Sources and rates of nitrogen on the nutrition and productive performance of determinate growth habit snap bean

Abstract

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 fertilizationare scarce, mainly with determinate growth habit genotypes, making it difficult to manage thisnutrient supply. The aim of this study was to evaluate the nitrogen nutrition and the productive performance of snap bean withdeterminate growth habit as a function of N sources and rates. The experiment was carried out inpots, under greenhouse conditions, inaEutrophicRed Oxisolwith 36.60 g dm-3of soil organic matter content.The cultivar ‘Macarrãorasteiro’TopSeedwas grownin 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), applied20% at sowing time, 40% at 12 days after emergence (DAE) and 40% at 20 DAE.It was evaluatedthe N content of the index leafandtheNaccumulationinshoots, the plant height at the endof 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 werenotinfluenced by anyof the factors studied