The influence of electrical conductivity of the nutritive solution on the accumulation of dry matter and nutrients contents in eggplant cultivated in coconut coir fibre

Abstract

Aiming to evaluate the effect of electrical conductivity (EC) of a nutritive solution on eggplant cultivated in coconut coir fibre, an experiment was conducted from April to August 2003, in greenhouse conditions in the Center of Agricultural Sciences of the Federal University of Ceará. The plants were cultivated in black polyethilene bags containing twelve litres of substrate. Nutritive solutions showing increasing concentrations of macronutrients, with an EC base of 1.0; 1.5; 2.0; 2.5; 3.0; and 3.5 dS.m-1, were applied three times per day, given that every four days water was applied for irrigation propose alone. The experimental design used was one completely randomized, with six treatments of EC of nutritive solution and five replicates. Dry matter yield of the stem, leaves and fruits, as well as nutrient content of leaves and fruits, were studied. The highest yield of the dry matter of the above-ground portion, stem, leaves, and fruits was obtained with a nutritive solution EC of 2.36; 2.44; 2.50; and 1.93 dS.m-1, respectively, with distribution amongst stem, leaves and fruits of 58; 30 and 12%, respectively. Nutrient content of the leaves and fruits increased according to the increment of EC of the nutritive solution, that of calcium, copper and zinc in the leaves, however, as well as that of calcium and magnesium in the fruits were below that which has been accepted as adequate, suggesting the need to increase the concentrations of these nutrients in the nutritive solution.