BIOSTIMULANT AND FOLIAR FERTILIZER IN THE REDUCTION OF PHYTOINTOXICATION IN SOYBEAN CAUSED BY 2,4-D

Abstract

The use of plant regulators and foliar fertilizers in crops has increased due to the benefits provided in plant nutrition and in tolerance to environmental stresses. The objective of this research was to evaluate the effects of plant regulator and foliar fertilizer in reducing injuries caused by the herbicide 2,4-D in two soybean varieties (M7110 IPRO and M7739 IPRO). Four experiments were conducted in randomized block design with four replications. In each experiment, ten treatments were used: single application of the plant regulator or foliar fertilizer at 0, 1, 3 and 5 days after application (DAA) of the herbicide 2,4 -D; application of half the dose of the plant regulator or leaf fertilizer at 0, 1, 3 and 5 DAA of the herbicide 2,4-D and the other half at seven days after the first application of the plant regulator or leaf fertilizer; only the application of 2,4-D; and not application of 2,4-D, plant regulator or foliar fertilizer. 2,4-D caused mild phytotoxicity (<10%) in soybean plants, regardless of the use of plant regulator or foliar fertilizer, which did not mitigate the injuries caused by the herbicide. The heights of plants and insertion of the first pod, the number of branches, pods per plant, grains per plant and the weight of a thousand grains in soybean plants were not affected by the treatments. For the variety M7739 IPRO, there was a reduction in grain yield in the control treated only with 2,4-D and when the plant regulator was applied up to 1 (one) day after the herbicide application. Both the plant regulator and the foliar fertilizer did not attenuate the herbicidal effects of 2,4-D, in the tested dose, for M7110 IPRO and M7739 IPRO soybean varieties.