Long-term effects of land use type and management on sorptivity, macroscopic capillary length and water-conducting porosity of calcareous soils

Abstract

Soil hydraulic properties are often influenced by agricultural activities. Knowledge of such properties is needed to understand the effect of agricultural practices on the soil water regime and catchment hydrology. In the present study, we investigated the effects of three land use types including orchard field, OF (without plowing), annual cultivated field, ACF (with seasonal plowing), and perennial alfalfa field, PAF (without plowing) on the soil’s water-conducting porosity at equivalent pore radius interval a to b, ε(a, b), sorptivity at applied tension ψ, Sψ, and macroscopic capillary length at tension interval ψi to ψi+1, λ(ψi, ψi+1) of calcareous soils. The mentioned hydraulic attributes were calculated from infiltration data obtained from tension-disk infiltration measurements at six tensions of 0–15 cm at 75 experimental locations (25 replications per land use). In general, it can be concluded that more macropores are present in the soils of PAF than in those of ACF and OF land uses, probably due to high organic matter content, long-term no-till conditions, positive effects of alfalfa root systems, low machinery/livestock traffic, and low soluble sodium content. In ACF, conventional tillage and high machinery traffic, and in OF excessive use of Na-rich manure fertilizers and high livestock traffic resulted in less macropores compared to PAF.