Grass and Forage Science最新文献

This study evaluated forage mass, nutritional value, forage intake, animal performance and economic indicators in Urochloa decumbens pastures under monoculture and a silvopastoral system (SPS) with Mimosa caesalpiniifolia (Benth.). The treatments were arranged in a randomised block design with three replications, and the experiment was conducted from 2020 to 2022 in Garanhuns, Brazil. We are using crossbred Holstein × Zebu calves under continuous stocking with variable stocking rate. No significant differences were detected in forage nutritional value or animal performance between systems. However, forage intake was higher in the SPS (3.29 vs. 2.54 kg DM animal⁻¹ day⁻¹), and during the rainy season SPS pastures showed greater crude protein concentration (127 vs. 94 g kg⁻¹ DM). The highest average daily gain (0.52 kg animal⁻¹ day⁻¹) and stocking rate (1.51 AU ha⁻¹) occurred during the first grazing season. Beef production did not differ statistically between systems (9 vs. 12 @ ha⁻¹ year⁻¹), but the presence of M. caesalpiniifolia enhanced economic performance in the SPS. Timber revenue compensated for lower meat yield, resulting in higher net profit (US$ 933.5 vs. US$ 642.9 ha⁻¹ year⁻¹) compared with monoculture. The equivalent annual net present value (US$ 192.8 ha⁻¹ year⁻¹) further confirmed the economic viability of tree-based livestock production. Therefore, although both systems produced similar forage mass, nutritive value and animal performance, the integration of woody legumes increased forage intake and improved profitability, highlighting silvopastoral systems as an efficient strategy for livestock production with additional revenue diversification.

Grassland is a key resource for livestock production, but it also provides biodiversity within agricultural landscapes. Improved management practices are required to reconcile competing demands for different ecosystem services provided by grasslands. This study investigated the effects of applied nutrients and sward composition on herbage biomass dry-matter (DM) yield in Northern Ireland. A long-term grassland experiment established with eight nutrient treatments (unfertilised control, inorganic fertiliser [NPK], cow and pig slurry at three application rates each) and two sward types (multi-species sward, MSS; permanent grassland, PG) was harvested as a silage-cut system three times (spring, summer and autumn) over 3 years. The mean annual yield of the MSS (12,010 kg DM ha⁻¹ year⁻¹) was 24% higher than PG (9670 kg DM ha⁻¹ year⁻¹). Seasonal effects on DM yield were highly significant for both sward types, with the greatest production in spring followed by summer and the lowest yield in autumn. Sward type × nutrient treatment interactions significantly affected the DM yield with the greatest DM yield for the high slurry treatments, while the NPK fertiliser treatment was similar to the low cow slurry treatment. The MSS had a greater DM production over a wide range of nutrient input levels which suggests that MSS can be introduced to both intensive (high input) and extensive (low input) grassland systems. Future research is required to evaluate the long-term performance of the MSS to provide greater DM production and the persistence of introduced species to improve sward biodiversity.

Accurate estimation of plant alpha diversity is crucial for understanding ecosystem dynamics and advancing biodiversity conservation. However, quantifying alpha diversity in grasslands remains challenging due to the small size of plant individuals and complex background interference. This study explores the use of UAV-acquired hyperspectral remote sensing data to estimate plant diversity in the Hunshandak Sandland, Inner Mongolia—a temperate continental monsoon grassland characterised by arid climates and desertified landscapes. Field surveys were conducted across areas with contrasting vegetation cover, collecting data on species richness, height and coverage. Four alpha diversity indices (species richness, Shannon-Wiener index, Simpson index and Pielou's evenness index) were calculated from the field data. A total of 1274 spectral vegetation indices, derived from spectral variation, principal components and texture features, were analysed. Spearman correlation analysis and random forest models were used to evaluate relationships between plant diversity indices and spectral metrics across gradients of vegetation coverage (indicated by NDVI) and species richness. The results showed that spectral indices derived from characteristic bands reflecting leaf pigment and photochemical traits—such as NDMI, NPCI and SRPI—and indices from the R package rasterdiv (e.g., NDMI-REN1, ARI-REN0, MVI-REN1) achieved high accuracy in estimating species richness. For the Shannon-Wiener index, Simpson index and Pielou's evenness index, the most effective indices were NDVI-REN1, ARImn and REP-CRE, respectively. Overall, spectral indices performed better in estimating the Shannon-Wiener (H), Simpson (D) and Pielou (P) indices than species richness. Estimation accuracy improved with increasing gradients of community coverage and complexity in grasslands. This study demonstrates the potential of UAV-based hyperspectral data for grassland diversity monitoring and highlights the importance of selecting context-appropriate vegetation indices to address challenges posed by vegetation cover and community complexity. These findings provide a foundation for developing efficient ecological monitoring models in sandy grasslands and analogous ecosystems.

