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Herbage Mass (herbage + mass)

Distribution by Scientific Domains

Earth and Environmental Science	100%

Selected Abstracts

Herbage mass and nutritive value of herbage of extensively managed temperate grasslands along a gradient of shrub encroachment

GRASS & FORAGE SCIENCE, Issue 3 2009
S. Kesting
Abstract Semi-natural grasslands often serve as important reserves of biodiversity. In Europe extensive grazing by livestock is considered an appropriate management to conserve biodiversity value and to limit shrub encroachment. However, little is known about the influence of shrubs on agronomic values. A gradient analysis of shrub-invaded temperate grasslands (from shrub-free to pioneer forest) in Germany was carried out to test the hypothesis that herbage mass and variables describing nutritive value of herbage decrease with increasing shrub encroachment. The herbage mass of dry matter (DM), variables describing the nutritive value of herbage, composition of the vegetation and mean of Ellenberg's indicator values were analysed with respect to the extent of shrubs. There was a reduction of herbage mass of DM from 3570 to 210 kg ha,1 with increasing shrub encroachment. Metabolizable energy concentration of herbage ranged from 8·9 to 10·2 MJ kg,1 DM and crude protein concentration from 72 to 171 g kg,1 DM, both measures being positively correlated with shrub occurrence. Increasing shrub occurrence was associated with a decrease in water-soluble carbohydrates concentration (from 151 to 31 g kg,1) and a reduction in the indicator ,forage value'. The results indicate a potentially large agronomic value for shrub-encroached temperate grasslands. [source]

Nutritional quality of semi-arid grassland in western Spain over a 10-year period: changes in chemical composition of grasses, legumes and forbs

GRASS & FORAGE SCIENCE, Issue 3 2000
Vázquez-de-Aldana
From 1987 to 1996, the nutritional quality of the main botanical components (grasses, legumes and forbs) in semi-arid grasslands in the dehesa ecosystem in western Spain was analysed. Herbage samples were collected at the end of spring, in 30 locations, at two different topographic positions (upper and lower slope zones). Herbage mass over 2 cm and proportion of botanical components were estimated and samples were analysed for crude protein, neutral-detergent fibre (NDF), hemicellulose, cellulose, lignin and in vitro dry matter digestibility (DMD). Analysis of variance revealed a significant effect of sampling year on the herbage mass, proportion of botanical components and their nutritional quality. The three botanical groups, grasses, legumes and forbs, followed similar year-to-year trends in their crude protein, cellulose and lignin contents and in vitro DMD. Herbage mass was not significantly related to any meteorological variables, suggesting that interannual variation in biomass production of botanically complex pastures cannot be explained by a single factor. However, annual precipitation was significantly related to the proportion of the botanical group that was dominant at each slope zone: grasses in the lower zone and forbs in the upper zone. In the upper zone, spring precipitation explained part of the interannual variation in the NDF, cellulose, lignin contents and in vitro DMD of the botanical components. [source]

Herbage mass and nutritive value of herbage of extensively managed temperate grasslands along a gradient of shrub encroachment

Herbage growth rates on heterogeneous swards as influenced by sward-height classes

GRASS & FORAGE SCIENCE, Issue 1 2009
ahin Demirba
Abstract The contribution of four classes of sward height to daily herbage growth rates of a heterogeneous sward in eight periods throughout a grazing season was investigated in two continuous cattle-grazing systems differing in intensity (moderate stocking rate: MC; lenient stocking rate: LC). At the beginning and end of periods of 12 to 28 d, the compressed sward height (CSH) was measured in exclusion cages at eighteen fixed points per cage to derive daily growth rates for the four classes of sward height. Stratified calibrations were made to relate sward height to herbage mass for each treatment in each period. Quadratic regressions described the relationship between herbage growth rate and initial CSH for each treatment in each period. For scaling up to the scale of the plot, CSH was measured monthly at 100 points per plot. Daily herbage growth rates declined from more than 100 kg dry matter (DM) ha,1 d,1 on both treatments at the beginning of the grazing season to 20 kg DM ha,1 d,1 or less, especially on treatment LC. This was due to the larger area covered by tall herbage on treatment LC than on treatment MC. On treatment MC, daily herbage growth rate was predominantly derived from short sward areas of up to 12 cm in height while sward areas taller than 12 cm contributed most to daily growth rates on treatment LC in early summer. The method used is considered suitable for estimating daily herbage growth rates of different classes of sward height in extensively managed pastures and can easily be adapted to deal with more heterogeneous swards than used in this study. [source]

