黄土丘陵区3种典型林地土壤持水能力研究

Study on Soil Water Holding Capacity of Three Typical Forest Lands in the Loess Hilly Region

为了揭示黄土丘陵区不同林地土壤涵养水源功能的差异,指导水源涵养林建设和经营,对属黄土丘陵区的山西省中阳县车鸣峪林场进行实地踏勘与咨询,选取山杨、刺槐、油松3种典型人工林为研究对象,分别设置20 m×20 m标准样地,在每个标准样地内采集0~10、10~20、20~30 cm土层土壤样品,包括土壤环刀样品和土壤散样,通过室内试验分析,测定土壤机械组成、土壤团聚体、土壤含水率、土壤容重、土壤总孔隙度等物理性质指标,系统研究了3种典型林地土壤物理性质及土壤持水能力。结果表明:3种典型林地土壤物理性质存在差异:土壤含水率表现为油松>刺槐>山杨;土壤容重刺槐样地最大、山杨样地最小,样地之间差异显著;土壤总孔隙度表现为山杨>油松>刺槐;各样地湿筛的团聚体平均质量直径和几何平均直径均小于干筛的,0~30 cm土层干筛团聚体平均质量直径总体表现为刺槐>油松>山杨,湿筛团聚体平均质量直径最大为山杨、最小为刺槐,即刺槐土壤团聚体稳定性最差、山杨团聚体稳定性最强;不同样地土壤饱和含水量、田间持水量、凋萎系数、土壤有效水存在差异,但整体上油松样地的水分状况较好,不同样地田间持水量和土壤有效水表现为油松>山杨>刺槐,凋萎系数表现为山杨>油松>刺槐。

The purpose of this paper is to reveal the difference of soil water holding capacity of different forest lands in the loess hilly region and guide the construction and management of water conservation forest system in this area.Based on the field survey and consultation of Chemingyu Forestry Station in Zhongyang County,Shanxi Province,which belongs to the loess hilly area,three typical forest lands of Populus davidiana Dode,Robinia pseudoacacia L.and Pinus tabulaeformis were selected as the research objects and 20 m×20 m standard plots were set up respectively.Soil sample in 0-10,10-20 and 20-30 cm soil layers were collected in each standard plot,including soil ring knife samples and soil loose samples.Soil mechanical composition,soil aggregate,soil water content,soil bulk density,soil total porosity and oth⁃er physical property indexes were measured by laboratory test,and soil physical properties and soil water holding capacity of three typical for⁃est lands were systematically studied.The results indicate that the soil physical properties of three typical forest lands exist differences.Soil water content of the typical forest land in the loess hilly region is Pinus tabulaeformis>Robinia pseudoacacia L.>Populus davidiana Dode.The soil bulk density of Robinia pseudoacacia L.is the largest and Populus davidiana Dode is the smallest,and the difference between each plot is significant.The soil total porosity is Populus davidiana Dode>Pinus tabulaeformis>Robinia pseudoacacia L..The mean weight diam⁃eter and geometric mean diameter of soil aggregates with wet sieves are smaller than those of dry sieves.The mean weight diameter of dry sieve soil aggregate in 0-30 cm soil layer is Robinia pseudoacacia L.>Pinus tabulaeformis>Populus davidiana Dode.The maximum of mean weight diameter with wet sieve soil aggregate is Populus davidiana Dode and which of the minimum is Robinia pseudoacacia L..That is to say,the soil aggregate stability of Robinia pseudoacacia L.is the worst and which of Populus davidiana Dode is the strongest.There are differences in soil saturated water content,field water capacity,wilting coefficient and soil available water in different plots,but the overall water status of Pinus tabulaeformis is better.The field water capacity and soil available water with different plots are Pinus tabulaeformis>Populus davidi⁃ana Dode>Robinia pseudoacacia L.,and the wilting coefficient is Populus davidiana Dode>Pinus tabulaeformis>Robinia pseudoacacia L..