滨海盐碱区不同林龄柽柳人工林土壤水分物理性质差异性

Soil Water-physical Properties of Tamarix chinensis Plantations with Different Ages in the Coastal Saline-alkali Region

为揭示柽柳人工林对黄河三角洲滨海盐碱地土壤水分物理性质的影响,对3种林龄(3、6、8 a)柽柳林地的土壤密度、土壤孔隙度、持水贮水能力以及渗透性进行了研究。结果表明:林龄和土层深度均可影响柽柳林地的土壤水分物理特性,其中土壤密度随林龄的增加呈降低趋势,随土层深度的增加呈增大趋势;土壤孔隙度、持水量、贮水量均随林龄的增大而增加,随土层深度的增加而降低;各指标在3 a与8 a林地间及表层土(0≤土层深度(H)<20 cm)与深层土(40 cm≤H<60 cm)间差异均显著(P<0.05);土壤入渗速率与入渗时间呈现明显的幂函数关系,初渗速率和稳渗速率在不同林龄林地间由大到小的顺序均表现为8、6、3 a,且8、6 a林地与3 a林地差异显著(P<0.05)。综合来看,随着林龄的增长,柽柳林中凋落物分解与细根生长的作用逐步增强,0 cm≤H<60 cm土壤剖面内的土壤密度、孔隙度、持水性及渗透性得到很大改善,土壤的通气性和透水能力明显提高。因此,在黄河三角洲滨海盐碱区营造柽柳人工林有利于改善土壤水分物理状况。

In order to reveal the effects of reforestation on soil water-physical properties in the coastal saline-alkali soil of Yellow River Delta,we studied soil particle density,soil porosity,soil water holding capacity and soil penetration rate of Tamarix chinensis plantations with different ages(8,6 and 3 a).Both stand age and soil depth could characterize the soil moisture-physical characteristics.The soil particle density decreased with increasing stand age and increased with the increase of soil depth,while the soil porosity,soil water holding capacity and soil water storage increased with increasing stand age and decreased with the increase of soil depth.There were significant differences in all the indexes between 3-and 8-a stands and between surface(0-20 cm)and deep(40-60 cm)soil(P<0.05).In addition,there was a power function relationship between soil infiltration rate and infiltration time.Furthermore,the rates of initial infiltration and steady infiltration decreased in the descending order of 8 a,6 a and 3 a in different ages stands,and there were significant differences between 3-and 8-a stands and between 3-and 6-a stands.In total,the effects of litter decomposition and fine root growth in T.chinensis were gradually increased with increasing stand age.The main manifestations were that soil particle density,porosity,water holding capacity,and permeability had been greatly improved in soil profiles of 0 to 60 cm,which made the soil aeration and the permeability were significantly increased.Our results suggested that establishing T.chinensis plantations could improve the soil moisture-physical condition in the coastal salinization area of the Yellow River Delta.