SciELO - Scientific Electronic Library Online

 
vol.28 issue1Impact of glyphosate associated with endosulphan and tebuconazole on the endosymbiotic microorganisms of the soybeanTifton 85 tolerance to glyphosate at different application times author indexsubject indexarticles search
Home Pagealphabetic serial listing  

Planta Daninha

Print version ISSN 0100-8358

Abstract

AVILA, L.A. et al. Non-tolerant rice production after using the ClearfieldTM rice system. Planta daninha [online]. 2010, vol.28, n.1, pp. 123-129. ISSN 0100-8358.  http://dx.doi.org/10.1590/S0100-83582010000100015.

The herbicides imazethapyr and imazapic used in the Clearfield rice system can persist in the soil and affect non-tolerant rice cultivars sown in rotation. The effect on rice plants can vary according to the cultivar and herbicide used in rotation. Thus, a field experiment was conducted to evaluate cultivar and herbicide options when growing non-tolerant rice after using Clearfield rice system. The experiment was installed in the 2006/07 growing season, in a lowland area located in Santa Maria, Rio Grande do Sul, Southern Brazil. The experiment was in a randomized block design with three replications in a factorial scheme. Factor A included two succession systems of Clearfield rice and non-Clearfield rice in the first three growing seasons (2003/04, 2004/05 and 2005/06): Succession 1 - two agricultural growing seasons using the Clearfield system with application of the herbicide mixture imazethapyr and imazapic (75 and 25 g a.i.. ha-1) and one growing season with non-tolerant rice, without application of imidazolinones; and Succession 2 - three growing seasons using Clearfield system and herbicide application at the same rate specified previously. Factor B included rice cultivars used in the fourth year (BR IRGA 409, IRGA 417, IRGA 422 CL and BRS 7 "TAIM"). Factor C included different herbicides used during the fourth growing season (2006/07), bispyribac-sodium, clomazone + propanyl, cyhalofop-butyl, quinclorac, penoxsulam. Rice production after using the Clearfield system requires at least one year without herbicide application (imazethapyr and imazapic) to avoid carryover to non-tolerant rice and yield reduction. A 30% grain yield reduction is caused by herbicide carryover to non-tolerant rice cultivated in areas where the Clearfield system had been used for three years. No difference was found in the non-tolerant rice cultivars used in this experiment, as all were susceptible to herbicide carryover. No increased injury was observed in rice plants due to herbicide application on the non-tolerant rice cultivars cultivated in rotation. However, it must be emphasized that it is necessary to choose a non-ALS inhibiting herbicide to reduce the pressure of selecting weeds resistant or tolerant to these herbicides.

Keywords : grain yield; plant injury; soil persistence.

        · abstract in Portuguese     · text in Portuguese     · pdf in Portuguese