Cationic nature of water and nitrogen in sunflower cultivation

In the Brazilian semi-arid region, it is common to find water with high salt concentrations and variations in its cationic composition. In this sense, the objective of this study was to evaluate the influence of irrigation with water of different salinities and cationic nature associated with nitrogen doses on the growth, physiology, and production of sunflower cv. BRS 324. The study was conducted in pots adapted as lysimeters, under field conditions, at the Center for Technology and Natural Resources of the Federal University of Campina Grande, during the period from November 2014 to January 2015. The design used was randomized blocks, in a 5 x 5 factorial scheme, with three replicates, with five combinations of salinity and cationic nature of water - S (S1 - Control; S2 - NaCl; S3 - CaCl2; S4 - KCl and S5 - NaCl+CaCl2+MgCl2) and five doses of nitrogen (N1 - 50; N2 - 75; N3 - 100; N4 - 125 and N5 - 150 mg of N kg-1 of soil). Water with electrical conductivity (EC) of 0.5 dS m-1 was used for irrigation for the control (S1) and 5.0 dS m-1 for the other treatments (S2; S3; S4 and S5).