Lai Shuaibin, Chang Runze, Xu Zhen, Wang Wen, Hou Fujiang
State Key Laboratory of Herbage Improvement and Grassland Agro-ecosystems, Key Laboratory of Grassland Livestock Industry Innovation, Ministry of Agriculture and Rural Affairs, Engineering Technology Research Center for Ecological Restoration and Utilization of Degraded Grassland in Northwest China, National Forestry and Grassland Administration, College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou, 730020, China.
Breeding Sheep Popularize Center of Yunnan Province, Yunnan Xundian, 655200, China.
J Environ Manage. 2025 Aug 15;393:126971. doi: 10.1016/j.jenvman.2025.126971.
The implementation of grazing practices and the introduction of leguminous species in grasslands are recognized as effective strategies for improving soil health and forage production. However, it is still uncertain if these benefits can be further improved by integrating appropriate sowing rates of legume species in grassland alongside with grazing. Therefore, a two-year field experiment was conducted in Southwest China to investigate the effects of grazing (0 and 3 cattle months ha) and reseeding rates of white clover (0, 20, 40, and 60 kg ha) on forage yield, soil nutrients and microbial activity). The results indicated that compared to the control, both enclosure and grazing significantly increased the above- and below-ground biomass as white clover reseeding rates increased, with no significant difference observed between the 40 kg ha and 60 kg ha reseeding rates. Under enclosure and grazing management, the two-year average above-ground biomass (AGB) increased by 17.3 % and 28.2 % (40 kg ha), 17.5 % and 35.9 % (60 kg ha) compared to the control (0 kg ha), respectively. In addition, the belowground biomass increased by 24.8 % under enclosure and 30.0 % under grazing at a white clover reseeding rate of 40 kg ha. Compared to the enclosed grassland, grazing significantly increased soil total nitrogen (STN), total phosphorus (STP), available nitrogen (SAN), and available phosphorus (SAP) contents but reduced the carbon-to- nitrogen ratio (C:N) and carbon-to-phosphorus ratio (C:P). The Shannon and Pielou_e indices of soil bacteria exhibited a significant increase following white clover reseeding, while soil bacterial diversity was reduced under grazing compared to the enclosure. The white clover reseeding had no significant effect on soil fungal diversity. Soil bacteria diversity in the 0-10 cm layer was significantly correlated with pH, STN, STP, SAN, C:N, and C:P, while the fungi diversity was significantly correlated with AGB, STN, STP, C:N, and SAP. Overall, the findings indicate that integration of grazing with an appropriate reseeding rate of leguminous specie enhances soil nutrient content, microbial activity, and forage productivity, providing valuable insights for the sustainable development of warm-season grasslands in southern China.
实施放牧措施以及在草原引入豆科植物被认为是改善土壤健康和提高牧草产量的有效策略。然而，通过在草原放牧的同时整合适当的豆科植物播种量，这些益处是否能进一步提升仍不确定。因此，在中国西南部开展了一项为期两年的田间试验，以研究放牧（0和3个牛月·公顷）和白三叶播种量（0、20、40和60千克·公顷）对牧草产量、土壤养分和微生物活性的影响。结果表明，与对照相比，随着白三叶播种量增加，围栏和放牧处理均显著提高了地上和地下生物量，40千克·公顷和60千克·公顷的播种量之间未观察到显著差异。在围栏和放牧管理下，与对照（0千克·公顷）相比，两年平均地上生物量（AGB）分别增加了17.3%和28.2%（40千克·公顷）、17.5%和35.9%（60千克·公顷）。此外，在白三叶播种量为40千克·公顷时，围栏处理下地下生物量增加了24.8%，放牧处理下增加了30.0%。与围栏草地相比，放牧显著提高了土壤全氮（STN）、全磷（STP）、有效氮（SAN）和有效磷（SAP）含量，但降低了碳氮比（C:N）和碳磷比（C:P）。白三叶播种后，土壤细菌的香农指数和皮洛均匀度指数显著增加，而与围栏相比，放牧降低了土壤细菌多样性。白三叶播种对土壤真菌多样性无显著影响。0-10厘米土层的土壤细菌多样性与pH、STN、STP、SAN、C:N和C:P显著相关，而真菌多样性与AGB、STN、STP、C:N和SAP显著相关。总体而言，研究结果表明，将放牧与适当的豆科植物播种量相结合可提高土壤养分含量、微生物活性和牧草生产力，为中国南方暖季草原的可持续发展提供了有价值的见解。
