Nutrient conductivity effects on sweet pepper plants grown using a nutrient film technique

Abstract

Sweet pepper (Capsicum annuum L.) plants were grown using Nutrient Film Technique (NFT) at electrical conductivity (EC) levels of 2 ,4, 6, 8, and 10 mS cm^‐1. Higher EC levels were achieved by adding concentrated KC1 solution to the basic nutrient solution maintained at EC 2 mS cm^‐1. An additional treatment of high Ca with EC 10 mS cm^‐1 was made up of a solution of KC1 and CaCl2 at a ratio of 3:1 (w/w). High nutrient conductivities resulted in high blossom‐end rot (BER) incidence. This was related to the suppression of Ca uptake and reduced accumulation in the fruit accompanied by an increase in the accumulation of Mg and particularly K. Extra Ca at the highest EC level promoted the accumulation of Ca by the fruit and reduced the incidence of BER. The reduction of Ca uptake in the fruit at higher EC was more pronounced at the blossom‐end of the fruit. Fractionation of Ca compounds revealed that higher EC levels reduced the physiologically active acetic acid soluble component, particularly during the BER sensitive rapid fruit growth stage.