Desempenho do pimentão vermelho sob lâminas de irrigação deficitárias com hidrogel e bioinsumos em ambiente protegido

Abstract

The production of colored bell peppers in semi-arid regions faces the challenge of reconciling high productivity with efficient water use. With this in mind, this study evaluated the performance of red bell pepper (Capsicum annuum L., cv. Taurus) cultivated in a greenhouse in the municipality of São Benedito–CE, under different irrigation levels (40, 60, 80, and 100% of ETc) combined with doses of the bio-input Protamin GR (50, 75, 100, 125, and 150% of the recommended rate) and a single dose of hydrogel, in addition to an extra treatment with full irrigation, 100% bio-input, and no hydrogel. The experimental design was a randomized block with split plots, totaling 84 experimental units. Variables of vegetative growth, yield, productivity, and physiology were measured, including leaf temperature [ΔT(Tc - Tar)] and the crop water stress index (CWSI). The results showed that vegetative growth was weakly sensitive to the treatments, but shoot fresh mass (SFM) and shoot dry mass (SDM) responded significantly, with the 60% irrigation level (517.4 g and 80.4 g, respectively) and the 125% dose (556.6 g and 90.5 g, respectively) showing the best performance for these variables. For the variable average fruit weight (AFW), the study also revealed significant statistical differences (p < 0.05), indicating that the 60% irrigation level (156.8 g), associated with hydrogel, achieved the best result. Fruit length (FL) also presented significant differences, with p < 0.01 for the irrigation factor, with the 60% ETc treatment showing the highest mean (128.8 mm). Regarding physiological variables, leaf water potential (Ψf), ∆T (12h), and CWSI (12h) also presented significant statistical differences (p < 0.05). Ψf was significantly affected by irrigation level, with the highest mean at 60% ETc (5.29 bar), while ∆T (12h) and CWSI (12h) responded to Protamin GR doses, with the highest mean values at 75% of the recommended rate [∆T(12h) = – 4; CWSI (12h) = 0.45]. Hydrogel contributed under deficit conditions but did not provide additional benefits under full irrigation. Overall, it was found that moderate water deficits, combined with a balanced use of bio-inputs, can reduce water consumption without compromising yield, promoting a more sustainable cultivation of bell peppers in greenhouse conditions.