Acidification characteristics and its influencing factors of red paddy soil derived from four parent materials in Southeast of China

Abstract

There are many types of parent materials of red paddy soil, however the acidification characteristics of paddy soil derived from different parent materials remain unclear in the past 40 years at Jiangxi Province, and the degree of soil properties on acidification is also still unknown. Therefore, four red paddy soil derived from Quaternary red earth (Qre), plate shale (P), red sand stone (Rs), granite (G) in Jiangxi Province was selected. We investigated the acidification characteristics and quantified the effect of soil factors on the acidification of red paddy soils derived from different parent materials. Results showed that related to the second soil survey (1980s), the pH of red paddy soil derived from four parent materials decreased by an average 0.47 unit, base saturation (BS%) decreased 13.93%, exchangeable acid (EA) and exchangeable aluminum (EAl) increased by 0.43 and 0.20 cmol·kg−1, respectively. The ∆pH of red paddy soil derived from Rs (0.56) and G (0.54) were higher than that of Qre (0.34) and P (0.32). The ∆BS% of of red paddy soil derived from G (22.53%) > Rs (17.61%) > Qre (8.27%) > P (2.66%). The ∆EA (0.76) and ∆EAl (0.62) of Rs is highest. The results of redundancy analysis (RDA) shown that soil properties of red paddy soil derived from four parent material could explain 43.1% variation of soil acidification. CEC7, silt, sand, and SOM could explain 36.3%, 4.6%, 1.4% and 1.2% variation of acidification, respectively. The difference of soil mineralogy including oxide and clay minerals is also the reason for the different acidizing characteristics of paddy soil derived from four parent material. Therefore, compared with the 1980s, there is significant acidification of red paddy soil in 2018 in Jiangxi Province. The acidification of red paddy soil derived from red sand stone and granite is higher than that of plate shale and Quaternary red earth. And, parent material affect acidification by soil physicochemical and mineralogical properties.