Effect of humic substances on nutrient uptake by herbage and on production and nutritive value of herbage from sown grass pastures

The effect of humic substances on the nutrient uptake, herbage production and nutritive value of herbage from sown grass pastures was studied in six field experiments. Commercial humic substances were applied in combination with mineral fertilizer or slurry, either as a solution (HF liquid; 8·3 kg humic substances ha⁻¹) or incorporated into the mineral fertilizer (HF incorporated; 3·6 to 6·4 kg humic substances ha⁻¹). A series of cuts, ranging from two to five cuts, was taken during the growing season. The general response in herbage production to application of humic substances was an increase in herbage mass of dry matter (DM) at the first cut although this was only significant in two experiments for the HF incorporated treatment. Total herbage production of DM over the growing season, however, was similar for treatments with or without application of humic substances. The overall effect of HF incorporated and HF liquid on the herbage mass of DM at the first cut across the experiments was calculated using a meta-analysis technique and it was shown that there was a significant proportional increase of 0·14 ( P  <   0·05) with the HF incorporated treatment and a non-significant increase of 0·08 with the HF liquid treatment compared to the control treatment. The nutritive value of the herbage at the first cut was similar across all treatments. In general nitrogen, phosphorus and potassium uptake at the first grass cut was higher after application of humic substances but only in one experiment was this increase statistically significant.     

Identifying suitable temperate grass species and cultural practices for herbage production in the mountain regions of North Vietnam

In North Vietnam, during winter, shortage of herbage constrains the profitability of dairy farming. The first objective of this study was to evaluate the potential of alternative temperate (C₃) forage species, namely common oat ( Avena sativa L.), lop-sided oat ( Avena strigosa Schreb.), Italian ryegrass ( Lolium multiflorum L.) and a commercial forage mixture (Avex), to address the shortage of herbage during winter in the mountain regions of North Vietnam. The second objective was to measure the effects of cultural practices (sowing rate, harvest interval and irrigation level) on yield of dry matter (DM), chemical composition, digestibility of DM and metabolizable energy (ME) concentration of herbage from the best adapted C₃ species previously tested (lop-sided oat). Four experiments were conducted. Oat species proved to be the best adapted species and produced the highest annual yield of herbage (7600 kg DM ha⁻¹) with a high nutritive value. Yields of DM of lop-sided oat were not affected by sowing rate of seed but increased as the length of harvest intervals increased from 30 to 45 and 60 d ( P  <   0·001). Crude protein concentration, digestibility of DM and ME concentration decreased as the harvest interval increased ( P  <   0·01). Irrigation increased the yields of DM of lop-sided oats by 1·3 ( P  <   0·05) but had no effect on the nutritive value of herbage. It is concluded that both common oat and lop-sided oat are suitable species to provide herbage in the winter for the mountain regions of North Vietnam.     

Nutritive value of herbage of five semi-irrigated pasture species across an irrigation gradient

As water resources become limiting, the need to produce stable amounts of herbage with a high nutritive value increases. An understanding of how levels of irrigation affect crude protein (CP) and neutral-detergent fibre (NDF) concentrations and, in vitro true digestibility (IVTD), is critical in the management of pastures. Smooth bromegrass ( Bromus inermis Leyss.), prairiegrass ( Bromus willdenowii Kunth), hybrid-bromegrass [meadow ( Bromus riparius Rehm.) × smooth bromegrass], creeping foxtail ( Alopecurus arundinaceus Poir.) and RS wheatgrass ( Elymus hoffmannii Jensen & Asay) were established under a line-source irrigation system to evaluate the effect of five water levels and three harvest dates on concentrations of CP and NDF, and values of IVTD. With CP concentration of herbage, there were positive linear significant relationships with decreasing water levels for all species. Rankings for mean CP concentrations across water levels and harvest dates were smooth bromegrass > RS wheatgrass > hybrid-bromegrass > creeping foxtail > prairiegrass. No consistent relationships with IVTD across water levels were detected among the species. Averaged across water levels, harvest dates and years, smooth bromegrass, hybrid-bromegrass and creeping foxtail had significantly higher IVTD values than RS wheatgrass and prairiegrass. Rankings of mean NDF concentrations across water levels and harvest dates combined over years were prairiegrass > RS wheatgrass > hybrid-bromegrass > creeping foxtail > smooth bromegrass. Herbage of smooth bromegrass had higher IVTD values and lower NDF concentrations than hybrid-bromegrass, prairiegrass, creeping foxtail and RS-hybrid at all water levels.     

