滨海湿地不同密度柽柳林土壤调蓄水功能

为探求黄河三角洲湿地土壤调蓄水功能的合理柽柳林密度,采用测量土壤入渗过程和水分物理参数相结合的方法,对不同密度柽柳林的土壤蓄水功能和水分调节能力进行研究。结果表明:①柽柳林随密度的增大具有显著提高细砂粒和降低粉黏粒含量的作用;中密度林分降盐抑碱效应明显,各密度林分表层盐碱含量低于20~40 cm土层;②土壤容重随林分密度增大表现为先减小后增大,孔隙度状况则与之相反,中密度、高密度、草地总孔隙度均值分别比低密度林分高12.9%、6.2%、4.4%;对表层的改良效果好于20~40 cm土层;③Horton模型可较好地模拟柽柳林的土壤入渗过程,中密度林分渗透性能最好,高密度次之,低密度最差;④饱和蓄水量、吸持蓄水量、滞留蓄水量及涵蓄降水量均表现为中密度>高密度>草地>低密度,表土层的水分调蓄功能好于下层;中密度、高密度、草地涵蓄降水量分别比低密度林分高28.4%、23.8%、14.1%。中密度柽柳林具有巨大的水分调蓄空间,其次为高密度,而低密度林分较差。

Capacity of soil water storage and regulation under different density forests of Tamarix chinensis Lour in coastal wetland

The objective is to explore the suitable forest density of Tamarix chinensis Lour on the capacity of soil water storage and regulation of wetlands in Yellow River Delta.The characteristics of soil water physical properties,soil infiltration,soil water storage and regulation of Tamarix chinensis under different density forests are analyzed.Soil infiltration course and hydrological properties are determined in field and laboratory.The results show that:① The amount of fine sand increased with the density forests of Tamarix chinensis increasing,while the amount of silt and clay decreased.The effect of controlling soil salinity and alkaline content of middle density forest is better than that of high and low density forests,and the soil salinity and alkaline content of 0-20 cm is lower than that of 20-40 cm;② Soil density decreased and then increased with the density forests of Tamarix chinensis increasing,while the soil porosity show a contrary tendency.Compared to the total porosity of low density forest,the increment of that in the middle,high density forest and grassland is 12.9%,6.2% and 4.4%,respectively,and these indexes of 0-20 cm are better than that of 20-40 cm;③ Soil infiltration course of forest field fitted Horton infiltration model well.Characteristics of soil infiltration show this order:Middle density forest>high density forest>low density forest> grassland;④ Characteristics of soil saturated water content,soil capillary,non-capillary porosity water-holding capacity and total absorption precipitation show this order:Middle density forest>high density forest>grassland>low density forest,and the capacity of soil water storage and regulation in 0-20 cm is better than that of 20-40 cm.Compared to the capacity of total absorption precipitation in low density forest,the increment of that in the middle,high density and grassland is 28.4%,23.8% and 14.1%,respectively.The largest capacity of soil water storage and regulation is the middle density forest,followed by high density forest,and low density forest is poor.