陕北黄土区衰退沙棘人工林改良土壤的作用

Soil Improvement by Degrade Sea-buckthorn Forests in Loess Region of Northern Shaanxi Province

为研究衰退沙棘人工林对土壤的改良功能,对陕北黄土区衰退沙棘人工林分轻度、中度、重度3种衰退类型进行了研究。结果表明:(1)3种衰退类型沙棘人工林0—60cm土层土壤速效磷、速效钾含量较对照均有提高。(2)轻度衰退沙棘人工林对40—60cm土层土壤有效氮,0—20cm速效磷含量有显著提高作用。对20—40cm土层土壤有效氮含量有极显著提高作用(由14.23mg/kg增至22.39mg/kg)。中度衰退沙棘人工林对20—60cm土壤有机质、有效氮有显著提高作用。重度衰退沙棘人工林对0—20cm土壤全氮含量的提高作用显著低于对照坡面。(3)3种衰退类型沙棘人工林对20—40cm土层速效磷含量的作用表现为中度衰退沙棘人工林最大,其次是轻度衰退沙棘林。其他土层则表现为随着衰退程度加深,沙棘人工林对土壤改良作用减弱。

In order to investigate the soil improvement by degrade sea-buckthorn forest, soil properties in 0-- 60 em soil layers under slightly, moderately and severely degrade sea-buckthorn forests were measured. （1） The concentrations of soil available P and K under the three degrade sea-buekthorn forests in 0--60 em soil layers were larger than those under undisturbed slopes. （2） The increases were significant at the level of 0.05 for the concentrations of soil available N in 40--60 cm soil layer and soil available P in 0--20 cm soil layer under slightly degrade sea-buckthorn forest. The increase was significant（at the level of 0.01） for the concentration of soil available N in 20--40 cm soil layer under slightly degrade sea-buckthorn forest（The a vailable N content increased from 14.23 to 22.39 mg/kg in 20--40 cm soil layer）. The increases were also significant（at the level of 0.05） for the concentration of soil organic matter and soil available N in 20--60 cm soil layer under moderately degrade sea-buckthorn forest. Decrease was significant（at the level of 0.05） for the concentration of soil total N in 0--20 cm soil layer under severely degrade sea-buckthorn forest. （3） The increases of soil available P in 20--40 cm soil layer under the three degrade sea-buckthorn forests were in the following order： moderately degrade forest〉slightly decayed forest〉severely degrade forest. Soil available P in the 0--20 and 20--40 cm soil layers increased as the following order： slightly degrade forest 〉 moderately degrade forest〉severely degrade forest.