Seasonal distribution of herbage mass and nutritive value of Prairiegrass (Bromus catharticus Vahl)

A reliable supply of herbage is a crucial feature of forage‐based livestock systems. Forage resources with winter‐active growth habits can help extend the growing season in early spring and late autumn in regions with mild‐winter conditions while drought‐ and heat‐tolerant plants help meet herbage needs during summer in humid temperate regions. The prairiegrass (Bromus catharticus, Vahl) cultivars, Grassland Dixon and Grasslands Lakota, provide resistance to foliar disease and cold in addition to sustained productivity when soil moisture is low, and could be useful over a wide range of growing conditions. The cultivars were sown in spring or summer to determine seasonal distribution of productivity and nutritive value of herbage grown in a cool‐temperate region. Stands established rapidly regardless of sowing time or cultivar and were virtually pure prairiegrass once plants were well‐established. Stand composition of broadcast sowings tended to be stable in subsequent growing seasons, whereas the amount of prairiegrass varied in no‐till stands. In the growing seasons after establishment, cumulative dry matter (DM) yield of Lakota was similar regardless of when it was sown, whereas DM yield of Dixon differed with sowing time and was less in spring‐ than summer‐planted stands. Rapid stand establishment, significant late‐season yield, consistent concentrations of crude protein, non‐structural carbohydrate and total digestible nutrients in herbage, and dominance of sward composition, suggest that prairiegrass cultivars, Dixon and Lakota, are excellent resources for forage‐based livestock production systems in humid temperate conditions.     

Morphological characteristics and nutritive value of some grass species in an arid ecosystem

An experiment was conducted on four genotypes of Cenchrus ciliaris, two genotypes of C. setigerus and one genotype each of Panicum maximum, P. antidotale and Lasirus sindicus grasses at CCS Haryana Agricultural University, Haryana, India in 2003 and 2004. Two cuts were taken in the months of September and November in each year. Measurements were made of seven morphological characteristics and the nutritive value of the grasses. The total green fodder yield was highest in C. ciliaris cv. IGFRI in 2003 and in C. ciliaris cv. CAZRI 75 in 2004. Total dry matter (DM) yield was highest in P. maximum cv. IGFRI and C. ciliaris cv. CAZRI 75 in 2003 and 2004, respectively. Crude protein and digestible DM yields were highest in C. ciliaris cv. CAZRI 75. It was concluded that C. ciliaris cv. CAZRI 75 can be recommended as the one with the most potential among the studied grasses for use in the arid regions of south‐west Haryana, India.     

Influence of solar radiation on the productivity and nutritive value of herbage of cool-season species of an understorey sward in a mature conifer woodland

Silvopastoral systems in the Appalachian region of the USA could increase the carrying capacity of livestock and contribute to a reliable supply of high‐quality herbage. In 2000, 2001 and 2002, the influence of solar radiation [0·20, 0·50 or 0·80 of maximum solar radiation (MSR); treatments 20‐, 50‐ and 80‐MSR respectively] on the productivity and nutritive value of a mixture of sown grasses and legumes established under a mature stand of conifers was investigated. Yields of dry matter (DM), crude protein (CP), total non‐structural carbohydrates (TNC) and total digestible nutrients (TDN) were greater for the 80‐MSR treatment except in 2000 when DM yield did not differ. As a proportion of the sward, introduced species (Dactylis glomerata L., Trifolium repens L., and Lolium perenne L.) increased over time for the MSR‐80 treatment, corresponding with a decrease in the proportion of bare area and of non‐introduced species. CP concentration of herbage was 207 g kg^?1 DM or greater across treatments and years with higher concentrations on the 20‐ and 50‐MSR treatments. Herbage from the 80‐MSR treatment had a greater concentration of TNC than that of the 20‐ and 50‐MSR treatments. Estimated concentration of TDN was similar for all treatments in 2000 and greater for the 80‐MSR treatment than the other two treatments in 2001 and 2002. High CP concentrations in herbage, as a result of appropriate thinning of trees in an Appalachian silvopastoral systems, could be utilized as a protein supplement to herbage with low CP and higher fibre concentrations.     

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

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.     