Seasonal changes in herbage mass and nutritive value of a range of grazed legume swards under Mediterranean and cool temperate conditions

GRASS & FORAGE SCIENCE, Issue 3 2007
U. Sölter
Summary Seasonal changes in herbage mass and herbage quality of legume-based swards under grazing by sheep or cattle were investigated at four locations in climatically different zones of Europe: Sardinia (Italy), southern France, northern Germany and south-west England (UK). At each location standard treatments were applied to legumes typical of species widely used in each locality: Medicago polymorpha in Italy, Medicago sativa in France, and Trifolium repens in Germany and in UK. At each site comparisons were made of two other legumes: Trifolium subterraneum and Hedysarum coronarium in Italy, Onobrychis sativa and Trifolium incarnatum in France, Trifolium pratense and Lotus corniculatus in Germany, and Trifolium ambiguum and L. corniculatus in UK. Legumes were sown in mixture with locally appropriate companion grasses, and measurements were made over two or three grazing periods. In Italy M. polymorpha swards gave the greatest herbage mass in grazing period 1 but H. coronarium was more persistent. At the French site all legumes established poorly with no significant herbage mass differences between treatments. At both the UK and German sites L. corniculatus maintained a high proportion of legume in the sward; T. repens showed poor persistence under continuous sheep grazing in UK but persisted under cattle grazing in Germany, while T. ambiguum was slow to establish in the UK, and T. pratense proved to be of comparable herbage mass to the standard T. repens -based sward in the last year of the experiment. The concentration of crude protein and in vitro digestibility of organic matter in the dry matter of herbage showed greater within-season variation than between treatments at each site. It is concluded that, in addition to currently used species, legume-based swards containing H. coronarium, O. sativa and L. corniculatus all have potential to contribute to forage production for low-input grazing and their use merits further consideration in systems of livestock production in Europe. [source]

Growth and chemical composition of wild oat (Avena fatua) under Mediterranean conditions

GRASS & FORAGE SCIENCE, Issue 1 2004
M. K. J. El-Shatnawi
Abstract Wild oat (Avena fatua) is an annual cool-season species that grows in areas with a Mediterranean climate and has potential as a forage source in Jordan. A field experiment was conducted during the growing seasons of 1999,2000 and 2000,2001 under sub-humid Mediterranean conditions at Samta in the Ajloun Mountains, Jordan. Data on seasonal herbage mass, morphology and chemical composition of wild oat were collected at 60, 80, 100, 120 and 140 days after emergence. Plant height increased rapidly beyond 100 days after emergence. The increase in herbage mass of dry matter was gradual and peaked at 140 days after emergence. The lowest concentration of crude fibre was at 60 and 80 days after emergence, with a range of 201,263 g kg,1 DM. Crude fibre concentrations (610,630 g kg,1 DM) peaked at 140 days after emergence (maturity). In contrast to concentrations of crude fibre, concentrations of crude protein decreased gradually with age. The calcium and phosphorus concentrations were sufficient to meet the maintenance requirements of ewes. [source]

Studying spatial and temporal dynamics of sward structure at low stocking densities: the use of an extended rising-plate-meter method

GRASS & FORAGE SCIENCE, Issue 4 2003
O. Correll
Abstract An extended rising-plate-meter method was used to study the spatial and temporal variability of the sward structure of extensively managed pastures over a grazing season. Two treatments of a long-term grazing experiment with heifers were investigated: extensive continuous grazing (EG) with a target sward height of 10 cm and intensive continuous grazing (IG) with a target sward height of 5 cm. Compressed sward height and related herbage mass (HM), dominant plant species and stage of development of phenology were determined at weekly or twice weekly intervals at fixed measuring points. The results demonstrated a strong variability in sward height and HM, especially on the EG treatment. The botanical composition of the standing herbage differed between treatments and between patches of different heights within the same treatment. In areas with a short sward, the herbage was predominantly composed of Agrostis capillaris, Festuca rubra and Trifolium repens. It was more evenly composed and also included taller growing species, such as Alopecurus pratensis and Galium mollugo, in areas with a tall sward. The area potentially available for reproductive development was high in the EG treatment and low in the IG treatment. The method employed proved suitable to provide a detailed description of the dynamics of the sward structure. [source]

