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EFFECT OF COMBINED OMISSION OF N, P, K AND S ON FOLIAR MACRONUTRIENT CONTENT OF GUAVA SEEDLINGS

This work had the objective of evaluating the effects of N, P, K and S deficiencies, when omitted in single or in pairs, on the macronutrient composition of the third leaf from the tip of young guava plants. The content of macro and micronutrients (B, Cu, Fe, Mn e Zn) in leaves, stem + branches and roots of plants grown in a complete nutrient solution for 70 days, was also evaluated. It was shown that the lack of a given element caused a decrease in its leaf concentration, but did not cause significant changes on the level of the other macronutrients in the leaves, except for K and Ca when N was omitted. The leaves were the major storage organ for macronutrients (above 50% from each one). About 57% of the B and 65% of Fe were accumulated in the leaves, while the remaining was distributed between stem + branches and roots in similar proportion. Only 23% of the total of Cu was accumulated in the leaves, while about 45% remained in the roots. The requirement of macronutrients followed the decreasing order: N, K, Ca, S, Mg and P; and the demand for micronutrients, followed the decreasing order: Mn, Fe, Zn, B and Cu.

guava; Psidium guajava; leaf nutrient content; accumulation of nutrients; nutrient solution


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