浙江农田土壤化学计量特征与有效铬预测模型OACSTPCD

To provide basic information of soil for crop production,a total of 3726 soil samples were collected,preprocessed,stored and detected from typical farmland in Zhejiang Province from 2008 to 2018.A total of 14 physicochemical indexes including Pondus Hydrogenii(pH)etc.,were detected for each sample.R software including multiple linear regression based on weighted least square method,was used to analyze the data.The results showed that:(1)The arithmetic mean value of pH of the samples was 5.82,and the pH of 79.6%soil samples was 4.500～6.500.The organic matter(oM)content of 90.8%soil samples ranged from 0 to 50 g/kg.The contents of total Nitrogen(tN),available Nitrogen(aN),available Phosphorus(aP)and available potassium(aK)in 84.0%soil samples were 0～4 g/kg,0～300 mg/kg,0～50 mg/kg and 0～150 mg/kg,respectively.The content of slow available potassium in 77.8%soil samples(saK)was 50～450 mg/kg.The contents of Cu,Zn,B,Mo and Cr in 91.8%soil samples were 0～40,0～100,0～2,0～10 and 0～100 mg/kg,respectively.The content of Mn and Fe in 87.8%soil samples were 0～80 mg/kg and 0～400 mg/kg.(2)Available chromium content is significantly correlated with saK,Cu,aK,pH,Mn,Zn,B,Mo,oM,tN and aN,and their relationship is expressed by robust regression equation as follows:yCr=-130.0+64.6xCu+50.6xpH+451.0xB-12.6xCu×pH-75.6xCu×B-84.9xpH×B-15.6xMn×B+13.8xCu×pH×B.In conclusion,the typical farmland soil in Zhejiang region is acidic.The oM contents of most soils(79.1%)were 20～50 g/kg,which was suitable for crop growth.The contents of N,Cr and K in soil varied moderately,and the coefficient of variation was 30%～90%.The contents of P,Fe,Mn,Cu,Zn,B and Mo in soil varied greatly,and the coefficient of variation was greater than one.Soil available Cr content was significantly correlated with 11 soil components such as saK and Cu,which could be quantitatively described by robust regression equation.