Effect of tillage and water pressure head on the hydraulic properties of a loamy soil surface

The effect of different tillage practices on soil hydraulic properties was studied in a mature, drip irrigated apricot orchard with a 7% slope, in Murcia (SE Spain). The soil had a loamy texture. Three soil tillage treatments were applied between the rows of trees: 1) control treatment (non-tilled, although weeds were cut to ground level using a blade attached to a tractor following the common practice of the area), 2) perforation treatment, in which soil surface was mechanically perforated with an adapted plough, and 3) mini-catchment treatment, in which small banks were manually raised perpendicular to the line of emitters. The perforation and mini-catchment treatments increased the infiltration of water into the soil surface: the hydraulic conductivity and sorptivity values were higher than those of the control treatment. Both tillage treatments were designed to prevent runoff and both increased rainwater penetration of the soil. They may therefore be useful as part of water management strategies in semiarid areas with scarce water resources, such as Mediterranean countries. The process of infiltration appears to be controlled more by gravity than by capillary forces since the values for time related to gravity were small. Additional key words: disk infiltrometers, hydraulic conductivity, infiltration, pore size, sorptivity, time related to gravity.