Manejo da Irrigação e da adubação nitrogenada para produção da cultura do pimentão

Abstract

Bell pepper (Capsicum annum L.) is a culture widely cultivated and commercialized worldwide, also standing out in the Brazilian agricultural market, where it has great economic and social importance. In agronomic terms, the crop is characterized by being very sensitive to water variations in the cultivation cycle and quite demanding in nutritional terms, requiring special attention to the management of fertilization and irrigation to obtain high yields. In view of the above, the objective was to evaluate the growth, productivity, gas exchange, water use efficiency and nutritional status of the pepper crop as a function of the management of water deficit and nitrogen fertilization. Two experiments were carried out at the Federal University of Ceará, Fortaleza, CE. In experiment 1, the experimental design was completely randomized, with seven treatments, four replications and plots consisting of two plants. The treatments consisted of replacing the water demand of the pepper crop in the phenological phases I, II, III and IV, as follows (in percentage terms of ETc): T1 – 100%/I, 100%/II, 100%/III and 100%/IV; T2 - 100%/I, 75%/II, 100%/III and 75%/IV; T3 - 100%/I, 75%/II, 75%/III and 75%/IV; T4 - 100%/I, 75%/II, 75%/III and 50%/IV; T5 - 100%/I, 50%/II, 75%/III and 50%/IV; T6 - 100%/I, 50%/II, 50%/III and 50%/IV; T7 - 100%/I, 50%/II, 50%/III and 25%/IV. In experiment 2, two nitrogen fertilization methods (conventional and fertigated) and five N rates (0, 240, 480, 720 and 960 kg ha-1) were evaluated in a completely randomized design, with four replications, in a factorial (2 x 5) and plots consisting of two plants. Irrigation management according to T2, T3 and T4 did not reduce the expression of the vast majority of vegetative variables and gas exchange, in relation to T1. The water deficit applied according to T2 can be used without significant reduction in productivity, providing 12,7% of water savings compared to T1. T1 and T2 provided the highest water use efficiency values. Regarding experiment 2, there was no interaction between the factors tested, and the fertilization methods significantly influenced only the average fruit mass (conventional > fertigated). N doses influenced all growth and post-harvest variables, with the exception of soluble solids. Physiological parameters and leaf N content were significantly influenced by N rates. Yield was adjusted in a quadratic polynomial model as a function of N rates, with a maximum estimated average of 13.05 t ha-1 at the optimal rate. of 615 kg ha-1 of N. It is concluded that the irrigation managements carried out according to T1 and T2 are the most recommended for the cultivation of sweet pepper in field conditions and that the dose of 615 kg ha-1 of N provides the productivity maximum of culture.