Acidity and basicity characteristics and acidification trend of the farmland soil in Huaibei Plain, Anhui Province

Soil pH values and related indicators were investigated for arable soil and deep soil samples from the Huaibei Plain, Anhui Province so as to understand the spatial distribution features of pH values in different soil conditions such as parental material, soil type and soil pH values. The comparison of pH values in arable soil and deep soil in the study area with the results obtained in the Second Soil Survey in Anhui Province in the 1980s was undertaken to outline tempo-spatially the change features of pH values and acidity change trend. The results demonstrate a distinct increasing acidification in arable soil, where acidic soil area accounts for approx. 63.38% of the study area. Late Pleistocene loess-like paleo-lacustrine facies sediments are characterized by distinct acidicity and dominated by acidified soil; while Holocene modern flood alluvial sediments are characterized by unobvious acidification and dominated by alkaline soil. 66.51% of the arable soil is acidified in comparison with the deep soil. More than 62.55% of the arable soil is acidified, when comparing with the data in the 1980’s. The geologic background and long-term utilization of chemical fertilizer may take responsibility for these phenomena.