Water requirement and single and dual crop coefficients of sesame cultivated in the coastal tablelands of Brazil

Abstract

Sesame irrigation is essential in drought-prone regions. However, information about the water needs of sesame is scarce. Therefore, the objective of this study was to determine crop evapotranspiration (ET_c) and the sesame crop coefficient (K_c) during the rainy (S1) and dry (S2) seasons in the coastal tablelands of Alagoas, Brazil. The BRS Seda cultivar was grown in Rio Largo, Alagoas, Brazil, between 2021 and 2022. A system with 25 drainage lysimeters was installed to estimate the daily and cumulative ET_c and the K_c for the entire crop cycle. The ET_c was partitioned into transpiration (T) and evaporation (E), and the basal crop coefficients (K_cb) and soil evaporation coefficients (K_e) were subsequently estimated. The daily and cumulative ET_c were 3.04 mm day⁻¹ and 450.4 mm cycle⁻¹, respectively, in S1 and 3.52 mm day⁻¹ and 440.1 mm cycle⁻¹, respectively, in S2. Regardless of the season, T was the main water flux (74%–80% of the ET_c). The mean values of K_c were similar for S1 (0.79) and S2 (0.75), and K_cb and K_e followed the same trend as T and E, respectively. The accumulated ET_c and K_c of sesame cultivated in the coastal tablelands of Alagoas, Northeast Brazil, are similar for the rainy and dry seasons.