Mixed cattle and sheep grazing reduces the root lifespan of the community in a desert steppe
Mixed cattle and sheep grazing reduces the root lifespan of the community in a desert steppe
复制标题
牛羊混合放牧减少了荒漠草原群落的根系寿命
DOI：
10.1016/j.ecolind.2022.109422
复制
发表时间：
2022-10
影响因子：
6.9
通讯作者：
Yana Zhang;Zhan-yi Wang;Peng Liu;Cheng-jie Wang
中科院分区：
文献类型：
--
作者：
Yana Zhang;Zhan-yi Wang;Peng Liu;Cheng-jie Wang
土壤是草地生态系统的主要碳库，植物根系周转是有机碳输入的重要途径。在研究草食动物对草地的影响时，通常采用单一动物种下的放牧强度，而在草地利用中，多种放牧是常见的。然而，很少有研究探讨了不同的牲畜物种和草食动物组合对草地群落根系生长的影响。我们使用微型电子管的方法，探讨了根生长在温带荒漠草原群落的牛羊放牧两年以上的反应。在根系特性和环境因子中，放牧方式（放牧、放牧、放牧和不放牧）是影响根系寿命的最显著的抑制因子。我们发现，牛羊混牧显著降低了群落的根系寿命，中位存活时间为120 d，观察期结束时的存活率仅为30%。与其它处理相比，牛羊混牧显著降低了植物根系的活根数（0.3724 ± 0.0453条/cm ~ 2）。混牧处理细根长度的变化（-0.012 ± 0.0013 mm/cm ~ 2）显著大于其它处理。群落根系寿命与地下/地上净初级生产力比值（BNPP/ANPP）呈显著负相关。牛羊混牧改变了植物碳的贡献模式，增加了土壤有机碳含量。因此，在适度放牧强度下，调整草食动物的组合是加快群落根系周转速率，加速植物光合作用碳输入土壤碳库，增加土壤碳储量的有效策略。
The soil is the primary carbon pool in grassland ecosystems, and the turnover of plant roots is an essential way of organic carbon input. Grazing intensity under a single animal species is usually used to explore the effects of herbivores on grassland, but multi-species grazing is common in grassland utilization. However, few studies have examined the impact of different livestock species and herbivore combinations on the root growth of the grassland community. We used the minirhizotron method to explore the response of root growth in a temperate desert steppe community to cattle and sheep grazing over two years. Among root characteristics and environmental factors, grazing method(cattle grazing; sheep grazing; cattle and sheep grazing; no grazing) is the most significant inhibiting factor affecting root longevity. We found that mixed cattle and sheep grazing significantly reduced the root lifespan of the community, with a median survival time of 120 d, and a survival rate of only 30 % at the end of the observation period. Compared with other treatments, mixed cattle and sheep grazing significantly reduced the number of live roots (0.3724 ± 0.0453 piece/cm2). The change in fine root length of mixed grazing (-0.012 ± 0.0013 mm/cm2) was considerably greater than other treatments. The root lifespan of the community was significantly negatively correlated with the ratio of belowground to aboveground net primary productivity (BNPP/ANPP). The mixed cattle and sheep grazing changed in the patterns of plant carbon contribution, and increased the organic carbon content of the soil. Therefore, under moderate grazing intensity, adjusting the combination of herbivores is an effective strategy to accelerate root turnover rate of the community, accelerate the input of carbon from plant photosynthesis into the soil carbon pool, and may increase soil carbon storage.