Estratégias de irrigação e aplicação foliar de rejeito de caulim no cultivo de feijão-caupi.

Abstract

Water scarcity in semiarid regions stands out as the main environmental factor limiting plant productivity. Faced with this challenge, efficient management of water resources and the adoption of mitigating strategies become crucial to ensure the sustainability of agricultural production systems. Therefore, this research aims to evaluate the effect of different irrigation depths and foliar application of kaolin waste on the growth, physiological parameters, and production of the cowpea cultivar BRS Tapaihum. The experiment was conducted in a greenhouse on campus I of the Federal University of Campina Grande. The treatments consisted of four irrigation depths - L (50, 75, 100, and 125% of Actual Evapotranspiration - ETr) and two concentrations of kaolin waste - C (0 and 50 g L-1), distributed in a completely randomized design, in a 4 x 2 factorial arrangement, with eight replicates and one plant per plot, totaling 64 experimental units. The growth, physiological, and production variables of cowpea beans were evaluated, and the data were subjected to principal component analysis. Irrigation with a depth of 125% of ETr positively influenced the growth of cowpea plants, while a depth of 100% of ETr favored the production of the bean, presenting the highest values in the production variables analyzed. Foliar spraying of kaolin waste, related to a depth of 75% of ETr, promoted the highest value of plant height, and, when associated with a depth of 50% of ETr, provided the highest values of chlorophyll content and relative water content. Furthermore, kaolin waste associated with the irrigation depth required by the crop (100% of ETr), despite providing the greatest pod length and the greatest number of grains per pod, did not result in the greatest total production, obtained in the treatment with the 100% ETr depth without the foliar application of kaolin waste (L3C0). The treatments did not significantly affect the carotenoid content and grain index.