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Decreased Soil Cation Exchange Capacity Across Northern China's Grasslands Over the Last Three Decades
Author(s) -
Fang Kai,
Kou Dan,
Wang Guanqin,
Chen Leiyi,
Ding Jinzhi,
Li Fei,
Yang Guibiao,
Qin Shuqi,
Liu Li,
Zhang Qiwen,
Yang Yuanhe
Publication year - 2017
Publication title -
journal of geophysical research: biogeosciences
Language(s) - English
Resource type - Journals
eISSN - 2169-8961
pISSN - 2169-8953
DOI - 10.1002/2017jg003968
Subject(s) - topsoil , environmental science , steppe , cation exchange capacity , soil carbon , soil water , grassland , ecosystem , vegetation (pathology) , soil science , agronomy , ecology , hydrology (agriculture) , geology , biology , medicine , geotechnical engineering , pathology
Cation exchange capacity (CEC) helps soils hold nutrients and buffer pH, making it vital for maintaining basic function of terrestrial ecosystems. However, little is known about the temporal dynamics of CEC over broad geographical scales. In this study, we used random forest method to compare historical CEC data from the 1980s with new data from the 2010s across northern China's grasslands. We found that topsoil CEC in the 2010s was significantly lower than in the 1980s, with an overall decline of about 14%. Topsoil CEC decreased significantly in alpine meadow, alpine steppe, meadow steppe, and typical steppe by 11%, 20%, 27%, and 9%, respectively. Desert steppe was the only ecosystem type that experienced no significant change. CEC was positively related to soil carbon content, silt content, and mean annual precipitation, suggesting that the decline was potentially associated with soil organic carbon loss, soil degradation, soil acidification, and extreme precipitation across northern China's grasslands since the 1980s. Overall, our results demonstrate topsoil CEC loss due to environmental changes, which may alter the vegetation community composition and its productivity and thus trigger grassland dynamics under a changing environment.