Effect of integration of planting date with stale seedbed, mechanical and chemical weed control on rapeseed yield in Varamin and Karaj

Field experiments were conducted at Varamin and Karaj in experimental fields in August and Septamber, respectively, to determine combination potential of planting date with stale seedbed, mechanical and chemical weed control on rapeseed weed control and its yields. Treatments consisted of 1) stale seedbed mechanical weed control, 2) stale seedbed Trifluralin (EC48%) Haloxyfop (EC10.8%), 3) stale seedbed Paraquat (SL20%), 4) Trifluralin Haloxyfop (EC10.8%), 5) a weedy check and 6) a weed free check. Results of experiments showed that in both of experimental area rapeseed yield reduced when planting date is delayed. In the Karaj Trifluralin Haloxyfop R methyl Ester and stale seedbed Trifluralin Haloxyfop R methyl Ester were the best treatments for rapeseed yield and weeds control. In Varamin because of proper growth of rapeseed, rapeseed had weed competion ability even in treatments without stale seedbed and without weed control and in term of yield did not show significant diference with stale seed deb or herbicides treatments. It seams that planting of rapeseed in proper time can cause rapeseed have a competitive power for weed control.