Zhao Jun, Feng Xiaoming, Deng Lei, Yang Yanzheng, Zhao Zhong, Zhao Pengxiang, Peng Changhui, Fu Bojie
State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-environmental Sciences, Chinese Academy of Sciences, Beijing, China.
Institute of Soil and Water conservation, Northwest A&F University, Yangling, China.
Front Plant Sci. 2020 Nov 27;11:573126. doi: 10.3389/fpls.2020.573126. eCollection 2020.
The transport of eroded soil to rivers changes the nutrient cycles of river ecosystems and has significant impacts on the regional eco-environment and human health. The Loess Plateau, a leading vegetation restoration region in China and the world, has experienced severe soil erosion and nutrient loss, however, the extent to which vegetation restoration prevents soil erosion export (to rivers) and it caused nutrient loss is unknown. To evaluate the effects of the first stage of the Grain for Green Project (GFGP) on the Loess Plateau (started in 1999 and ended in 2013), we analyzed the vegetation change trends and quantified the effects of GFGP on soil erosion export (to rivers) and it caused nutrient loss by considering soil erosion processes. The results were as follows: (1) in the first half of study period (from 1982 to 1998), the vegetation cover changed little, but after the implementation of the first stage of the GFGP (from 1999 to 2013), the vegetation cover of 75.0% of the study area showed a significant increase; (2) The proportion of eroded areas decreased from 41.8 to 26.7% as a result of the GFGP, and the erosion intensity lessened in most regions; the implementation significantly reduce the soil nutrient loss; (3) at the county level, soil erosion export could be avoided significantly by the increasing of vegetation greenness in the study area ( = -0.49). These results illustrate the relationships among changes in vegetation cover, soil erosion and nutrient export, which could provide a reference for local government for making ecology-relative policies.
被侵蚀土壤向河流的输送改变了河流生态系统的养分循环，对区域生态环境和人类健康产生重大影响。黄土高原是中国乃至世界重要的植被恢复区，曾经历严重的土壤侵蚀和养分流失，然而，植被恢复对防止土壤侵蚀输出（至河流）及其导致的养分流失的程度尚不清楚。为评估退耕还林工程第一阶段（1999年启动至2013年结束）对黄土高原的影响，我们分析了植被变化趋势，并通过考虑土壤侵蚀过程，量化了退耕还林工程对土壤侵蚀输出（至河流）及其导致的养分流失的影响。结果如下：（1）在研究期的前半段（1982年至1998年），植被覆盖变化不大，但在退耕还林工程第一阶段实施后（1999年至2013年），研究区域75.0%的植被覆盖显著增加；（2）退耕还林工程使侵蚀面积比例从41.8%降至26.7%，多数地区侵蚀强度减轻；该工程显著减少了土壤养分流失；（3）在县级层面，研究区域植被绿度增加可显著避免土壤侵蚀输出（ = -0.49）。这些结果阐明了植被覆盖变化、土壤侵蚀和养分输出之间的关系，可为地方政府制定生态相关政策提供参考。
