为了解沙棘人工混交林的改土效应,实验采用国家标准森林分析方法进行研究,结果表明:沙棘人工混交林增强了土壤稳定性,改善了土壤理化性质,具有良好的改土效应。土壤的水稳性团聚体比油松纯林提高了20.8%,而表征土壤团聚体稳定程度的破坏率却比油松纯林低40.76%;土壤容重和坚实度分别较油松林低5.9%和15.1%,孔隙度和通气度分别高12.16%和16.9%,持水量和含水量高13.6%和5.9%;有机质、全N、P2O5、速效P、速效K较油松纯林分别增长了10.5%、22.6%、20.2%、25.4%和12.6%;林内蛋白酶、蔗糖酶、过氧化氢酶、多酚氧化酶分别比纯林平均提高了17.5%、89.6%、2.9%、39.1%;沙棘-油松混交林改土效果优于沙棘-侧柏混交林;随着林龄增加,改土效果越佳。

The experiment applied national standard forest analysis method to study the effect of improved soil on Hippophae Rhamnodies mixed plantation.The result indicated that the Hippophae Rhamnodies mixed plantation intensified soil stability,improved soil physical and chemical properties,and increased soil decomposed degree.There is a good improving effect on soil.Compared with pure Chinese pine plantation the soil waterstable aggregate increased by 20.8% and the destroy percentage of soil surface layer aggregate stability reduced by 40.76%.The soil density,bulk density and stability were 5.9% and 15.1% lower,prosity and ventilation degree were 12.16% and 16.9% higher,water retaining content and moisture were 13.6% and 5.9% higher,organic matter,total N,P2O5,available P and K increased by 10.5%,22.6%,20.2%,25.4% and 12.6%respectively.Soil protease,sucrase,CAT and polyphenoloxidase activities increased by 17.5%,89.6%,2.9% and 39.1%.The effect of improved soil on Hippophae Rhamnodies and Chinese pine mixed plantation is better than that on Hippophae Rhamnodies and Platycladus Orientalis mixed plantation.The effect of improved soil on mixed plantation becomes better with ageing of trees.