Sources and rates of nitrogen on the nutrition and productive performance of determinate growth habit snap bean (original) (raw)

Snap bean is a vegetable crop presenting high requirements of mineral nutrients, such as nitrogen (N). However, studies on the response of this crop to N fertilization are scarce, mainly with determinate growth habit genotypes, making it difficult to manage this nutrient supply. The aim of this study was to evaluate the nitrogen nutrition and the productive performance of snap bean with determinate growth habit as a function of N sources and rates. The experiment was carried out in pots, under greenhouse conditions, in a Eutrophic Red Oxisol with 36.60 g dm-3 of soil organic matter content. The cultivar 'Macarrão rasteiro' TopSeed was grown in a completely randomized design at factorial scheme 3x4, with four replications. It was studied three sources of N (urea, ammonium sulfate and sulfammo) and four rates (0, 40, 80 and 120 kg N ha-1), applied 20% at sowing time, 40% at 12 days after emergence (DAE) and 40% at 20 DAE. It was evaluated the N content of the index leaf and the N accumulation in shoots, the plant height at the end of the cycle and the number, total fresh mass, mean fresh mass and mean length of pods. The N content of the index leaf and N accumulation in shoots were linearly increased by the N rates, regardless of the N source, while the plant height and the pod's characteristics were not influenced by any of the factors studied.