The efficacy of chemical options to control Echinochloa crus-galli in dry-seeded rice under alternative irrigation management and field layout

摘要

Alternative irrigation systems are viable options to reduce water footprint in rice; however, it could increase the difficulty of controlling weeds, as the water layer prevent weed emergence. Despite the environmental importance, there is no knowledge regarding effective chemical control of Echinochloa cries-gain (L.) P. Beauv. under contrasting field layouts and irrigation systems in dry-seeded rice. In this study, we quantified the efficacy of some pre-emergence (PRE) and post-emergence (POST) herbicide sequences and tank mixtures to control E. crus-gaUi under continuous and intermittent irrigation at two different field layouts. The experiment was conducted during three growing seasons between 2012 and 2014, in two edaphoclimatic regions of Uruguay. The rice yield was directly related to the efficacy of controlling of E. crus-galli at flowering (R-2 approximate to 0.60). The efficacy of chemical options to control E. crus-galli was not affected by the irrigation or the field layout system. Clomazone PRE followed by penoxsulam was the most effective option (80% weed control). The results suggest that chemical options are available to control E. crus-galii when applying alternative field layout and irrigation systems that promote improved water efficacy in rice. We expect this new approach to control E. crus-galli be useful in reducing water needs, and hence making rice production more sustainable.