Characteristics And Trend Of Quaternary Red Soil Acidification Under Different Utilization Modes

The hilly area of Southeast China is a major oil producing area in China,with abundant water and heat resources,and its main soil type is red soil.But in recent years,the acidification of red soil is becoming more and more serious,which poses a serious threat to the agricultural production and the ecological environment.Therefore,this study is based on the red soil ecological experimental station of the Chinese Academy of Sciences of Yingtan city in Jiangxi Province,to explore the characteristics of the acidification of red soil under the surrounding vegetation types and to predict the acidification trend.The main results are as follows:（1）Compared with 1985,the distribution of pH in soil was normal distribution in2016,and the coefficient of variation decreased significantly.From 1985 to 2016,red soil was significantly acidified in 31 years,and soil pH decreased by 0.32 units,with an average annual decline of 0.01 units.The soil organic matter increased significantly from 31 g·kg^-11 to 19.69 g·kg^-1 in 1985,and increased by 0.27 g·kg^-1per year,indicating that soil organic matter accumulates year by year under different utilization.（2）In Quaternary Red Soil under 5 vegetation types,the pH of soil 0-40cm was significantly lower than that of 60-100cm,indicating that the effect of different vegetation on the acidity of red soil at the bottom is not significant,mainly on 0-40cm soil layer.In the 5 vegetation types,in addition to Dryland Crop peanut,other vegetation and soil pH decreased with soil depth increased（0-100 cm）increased significantly,the soil pH is higher than that of soil pH other vegetation,and profiles of pH between 4.2⁶.6,which belong to acid soil.（3）Surface soil acidification rate under different vegetation types have obvious differences,the surface soil acidification rate average order of Yang Meiyuan(0.77kmolH⁺·hm²·a^-1)>rice(0.64 kmolH⁺·hm²·a^-1)>oak wood(0.47kmolH⁺·hm²·a^-1)>pine mixed forest(0.38 kmolH⁺·hm²·a^-1)>peanut(-0.05kmolH⁺·hm²·a^-1)under different vegetation types to predict soil acidification time there are obvious difference.In the forest vegetation,Yang Meiyuan soil acidification rate is the fastest,pH in 10 years can be decreased to 4,pH dropped to 3.5 to 20 years to be possible;in the farmland crops in paddy soil pH in 30 years will be reduced to 4,pH decreased to 3.5 in about 45 years the time may occur,and peanut is not currently maintaining the soil acidification,maintaining the balance of soil acid-base equilibrium.