Nutrient export by cupuassu fruits grown in the Brazilian Amazon

Abstract: In Theobroma grandiflorum (cupuassu) orchards, efficient nutrient management is essential to achieve high yields and fruit quality. Thus, fertilization programs should be guided by the concentration of nutrients exported by fruits, as observed with other fruit species. The aim of this study was to quantify the export of macro and micronutrients by fruits of cupuassu genotypes, in order to guide nutrient replacement recommendations replacement. Six cupuassu genotypes (‘BRS Careca’, ‘BRS Fartura’, ‘BRS Duquesa’, ‘BRS Curinga’, ‘BRS Golias’ and ‘genotype 63’) were used, and 40 fruits per genotype were sampled, totaling 240 fruits, in the municipality of Tomé-Açu (Pará/Brazil). Fruits were broken and manually pulped and then separated into peel, seed and pulp. In each fruit part, the contents of macro and micronutrients were analyzed, and later extrapolated to ton of fresh fruits. Potassium was the macronutrient most exported by cupuassu fruits, and ‘genotype 63’ accounted for the largest exports per ton of fresh fruits of this nutrient. The export of nutrients per ton of fresh fruits followed this order for macronutrients (kg ton-1): K (4.34), N (2.73), P (0.54), Mg (0.40), S (0.29), Ca (0.26) and for micronutrients (g ton-1): Zn (6.24), Fe (4.97), Mn (3.49), Cu (2.45), Ni (0.18) and Mo (0.11). The average replacement per plant and per year, during the productive phase, for the five Cupuassu genotypes is 471 g of K2O, 326 g of N, 245 g of P2O5, 27 g of CaO, 56 g of MgO, 63 g of SO4-2 and 15 g of Fritted Trace Elements (FTE).