干热河谷冲沟不同部位土壤水分物理性质研究

Study on Soil Water-physical Properties of Different Gully Positions in Dry-hot Valley

本研究通过对元谋干热河谷典型冲沟集水区、沟头和沟床的考察采样及室内实验分析,研究了冲沟不同部位的土壤水分物理性质。结果表明:1冲沟不同部位土壤容重差异显著,其大小表现为:集水区>沟床>沟头,分别为1.71,1.58,1.45 g/cm3,且集水区、沟头和沟床土壤容重均随土层深度的增加而增大;2各部位土壤总孔隙度和毛管孔隙度均表现为:沟头>沟床>集水区,且其均随土层深度的增加而呈现逐渐降低的趋势;3土壤田间持水量和毛管持水量在试验土层中均表现为:沟头>沟床>集水区,土壤饱和蓄水量则是:集水区>沟床>沟头;冲沟不同部位的土壤田间持水量、毛管持水量、饱和蓄水量和毛管蓄水量随土层深度的变化趋势相似,均是随土层深度的增加而降低。

Based on the soil sample collections and laboratory tests of a whole gully, e.g. drainage area, gully head and gully bed, the soil water-physical properties of different positions were studied in this paper. The results showed that： （i）The soil hulk density of different gully positions showed significant difference, following the order： drainage area 〉 gully bed 〉 gully head, which were 1.71, 1.58 and 1.45 g/ cm^3, respectively. And the bulk density of different gully positions increased with the soil depth increasing. （ii） Soil total porosity and capillary porosity of different positions were as follows ： gully head 〉 gully bed 〉 drainage area, which decreased with the soil depth increasing. （iii） The field water capacity and capillary water capacity in the soil layers were in the order of gully head 〉 gully bed 〉 drainage area,however, the soil saturated storage capacity showed the opposite order. In addition, the change trends of the field capacity, capillary water capacity, saturated storage capacity and capillary storage capacity in gully different positions were similar, and all decreased with the soil depth increasing.