Physical and mechanical properties of a clayey soil as affected by tillage systems for wheat growth

The effect of tillage systems on soil physical properties of a clayey soil was studied. Tillage systems consisting of conventional tillage I ( CT1), conventional tillage II ( CT2), reduced conventional tillage ( RCT), reduced tillage ( RT) and no tillage ( NT) were carried out in autumn after harvest of sugar beet. Significant differences between tillage systems were recorded on the measured properties, apart from moisture content, at 15 - 30 cm soil layer. The CT1, CT2 and RCT systems resulted in similar penetration resistance and bulk density values below the 15 cm soil depth, while the RT and NT systems resulted in higher but similar values. The mean penetration resistance values were less than 1 MPa in the CT1, CT2 and RCT systems at the 0 - 15 cm depth, while they were 1.41, 1.84 MPa in RT and NT, respectively. The mean total porosity increased with tillage from 8.2 to 28% when compared with NT. The CT1, CT2 and RCT systems resulted in lower moisture content at the 0 - 15 cm depth. The lowest moisture content occurred in RCT ( 24.4%) and the highest in NT ( 30.9%), while it was 30.3% in RT system. The lowest and highest mean weight diameter values were reported for the RT ( 1.36 mm) and NT ( 2.37 mm) systems, respectively. The lowest wheat grain yield was obtained in NT ( 4.14) and the highest in CT1 ( 5.24 Mg ha(-1)). A significant difference occurred between only NT and the other systems. When both grain yield and advantages of reduced tillage are considered, the RT system is recommended.