Efeito do estresse hídrico em diferentes fases de crescimento do amendoim com uso de hidrogel

Abstract

The peanut crop (Arachis hypogaea L.) has great socioeconomic importance, especially in semi-arid regions where water limitation is one of the main factors reducing productivity. The use of hydroretentive polymers emerges as an alternative to improve soil water retention and mitigate the effects of water deficit. In this context, the objective of this study was to evaluate the effect of water stress at different growth stages of peanut, associated with the use of a hydroretainer, on vegetative and productive development variables. The experiment was conducted in a greenhouse under a completely randomized design in a 2 × 4 factorial arrangement with four replications, in which factor 1 consisted of the presence and absence of the hydroretainer, and factor 2 corresponded to periods of water stress (30–45, 45–60, and 60–75 days after emergence – DAE), in addition to full irrigation as control. The evaluated variables were number of leaves, plant height, stem diameter, relative chlorophyll index, shoot dry mass, number of pods, and number of seeds per plant. The data were subjected to analysis of variance (ANOVA) using the F test, and means were compared by Tukey’s test at 5% probability. At 30 DAE, plants without the hydroretainer showed greater stem diameter (3.15 mm) compared to those with the polymer (2.80 mm). At 45 DAE, water stress significantly reduced the number of leaves and plant height, evidencing the crop’s sensitivity to water restriction at this stage. At 60 DAE, the hydroretainer increased leaf emission, while stress between 45–60 days reduced growth. At 75 DAE, significant effects of both the hydroretainer and water stress were observed for number of leaves, plant height, stem diameter, relative chlorophyll index, and shoot dry mass, with interaction for number of leaves. The highest means were recorded under full irrigation, whereas the 60–75 day period caused the greatest reductions, standing out as the most critical phase of the cycle. The peanut crop proved to be sensitive to water availability, especially during flowering and pod formation, when water deficit significantly reduced vegetative and physiological parameters. The use of hydroretainers proved to be a viable management alternative, capable of partially mitigating the negative effects of water restriction during critical stages of development.