我国农田总氮流失影响因素分析

Investigations into the Farmland Total Nitrogen Loss in China

利用第一次全国农业污染源普查的70个样本数据,对农田非点源污染总氮(TN)流失系数与6个影响因素间的关系进行相关和回归分析。结果表明,土地利用方式X3、土壤质地X4、施氮量X5、年降雨量X64个因素对农田TN流失系数有显著影响。由标准化回归系数得知,各因素对流失系数影响的大小顺序为X6>X5>X3>X4。在此基础上所建立的我国农田TN流失系数的回归方程为Y=-5.3+0.28X6+0.017X5+4.563X3+0.088X4,通过16个文献数据对该模型进行验证,结果显示该模型具有很好的预测能力,可用于我国不同地域农田TN流失系数的估算。

The determination of total nitrogen（TN） loss coefficient is of very importance for evaluating the impact of non-point source pollution on the agricultural environment.On the basis of seventy data of the samples collected from First National Census of Agricultural Pollution Sources,a mathematical model based on SPSS（Statistical Product and Service Solutions） software was built,which was used to analyze the impact of six influential factors,in term of terrain slope（X1）,type of farmland（terrace field or not,X2）,land utilization pattern（X3）,soil texture（X4）,nitrogen application level（X5）,and annual rainfall（X6）,on the TN loss coefficient of agricultural non-point source pollution.The correlation and regression demonstrated that X3,X4,X5 and X6 have significant impact on the TN loss coefficient,with influence degree decreasing as X6X5X3X4 based on the comparison among the standard regression coefficients.On the other hand,the impact of X1 and X2 on the TN loss coefficient could be neglected.Further,a multiple linear equation,with the form of Y=4.563X3＋0.088X4＋0.017X5＋0.28X6-5.3,was obtained to precisely calculate the TN loss coefficient,which was validated using the data collected from 16 references,confirming that the regression model established in this work was suitable for predicting the TN loss from farmland due to the non-point source pollution in different regions of China.