Produtividade e qualidade tecnológica da cana-de-açúcar inoculada com bactérias diazotróficas.

Abstract

The discovery of alternatives to nitrogen nutrition and growth promotion in plants of cane sugar is a matter of interest in reducing emissions of greenhouse gases and increasing energy balance for ethanol production from sugar cane. Alternatives are coming from the very nature of potential for productivity gains in a sustainable manner. One such alternative is the use of bacteria capable of promoting plant growth through mechanisms such as biological nitrogen fixation (BNF) and the production of hormones. The aim of this study was to evaluate the yield and technological quality of varieties of sugar cane inoculated with a mixture of diazotrophs in the cycle of plant cane and ratoon cane, and in this second case associated with increasing levels of nitrogen. Two experiments were conducted on two plants sugar cane in São Paulo. The test plant cane was installed in April 2008 and the test was evaluated stumps for two years beginning in November 2008. In the experiment of sugarcane plant were tested seven varieties of cane sugar: RB72454, RB867515, RB855453, RB92579, RB935744, SP81- 3250 and CEC-15, inoculated and uninoculated. The plots consisted of six furrows of 10 m, with spacing of 1.40 m, total 84 m2 per plot. The experimental design was randomized blocks with four replications. In ratoon cane was used SP80-3280. Doses were used in inoculation (105 and 106 cel mL-1) linked to nitrogen (50, 100 and 150 kg ha-1 N). The experimental design was a randomized block in split plot with five replications. The application of the inoculant was done mechanically with a tractor and sprayer. Were assessed, and the agronomic parameters, agribusiness and economic parameters. In the experiment in plant cane, inoculation caused a significant increase in the crop yield in the variety RB72454. No responses were observed in other studied varieties for yield, but significant responses were observed for technological attributes. Inoculation caused a significant increase in the ATR in varieties RB72454, RB855453, RB92579 and SP81-3250. In the ratoon experiment increases were observed in the crop yield and there was a significant response in some technological attributes in the variety SP80-3280. Inoculation increased the productivity and mechanical application is efficient and profitable for the producer. The results demonstrate the feasibility of technology for the cane sugar with gains in productivity and environmental gains mainly.