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Significant soil acidification caused by grazing exclusion across China’s grassland areas
Author(s) -
Hong Jiangtao,
Xu Xin,
Pang Bo,
Ma Xingxing,
Wang Xiaodan
Publication year - 2020
Publication title -
land degradation and development
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.403
H-Index - 81
eISSN - 1099-145X
pISSN - 1085-3278
DOI - 10.1002/ldr.3722
Subject(s) - grazing , environmental science , grassland , ecosystem , biogeochemical cycle , agronomy , grassland degradation , biomass (ecology) , soil water , soil carbon , soil ph , ecology , biology , soil science
Soil pH is strongly associated with soil biogeochemical cycles and biodiversity in terrestrial ecosystems. Grazing exclusion (GE) has been widely adopted as an effective practice to restore degraded grasslands. However, the effect of GE on soil pH is still poorly understood and remains inconclusive. We synthesized data for 63 sites from the peer‐reviewed literature and 43 additional field sites and investigated the differences in soil pH following grazing exclusion across China’s grasslands. The mean pH across all samples decreased by 0.13 units with grazing exclusion (mean pH 8.15 and 8.02 for the grazed and grazing exclusion groups, respectively, p < 0.001). The pH of the surface soil (0–20 cm) showed the greatest rates of decrease in grazing exclusion grasslands, whereas the pH of the deep soil layers (20–100 cm) showed a limited response to grazing exclusion. In general, the largest rate of decrease in soil pH occurred after medium‐term periods (5–15 years) of grazing exclusion, whereas a smaller rate of change was found over short‐ (≤5 years) and long‐term periods (≥15 years) of grazing exclusion. Of the environmental factors examined, the climatic conditions, accumulation of biomass and the soil carbon and nitrogen dynamics were important factors influencing soil pH following grazing exclusion. Our results indicate that grazing exclusion causes significant soil acidification, especially in surface soils and humid areas. Our results provide an important reference for the future management of China’s grasslands.