Abstract:

The Southern Jiangsu Province is one of the major Chinese grain-producing areas, where the quality of cultivated soil and
farm produce are significantly affected by the changes of soil pH values. Through the investigation of pH values of cultivated soils in theSouthern Jiangsu Province in 2010s, and comparing with two spatial distribution maps of soil pH in 1980 and 2003 from previousstudies, the spatial-temporal variation of pH values and associated factors have been discussed in this paper. The results showed that the spatial distribution pattern of soil pH in 2010s was significantly different from that in 1980, with lower soil pH values in the west part of the study areas than those in the east in 2010s, which is associated with natural conditions and social behaviors. Two phases of pH change have been observed in the context of complex changes in soil chemical properties during the past 30 years. The variation trends of pH values in different regions from 1980 to 2003 were similar to the major trends from 1980 to 2010s, while transformations have emerged in the last decade since 2003, especially presented in Jurong city where soil acidification has occurred in the later 10 years after alkalization in previous 20 years, and Suzhou-Wuxi Countries where it displayed the opposite trend. The decrease of pH values in soils can be explained by both heavy application of chemical fertilizers and industrial acid deposition. In addition, urbanization and cement production also played an important role in the pH increase. It is concluded that the different variations of pH values are caused by the waxing and wining of buffer substances in soil, which are mainly forced by the changes in land utilization in different regions.

Key words: the Southern Jiangsu Province, soil pH, spatial-temporal variation