Preliminary study on weed control in dry seeded rice (DSR) after winter wheat.
In field trials in Henan, China, in irrigated dry sown rice cv. Yujing 2 sown after winter wheat, weeds affected the growth yield of the rice mainly through reducing panicle numbers, seed setting, 100-grain wt and panicle length. The major weeds present were Echinochloa crus-galli, Eleusine indica, Digitaria sanguinalis, Rorippa islandica, Portulaca oleracea, Cyperus rotundus and C. difformis. Grasses presented the most severe problem despite their relative density being lower than that of broadleaved weeds. Weed competition was greatest 25-40 d after sowing. Control recommendations include the use of nitrofen immediately after sowing, hoeing 3 weeks after sowing and hand weeding 5-7 weeks after sowing.