The effect of stocking rate and calving date on grass production,utilization and nutritive value of the sward during the grazing season

A 2‐year whole‐farm system study compared the accumulation, utilization and nutritive value of grass in spring‐calving grass‐based systems differing in stocking rate (SR) and calving date (CD). Six treatments (systems) were compared over two complete grazing seasons. Stocking rates used in the study were low (2·5 cows ha^?1), medium (2·9 cows ha^?1) and high (3·3 cows ha^?1), respectively, and mean CDs were 12 February (early) and 25 February (late). Each system had its own farmlet of eighteen paddocks and one herd that remained on the same farmlet area for the duration of the study. Stocking rate had a small effect on total herbage accumulation (11 860 kg DM ha^?1 year^?1), but had no effect on total herbage utilization (11 700 kg DM ha^?1 year^?1). Milk and milk solids (MS; fat + protein) production per ha increased by 2580 and 196 kg ha^?1 as SR increased from 2·5 to 3·3 cows ha^?1. Milk production per ha and net herbage accumulation and utilization were unaffected by CD. Winter feed production was reduced as SR increased. Increased SR, associated with increased grazing severity, resulted in swards of increased leaf content and nutritive value. The results indicate that, although associated with increased milk production per ha, grazed grass utilization and improved sward nutritive value, the potential benefits of increased SR on Irish dairy farms can only be realized if the average level of herbage production and utilization is increased.     

Inclusion of alfalfa improves nutritive value and in vitro digestibility of various straw–grass mixed silages in Tibet

To enlarge the feed resources and enhance the utilization efficiency of straws as ruminant feed in Tibet, four kinds of local crop straws with tall fescue (Festuca arundinacea Schreb.) based on the ratio of 40/60 (fresh weight) were ensiled with four levels (0, 10%, 20% and 30% of fresh weight) of alfalfa (Medicago sativa L.), respectively. The laboratory silos (1L) were opened after 45 days of ensiling, and the fermentation characteristics, nutritive value and in vitro digestibility of the mixed silages were analysed. The silages including alfalfa had significantly (p < 0.05) or numerically (p > 0.05) higher lactic acid and crude protein contents, lactic acid bacteria counts, in vitro digestibility of dry matter, neutral detergent fibre (NDF) and acid detergent fibre (ADF), and lower NDF and ADF contents than controls. The results suggest that inclusion of alfalfa to mixtures of straws and tall fescue had favourable effects on fermentation quality and obviously improved the nutritive value and in vitro digestibility of mixed silages. This effect was most evident when the inclusion proportion of alfalfa was 30% in oat straw mixed silage.     

Open pasture,silvopasture and sward herbage maturity effects on nutritive value and fermentation characteristics of cool‐season pasture

In Appalachian USA, silvopasture offers promise of increased farm productivity. A synchronized, temporal understanding of open pasture (OP) and silvopasture (SP) nutritive characteristics is essential for grazing system development. We examined pasture‐type nutritive‐value relationships when herbage was harvested based on morphological maturity rather than calendar date. Neutral detergent fibre and acid detergent fibre (ADF and NDF) content were greater in silvopasture, while organic matter (OM) was lower (P < 0·05). Digestibility of SP herbage dry matter (DM) and OM tended (P = 0·10) to be lower (418 vs. 471 and 437 vs. 491 g kg^?1 respectively). Neutral detergent fibre digestibility was greater (P < 0·05) for OP than SP forage (538 vs. 480 g kg^?1), and ADF tended to be greater (P = 0·10; 551 vs. 501). Open‐pasture forage fermentation effluent exhibited slightly higher microbial richness and Shannon diversity than SP. However, overall community composition of both bacteria and archaea did not differ between pasture types or sampling times. Pasture types show proximate analyses differences generally favourable to OP, although both have similar overall nutritive value. In addition, the SP sward exhibited a 4‐ to 6‐days delay in reaching equivalent maturity. Conversion of farm woodlots to SP would increase overall herbage production and improve pasture management flexibility.     

Agronomic performance and nutritive value of common and alternative grass and legume species in the Peruvian highlands