The effect of sward structure as influenced by ryegrass genotype on bite dimensions and short-term intake rate by dairy cows

GRASS & FORAGE SCIENCE, Issue 1 2003
P. D. Barrett
Abstract The effects of genotypic variation in ryegrasses on sward structure, bite dimensions and intake rate by dairy cows were investigated. Two experiments were conducted. In Experiment 1, swards were in a vegetative state whereas, in Experiment 2, they were partly reproductive and were taller with higher herbage mass but lower leaf proportion than in Experiment 1. Applicability of relationships between sward structure and bite characteristics, previously established from artificial or hand-constructed swards, to field conditions were tested. Additional short-term intake rates and/or sward structural characteristics were considered as indicators of potential intake for use in protocols for the evaluation of grass varieties. Four cultivars were studied: AberElan, Twins (diploid and tetraploid perennial ryegrasses respectively), Polly, a hybrid ryegrass (perennial × Italian ryegrass) and Multimo (Italian ryegrass), each established in 200-m2 plots in four replicated blocks. Herbage intake rate was determined by short-term liveweight change (taking account of insensible weight loss) using 16 dairy cows allocated to four balanced groups with each plot grazed by one group for a 1-h assessment period. One block was grazed per day, over a 4-d experimental period, with each group grazing each variety in a complete crossover design. Sward characteristics and bite rate were also measured in both experiments. Bite dimensions were subsequently estimated, with bite depth being determined as a function of extended tiller height (ETH) in both experiments. Within both experiments, bite mass and intake rate did not differ significantly between swards of different cultivars despite swards containing Multimo generally having a higher ETH and water-soluble carbohydrate concentration and lower green leaf mass, sward bulk density and neutral-detergent fibre concentration than the other swards. However, bite depth was significantly higher (P < 0·01) in swards containing Multimo swards than in the others and, in Experiment 1, bite depth, as a proportion of ETH, was higher in swards containing Multimo and lower in those containing Twins than in the other two cultivars, whereas there was no difference in Experiment 2. Taking both experiments together, the mean bite depth was 0·5 of ETH with sward bulk density accounting for almost half the variance in the relationship between bite depth and ETH. The bulk density of the bite (bite mass per unit bite volume), measured in Experiment 2, followed a similar pattern to sward bulk density, increasing in the order Multimo, Polly, AberElan and Twins. It is concluded that the relationships between sward characteristics and bite dimensions, derived from artificial swards, are applicable to field swards, although the range in natural ryegrass sward characteristics is usually not as wide as in experiments using artificial swards. Lack of precision in the measurement of short-term intake and in sward-based measurements is likely to preclude their use in the evaluation of grass varieties. [source]

Nutritional quality of semi-arid grassland in western Spain over a 10-year period: changes in chemical composition of grasses, legumes and forbs

Setting management limits for the production and utilization of herbage for out-of-season grazing

