洞庭湖区主要森林类型土壤持水性能研究

Research on water holding capacity of forest soil around Dongting Lake

采用野外定位观测与室内实验相结合的方法,对洞庭湖区具有代表性的森林土壤持水性能进行研究。结果表明:(1)土壤容重随着土壤深度的增加而增大,土壤表层容重变化幅度大于土壤深层。不同林地土壤容重变化范围为1.03~1.53 g·cm^(-3),平均值大小表现为杉木林(1.18 g·cm^(-3))<杨树林(1.36 g·cm^(-3))。(2)林地土壤孔隙度和非毛管孔隙度随着土壤深度增加而减小,土壤孔隙度平均值大小为杨树林(33.15%)<杉木林(38.53%)。(3)土壤有效蓄水量平均值大小为杨树林(2 206.50 t·hm^(-2))<杉木林(2 235.91 t·hm^(-2))。相对于杨树林而言,杉木林的土壤蓄水能力较强。(4)土壤的持水性能和土壤物理性质指标之间的相关性分析表明,林地土壤的最大蓄水量和有效蓄水量主要取决于土壤的孔隙状况。

Dongting Lake is our country＇s important wetland ecological function area, which has the extremely important ecological function. Based on field observation and indoor experiment methods, The author choose the typical forest soil water holding capacity from it and make a quantitative analysis. The results are as follows：（1） Woodland soil bulk density increases with increasing soil depth, variations in soil bulk density is greater than the deep soil. And the soil bulk density ranged between 1.03 ~ 1.53 g·cm^（-3）, and the average of soil bulk density was Chinese fir forest（1.18 g·cm^（-3）） Poplar forest（1.36 g·cm^（-3））;（2） Forest soil porosity and non-capillary porosity decreased with soil depth, and the average of soil porosity was Poplar forest（33.15%） Chinese fir forest（38.53%）;（3） The average of soil effective storage water capacity was Poplar forest（2 206.50 t·hm^（-2）） Chinese fir forest（2 235.91 t·hm^（-2））. By comparison, the water storage capacity of Chinese fir forest was stronger than the Poplar forest;（4） Soil water holding capacity and the soil physical properties index correlation analysis showed that the soil of the largest storage capacity and the effective storage capacity mainly depends on the porosity of the soil condition. The above conclusions provide data support for forest water conservation function around Dongting Lake.