The flow of photosynthesized carbon (C) from plants to soil and its loss from the respiration in the soil-plant system were measured via in situ ¹³CO₂ pulse labeling pasture in overgrazed and long-term grazing exclosures (where grazing was not permitted for 5, 10, and 30 years). During a 30-day chase period, the allocation of newly assimilated C in the shoots, roots, and soil of grazing-excluded grasslands was higher than that in overgrazed grasslands. But the newly assimilated C allocated to shoots and soil respiration in overgrazed grasslands was significantly higher than that in grazing-excluded grasslands. Thirty days after labeling, 35% and 40% of the newly assimilated C in overgrazed grasslands were lost through shoots and soil respiration, respectively. The shoot ¹³C recovery was 32% in the 30 years 30 days after labeling, which was significantly higher than that obtained at the 5 and 10 years exclosure sites. Root and soil ¹³C recoveries in the 5- and 10-year exclosures were higher than those at the 30-year sites. In the grazing-excluded grasslands, the amount of ¹³C in soil organic C peaked 3 days after ¹³CO₂ exposure and became relatively stable after 19 days of assimilation. The mean C residence time for non-structural C used in the soil respiration under overgrazing (10 days) was shorter than that under 5- (20 days) and 10- (17 days) or 30-year exclosures (14 days). Compared to overgrazing, grazing exclosure, especially moderate grazing exclosure, led to more allocation of newly assimilated C in the plant-soil system but fewer allocation in shoots and soil respiration.

通过过度放牧和长期放牧的放牧（不允许放牧）中的原位 ¹³ CO ₂脉冲标记牧场，测量了植物到土壤的光合作用碳（C）的流量以及土壤-植物系统中呼吸的损失。 5、10和30年）。在为期30天的追赶期中，放牧排除的草地的新芽，根和土壤中新吸收的碳的分配高于过度放牧的草地。但是，在过度放牧的草地上，分配给枝条和土壤呼吸的新吸收的碳显着高于排除草场的草地。贴标后的30天，过度放牧的草地中新吸收的C分别通过枝条和土壤呼吸损失了35％和40％。拍摄标记后30天的30年中¹³ C回收率为32％，显着高于5年和10年暴露地点的¹³ C回收率。5年和10年暴露的根和土壤¹³ C回收率高于30年位点。在排除草场的草原中，土壤有机碳中¹³ C的含量在¹³ CO ₂后3天达到峰值。暴露，经过19天的吸收后变得相对稳定。过度放牧（10天）下土壤呼吸中非结构碳的平均碳停留时间要短于5-（20天）和10-（17天）或30年（14天）的土壤呼吸时间。与过度放牧相比，放牧，特别是中度放牧的放牧导致新吸收的碳在植物-土壤系统中的分配增加，但在枝条和土壤呼吸中的分配减少。