Adubação nitrogenada no desempenho agronômico e na atividade da redutase do nitrato em arroz: adubação nitrogenada no desempenho agronômico e na atividade da redutase do nitrato em arroz

Abstract

Phytotechnical techniques that result in high productivities, efficient products, are dependent on large national and international companies, as well as some public institutions, which offer these technologies to producers who yield high monetary profits the same. Upland rice is seen by Brazilian producers as a culture to open up the area to other more profitable ones, and their investments are minimal, thus reflecting for multinat ionals, as a crop that will return few returns on investments for specific rice research. Thus, we have some shortcomings in technical information for upland rice, some of which are possible influences on why rice paddy productivity is 50% or higher than when planted in highland. Because it is a characteristic that involves several phytotechnological information, the general objective of the work was to search results in the nutritional part of upland rice culture. The objective of this study was to evaluat e the effect of treatments with different doses and sources of nitrogen (N) on vegetative and reproductive characteristics of upland rice, as well as to evaluate the efficiency of nitrate reductase enzyme activity in upland rice. These experiments were conducted in the experimental field of UFLA, being installed in plots of 4 lines of 3 m spaced of 0,35 m, in the years of 2015/2016 and 2016/2017. DBC with factorial 4x4 and 3 replicates were used. In the first article, height, lodging, productivity, grains, weight of 1000 grains and yield were evaluated, and it was concluded that doses and nitrogen sources do not influence the productive factors of upland rice cultivation. There is great influence of the environment on plant responses to nitrogen application, observing superior results in different agricultural years. In article 2, the nitrate reductase activity in the laboratory was evaluated on different days after application of the treatment in the laboratory, and it was concluded that different doses and sources of N do not statistically influence nitrate reductase activity in rice plants of after experimentation in vivo in the laboratory, but that probably the genotype of each cultivar varies in its efficiency of N absorption that consequently would influence the nitrate reductase activity. The activity of nitrate reductase is higher in the juvenile period of upland rice plants, decreasing with the maturity of these plants.