Rendimento do feijão-caupi submetido ao estresse hídrico em diferentes cenários produtivos.

Abstract

Cowpea can be cultivated in different soil, climate and technological conditions, and its productivity is strongly influenced by climatic conditions. Therefore, two experimental campaigns were carried out, the first from February 2 to May 14, 2021 (rainy season) and the second from September 1 to November 9, 2021 (dry season) at the Experimental Station (EstAgro) belonging to the Academic Unit of Atmospheric Sciences (UACA) of the Federal University of Campina Grande - UFCG, with the objective of evaluating the influence of water stress on productive components (productivity, biomass, harvest index and water use efficiency), water demand and economic viability of cowpea cv. ‘Costela de Vaca’, cultivated in different planting seasons (rainy and dry), as well as the calibration and validation of the AquaCrop model for these conditions. The experimental design used was in randomized blocks, in a 2 x 5 factorial scheme (culture period x water stress), with four replications. The treatments consisted of two planting periods (rainy and dry) and five forms of water stress (no water stress, water suspension of 5, 10 and 15 days and rainfed planting), in a no-tillage system. Regardless of the cowpea cultivation period, water stress resulted in a reduction in grain yield, biomass, harvest rate and water use efficiency, with more evident reductions in rainfed cultivation. There was a greater need for water by the cowpea crop grown in the dry season. Cowpea presented positive results of economic viability in both growing seasons, as long as it is irrigated throughout its cycle, and water stress does not exceed 10 days in its reproductive phase. The AquaCrop model showed excellent performance in the simulation of grain yield and biomass of cowpea under water stress conditions in its reproductive phase, cultivated in the rainy and dry seasons. Agricultural practices of no-till and use of ground cover provided the maintenance of soil moisture, resulting in higher yields of cowpea, even though its cultivation was influenced by the climatic conditions of the growing season and water stress.