Performance of Crops Grown in Succession to Soybeans Treated with Different Residual Herbicides

Abstract

Herbicides with residual effect applied in soybeans may affect the productivity of late harvest crops grown in succession. Thus, the objective of this research was to evaluate the agronomic performance of adzuki bean crops, crambe, millet and palisade grass pasture grown in succession to soybean crop treated with residual herbicides, as well as assess the contribution in weed management. Four trials were conducted in field conditions at the soybean crop in the harvest and then succeeded by adzuki bean crops, crambe, millet and palisade grass as late harvest. An experimental design was adopted in a randomized block arrangement with four replications and nine treatments represented by the application of residual herbicides: imazethapyr (1.0 and 1.5 L ha-1), chlorimuron (60 and 90 g ha-1), fomesafen (1.0 and 1.5 L ha-1) and chloransulan methyl (74.6 and 71.4 g ha-1) and without herbicide control, kept in manual weeding. The herbicides were efficient in weed control in soybeans, not affecting crop yield. However, there was no residual activity of herbicides contribution in reducing infestation in the late harvest crops. The herbicides did not promote phytotoxicity to crops of crambe, beans, millet and palisadegrass pasture when they were compared with the other treatments. The beans treated with methyl chloransulan, regardless of dose, showed a higher yield. The absence of phytotoxicity to crops can be associated with rainfall incident on soybens which contributed to the dissipation of herbicides.

Pre-Emergent Herbicide Application Performed After Crop Sowing Favors Pigweed (Amaranthus Spp.) and White-Eye (Richardia Brasiliensis) Control in Soybeans

“…Moreover, some pre-emergent herbicides display herbicidal modes of action which are not available for use as a post treatment, allowing for an effective rotation of modes of action, which, in turn, can effectively delay or prevent the evolution of herbicide resistance in weed populations (NUNES et al 2018). However, various factors must be taken into account when planning pre-emergent herbicide applications, as misuse can lead to severe crop phytotoxicity or even affect the subsequent crop species in the area due to herbicide residues in the soil -a phenomenon known as carry-over (WALSH et al 2015;SOUSA et al 2018).…”