Farmers' weed control technology for water-seeded rice in North America.
Water-sowing, a method of direct-broadcast sowing of rice, which began in California during the 1920's as a cultural method to control Echinochloa crus-galli var. crus-galli by continously flooded water management is described. The development of aerial sowing for speed and economy was responsible for the adoption of water-sowing in all Californian rice fields and in a large percentage of the rice areas in Arkansas, Louisiana, Mississippi and Texas and this sowing method is now a major cultural component of integrated systems of weed control in which chemical components have become increasingly essential. Many aquatic weeds thrive under water management practices sown and they are controlled mainly by phenoxy herbicides. The recent introduction and spread of E. oryzoides and E. phyllopogon in California have caused rice farmers to rely on herbicides such as molinate or propanil to protect the crop from serious losses in yield and grain quality. Farmers willingly pay c.7% of the crop production value for weed control.