Short-Term Effects of Soil Management Strategies on the Hydro-Physical Properties of Soil and Wheat Yield in an Arid Region in Southwestern Iran.

This study is aimed to compare the hydrophysical properties of Cambisols and wheat yield on plots under different soil management strategies. The soil (0–20 cm) consists of 21% sand, 37% silt, and 42% clay. This experiment was conducted with three tillage system types (TST) in main plots (reduced tillage using combined tillage: T1, reduced tillage comprised of chisel plough: T2 and conventional tillage: T3), three harvest residue covers (HRC) in sub-plots (no residue: C1, 40% wheat residue: C2, and 80% wheat residue: C3), and three implement forward speeds (IFS) in sub-subplots (4 km/h: S1, 7 km/h: S2, and 10 km/h: S3). Infiltration tests were performed by single-disc tensions infiltrometer with a diameter of 20 cm at successive applied matric suction (h) of 20, 14, 4, 1, and 0 cm. Mean comparison results showed that soil organic matter decreased in T3 treatment, due to soil aggregate degradation. T3, C3, and S3 treatments increased the hydraulic conductivity at matric suction (h) of 1 cm by increasing the number of macropores per unit area and their contribution to the saturated water flux. In contrast, T1 treatment increased hydraulic conductivity at h of 4, 14, and 20 cm by increasing the number of meso- and micropores. The contribution of micropores to the saturated water flux, hydraulic conductivity at h = 20 cm were higher in residual-cover-free plots. Hydraulic conductivity at h of 1, 4, and 14 cm increased with increasing HRC due to an increase in the number of macro- and mesopores and their contribution to the saturated water flux. Macroscopic capillary length () under T1, T2 and S1 was more than those under T3 and high IFS. T3 treatment also reduced likely due to its destruction effects on pore continuity. The application of T2, C2, and S2 treatments led to maximum wheat yield, likely by minimizing mechanical manipulation, reducing evaporation and improving soil moisture conditions. [ABSTRACT FROM AUTHOR]