Effects of tillage systems and crop rotations on soil physical properties, weed population and wheat grain yield under rainfed condition

An experiment was conducted to determine the effects of three tillage systems and no till in three crop rotations on soil physical properties, weed population and wheat yield in Tajarak Research Station (Kaboudarahang Township), Hamedan, as split plot experiment on the basis of RCBD with three replications in growing seasons 2012 to 2014. Tillage methods including (T1) conventional tillage (moldboard plow + cyclotiller equipped with roller), (T2) combination tiller (chisel plow equipped with roller), (T3) combination tiller (sweep plow equipped with roller) and (T4) direct drilling and crop rotations including: (R1) fallow–wheat, (R2) wheat–wheat (R3) chickpea-wheat were arranged in sub and main plots, respectively. Some of soil physical properties including: bulk density and cone index and also weed density, yield and yield components of wheat were determined. The results showed that crop rotations and soil tillage methods had not significantly effect on cone index and bulk density. The effect of crop rotation on weed populations was not significant, but the effect of soil tillage methods on this trait was significant. Conventional tillage (227.1 kg/ha) and direct cropping (626.8 kg/ha) had the lowest and highest weeds quantity, respectively. In dry year (2012-13), wheat grain yield under direct drilling was greater than conventional tillage.