostem, and analysed separately.With very mild winters and adequate water supply, swards had good persistence and production for 2 years. Total yield in the first year (10.5 t DM ha−1) was similar for both species. Yields in the second year were (t DM ha−1) 13.4 and 18 for Matua and 11.1 and 13 for Caramba under frequent and infrequent cutting respectively. Leaf contributed 58% to yields and reproductive pseudostem 35%. Infrequently cut plots had: 23% higher dry matter yields, primarily due to higher yields of reproductive pseudostem; higher yields of most chemical components and higher contents of water‐soluble carbohydrates and cell walls; lower digestibility and nitrogen content. Cell wall content was consistently higher in Matua but otherwise herbage quality was similar for the two species. It is suggested that prairie grass should be considered as a replacement for spring‐sown Westerwolds ryegrass on sandy soils in The Netherlands.
Herbage production and nitrogen recovery from slurry injection and fertilizer nitrogen application
Authors: LONG F. N. J. , GRACEY H. I. 
Published: April 2006

AbstractAn experiment was carried out during 1986 and 1987 to examine the effects of mid‐season slurry injection and fertilizer‐nitrogen (N) application on herbage dry matter (DM) yield and N recovery. Cattle and pig slurry were injected at 56 and 112 m3 ha−1 into an established sward. Five rates of fertilizer‐N, as calcium ammonium nitrate, ranging from 0 to 120 kg ha−1 in 30‐kg increments, were superimposed on these treatments, and in both years DM yield was measured in one cut after 70 d regrowth. Slurry treatments increased herbage DM yields significantly (P < 0‐001). The efficiency of slurry total N compared with calcium ammonium nitrate‐N averaged 53% in 1986 and 86% in 1987. The mean apparent recovery of slurry total N in herbage was 55% in 1986 and 40% in 1987. Fertilizer‐N application increased (P < 0.001) the mean yields of herbage in both years but when combined with some of the slurry treatments, DM yields over the five N‐levels did not differ significantly, giving rise to interactions in 1986 (P < 0‐001) and 1987 (P < 001). It is concluded that mid‐season injection of slurry can be an effective means of utilizing slurry‐N in terms of herbage DM production and consequent N use.
The effect of nitrogen in cattle slurry and mineral fertilizers on nitrogen fixation by white clover
Authors: NESHEIM L. , BOLLER B. C. , LEHMANN J. , WALTHER U. 
Published: April 2006

AbstractThe influence of N in slurry or in mineral fertilizers on herbage yield and nitrogen fixation by white clover grown in mixed swards was investigated. Two levels of N in cattle slurry were compared with a range of mineral N fertilization. The percentage of N derived from symbiosis (% Nsym) was measured by the 15N‐isotope dilution method. The measurements were made in spring 1987 in two 4‐year‐old field trials, and included two out of five harvests.The % Nsym was approximately 90% without N fertilization. It decreased in response to both mineral N and N in slurry but did not fall below 63%. The sum of two harvests revealed that 51·2 kg N ha−1 were fixed in the absence of N fertilization. With 75 kg mineral N ha−1 or 50 m3 cattle slurry ha−1, the yield of fixed N decreased to 17·2 and 24·9 kg ha−1, respectively. When compared on the basis of the fertilizer effect on dry matter yield and N concentration of perennial ryegrass, the decrease in yield of N fixed due to treatment with cattle slurry was less than that due to mineral N fertilizer. This was owing to the smaller extent of the depression in the proportion of white clover in the sward when the same amount of N was applied in cattle slurry, as compared with mineral fertilizer, although % Nsym responded similarly to both types of N fertilization.