Environmental Acidification Due to Soil Acid Changes of Different Land Use Patterns

摘要

A survey was carried out to investigate the acidification due to acid changes of different land use patterns. The results showed that soil acidification happened in the arable land and forest land in topsoil of 0～10 cm depth, 0.42 and 0.24 pH unit~(-1) lower than that of in 80～100 cm depth. The lowest cation exchange capacity (CEC) (11.99 cmol·kg~(-1)) was got in the topsoil of paddy soil, while the highest one was in the topsoil of grassland with 19.26 cmol·kg~(-1). A catastrophe point of cation exchange capacity of soils was found between 20～30 cm except for orchard soil. Organic matter in forest soil decreased sharply by 2.21% in 0～10 cm as compared with that of in 80～100 cm and little decrease about 0.97% was found in the orchard soil. The pH and magnetic susceptibility showed similar variation trend. Multiple linear regression analysis showed that there was a negative relationship between pH and low magnetic susceptibility. Our results also showed that the free iron, low magnetic susceptibility and amorphous ferric oxide were the main factors on the changes of pH in the arable land and forest soil, grassland and paddy soil, and the orchard soil, respectively.