Extração e exportação de nutrientes por cultivares determinadas e indeterminadas de feijão-comum

Abstract

ABSTRACT There is evidence that the dry mass and nutrient accumulation rates of earlier (determinate) cultivars are faster than those of normal or late cycle (indeterminate). This study aimed to quantify the nutrient extraction and export and calculate the harvest index of determinate and indeterminate common bean cultivars. A randomized block design was used, with four replicates and eight cultivars (BRS FC104, TAA Gol, BRS Estilo, BRSMG Uai, IPR Tuiuiú, BRSMG Marte, Pérola and TAA Dama). The accumulation of dry matter and nutrients at the vegetative and reproductive stages, grain yield and grain nutrient export were determined. The early cultivars TAA Gol and BRS FC104 (Type I - determinate) accumulated more dry matter and nutrients during the vegetative stage than the indeterminate types II and III. However, from R7, no differences were observed among the cultivars for extractions or nutrient exports and harvest index. The cultivars exported 33, 11, 17, 2.3, 2.2 and 1.5 kg t-1 of grain for N, P2O5, K2O, S, Mg and Ca, respectively. Micronutrient exports were 14, 3.7, 70, 13 and 34 g Mg-1 of grain for B, Cu, Fe, Mn and Zn, respectively. The TAA Gol and BRS FC104 determinate cultivars reached the R9 stage at 77 days and the indeterminate cultivars at 85 (BRSMG Marte), 90 (IPR Tuiuiú and BRSMG Uai) and 93 days (TAA Dama and Pérola). BRS Estilo, BRS FC104 and TAA Gol had the lowest grain yield (< 2,200 kg ha-1) and TAA Dama the highest grain yield (3,275 kg ha-1).