Absorption, Accumulation and Export of Macronutrients by Common Bean Irrigated, and Influenced by Nitrogen Fertilization

The study was aimed at evaluating the absorption, accumulation and export of macronutrients, as well as the interference of the addition of N doses in the absorption of macronutrients by common bean (Phaseolus vulgaris L.) irrigated. This study was conducted using 4x4 factorial design, which included four nitrogen doses in seedling (0, 40, 80 and 120 kg ha-1) and four sidedressing nitrogen doses (0, 40, 80 and 120 kg ha-1). A second study was made to evaluate the curve of absorption of nutrients, with eight treatments defined per time of plant sampling on days after the emergence (DAE)-10, 20, 30, 40, 50, 60, 70 and 80 DAE. Nutrient content absorbed by leaves, stem, bark and flower, seeds and shoot were characterized at the end of bean cycle. The absorption of nitrogen (N), potassium (K) and calcium (Ca) increased with the addition of doses of N between 40 and 80 kg ha-1, and decreased at largest dose of N (120 kg ha-1) in sidedressing, suggesting the occurrence of phytotoxic effect in common bean by excess of N. The rate of maximum accumulation of nutrients in the leaves of bean was obtained between 28 and 31 DAE (R5-R6 stages). The absorption and export of nutrients in the shoot and seeds had the following order- K>N>Ca>S>P>Mg, and obtained in the shoot the accumulation of 136,118, 82, 21, 13 and 12 kg ha-1, respectively. Seeds were the component of plant with highest macronutrients accumulation, suggesting a high export rate of nutrients by the crop.