The agronomic performance and nutritive value of twelve annual and perennial grasses and legumes were analysed in order to define alternatives to local forages for dry-season feeding of ruminants in the Peruvian Andes. There were twelve species and two fertilizer treatments (no fertilizer and a N;P;K fertilizer mainly applied at sowing) in an experiment with a randomized complete block design with three replicates at each of two sites. Plant height, soil cover by forage and weed species, frost damage, dry matter (DM) yield and nutritive value of herbage were evaluated in 2005 and 2006. Among the annual species, Hordeum vulgare L. cv. UNA 80 and × Triticosecale Wittm. had the highest DM yields when fertilized (8226 and 6934 kg ha⁻¹ respectively). Without fertilizer the alternative cultivars had similar DM yields to that of the local forages. Cultivars of Avena sativa L. had lower concentrations of neutral-detergent fibre (NDF) (557 g kg⁻¹ DM) and higher concentrations of predicted net energy for lactation (5·86 MJ kg⁻¹ DM) than the other annual grass species (625 g kg⁻¹ DM and 5·01 MJ kg⁻¹ DM respectively), while the legumes were superior in concentrations of crude protein (277 g kg⁻¹ DM) and NDF (362 g kg⁻¹ DM). Considering the low agronomic performance of the perennial forages, a mixture of fertilized annual grasses and legumes appears the most appropriate approach to meeting the demand for forage of high nutritive value in the Peruvian highlands.     

Effects of grazing and precipitation on herbage production,herbage nutritive value and performance of sheep in continental steppe

The present study highlights the effects of sheep grazing and precipitation on herbage and animal performance in a grazed steppe of Inner Mongolia. Experimental data were collected during grazing periods of four consecutive years (2005–2008), and effects were analysed across a gradient of seven grazing intensities. Variation in annual precipitation, reflected by the effect of ‘year’, was the major factor affecting herbage; i.e., the production and nutritive value of herbage increased with increasing precipitation. Herbage parameters were also affected by grazing intensity, as herbage production (HP) and herbage nutritive yields decreased, while herbage nutritive values increased with increasing grazing intensity. The grazing‐induced decrease in herbage nutritive yields suggests that decreases in HP offset the positive effect of grazing on the nutritive value. Liveweight gain (LWG) was predominantly affected by grazing intensity, as LWG per sheep and per ha decreased and increased, respectively, with increasing grazing intensity. However, responses varied among years: LWG per sheep was maximized by light grazing in the drought year and by moderate grazing the wet year. Our results showed that herbage shortage at high grazing intensities reduces LWG per sheep and thus diminishes responses in LWG per ha. Nevertheless, the highest grazing intensity provides highest animal production per ha in the short term; however, this is not sustainable in the mid‐ and long term because decreasing HP induces degradation processes. Based on our results, a reduction in grazing intensity that still provides 78% of the maximum LWG per ha meets the requirements of a sustainable grazing management.     

Influence of cutting regime and fertilizer application on the botanical composition,yield and nutritive value of herbage of wet grasslands in Central Europe

The changes in dry matter (DM) yield, botanical composition and nutritive value of herbage to ruminants of two wet grasslands, Arrhenatherum elatius grassland (Experiment 1) and a Molinia caerulea fen meadow (Experiment 2), in which a range of cutting and fertilizer treatments were imposed in 1999, were assessed after 4–7 years of treatment imposition. Both experiments had a split‐plot design with four replicates. In Experiment 1 the three main‐plot cutting treatments were two cuts with a delayed first cut, three cuts and four cuts during the growing season of each year. In Experiment 2 the cutting treatments were two cuts with a traditional harvest time, two cuts with a delayed first cut and three cuts. The four sub‐plot fertilizer treatments were an unfertilized control, application of a phosphorus and potassium (PK) fertilizer, application of a nitrogen (N) and PK fertilizer to the first cut only (N₁PK) and application of PK plus N applied to each of two, three or four cuts (N_c PK). Application of fertilizer influenced yield and botanical composition of herbage more than the cutting treatments while the opposite occurred for nutritive value of the herbage. Application of fertilizer increased the proportion of tall grasses in Experiment 1 and forbs in Experiment 2. The proportion of Equisetum palustre, present only in Experiment 1, was reduced from 0·33 to less than 0·01 by increased cutting frequency together with the NPK fertilizer treatments. In Experiment 1 diversity of vascular plants was negatively affected only by the four‐cuts treatment while on both wet grasslands other cutting and fertilizer application treatments had no effect. Changes in DM yield of herbage caused by the cutting and fertilizer application treatments were similar for both vegetation types with DM yield increased significantly by fertilizer application but only slightly or not reduced by increasing the cutting frequency. Nutritive value of herbage was positively correlated with cutting frequency and was most influenced at the first cut.     