Senesced annual legumes provide nutrients for small ruminants during summer, yet grazing pressure may significantly deplete seedbanks. We quantified seed passage and nutritional value of pods from 15 modern pasture legume cultivars fed to sheep in metabolism crates. Seed passage ranged from 8% (serradella, Ornithopus spp.) to 87% (biserrula, Biserrula pelecinus), with significant differences observed between species and among accessions within species. To extend the analysis, we incorporated 38 data points from historical studies, revealing that seed passage was best predicted by an exponential regression model incorporating individual seed mass and hardseededness. Seed passage declined sharply with increasing seed mass; a 0.3 mg increase corresponded to a 25% reduction in passage. In clovers (Trifolium spp.), hardseededness and seed mass were strong predictors of seed passage, explaining 64% and 58% of the variation. In contrast, seed mass accounted for 27% of variation in passage of medics (Medicago spp.). Dry matter digestibility of pods (51%–63%) and seeds (75%–90%) varied, as did crude protein content. If a sheep consumed 1 kg of pods, the ME apparently digested from 0.3 to 6.9 MJ, while energy lost via seed passage was 0.3 to 2.7 MJ. Bladder clover (Trifolium spumosum) appears well-adapted to endozoochory, producing large quantities of small, hard seeds (42% passage) that are embedded in senesced pod material that is nutritionally rich and easily prehended. Agronomists can improve persistence and summer feeding value of aerial seeded legumes by selecting for traits associated with feeding value and seed passage.

Legumes, through atmospheric N fixation, enhance soil health and fertility by increasing organic matter and nitrogen (N) availability. This study evaluated the productivity, N fixation and N transfer from annual legume mixtures (LM) to a companion ryegrass (Lolium multiflorum) in mixed swards, under Mediterranean conditions. The LM swards with different phenologies (designated M400, M500 and M600), comprised cultivars of Trifolium subterraneum, T. michelianum and Medicago polymorpha, grown either alone or in combination with ryegrass (LM + R). Plots were established in May 2014 and were evaluated from 2014 to 2017. Dry matter production varied significantly among LM, LM + R and ryegrass monocultures across the different years. The LM + R swards produced 35%–47% more dry matter than LM swards and 33%–68% more than ryegrass alone. The mixture M400 + ryegrass achieved the highest production (6.64 t ha⁻¹ average; 14.85 t ha⁻¹ in 2015). N derived from the atmosphere ranged from 84% to 94% in LM swards. The mixture M500 fixed the highest amount of N across years. The nitrogen yield (kg N ha⁻¹) was higher in LM + R swards compared to LM alone. M600 showed the highest N transfer to ryegrass. All LM + R swards had land equivalent ratio (LER) > 1, indicating better resource use than monocultures. The demonstrated benefits of mixed cropping systems—higher productivity, enhanced N fixation, effective N transfer and improved resource use efficiency—align with the goals of reducing synthetic fertiliser dependency and mitigating environmental impacts.

Grazing management critically depends on practical, efficient, and parsimonious methods for estimating herbage mass to enable prompt decision-making under diverse pasture conditions. This study evaluated the rising plate meter (RPM) as a rapid, non-destructive tool for herbage mass estimation in multispecies swards (MSS) compared to perennial ryegrass (PRG) and PRG–white clover (PRGWC) swards. Five field trials at three Irish sites produced a dataset of 1220 observations (herbage mass range per harvest: 310–3991 kg DM ha⁻¹). Five calibration models were developed and compared: Model 1 used a fixed multiplier approach (herbage height [HH] × 250); Model 2 included HH; Model 3 incorporated HH and sward type; Model 4 included HH and season and Model 5 incorporated HH, season and sward type along with their interaction. Model 5 achieved the highest statistical performance with the lowest root mean square error (RMSE; 244 kg DM ha⁻¹), highest coefficient of determination (R²; 0.81) and lowest AIC value demonstrating the theoretical benefit of including seasonal and sward-specific effects. However, Model 1, while slightly less accurate (RMSE = 277 kg DM ha⁻¹; R² = 0.75), performed robustly despite its greater parsimony and ease of use. For routine on-farm decision-making, the marginal improvements provided by Model 5 may not justify its added complexity. These results suggest that the simple RPM calibration equations can provide herbage mass estimation in MSS that are no less effective than those used in PRG and PRGWC systems.