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

Evandro Manoel Da Silva,Reginaldo Gomes Nobre,Benedito Ferreira Bonifácio,Hans Raj Gheyi,Lauriane Almeida Dos Anjos Soares

doi:10.4136/ambi-agua.2780

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.

Highlights

West Indian cherry (Malpighia emarginata D.C.) is one of the promising species in the fruit sector in the semi-arid region of Northeastern Brazil
K can minimize the effects of salinity by promoting the control of cell turgor, regulation of stomatal conductance, activation of enzymes, and translocation of carbohydrates in plants (Almeida et al, 2017; Hasanuzzaman et al, 2018). Based on these hypotheses and on the need for utilization of saline water in the cultivation of fruit crops and fertilization management strategies to mitigate the negative effects of salinity, this study evaluated the effect 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 treatments were distributed in randomized blocks, with three replicates, in a 5 × 4 factorial scheme, corresponding to five salinity levels of irrigation water (0.3; 1.3; 2.3; 3.3 and 4.3 dS m-1) and four combinations of nitrogen and potassium doses (C1 = 70% N + 50% K2O; C2 = 100% N + 75% K2O; C3= 130% N + 100% K2O and C4= 160% N + 125% K2O of the dose recommended for West Indian Cherry for the second year), each plot consisting of one plastic container with one plant, totaling 60 experimental units

Summary

Introduction

West Indian cherry (Malpighia emarginata D.C.) is one of the promising species in the fruit sector in the semi-arid region of Northeastern Brazil. The reduction of water volume in water sources and the high concentration of salts in irrigation water may become limiting factors for the exploitation of this crop in the semi-arid region of Northeastern Brazil (Lima et al, 2019a) In this region, salt stress stands out among the abiotic stresses that most hamper the growth and production of agricultural species (Carneiro et al, 2002), due to the reduction in the osmotic potential of the soil solution and the occurrence of nutritional imbalance and physiological disorders through metabolic alterations such as oxidative stress (Mendes et al, 2011), caused by the effect of the high concentration of toxic ions, especially Na+ and Cl-, in the protoplasm (Flowers et al, 2014), which promote structural changes and rupture of cell membranes (Ferraz et al, 2015). Some studies have shown that the increase in potassium doses mitigated the deleterious effect of salt stress on plant growth, the number of fruits and total weight of fruits per plant (Lima et al, 2019b) and of nitrogen and phosphorus proportions on photochemical efficiency and growth (Sá et al, 2018a), photosynthetic pigments (Sá et al, 2018b), and the number of fruits per plant (Sá et al, 2019)

Methods

Results

Conclusion