Interação da adubação nitrogenada e molíbdica em cana-de- açúcar

Abstract

Spending on fertilizer are considerable and have great participation in the total cost in sugar cane farming, the nitrogen fertilization being a relevant part in the final price due to its variable cost, dependence on foreign markets and low use of mineral-N . Also considering that there are still doubts about the response of sugar cane plant to this fertilizer, it is evident the necessity for research to better clarify its role in the development of plant-cane , as well as the development of practice to potentialize the use of N . As a possible potentiating effect of the process of a more efficient use of N, the presence of appropriate levels of Mo seems to contribute significantly so that this occurs. The Mo participates in the activity of nitrate reductase in plants and of nitrogenase in diazotrophs bacteria, highlighting its importance in fertilization. Therefore, this study aimed to measure the contribution of Mo in increasing the efficiency of nitrogen fertilization in order to minimize costs and dependence on the supply of N in the form of minerals for sugar cane . The experiments were carried out in the field, in three different environments, two located in the state of Pernambuco and one in the state of Paraíba. The treatments consisted of five doses of nitrogen and five doses of molybdenum. We evaluated the levels and the extraction of nutrients in leaves, stems and pointers as well as their influence in agricultural productivity and technological variables inherent in the culture. It was observed that the doses of N and Mo, as well as the interaction between the two nutrients affected the contents and the extraction of both components on the part of the sugar cane. Nitrogen fertilization promoted an increase on N levels in the contents of the aerial parts (stem, leaf and pointer), increase in productivity and the amount of sugar in sugar cane in cane plant cycle. Molybdenum fertilization increased the N content in aerial parts (stem,leaf and pointer), increased the accumulation of N and increased the efficiency of N use by contributing to productivity gains of sugar cane in cane plant cycle.