Adubação nitrogenada sobre rendimento industrial e composição dos grãos de arroz irrigado

Abstract

The effect of nitrogen (N) fertilization levels was assessed by the industrial yield, the incidence of chalky and white belly grains as well as protein and amylose content of IRGA 422CL cultivar polished grains. The experiment was consisted with N levels applied in coverage using urea as a N source. The first application (0, 40, 63, 80 and 120kg ha-1 of N) was carried out on a main plot (10x5m) and the second application (0, 25, 50 and 75kg ha-1 of N) on a subplot (2,5x5m). Therefore, 20 treatments were obtained varying from 0 to 195kg ha-1 of N applied during cultivation. The nitrogen levels presented a positive quadratic influence on the yield of whole grains (R2=0.75) and a negative influence on the percentage of broken grains (R2=-0.89), not demonstrating significant effects on the percentage of rice hulls + bran. The nitrogen levels influenced protein content in a positive linear way (R2=0.81) and amylose content in a negative linear way (R2=-0.66), in IRGA 422CL cultivar food-irrigated polished grains.