Chemical characteristics and compatibility of mixtures at different agricultural application rates

Abstract

Tank mixes are widely used to control weeds, fungi, insects, and nematodes to increase the control spectrum. However, little is known about the interactions that may occur due to the different types of formulations and products used. This study aimed to evaluate the interaction and compatibility between different classes of products (herbicides, fungicides, insecticides, biostimulants, foliar fertilizers, and adjuvants) on the physical-chemical parameters of sprays commonly used in farming. The concentration of the sprays was stipulated by adopting a spray volume between 100, 50, and 10 L ha-1 and the dose recommended by the manufacturers. The characteristics evaluated were physical compatibility (presence or absence of flocculation, sedimentation, phase separation, formation of lumps, oil separation, formation of crystals and cream, and foam formation) and chemical compatibility (pH and electrical conductivity). The products tested have different affinities with the adjuvants and it is not possible to generalize the recommendations. The physicochemical compatibility between products of different classes of action and the adjuvants evaluated is dependent on the rest period, with constant agitation being essential before and during application for Glifotal®, 2.4 D®, Smart Trio®, and B-Moly®, in addition to molecular incompatibility separation occurring between 5-30 min after preparation of syrup for 2.4 D®, Smart Trio®, B-Moly®, Fosert®, Glyphosate®, Zethamaxx®, Bravonil®, Engeo®, Completo®, Plant Start®, Smart Cooper®, Manni Plex cal mg®, Manni Plex k® and Smart Zn®. pH also has a strong influence in some mixtures of syrups where flocculation occurred for the products Bravonil®, Engeo®, Completo®, Plant Start®, Smart Cooper®, and Smart Zn®, as well as the formation of lumps due to the concentration for Engeo®, Completo®, Plant Start®, and Smart Cooper®. It is concluded that dosages, homogenization, interactions between molecules of the same or different classes, and physicochemical parameters such as pH and electrical conductivity influence the obtaining of compatible application grouts.