黄河三角洲不同刺槐混交林的土壤持水能力

Soil Water-holding Ability in Different Mixed Black Locust Plantations in the Yellow River Delta

在黄河三角洲盐碱地,以无林地作为对照,调查刺槐臭椿混交林、刺槐白榆混交林、刺槐白蜡混交林、刺槐纯林4种林分不同土壤层的盐碱度、容重和孔隙度、枯落物层和土壤持水能力等指标。结果表明:(1)除刺槐白蜡混交林土壤表层有一定的返盐现象外,其余林分均具有一定的压盐抑盐效果,且pH值多随土壤深度的增加而升高;(2)不同混交林的枯落物层总蓄积量范围为2.03～12.15t/hm2,半分解层大于未分解层,表现出造林地显著高于无林地,但是刺槐混交林略小于刺槐纯林;(3)不同林分的枯落物最大持水量与其蓄积量的趋势基本一致,在3.79～19.59t/hm2之间,有效持水量在2.74～13.48t/hm2之间,二者的变化趋势并不完全一致;(4)与无林地相比,林地的土壤容重显著减小,而土壤孔隙度增加,其中混交林好于纯林,其土壤饱和蓄水量、毛管蓄水量从大到小依次为刺槐白蜡混交林、刺槐白榆混交林、刺槐臭椿混交林、刺槐纯林、无林地。因此,为发挥刺槐在黄河三角洲盐碱地的改良土壤、涵养水源等方面的作用,建议营造混交林。

The indexes such as soil salinity,density,porosity and water-holding characteristics of different soil layers were investigated among 4 black locust plantations,including pure black locust stand,mixed stand of black locust and tree of heaven,black locust and white elm,and black locust and chinese ash in the Yellow River Delta.Results indicate that：（1） Except mixed black locust and chinese ash plantation shows a certain accumulative salinity in the top soil layer,that of mixed stands of black locus decrease obviously,and soil pH values increase with the soil depth increasing.（2） The total litter storages of the mixed locust forest are less than that of pure plantation,and all of them are higher than bare land,ranging from 2.03 t/hm2 to 12.15 t/hm2,and half decomposed litter is higher than undecomposed litter.（3） The maximum litter water-holding capacities of different stands have the same trend with their litter storages,ranging from 3.79 t/hm2 to 19.59 t/hm2,which do not keep accordance with that of their available water-holding capacities,ranging from 2.74 t/hm2 to 13.48 t/hm2.（4） Compared with bare land,the soil density decrease while the soil total porosity increase under different plantations,which the soil saturative water holding capacity and the capillary water-holding capacity show the same order： Black locust and chinese ash 〉black locust and white elm 〉black locust and tree of heaven 〉pure black locust 〉bare land.Therefore,mixed black locust plantation should be applied in saline-alkali soil of the Yellow River Delta to improve the soil quality and water conservation,etc.