Balanço nutricional de plantas de arroz irrigado pelo método CND

Abstract

The nutritional status of rice plants is one of the main factors that influence the productivity of the crop. However, mineral fertilizers for high yields are responsible for high production costs and often environmental contamination. Resource use efficiency is essential for the sustainability of the rice system. The objectives of this study are: 1) to analyze the concentration of nutrients in the leaf based on the CND method in rice-growing regions of Rio Grande do Sul; 2) analyze the concentration of nutrients in the soil and relate it to the nutrients present in the leaf; 3) to evaluate the nutritional composition of the cultivars produced in the state; and 4) develop a “CND-irrigated rice” software from the results obtained and generate a register. Soil, leaf tissue and meteorological variables (maximum and minimum temperature and incident solar radiation) were analyzed in 26 municipalities in southern Brazil, totaling 96 commercial field. The CND-r² methodology was used in leaf tissues. It was possible to establish critical levels, sufficiency ranges and CND indices for the nutrients N, P, K, Ca, Mg, S, Zn, Fe, Mn, Cu and B. The results indicate a positive balance for K and B and a negative balance for S, following the requirements of the current recommendation system. The multivariate analysis was able to distinguish 5 groups of genotypes with different nutritional behavior of the cultivars: BRS A701, BRS PAMPEIRA, GURI INTA CL, IRGA 424 RI and IRGA 431 CL. These results are important to provide information on crop nutrition and may help producers in management and fertilization recommendations, reducing production costs and risk of environmental contamination.