Fixação biológica de nitrogênio e nutrição nitrogenada em cana planta inoculadas com bactérias diazotróficas

Abstract

The sugarcane (Saccharum spp.) Is a widespread culture in tropical and subtropical regions, with Brazil as the world's leading producer. Given the expansion and continuous agricultural growth of the culture of sugarcane in the country, productive development should occur in parallel with agricultural techniques aimed at economic viability and to minimize the degradability of the environment. In this context, the biological nitrogen fixation (BNF) emerges as a usage option in production systems, supplying all or part of nitrogen nutrition of sugarcane. Thus the aim of this study was to evaluate the inoculation of bacterias diazotrophic in sugarcane plants. The experiment was conducted at the Experimental Station of Cane Sugar Carpina, PE, the Federal Rural University of Pernambuco. Para tal, foi conduzido um experimento em campo, cultivado em um ARGISSOLO VERMELHO AMARELO distrocoeso. For this, an experiment was conducted in the field, cultivated in a Alfissol distrocoeso. The test consists in the cultivation of sugarcane, varieties RB 92579 and RB 867515, inoculated with three bacterial genera (Pantoea sp., Stenotrophomonas sp., Burkholderia sp.) Were inoculated separately composing a treatment each and one with the mixture the three bacterial genera, and two witnesses, one with N another without the N. To evaluate the experiment was performed soil collection on the implementation of the experiment, before fertilization, and 120, 240 and 360 days after planting (DAP) to determine the N content, with subsequent use in the balance of N. As well as, growth analysis was performed (diameter, plant height, number of leaves), dry matter determination, estimation of nitrogenase activity. The evaluation of the natural abundance of the isotope 15N, so with the chlorophyll, biochemical and N content to 120, 240 and 360 DAP. Agricultural productivity, industrial productivity, total recoverable sugars and shoot dry weight were measured at the end of the trial period. The variable, content and N content, growth, photosynthetic pigments, proteins and amino acids, as well as the N content and C, ratio C / N of the soil to be analyzed generally, it is observed behavior that resemble, because there were significant differences, most of the time the inoculated treatments did not differ from witnesses, not making clear the character responsive to bacterial inoculation. Unlike occurred with the activity of the activity that treatment BK, MB and PT had higher AN that TN. The BNF was not detected in the technique of natural abundance of 15N isotope. Unlike happened with the results for the BNF contribution determined by estimated the total balance of nitrogen in the soil system / plant, in which, despite no significant difference in the balance of N it was observed that different inoculated treatments were responsive to the varieties , RB92579 and RB867515. It was also observed that the inoculation of bacteria caused increased TCH and ATR compared to treatment in nitrogen varieties RB92579 and RB867515. According to the results, it can be said that the inoculation of nitrogen fixing bacteria in sugarcane plants of varieties, RB867515 and RB92579, promoted the development of culture.