Respostas morfo-fisiológicas da soja submetida à estresse hídrico e aplicação de bioestimulante

Abstract

Soy is considered the main agricultural crop of economic importance for Brazil. Water availability is one of the determining factors for its correct development and productivity. The biostimulants based on the extract of the seaweed Ascophyllum nodosum present substances with the objective of protecting the plants from stressful effects, caused by biotic and abiotic stresses, such as water deficiency. Thus, the general objective of this study was to evaluate the effect of two biostimulants (via seed treatment: Seed + and via aerial part application: Crop +) in mitigating damage caused by water deficiency in the morphophysiological characteristics and in soybean productivity. The experiment was carried out in the field, in the 2017/2018 and 2018/2019 agricultural seasons), in an experimental area in the municipality of Santa Maria - RS. The design used was randomized blocks (DBC), in a 2x6 factorial scheme, with four replications. Factor A was composed of six managements of biostimulants (control without application; Seed +; Seed + + Crop + (V5); Seed + + Crop + (V5 and R1); Crop + (V5) and Crop + (V5 and R1)) and factor D were Two soil water conditions (with and without water deficiency) were used, totaling 12 treatments. 24 “mini greenhouses” were made to subject water deficiency to soybean culture. For monitoring irrigation, the HidroFarm equipment and the presence of tensiometers in the experimental area were used. The results obtained in the experiments confirm the hypothesis of increased tolerance of soybean plants to water deficiency, as there was a significant effect of the management with tested biostimulants, on analyzed morphophysiological variables, such as the increased defense of the plants against the formation of ROS, photosynthetic activity , yield and productivity components. The beneficial effect found in the application of biostimulants on soybean plants, is more apparent in plants subjected to conditions of environmental stress than in plants grown in an environment favorable to their growth and development, especially when handling prior to the occurrence of stressful activity.