Corn and soybean yields as affected by cover crops and herbicide timing under no-tillage system

Abstract

-To achieve better results in the no-tillage system (NTS), it is important to properly manage the cover crop prior to planting by using herbicides, usually glyphosate. The effect of glyphosate on plant coverage is slow, and plants take a few days to die completely. Thus, when applying the herbicide on the same day of planting soybean or corn, cover crops are still alive and standing, causing initial shading on seedlings of the crop and delaying its establishment. Therefore, this study aimed to evaluate the effect of distinct cover crops and their timing of desiccation prior to planting soybean or corn, on crop yield and yield components. Two experiments were installed, one for soybean and another for corn. Each experiment consisted in combining three cover crops (Brachiaria brizantha, common bean or millet) chemically desiccated at two timings before planting the crop (15 or 0 days before planting) under no-tillage system (NTS). Experiments were installed in a completely randomized block design with five replications. Brachiaria brizantha produced the highest amount of biomass; common bean and millet as cover crops allowed higher soybean grain yields; herbicide application under common bean, millet and Brachiaria brizantha 15 days before planting soybean allowed higher crop grain yields; desiccation timing of common bean did not affect corn grain yield; Brachiaria brizantha should be desiccated 15 days before planting corn to allow maximum grain yield; when millet was used as a cover crop, glyphosate application at planting of corn allowed the highest grain yield. Keywords: Brachiaria brizantha, Pennisetum glaucum, Phaseolus vulgaris, Zea mays, Glycine max, herbicidetiming. RESUMO -Para alcançar melhores resultados no sistema plantio direto (SPD), é importante o adequado manejo das plantas de cobertura com herbicida, normalmente o glifosato. O efeito do glifosato nas plantas de cobertura é lento e essas coberturas demoram alguns dias

Assessing Seasonal Methane and Nitrous Oxide Emissions from Furrow-Irrigated Rice with Cover Crops

“…The time of cover crop termination is one of the biggest challenges for their successful field implementation. Termination of cover crops two weeks prior to crop planting is suggested to avoid the adverse effect of cover crop biomass on planting operations, physical impedance for crop emergence, shading and translocating the herbicide to nontarget plants [31,32]. In this study, the presence of cover crop biomass affected the perfomance of the air seeder during planting such that some rice seeds did not have adequate contact with soil, resulting in reduced germination.…”