Cover crops are known for their ability to improve the physical conditions of soils, reduce erosion and nutrient losses in the system. However, in recent years they began to gain relevance to suppress weeds and reduce the application of herbicides.
Weed management gained special relevance in recent years due to the advancement of herbicide-resistant species, among which the red yuyo, the rough grass and the aleppo sorghum stand out. Diego Ustarroz –of INTA Manfredi- recognized that “resistant weeds are one of the main concerns, since they increase production costs and generate uncertainty due to the reduction of chemical control alternatives in direct sowing plans”. For this reason, he explained, “there is a great demand for information on non-chemical weed management practices that, in turn, can be complemented with the use of herbicides.”
Faced with this context, an INTA team carries out experiences of mechanical weed control with minimal soil removal and inclusion of cover crops in lots that were occupied by soybeans and are destined for the sowing of late corn. These evaluations showed that cover crops save up to two herbicide applications, since they help suppress weeds, without reducing the yield of late corn.
“Among the species we evaluated, the one that gave the best result against weeds is rye, even in years in which rainfall was lower than normal in the region,” explained Ustarroz, who specified that “in those cases it was necessary to increase nitrogen fertilization because some of the nitrogen absorbed by the cover crop is not released in time to be available for corn. It is something that can be managed by achieving good productions and reducing the application of herbicides ”.
The work carried out in Manfredi also included experiences with other cover crops, such as vetch, “which are better from the point of view of nitrogen, because they do not generate a reduction, but in dry years they imply problems in the yield of corn because the amount of The water consumed by vetch is greater than that of rye, ”said Ustarroz.
This topic will be one of the topics on June 9 and 10, when the III Argentine Congress of Weeds will be held online under the slogan “Science, production and society: towards sustainable management.” The Congress aims to bring together and promote the exchange of researchers, teachers, advisers, producers, and agribusiness actors, on the basis of the presentation and dissemination of scientific and technological knowledge that guide the design of alternative and superior approaches to those employed in the present. Several INTA researchers will participate actively in the conferences or as moderators of work tables.
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