Crescimento e fisiologia de aceroleira irrigada com águas salinas sob adubação nitrogenada e potássica.

Abstract

The use of saline water in irrigated areas in the Brazilian semi-arid region has intensified mainly due to the long periods of drought, resulting in reduced crop growth and productivity, as result of osmotic, toxic and nutritional imbalance effects, which may be mitigated by management of manuring. In this sense, the objective of the research was to evaluate the effect of different salinities on irrigation water in interaction with combinations of nitrogen and potassium fertilizations on the growth and physiology of acerola plants at 200 days after transplanting. The experiment was realized in the field at the CCTA / UFCG, in a in a lineation block design, with treatments disposed in a 5 x 4 factorial scheme, referring to five irrigation water salinities adjusted for electrical conductivity (CEa) of 0.3; 1,3; 2,3; 3.3 and 4.3 dS m-1 in interaction with four combinations (NK) of nitrogen (N) and potassium (K2O) doses, with NK1 = 70% N + 50% K2O; NK2 = 100% N + 75% K2 O; NK 3 = 130% N + 100% K 2 O and NK 4 = 160% N + 125% K 2 O. Three replicates were used andplot consisting of a lysimeter of 60 Liters containing a plant, totaling 60 lysimeters in the experiment. The cv. White flower, grafted on rootstock cv. Reed. It was found that the majority of growth and physiological variables were not compromised by irrigation with water salinity up to 4.3 dS m-1. There was no salt stress mitigation by the combination of nitrogen and potassium fertilization rates on stem diameter below grafting and diameter of primary branches affected by water salinity. The combination of the doses of 70% N (35 g of N) + 50% K2O (20 g of K2O) promoted, in an isolated way, increased gas exchange and the highest growth of the acerola plants.