Assessing population maturity of three perennial grass species: Influence of phenology and tiller demography along latitudinal and altitudinal gradients

To assess the whole‐sward maturity, which is a primary concern for grassland managers, we studied three forage grass species with contrasting phenology over a range of climatic conditions among sites. We considered two main issues: (i) How is grass population maturity related to population phenology, and is this relation affected by environmental factors? and (ii) Is the sum of temperatures a good index to describe phenological development under contrasting climates? To explore the role of temperature accumulation in species population development, we described the phenological development of populations of three grass species along latitudinal and altitudinal gradients at eight locations across France. We used a numerical index of tiller development to quantify sward morphological structure and discriminate phenological peak from average maturity. We report that phenological development rates were similar among sites for each species, but required fewer growing degree days to start at higher latitudes and altitudes. However, we found that population maturity and phenological peak differed significantly due to among‐site variability in vegetative tiller percentage in whole‐population biomass. Our results underlined the importance of considering tiller distribution among phenological stages, especially tiller development synchrony, together with phenology to assess sward maturity in semi‐natural permanent grasslands.     

Seasonal productivity and nutritive value of temperate grasses found in semi-natural pastures in Europe: responses to cutting frequency and N supply

Monocultures of thirteen perennial C₃ grass species that co‐occur in temperate semi‐natural grassland communities in Europe were compared in a factorial field design of two levels of N supply and two levels of cutting frequency. Above‐ground yield of dry matter (DM), crude protein (CP) concentration and pepsin‐cellulase DM digestibility of herbage were measured in two successive years. Species was the largest source of variability in yield of DM and DM digestibility of herbage, while CP concentration of herbage responded more to management factors. The highest mean DM yields and values of DM digestibility of herbage were achieved in spring for Festuca arundinacea and in autumn for Phleum pratense. Poa trivialis and Festuca rubra had the lowest DM yield and DM digestibility values, respectively, regardless of seasons and treatments. For all species CP concentration in herbage increased in response to an increase in cutting frequency and N supply by an average of 46 and 34 g kg^?1 DM respectively. Differences between years and seasons indicated the importance of plant phenology on nutritional variables and the influence of environmental factors on species performance. Species ranking was compared according to their annual digestible DM and CP yields. The results show that some grasses have a nutritive value which is comparable to that of forages selected for high yields.     

Changes in nutritive value and herbage yield during extended growth intervals in grass–legume mixtures: effects of species,maturity at harvest,and relationships between productivity and components of feed quality

There is a lack of information on the effects of companion species in grass–legume mixtures on herbage yield and quality changes during prolonged growth. Such information is relevant for harvest planning and estimation of consequences for feeding value of conserved feed when harvesting is delayed. Perennial ryegrass was sown with each of four legumes: red clover, white clover, lucerne and birdsfoot trefoil, and white clover was sown with hybrid ryegrass, meadow fescue and timothy. Effects of species composition on herbage yield, contents of N, neutral detergent fibre (NDF), acid detergent fibre (ADF) and lignin, ash and in vitro organic matter digestibility (IVOMD) were studied in entire herbage and in component species during 2 years in a small‐plot cutting trial in Denmark. In May and August, the dynamic development of components of feed value and their interrelationships were investigated by sampling at optimum harvest date (i.e., normal practice) ± 1 week (t = ?1 to t = +1). Herbage digestibility and contents of N and ash decreased while those of fibre compounds increased during the 2 weeks from t = ?1 to t = 1 in all species. In May, contents of ADF and lignin increased at a faster rate in legumes than in grasses; in August, NDF and ADF increased most quickly in legumes. Generally, N contents and IVOMD declined at similar rates in grasses and legumes, but, within each group, differences in yield and quality development occurred among species. The relationship between weekly growth rate and change in quality parameters differed among species and functional groups, i.e., grasses and legumes. Results are discussed in the context of quantifying the impact of delaying the harvest date of grass–legume mixtures and relationships between productivity and components of feed quality.     

Effect of plant spacing and nitrogen fertilizer levels on the growth,dry‐matter yield and nutritive quality of Columbus grass (Sorghum almum stapf) in southwest Nigeria

