Restoration Measures Supported Surface Soil Carbon and Nitrogen Density in Alpine Grassland of Sanjiangyuan Region, China
Dongdong Chen 1  
,   Qi Li 1,   Fuquan He 1,   Xin Chen 1, 2,   Shixiao Xu 1,   Xinquan Zhao 1  
,   Jingmei Li 3,   Lihua Liu 4,   Liang Zhao 1  
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Key Laboratory of Adaptation and Evolution of Plateau Biota, Northwest Institute of Plateau Biology, Chinese Academy of Science, Xining, Qinghai, China
Graduate University of Chinese Academy of Sciences, Beijing, China
Qinghai Academy of Social Sciences, Xining, Qinghai, China
Qinghai Engineering Consulting Center, Xining, Qinghai, China
Submission date: 2019-10-09
Acceptance date: 2019-11-19
Online publication date: 2020-03-27
Publication date: 2020-05-12
Pol. J. Environ. Stud. 2020;29(5):3071–3083
Soil carbon (C) and nitrogen (N) have different responses to different restoration measures. In this paper, surface (0-30 cm) soil C and N densities under different restoration measures in the Sanjiangyuan region were investigated and analyzed. The results showed that although there was no significant difference between rest-grazing (RG) and normal grazing (NG) grassland, SOCD in RG increased by 10.15%, and total N density (TND) increased by 8.56% in the year of the experiment. Compared with cropland, 8 years after Grain for Green (GFG), SOCD increased by 10.49-19.31%, SICD increased by 22.47-54.20%, and TND increased by 1.3-17.45%. Compared with HTT (extreme degradation-black soil beach), 12 years after planting artificial grassland, SOCD increased by 43.97-77.21%, SICD increased by 89.19-716.22%, and TND increased by 49.16-71.40%. Conclusions: Differences in soil types and climatic zones were responsible for the differences in soil C and N in different regions. Short-term grazing rest in Sanjiangyuan region has a certain effect on soil fertility restoration. Implementing the GFG project in the agro-pastoral ecotone improved soil fertility and, concurrently, moderate disturbance should be carried out on the basis of increasing vegetation diversity. Artificial grassland planting on black soil beach can improve soil quality, and moderate grazing disturbance in winter had the best immobilization effect on SIC, while no disturbance in the whole year was beneficial to the accumulation of organic matter. Both biological and abiotic factors have affected soil C and N content and density, but the degree of the influence varied with geographic location.