YIELD AND QUALITY OF SNAP-BEAN SEEDS AS FUNCTION SOURCES AND LEVELS OF NITROGEN
ADEMAR P. DE OLIVEIRA,, EUSINIA L. PEREIRA, RISELANE DE LUCENA ALCÂNTARA BRUNO, EDNA U. ALVES, RUBENS F. DA COSTA, FRANCISCO ROMEU F. LEAL
The application of three nitrogen sources in five concentrations each were studied in the physiological quality and yield of snap-bean seeds, cv. Macarrão Trepador Hortivale, from September/2000 to February/2001, in the Centro de Ciências Agrárias of the Universidade Federal of Paraíba, in Areia. A randomized complete block design was used, with treatments distributed in factorial scheme of (3 x 5) + 1, corresponding to nitrogen sources (calcium nitrate, ammonium sulfate and urea) and the second the five N levels (0, 25, 50, 75 and 100 kg.ha-1), and an additional treatment (without fertilization), in four replications. At 100 kg.ha-1 of N, the sources nitrate of calcium and sulfate of ammonium and urea at 55 kg.ha-1 of N presented the highest snap-bean seed yields, 2.571, 3.219 and 2.221 kg.ha-1, respectively, which surpassed the national average by 1.517, 1.219 and 1.221 kg.ha-1. The N in all the sources influenced the germination and the vigor positively (germination speed index and field emergence) of snap-bean seeds. At 68,8 and 49kg.ha-1 of N, calcium nitrate and urea were responsible for the maximum values for germination percentage, 72% and 75%, respectively. For ammonium sulfate there was a linear increase in the germination percentage, as the levels of N increased and at 100 kg.ha-1 of 84% germination was obtained. The germination speed Index showed higher values, 6,0; 7,7 and 6,9 at 49; 71 and 53 kg.ha-1 N, calcium nitrate, urea and ammonium sulfate, respectively. The field emergence increased linearly with calcium nitrate concentrations reaching the maximum emergence (70%) obtained at the 100 kg ha-1 N concentration in each source. The ammonium sulfate should be recommended as a source of N, in snap-bean seed production programs.
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