杨树刺槐混交对土壤养分和酶活性的影响

Influence of Planting, Poplar Mixed with Black Locust Upon Soil Nutrients & Soil Enzyme Activities

通过对黄河三角洲滨海盐碱地上杨树、刺槐混交试验林中各种林分类型土壤主要养分指标和几种主要酶活性的测定及相关分析得出如下结论：（１）混交林土壤各层次ｐＨ使普遍低于杨树纯林，而有机质等主要养分指标含量则高于杨树纯林；（２）混交林土壤各层次微生物碳量及脲酶等几种主要酶活性一般高于杨树纯林；（３）许多土壤养分含量和酶活性呈显著的相关关系，从侧面揭示在较差的立地上杨树、刺槐混交造林的生长效果大多优于杨树纯林的机理所在。

By determining and correlative analyzing major soil nutrients and enzyme activities in different types of forest stands in a mixed poplar--locust experimental plantation on coastal saline--alkali site in the Yellow River Delta, following conclusions were drawn: (l) pH value of each layer of the soil profiles in mixed stands was generally lower than corresponding one in pure poplar stands, while the concentrations of organic matter and other main nutrients were higher in the mixed stands; (2)Soil microbial biomass, urease and some other enzyme activities were commonly greater in each soil layer in mixed stands; (3) Many soil nutrients were pronouncedly correlated with enzyme activeties. These results would help reveal the mechanhisms from an aspect that why plantations of poplar mixed with black locust on poor sites usually grow better than pure poplar stands.