Saline waters and nitrogen/potassium fertilization combinations on physiological aspects and production of West Indian cherry

Águas salinas e combinações de adubação com nitrogênio/potássio sobre aspectos fisiológicos e produção de aceroleira

Abstract

This study evaluated the influence of combinations of nitrogen and potassium doses on the physiology and fruit production of West Indian cherry irrigated with waters of different salinities in the second year of cultivation. The experiment was conducted in the municipality of Pombal-PB, Brazil, in plastic containers adapted as lysimeters installed in the field, in a randomized block design, 5 x 4 factorial scheme corresponding to five levels of electrical conductivity of irrigation water (ECw): 0.3, 1.3, 2.3, 3.3 and 4.3 dS m^-1, and four combinations of nitrogen and potassium fertilization: 70% N + 50% K₂O; 100% N + 75% K₂O; 130% N + 100% K₂O and 160% N + 125% K₂O of the dose recommended for West Indian cherry, with three replicates and one plant per plot. The cv. ‘Flor Branca’ was grafted on the cv. ‘Junco’, between 420 and 550 days after transplanting. Nitrogen and potassium combinations did not mitigate the deleterious effects of water salinity on the physiology and fruit formation of West Indian cherry. An increase in ECw intensifies the intercellular electrolyte leakage and reduces the water potential in the branch, chlorophyll content in the leaves, CO₂ assimilation rate, equatorial and polar diameters as well as the mass of fruits. Fertilization of plants with 70% N + 50% of K₂O, compared to the other fertilization combinations, causes less intercellular electrolyte leakage and promotes higher CO₂ assimilation rates, higher chlorophyll content in leaves, and fruits of larger size and mass.

Keywords:
Malpighia emarginata D. C; mineral fertilization; salt stress