Management of blood grass (Isachne miliacea Roth ex Roem et Schult) in wetland rice

Abstract

Field experiments were conducted during Kharif and Rabi seasons of 2015 at the State seed farm, Kottarakkara, Kerala in a wetland field heavily infested with blood grass (Isachne milacea Roth ex Roem et Schult ) to develop an effective strategy for managing the weed. The experiment was laid out in a split plot design with combinations of tillage and water regimes as main plot treatments and weed management practices as sub-plot treatments. The results revealed that an integrated strategy involving intensive tillage (three ploughings fb puddling), deep water ponding (i.e., > 7.5 cm up to panicle initiation and saturation thereafter) and application of azimsulfuron @ 35 g ha-1 at 3-5 leaf stage of the weed was the most efficient treatment for managing the weed in terms of weed control efficiency (WCE), crop performance and net income. Combining these modified cultural practices with either (bispyribac sodium + metamifop) @ 70 g ha-1 or fenoxaprop-p-ethyl @ 60 g ha-1 were alternate strategies for management of this noxious wetland weed. Pre-plant application of oxyflourfen @ 0.15 kg ha-1 fb hand weeding when combined with deep water ponding and intensive tillage recorded high WCE, but was inferior in terms of economics. Combinations with manual weeding though uneconomic, were efficient in managing the weed, and recorded higher yield and hence could be an option for organic rice cultivation.