Weed management practices in machine transplanted rice cultivation

The yield performance of lowland rice varieties depends on the method of crop establishment. However, yield of transplanted rice is generally believed to be higher than that of dry-seeded rice. Broadcasting is the most widely practiced establishment method by Sri Lankan paddy farmers. Though it is easier to be practised it has several disadvantages such as high weed infestation, high insect pest infestation and lodging. Under the Yaya 11 program, farmers were introduced machine transplanting by Department of Agriculture. Inter row spacing of the transplanting machine is a fixed value of 30 cm. It allows a severe weed infestation in the field and finally results a remarkable yield loss. Weed management is an essential practice in machine transplanting. Farmers are looking for a better weed management practice in machine transplanting. This study was conducted with the objective of finding out a better weed management practice in machine transplanting. A farmer’s field demonstration experiment was conducted at Manapaha in Kurunegala district in Maha 2015/2016. The demonstration was to test 07 treatments namelyT1=Pretilachlor 300g/l+Pyribenzoxim 20g/l followed by Weedering twice, T2= Pretilachlor 300g/l +Pyribenzoxim 20g/l, T3= Pretilachlor 300g/l EC, T4= Pretilachlor 300g/l EC followed by Weedering twice, T5=Weedering twice (at 2 WATP and 4WATP), T6=Hand-weeding and T7=No-weeding. All treatments ultimately gave a significantly higher yields than no-weeded control. It is clear that weed control is essential in machine transplanted rice cultivation. Pretilachlor 300g/l EC was well performed among all herbicide treatments in machine transplanted rice cultivation.