0.01molL-1CaCl2作为土壤不同N素形态浸提剂的研究

本文用荷兰8种表土测试不同温度下0.01molL^-1CaCl₂提取液和淋滤液中N素各形态。试验结果表明温度对NO₃^--N提取量和淋滤量无影响,但对NH₄⁺-N、可溶性总N和还原态N影响显著;可溶性有机态N的释放服从一级动力学方程:N_t=N₀(1-e^-kt),非线性最小二乘法能满意地拟合动力学实验结果。测定0.01molL^-1CaCl₂提取液中的可溶性有机态N对预测土壤N素矿化、合理推荐施肥及防止N素污染可能是一个很有前途的指标。

ASPECTS OF THE STUDY OF 0.01 molL-1 CaCl2 AS EXTRACTING SOLUTION FOR DIFFERENT N FRACTIONS IN SOILS

Eight Dutch surface soils were used in this study to analyse different N fractions in 0.01 mo1L^-1 CaCl₂ extracts and percolates at different temperatures.The results obtained showed that:(1)The temperature of 0.01 mo1L^-1 CaCl₂ extracting and percolating solution had no influence on amount of NO₃^--N,the extractability of other N fractions (NH₄^2-,total soluble N and reduced N),however was evidently affected by the temperature in 0.01 mo1L^-1 CaCl₂ solution.The hydrolysis of organic N was the predominant reason for this influence.(2) The release of organic soluble N obeyed the first order kinetics.A nonlinear least square method could bestfit the experimental data into the model N_t=N₀(1-e^-kt) with Rsquared being than 0.99.(3) The kinetic values No were highly consistent with the soluble reduced N in extraction exeperiment.The 0.01 mo1L^-1 CaCl₂ sollution exetracted and released the labile organic N fraction.The determinations of soluble orgaraic N in 0.01 mo1L^-1 CaCl₂ solution looked promising as a property for prediction of N mineralization,N fertilization and N pollution.