Respostas de genótipos de Coffea arabica à aplicação de fósforo em substrato com ácido cítrico

Abstract

The addition of citric acid to the substrate may potentiate the availability of phosphorus in coffee seedlings. The growth and accumulation of nutrients by Coffea arabica seedlings on substrate treated with citric acid with different doses of P2O5 was evaluated. The experimental delineation was arranged in randomized block design (DBC), with five repetitions in 3 x 4 factorial scheme, consisting of three genotypes (Catuai Vermelho IAC 99, Mundo Novo IAC 379-19 and Oeiras MG 6851) submitted to four doses of P: zero, 450, 900 and 1,800 mg dm-3 P2O5). Single superphosphate was used as the source of P2O5. The seedlings, when presenting the first cotyledonous leaves, was applied anhydrous citric acid at dose of 0.425 mg dm-3 per seedling. After 180 days, the variables of growth, accumulation of dry matter and nutrients by coffee plants were evaluated. The doses of P2O5 in substrate treated with citric acid, positively influenced the growth of coffee seedlings. The highes accumulation of biomass and nutrients were mostly in the dose of 900 g m-3 P2O5. No variation was observed among genotypes in relation to foliar nutritional analysis. The increase of phosphorus doses in substrate treated with citric acid increases the concentrations of Ca, Mg, Fe and Zn in the foliar tissues of coffee plants.