Key Laboratory for Model Innovation in Forage Production Efficiency, Ministry of Agriculture and Rural Affairs, PR China, Ningxia University, 489 Helanshan West Road, Yinchuan, 750021, Ningxia, China; Grassland and Animal Husbandry Engineering Technology Research Center of Ningxia Province, Ningxia University, 489 Helanshan West Road, Yinchuan, 750021, Ningxia, China; College of Forestry and Prataculture, Ningxia University, 489 Helanshan West Road, Yinchuan, 750021, Ningxia, China.
Key Laboratory for Model Innovation in Forage Production Efficiency, Ministry of Agriculture and Rural Affairs, PR China, Ningxia University, 489 Helanshan West Road, Yinchuan, 750021, Ningxia, China; Grassland and Animal Husbandry Engineering Technology Research Center of Ningxia Province, Ningxia University, 489 Helanshan West Road, Yinchuan, 750021, Ningxia, China; College of Forestry and Prataculture, Ningxia University, 489 Helanshan West Road, Yinchuan, 750021, Ningxia, China; Breeding Base for State Key Laboratory of Land Degradation and Ecological Restoration of Northwest China, Ningxia University, 489 Helanshan West Road, Yinchuan, 750021, Ningxia, China.
J Environ Manage. 2024 Sep;368:122213. doi: 10.1016/j.jenvman.2024.122213. Epub 2024 Aug 17.
To understand how nutrient cycling and sequestration are influenced by different grazing periods, the C:N:P stoichiometry features of the plant-soil interface in the desert steppe were measured and evaluated. The 5-year seasonal grazing experiment employed four grazing period treatments: traditional time of grazing (TG), early termination of grazing (EG), delayed start of grazing (DG), and delayed start and early termination of grazing (DEG). Additionally, fenced off desert steppe served as the control. The grazing periods each had a differing impact on the C:N:P stoichiometry in both plant functional group and soil depth comparisons. Compared to the EG, DG, and DEG treatments, the TG treatment had a more significant impact on the C, N, and P pools of grass, as well as the C:P and N:P ratios of forbs, but had a reduced effect on the C:P and N:P ratios of legumes. In contrast to plants, the DG treatment exhibited greater advantages in increasing C pools within the 0-40 cm soil layer. Furthermore, in the 10-20 cm soil layer, the C:P and N:P ratios under the EG treatment were significantly higher, ranging from 8.88% to 53.41% and 72.34%-121.79%, respectively, compared to the other treatments (TG, DG, and DGE). The primary drivers of the C, N, and P pools during different grazing periods were above-ground biomass (AGB) and litter biomass (LB). Both lowering the plant C:P and N:P ratios and considerably raising the plant P pool during different grazing periods greatly weakened the P limitation of the desert steppe environment. It is predicted that delayed start grazing might be a management strategy for long-term ecosystem sustainability, as it regulates above-ground nutrient allocation and has a positive effect on soil C and N pools.
为了了解不同放牧时期如何影响养分循环和固存,本研究测定并评估了荒漠草原植物-土壤界面的 C:N:P 化学计量特征。采用 5 年季节性放牧实验,设置了传统放牧时间(TG)、早期终止放牧(EG)、延迟开始放牧(DG)和延迟开始及早期终止放牧(DEG)4 种放牧时期处理,同时设置了围封的荒漠草原作为对照。各放牧时期对植物功能群和土壤深度的 C:N:P 化学计量比均有不同的影响。与 EG、DG 和 DEG 处理相比,TG 处理对禾草的 C、N 和 P 库以及杂类草的 C:P 和 N:P 比影响更大,但对豆科植物的 C:P 和 N:P 比影响较小。与植物相反,DG 处理在增加 0-40 cm 土壤层的 C 库方面表现出更大的优势。此外,在 10-20 cm 土壤层,EG 处理的 C:P 和 N:P 比显著高于其他处理(TG、DG 和 DGE),范围分别为 8.88%-53.41%和 72.34%-121.79%。不同放牧时期 C、N 和 P 库的主要驱动因素是地上生物量(AGB)和凋落物生物量(LB)。在不同放牧时期降低植物 C:P 和 N:P 比,显著提高植物 P 库,极大地削弱了荒漠草原环境的 P 限制。预计延迟开始放牧可能是一种长期生态系统可持续性的管理策略,因为它调节地上养分分配,对土壤 C 和 N 库有积极影响。