绿洲盐化潮土有效锌含量与盐分离子的相关性及通径分析

Correlation and Path Analyses of Available Zinc Contents and Salt Ions in Saline Fluvo-aquic Soil of Hexi Oasis Area

以张掖市甘州区和临泽县绿洲盐化潮土为研究对象,通过采集具有代表性、正常耕作种植、前茬为玉米的典型地块0~20 cm耕层土样分析化验,研究了区域土壤有效锌和盐分离子含量特征,运用通径分析方法研究了它们之间的相关性及不同盐分离子对土壤有效锌含量的影响程度。结果表明,河西绿洲灌区盐化潮土有效锌含量介于0.289~0.736 mg/kg之间,平均为0.473 mg/kg,变异系数为18.68%,超过70%的土壤低于缺锌临界值(0.5 mg/kg),且土壤有效锌含量有随含盐量升高而降低的趋势。土壤有效锌含量与HCO_3~–、Mg^(2+)、Na^+含量之间呈极显著负相关,与Cl~–、Ca^(2+)、K^+含量之间呈显著负相关,与SO_4^(2–)含量之间的相关性不显著。Mg^(2+)对土壤有效锌含量表现出强烈的直接和间接负效应,HCO_3~–表现出很大的直接负效应和强烈的间接正效应,Cl~–、K^+和Na^+均表现出较强的直接和间接负效应,SO_4^(2–)表现出较弱的直接和间接正效应,Ca^(2+)表现出较弱的直接和间接负效应。Mg^(2+)、HCO_3~–和Na^+是影响土壤有效锌含量变化的3个主导因素,对决定系数R^2的贡献超过了68%。

Typical saline fluvo-aquic topsoil samples （0-20 cm） were collected under the conventional cultivation of maize in Ganzhou district and Linze county of Zhangye City in Hexi oasis irrigation area, the characteristics and correlation of the contents of available zinc and salt ions as well as the effects of various ions on the content of available zinc were studied with the method of path analysis. The results showed that available zinc content ranged from 0.289 to 0.736 mg/kg with an average of 0.473 mg/kg and a variation coefficient of 18.68%. Available zinc contents of more than 70% of the studied soil samples were lower than the deficient level （0.5 mg/kg）. Available zinc content had negative correlation with salt content, it was extremely significantly correlated with the contents of HCO3-, Mg2＋ and Na＋, and significantly correlated with the contents of Cl-, Ca2＋ and K＋, but not significantly correlated with the content of SO42-. Mg2＋ showed strong direct and indirect negative effects on available zinc content, HCO3- showed more strong direct negative effects and strong indirect positive effects; Cl-, K＋ and Na＋ showed more strong direct and indirect negative effects, SO42- showed mild direct and indirect positive effects, Ca2＋ showed mild direct and indirect negative effects. Mg2＋, HCO3- and Na＋ were the three dominant affecting factors on available zinc contents, and they in total decided 68% more of the determinative coefficient R2.