Improving the quality of irrigated pastures can increase the profitability of ruminant production systems. Increasing pasture plant biodiversity is beneficial for ruminants, pollinators, and soil health, but it is challenging to manage weed incursion in seeded mixed-species pastures. This study assessed the weed incursion that resulted when forage legumes or grasses were seeded as binary mixtures with one of four non-legume forbs. Defoliation occurred at 6-week intervals as either mowing or mob grazing. Forbs were chicory, plantain, Lewis flax, or small burnet and forages were alfalfa, birdsfoot trefoil, creeping foxtail, intermediate wheatgrass, kura clover, meadow bromegrass, orchardgrass, perennial ryegrass, reed canarygrass, sainfoin, smooth bromegrass, tall fescue, and white clover. Four defoliations per year occurred between May and September for two years. Eight replications were grouped into four blocks and each pair in a block was randomly assigned to the two defoliation treatments, mob grazing or mowing. Plots were 1.5 m2 and were assessed visually before each defoliation for the percentage of forage, forb, and weed. Chicory was the most dominant of the four forbs, and relative to legumes, most grasses suppressed both forb establishment and weed incursion under both grazing and mowing. There were no statistically significant effects of defoliation treatment on weed incursion.

Biocrusts play an essential role in maintaining ecosystem stability, which is common in arid and semi-arid areas. Although there have been some previous studies on the stoichiometry of biocrust subsoil in grazing systems, further research is needed to assess the effects of varying grazing intensities. Four grazing gradients were established to investigate the change mechanism of biocrust subsoil stoichiometry under grazing conditions, considering its seasonal response. These findings revealed that biocrusts' coverage and their chlorophyll content showed a parabolic trend of increasing and then decreasing with the increase in grazing intensity. At the same time, their standard response thresholds to grazing intensity ranged from 2.67 to 5.33 sheep/ha. Moreover, the premise that the biocrust is damaged by grazing trampling has become a consensus; our study found that the biocrust still played an important role, although its structure was destroyed because of its greenness (BG) increased. The influence of grazing intensity on the biocrust subsoil stoichiometry is unquestionable; in addition, they are influenced by a combination of vegetation (10% and 19%) and environmental influences (6% and 18%). Furthermore, it was observed that these changes did not compensate for the reproduction and development of biocrusts in grazing-induced trampling damage. In this study, the integrated consideration of biocrusts into the grazing system fully affirmed its essential role. Additionally, it clarified the pathways and effect of grazing on biocrusts subsoil stoichiometry, providing a new perspective and reference for developing grazing strategy on the Loess Plateau.

Acacia hybrid (Acacia mangium Willd. x A. auriculiformis A. Cunn. Ex Benth.) dominates plantation wood production in central Vietnam. Dependence on a single species may increase biological risks. The potential of eucalypt as an alternative was examined by comparing the growth and survival of acacia hybrid and eucalypt hybrid (Eucalyptus urophylla S.T. Blake x E. pellita F. Muell.) clones in Quang Tri province at three planting densities (1333, 1667 and 2222 trees ha-1). The experiment was planted on an eroded shallow soil common in the region. At age 5 years, survival of acacia (74%) was higher than that of eucalypt (67%), a consequence of high mortality from wind damage for one eucalypt clone. Eucalypt was taller by about 2 m, but stem diameters of acacia and eucalypt were very similar. For both taxa, diameter decreased significantly as planting density increased. Across planting densities, mean standing volume was 107 and 108 m3 ha-1 for acacia and eucalyptus, respectively. Linear regressions of stocking at 5 years on volume accounted for over half of the variance in acacia and eucalypt plot volumes, demonstrating the strong effect of stocking on yield. There were similarly strong effects of stocking on stem diameter. Acacia hybrid plantations of nearby small growers had stockings at age 5 years that averaged over 2500 stems ha-1. Growers planted at higher densities and allowed their trees to multi-stem. Their standing volumes at age 5 years ranged from 83 to 102 m3 ha-1. Understanding how to reduce tree mortality would assist growers to choose planting densities and stand management that optimise growth, log diameter classes and net returns.