A field experiment was conducted in 2006 and 2007 to determine the agronomic performance and nutritive value of Sorghum almum for introduction in the derived savannah area of Nigeria. The experiment was arranged in a 2 × 4 factorial design with 2 plant spacings (0·5 × 0·5 m and 1·0 × 1·0 m) and 4 nitrogen (N) fertilizer levels (0, 60, 120 and 180 kg N ha^?1). Plant height, tiller number, leaf proportion, biomass yield and nutritive value of the herbage were evaluated as part of the search for alternatives (especially drought tolerant) to local forages for dry season feeding of ruminants. Herbage yield data were tested for linear, quadratic and cubic trends to identify the optimal fertilizer levels for both spacings. Spacing × N interactions (P < 0·05) were observed for plant height and tiller number in both years. Agronomic performance was marginally better in 2007 compared with 2006. The maximum dry‐matter (DM) yield of 3500 and 3740 kg ha^?1 for the more dense row spacing (0·5 × 0·5 m) was achieved at N fertilizer levels of 144 and 149 kg N ha^?1 for 2006 and 2007 respectively. For the less dense (1·0 × 1·0 m) row spacing, the maximum DM yield of 3020 and 3240 kg ha^?1 was achieved at 51 and 97 kg N ha^?1 for 2006 and 2007 respectively. The crude protein content of the grass ranged from 61 to 89 g kg^?1 DM, while the neutral detergent fibre (NDF) content ranged from 700 to 734 g kg^?1 DM. The ability of S. almum to persist into the second year in this region is seen as a promising index as persistence is one of the characteristics of a good forage plant. Considering the exorbitant price of N fertilizer, less dense row spacing with N fertilizer rate in the range of 50–100 kg N ha^?1 is hereby recommended for this region.     

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

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.     

Seasonal nitrogen effects on nutritive value in binary mixtures of tall fescue and bermudagrass

The addition of cool‐season, tall fescue [Lolium arundinaceum (Schreb.) Darbysh.], to warm‐season, bermudagrass [Cynodon dactylon (L.) Pers.], pastures can improve forage productivity and nutritive value. Effects of four binary mixtures consisting of cv. Flecha (incompletely summer dormant) and cv. Jesup (summer active) tall fescue overseeded into established stands of cv. Russell and cv. Tifton 44 bermudagrass and three seasonal N treatments were evaluated on dry‐matter (DM) yield, crude protein (CP), in vitro true digestible DM (IVTDDM), acid detergent fibre (ADF) and neutral detergent fibre (NDF). Nitrogen‐timing treatments were 168 kg N ha^?1 (as ammonium nitrate) split into three applications per season with an additional 8·6 t ha^?1 of broiler litter (as‐is moisture basis) split into two applications varied to favour either tall fescue (in October and January), bermudagrass (in March and May) or both grasses (in January and March). Treatment effects were determined in samples of mixed herbage harvested in April, May, July, August and September of 2009 and 2010. Regardless of bermudagrass cultivar, herbage DM yield was greater (P < 0·05) in Flecha–bermudagrass than Jesup–bermudagrass in July of both years and in August 2010. Nutritive value generally was greatest in Jesup–Tifton 44, based on high CP and IVTDDM, and low ADF and NDF. Averaged across mixtures, avoiding fertilizer N and litter applications beyond April increased (P < 0·01) DM yield in April and May and IVTDDM in July (603 vs. 629 g kg^?1; 2‐year average) and August (618 vs. 660 g kg^?1) compared with applications in January–July. The timing of N and broiler litter applications on tall fescue–bermudagrass to favour growth of tall fescue appeared to increase fescue cover during the cool season and nutritive value of the mixed herbage during the warm season.     

Chemical composition and in vitro total gas and methane production of forage species from the Mid Rift Valley grasslands of Ethiopia

There is increasing interest in sustainable land use in the tropics to optimize animal production while also reducing methane (CH₄) emissions, but information on nutritive value and CH₄‐emission potential of tropical forage species is limited. Samples of 24 grasses and five other forages were collected during the main rainy season on randomly positioned quadrats in semi‐arid grassland in the Mid Rift Valley of Ethiopia. Samples were pooled by species, analysed for chemical composition and incubated with rumen fluid to determine total gas and CH₄‐emission potentials using a fully automated in vitro gas production apparatus. Organic matter digestibility (OMD) and metabolizable energy (ME) contents were calculated from chemical composition and gas production data. Large variability was observed among forages for all nutritional variables considered. The grasses Eleusine multiflora, Pennisetum stramineum, Dactyloctenium aegyptium, Eragrostis aspera, Cenchrus ciliaris and Eragrostis cilianensis showed relatively high OMD (68–72%) and ME values (9·1–10·2 MJ kg^?1 dry matter). Melinis repens, E. multiflora and the non‐legume forb Zaleya pentandra showed relatively low CH₄ to total gas ratios; these species may have potential for use in low CH₄‐emission forage diets. Acacia tortilis fruits had high content of crude protein and moderate ME values, and may be an ideal feed supplement for the grazing ruminant. Sodium content was below the recommended level for ruminants in all the forage species. Overall, the pasture stand during the main growing season was evaluated as having moderate nutritional quality.