Effect of Tillage Systems with Corn Residue on Grain Yield of Rapeseed in Moghan Region

This study carried out to evaluate the effect of different tillage systems on rapeseed yield (hayola 401) planted in corn residues. This experiment was done in Moghan region with clay soils during 2009-2012. Different seedbed preparation methods include MT: moldboard + disk tillage (conventional tillage was included)، SCT: Stem Crusher + chisel + disk tandem harrow، STT: Stem Crusher + double-disc، CT: chisel + disk tillage and DD: two heavy disks. The experiment was conducted in a randomized complete block design with four replications. The results showed that soil bulk density in the 0-10 cm layer was not significant in different tillage treatments، but it was significantly higher than the conventional tillage in 10-20 cm depth. However، penetration resistance in 10-30 cm under DD was significantly higher than other treatments، but it was not significant in 0-10 cm layer among all tillage treatments. Thus، Comparison of the soil bulk density، penetration resistance، and plant establishment showed that the reduced tillage in canola seedbed preparation was effective. Besides، the surveys indicated that there was a significant different between MWD after primary and secondary tillage. The mean diameter weighted under SCT and DD، were 1. 19 and 1. 24 cm، respectively had the best status. The highest value and the worst status of this parameter observed for MT which was 1. 92 cm. The highest rate of grain yield obtained by application of treatment SCT، and it was 2563. 8 kg ha-1، The SCT treatment can be recommended as an effective canola bed preparation due to its significant saving in time and cost after corn harvesting.