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Soil structure is one of the most important soil characteristics that can be modified by tillage practice due to the effects on porosity (shape, volume and continuity of pores) and soil hydraulic conductivity contributing to create optimal conditions to plant growth and crop establishment.

Continual soil inversion can in some situations lead to a degradation of soil structure, decreasing in available soil water, depletion of soil organic carbon, and increasing greenhouse gases emissions into the atmosphere.

The main objective of this work was to evaluate, under semi-arid Mediterranean conditions of Southern Italy, the effects of soil tillage on the soil hydraulic conductivity (K) evaluated for three consecutive years in a long-term research (over 20 years) regarding a cultivation of winter durum wheat.

The effects of soil tillage on hydraulic conductivity were evaluated by means of infiltration experiments carried out in 3 years on a clay soil submitted to conventional and minimum tillage. Starting of measurements of single values the K functions, effective porosity (as number and volume of pores per unit area) and contribution of macropores and mesopores were determined.

The bimodal two-line exponential functions were found to be adequate to describe K near saturation quantifying the water flux in the macro-mesopore system, with large increases in K observed for small increases in soil water pressure head regardless of tillage management.

Our results highlighted a significant equivalence of soil hydraulic properties between conventional and minimum tillage. Therefore, for the case study carried out for the typical cropping system of Southern Italy, the shallow soil tillage can be considered preferable to deepest plowing because of lower impact in term of cost and greenhouse gases emissions in the environment. (C) 2012 Elsevier B.V. All rights reserved.