Economic and Agronomic Positioning of Fungicides in Conditions of Water Deficit in Soybean Cultures

Abstract

<p><strong>Background. </strong>The management of diseases in soybean crops demands a great economic cost with fungicide applications. Therefore, unnecessary or excessive applications can promote negative environmental results. Therefore, understanding the weather conditions and the development of diseases in the crop is essential to avoid the unnecessary use of fungicides, consequently reducing costs and ensuring the sustainability of the activity. <strong>Aim.</strong> The aim is to identify which yield components are quantitatively affected, and which aspects of the chemical composition of the grains are qualitatively influenced by fungicide management, in addition to relating the cost-benefit rate of sequential applications or previously stipulated management in the soybean crop, as well as their economic effects under water deficit conditions. <strong>Methodology. </strong>The trial was carried out using a randomized block design composed of 4 replications. The trial consisted of 5 kinds of fungicide management, defined by the time and number of applications, during the development cycle of the Lança cultivar, in the 2019/2020 crop season. Soybean agronomic traits and nutritional attributes were evaluated. <strong>Results. </strong>Unfavorable climate conditions contributed to the low rate of Asian rust infection during the soybean development cycle. The different kinds of fungicide management influenced soybean performance for the main agronomic variables studied. For the chemical composition of the grains, there was no statistical difference in relation to the different kinds of fungicide management. <strong>Implications. </strong>The results indicate that the management of fungicides must be carried out according to the meteorological conditions of the year of cultivation. <strong>Conclusion.</strong> Management without fungicide application maximized grain yield and promoted the highest economic return.</p>