Studies On The Spatiotemporal Variations Of Typical Physicochemical Properties Of Soil In Paddy Fields In Guangdong Province

Land resources are the material basis and valuable resources for human survival and development.The basic situation of our country is that the population is large,the cultivated land is small,and the reserve resources of cultivated land are insufficient,so it is of great strategic significance to maintain a certain amount of cultivated land for the maintenance of national food security and social stability.The paddy field is the production resource of the main grain crops in Guangdong Province.The study of the physical and chemical properties of paddy soil in Guangdong Province can provide reference for the protection of cultivated land,the application of soil formula fertilization,the design of cultivated layer in paddy field reclamation project,and the peeling thickness of cultivated layer in construction project.The purpose of this paper is to find out the spatial variation characteristics,spatial distribution pattern and driving factors of the multiple physical and chemical properties of paddy soil in the historical period and modern era.Data in this paper are derived from the national earth system science data center and Soil Series of China Guangdong,including soil spatial geographical coordinates,soil layer thickness,soil mechanical composition,soil pH value,soil organic matter content among 1980 and 2013.By using classical statistics to test the normal distribution,correlation analysis and significant difference analysis of the physical and chemical properties of paddy soil,using geostatistics method to construct spatial variation function model to analyze its spatial variation structure characteristics,using ordinary Kriging method and GS + software,the spatial distribution map of typical physical and chemical properties of paddy soil in Guangdong Province is obtained,which shows the spatial variation of the soil directly.The main research results are as follows:.(1)Changes of soil physical and chemical properties in paddy field: the average soil thickness of cultivated layer increased by 1.82% over the past 33 years,among which the increase of flooded rice soil was the largest;soil clay content increased by 40.66%,salty acid rice soil increased the most;soil pH decreased by 4.26%,salinized paddy soil acidified the most;soil organic matter decreased by 25.94%,cementitious rice soil decreased the most;soil nitrogen content increased by 25.74%,and rinsing paddy soil increased the most.(2)Soil pattern of cultivated layer in paddy field: the average soil thickness of cultivated layer is 15.63 cm,its distribution pattern is that the central region decreases north-south;the average clay content is 29.68%,and its distribution pattern decreases from central to northeast and southwest;the average pH value is 5.40,its distribution pattern decreases from northeast to southwest;the average organic matter content is 19.41 g/kg,its distribution pattern decreases from south-central to surrounding.(3)The driving factors affecting the properties of cultivated layer in paddy field: soil thickness was negatively correlated with annual mean temperature;soil pH was positively correlated with altitude;soil organic matter content was positively correlated with clay content.