非连续时空统计条件下土壤中Cd有效态含量与全量的相关性分析

Relationship Between Available Cd and Total Cd Concentration in Soil Under Non-continuous Spatio-Temporal Statistic Condition

以全国重点区域土壤环境质量数据库为数据源,依据pH值、有机质含量、阳离子交换量筛选出时间、空间分布不连续的3组402个土壤样品,对土壤中Cd有效态含量与全量的相关性进行了统计分析。结果表明,在pH值5~6.5与有机质含量1%~2.5%、pH值5~6.5与有机质含量2.5%~4%、pH值7.5~8.5与有机质含量1%~2.5%和阳离子交换量均为15~30 cmol(+).kg-1的土壤条件下,土壤中的Cd有效态含量与全量之间均存在显著的相关性,其相关系数分别为0.937,0.652,0.372;以上3种土壤条件下均能在Cd有效态含量与全量之间建立起有意义的回归方程,分别为:Y=0.007+0.369X+0.164X2-0.043X3(R2=0.881,P<0.001);Y=0.01+0.619X?1.630X2+2.585X3(R2=0.475,P<0.001);Y=0.335-5.941X+39.123X2-78.075X3(R2=0.244,P<0.001)。相对人工控制条件下的盆栽试验而言,由于各回归方程来自自然条件下的大样本田间统计,对农业生产更具指导意义。

This study aims to identify the relationship between available Cd and total Cd concentration in soil.402 soil cadmium content data with non-continuous spatio-temporal distribution were chosen from the typical region soil environmental quality database according to pH,organic matter concentration(OMC),CEC,and were classified to 3 groups: group I,II,III were data of specific soil at pH 5~6.5 with OMC(1~2.5%),at pH 5~6.5 with OMC 2.5~4%,at pH 7.5~8.5 with OMC 1~2.5%(CEC =15~30 cmol(+)·kg^(-1)).The results showed that there was a significant correlation between soil available Cd content and total Cd content for 3 group data(r= 0.937,0.652,0.372).The linear regression equations for data of 3 groups between the available Cd content and total Cd content in soil were Y=0.007+0.369X+0.164X^2-0.043X^3(R^2=(0.881),P<0.001,Y=0.01+0.619X―1.630X^2+2.585X^3(R^2=0.475,P<0.001,Y=0.335-5.941X+39.123X^2-(78.075)X^3(R^2=0.244,P<0.001,respectively.The results provide a scientific guide to agriculture production.