Performance of RR soybean submitted to postemergence application of glyphosate with a foliar elicitor product

ABSTRACT With the advent of glyphosate-resistant soybean, postemergence applications of the herbicide have become routine. In this way, problems related to the selectivity of glyphosate have been shown to be increasingly intense, due to the use of increased dosages and applications of the herbicide at unrecommended moments. In order to evaluate the agronomic performance of soybean plants subjected to the postemergence application of glyphosate – both in isolation and together with Crop+ – at different stages and dosage levels, a randomized block design experiment was carried out with two adjacent checks and four repetitions. The treatments consisted of: glyphosate (1296 g·ha-1); glyphosate + Crop+ (1296 + 0.25 g or L·ha-1); glyphosate + Crop+ (1296 + 0.5 g or L·ha-1); glyphosate (2592 g·ha-1); glyphosate + Crop+ (2592 + 0.25 g or L·ha-1); glyphosate + Crop+ (2592 + 0.5 g or L·ha-1); 2 × glyphosate (2 × 1296 g·ha-1); 2 × glyphosate + Crop+ (2 × 1296 + 0.25 g or L·ha-1); 2 × glyphosate + Crop+ (2 × 1296 + 0.5 g or L·ha-1) and Crop+ (0.5 g·ha-1). The phytotoxicity, soil plant analysis development (SPAD) index, height, stand, mass of 100 grains, and yield of the soybean plants were evaluated. The use of Crop+ on soybean plants led to an increase in the SPAD index; the use of Crop+ in association with glyphosate made possible the attenuation of visible symptoms of damage, preventing reductions in crop yield.

摘要 随着抗草甘膦大豆的推广应用，该除草剂的苗后施药已成为常规田间作业。在此背景下，由于除草剂使用剂量不断提升且施药时机选择不当，草甘膦选择性相关问题愈发突出。为评估不同施药时期与剂量水平下，单独施用草甘膦或其与助剂Crop+复配后大豆植株的农艺表现，本研究采用随机区组设计开展田间试验，设置2个相邻对照，重复4次。试验处理设置如下：单剂草甘膦（1296 g·ha⁻¹）、草甘膦+Crop+（1296 + 0.25 g或L·ha⁻¹）、草甘膦+Crop+（1296 + 0.5 g或L·ha⁻¹）、单剂草甘膦（2592 g·ha⁻¹）、草甘膦+Crop+（2592 + 0.25 g或L·ha⁻¹）、草甘膦+Crop+（2592 + 0.5 g或L·ha⁻¹）、双倍剂量草甘膦（2×1296 g·ha⁻¹）、双倍剂量草甘膦+Crop+（2×1296 + 0.25 g或L·ha⁻¹）、双倍剂量草甘膦+Crop+（2×1296 + 0.5 g或L·ha⁻¹）以及单剂Crop+（0.5 g·ha⁻¹）。本试验测定了大豆植株的药害程度、土壤植物分析仪（SPAD）指数、株高、保苗株数、百粒重及籽粒产量。在大豆植株上施用Crop+可提升SPAD指数；将Crop+与草甘膦复配使用，能够减轻可见的药害症状，避免作物产量降低。