Nutritional deficiency on young guava plants due to the simultaneous omission of two macronutrients

Abstract

This work, carried out under greenhouse conditions, had the objective of evaluating the effects of N, P, K and S deficiencies, when omitted in pairs, on young guava plants. Eleven treatments were applied, namely: complete, minus N, minus NP, minus NK, minus NS, minus P, minus PK, minus PS, minus K, minus KS, and minus S. Typical deficiency symptoms for each individual element and combinations thereof were observed and confirmed through mineral analyses of the third leaf from the tip. Dry matter yield was reduced in all treatments, particularly in the minus N and minus P treatments, in which dry matter reduction was about 77% and 54% respectively. Omission of a given nutrient caused a drop on its concentration with reference to the complete treatment, except for the leaf K level in the minus NK treatment. When a pair of elements was not present in solution, typical visual symptoms for each element were observed, either in the young or older leaves according to its mobility. These results therefore showed that double deficiencies of NS, PK, PS and KS were evident.