Crop rotation and tillage effects on selected soil physical properties of a Typic Haploxerert in an irrigated semi-arid Mediterranean region

Physical, chemical and biological attributes of soil surface are significantly affected by tillage practices and crop rotation. The objective of this study was to determine the short-term (2006-2009) effects of conventional and conservational tillage practices on selected soil physical properties of a heavy clay soil under two wheat-corn and wheatlegume rotation in a semi-arid Mediterranean Region. Treatments included conventional tillage with residue incorporated in soil (CT1), conventional tillage with burned residue (CT2), reduced tillage with heavy tandem disc-harrow (RT1), reduced tillage with rotary tiller (RT2), reduced tillage with heavy tandem disc harrow fallowed by no-tillage (RNT) and no tillage (NT). Disturbed and undisturbed soil samples were collected to determine saturated hydraulic conductivity (HC), bulk density (BD), mean weight diameter (MWD), available water content (AWC) and total porosity at 0-10, 10-20 and 20-30 cm depths. The highest HC values of 0-10 cm and 10-20 cm depths were obtained with CT1 (9.70×10-6 m s-1, 8.74×10-6 m s-1) and CT2 (9.39×10-6 m s-1, 8.58×10-6 m s-1) applications. CT2 treatment destructed the soil aggregates and resulted in greater bulk density and low total porosity at 0-10 cm depth. The available water content at 0-10 cm depth was significantly reduced with the CT1 (P<0.01) and CT2 applications (P<0.05). Although three years of no-tillage application in clay rich soils caused higher bulk density and low porosity, increase in MWD is an indication of soil and water conservation. Therefore, no till and reduced till applications should be adapted to the farmers’ conditions for sustainability in agriculture..

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Keywords: Conventional tillage ، Hydraulic conductivity ، Physical properties ، Notillage ، Porosity ، Residue burning ، Rotation ، Tillage systems