Saturated Hydraulic Conductivity Variation in Cultivated and Virgin Soils

摘要

Variation of saturated hydraulic conductivity (Ks) values of soils under diverse management practices may be needed to determine the required sample number, sample size, and chose suitable sample scheme for characterize the Ks values used in water flow and solute transport modelling studies. The purpose of this study was to examine the variability in Ks and try to understand some part of the determinism of this variability in virgin and adjacent cultivated field using 36 undisturbed soil samples from each location with 0.5-m grid space. Ks was measured with 100 cm3 undisturbed soil cores in laboratory using falling or constant head methods. The results showed that variability of ln (Ks) values (variance = 10.3) at the cultivated site was 2.5 times greater than that (variance = 2.5) at the virgin site. Furthermore, significant Ks differences exist between cultivated sample locations and within the rows of each cultivated location. Greater variations occurred in two cultivated locations may be attributed to compaction by traffic and soil tillage resulting in heterogeneous bulk density over the study area.