GRASS & FORAGE SCIENCE, Issue 1 2000
Laidlaw
Three experiments were carried out on perennial ryegrass-dominant swards to provide a basis for recommendations for the limits to (a) building up and timing of utilization of a herbage ,bank' for out-of-season grazing and (b) duration and intensity of early spring grazing in the United Kingdom and Ireland. In experiment 1, the effect of regrowth interval (from 7 September, 20 October, 17 November or 15 December) in autumn on herbage accumulation, leaf turnover and on subsequent spring growth was investigated. Swards regrown from early September reached maximum herbage mass (about 3 t ha,1 DM) and leaf lamina content in mid-November, by which time senescence rate exceeded rate of production of new leaves. New leaf production and senescence rates were greater in swards remaining uncut until December than in those cut in October or November. Time of defoliation up to December had no effect on spring herbage mass in the subsequent spring. Defoliating in March reduced herbage mass in late May by less than 20%. Experiment 2 investigated the progress in herbage growth and senescence in swards regrowing from different times in late summer and autumn to produce herbage for utilization beyond the normal grazing season. Treatments in a randomized block design with three replicates were regrowths from 19 July, 8 August, 30 August and 20 September. Based on a lower ceiling of leaf and total herbage mass being reached with progressively later regrowths, beyond which leaf senescence generally exceeded leaf production and herbage mass declined, it was concluded that currently recommended rotation lengths for this period should extend from 3 weeks in late July to 8 weeks for swards previously grazed in mid-September. In both experiments, leaf senescence commenced earlier (by one leaf-age category) than previously published estimates and so brought forward the time at which senescence rates balanced leaf growth rates. In experiment 3, designed to evaluate the effect of daily grazing period and intensity in early spring on herbage regrowth, dairy cows grazed successive plots (replicates) for 2 or 4 h each day at two intensities (target residual heights of 5 or 7 cm) in March to mid-April. Regrowth rate was similar in all treatments including the ungrazed control, despite soil moisture content being relatively high on occasions. Tiller density was significantly reduced in May by grazing plots in early or mid-April. It is concluded that in autumn there are limits to which rotation lengths should be extended to produce herbage for out-of-season grazing owing to attainment of ceiling yields. Although utilization in early spring may reduce herbage availability in spring, out-of-season utilization need not reduce herbage growth rates in early spring. [source]

Analysis of a Japanese Black Cattle-rearing system utilizing a bahiagrass (Paspalum notatum Flügge) pasture: 3.

GRASSLAND SCIENCE, Issue 3 2006
Intake from pasture
Abstract A Japanese Black Cattle-rearing system utilizing a bahiagrass (Paspalum notatum Flügge) pasture in coastal Miyazaki, southern Japan, was analyzed in terms of intake from pasture. In a field approach, herbage intake by grazing cattle was measured for nine periods (1,5 days) during a grazing season (May,October) along with some other variables (e.g. air temperature, herbage mass, digestibility of grazed herbage), under varying levels of supplementary feeding. The intake from the pasture was most closely related to the intake of supplement, showing a negative linear response at a substitution rate of 0.736,0.750. The intake under no supplementation, i.e. a maximum intake from the pasture, was lower than the voluntary intake predicted with feeding standards. In a modeling approach, a semi-mechanistic model for predicting grazing intake was developed using information from the literature as well as the field data. The performance of the model was acceptable. The model showed similar substitution rates (0.64,0.69), and considerable intake restriction (nearly 30%) that is not attributable to limitations by herbage mass, herbage allowance, diet digestibility or air temperature. The results indicate that a low maximal intake by the animals due to low grazing motivation is a major characteristic of the system where supplementation is a usual management practice. [source]

Productivity of Bahiagrass Pastures in South-western Japan: Synthesis of Data from Grazing Trials

JOURNAL OF AGRONOMY AND CROP SCIENCE, Issue 2 2006
M. Hirata
Abstract This study examined the rate of herbage production and herbage quality of bahiagrass (Paspalum notatum Flügge) using data from five grazing trials in the low-altitude region of Kyushu, south-western Japan, in an effort to (a) evaluate productivity of bahiagrass pastures, (b) analyse its relationship to meteorological, vegetational and managerial variables, and (c) obtain implications for better management of bahiagrass pastures. The rate of herbage production, ranging from ,56 to 213 kg DM ha,1 day,1, tended to increase from spring (April,May) to mid-summer (July) and decrease thereafter. The rate was expressed by a multiple regression equation where nitrogen fertilizer rate, air temperature, rainfall and herbage mass had positive effects. Dry matter digestibility (DMD) and crude protein (CP) concentration of herbage were in the range of 471,727 and 84,161 g kg,1 DM respectively. DMD was expressed by a regression equation where the day number from 1 April and herbage mass had negative effects, and the sampling height and nitrogen rate had positive effects. CP concentration was expressed by an equation showing a positive effect of nitrogen rate and a negative effect of herbage mass. The results indicate that management of bahiagrass pastures should aim at maintaining herbage mass closely above the critical level below which intake by grazing animals is restricted, in order to increase quality and ensure quantity. This is particularly important when nitrogen fertilizer is applied. [source]