黄土高原残塬沟壑区坡地刺槐不同皆伐更新幼林地土壤水分动态

WATER TRENDS OF YOUNG REGENERATED FORESTLANDS OF BLACK LOCUST ON GULLY SLOPE

坡地刺槐林成熟后便须进行皆伐更新，更新方式可采取萌芽更新和带状混交更新两种方式。分析了刺槐林更新改造后林地土壤水分动态和空间变异规律及林地耗水特征的变化，结果表明，刺槐林皆伐更新促进了200cm以下深层土壤水分向根层的补给，导致更新幼林地土壤湿度较未更新林地明显提高，而其林地耗水总量却较来更新林地并未减少，甚至增加，表现出富足型的耗水特征。此外，刺槐林更新改造后不会因逐流量的增加而引起新的水土流失，保证了坡地刺槐皆伐更新的可行性。

The Blacklocust (Robinia pseudoacacia L. )forest on gully slope need regenerationimprovement when they get mature. Two regeneration methods: germination and mix-affore-tation with other species in strips may be adopted. The water trends and its spatial variation aswell as the waer consumption characteristics of regenerated forestland have been analysed. Theresults show that the regeneration of black locust forest would encourage the water supplyfrom deep soil zone below 200 cm to roots soil zone and lead to the soil moisture of regeneratedforestland being higher than that of no-regenerated forestland, although the water consump-tion of regenerated forestland might not derease. In addition, the regeneration would not leadto advanced soil and loss although the runoff increase and this ensure the feasibility of regener-ation.