José A. F. Cardoso

Produção de girassol sob estresse salino e adubação nitrogenada

SUMMARY : SUNFLOWER PRODUCTION UNDER SALINE STRESS ANDNITROGEN FERTILIZATION The limited availability of low-salinity water in Brazilian semiarid region causesproducers to use water of moderate to high salinity for irrigation. In view of the increasingimportance of sunflower ( Helianthus annuus L.) in this region as a potential source of renewableenergy, this study was conducted to evaluate sunflower crops irrigated with different watersalinity levels (ECw) and fertilized with nitrogen. The experiment was conducted in a greenhouseof the Federal University of Campina Grande (UFCG), from July to October 2009, in arandomized block design, to test five ECw levels (0.5 - control, 1.6, 2.7, 3.8, and 4.9 dS m -1 )and four N rates (50, 75, 100 and 125 % of the rate recommended for pot experiments) in a5 x 4 factorial scheme, with three replications. The salinity of irrigation water and nitrogenfertilization affected the sunflower plants in independent ways. Water salinity affected the leafarea, biomass of aerial parts and roots, weight and total production of achenes and harvestindex linearly and negatively. Higher N rates on the other hand reduce the crop cycle andperiod from achene formation to physiologic maturity, and increased its mass.Index terms: