Molybdenum and nitrogen interaction in sugarcane

Abstract

Improving the sustainability of biofuel production from sugarcane depends on Nitrogen Use Efficiency (NUE) increasing. Sugarcane growers have adopted the practice of foliar fertilization at the time of higher nutritional demand to increase the NUE. Associated with this, molybdenum (Mo), a co-factor of enzymes in the nitrogen cycle (N), will be officially recommended in the São Paulo State, and the adoption of the recommendation depends on the implementation viability. One alternative is foliar application of the Mo combined with N. The hypothesis of this study is that the combined supply of Mo and N increases NUE compared to the isolated N foliar application. The objective will be to evaluate the effect of N and Mo applied via leaf on nutrition, N metabolism and sugarcane yield. The study will be divided into two stages: i) experiment in controlled condition to evaluate NUE and N metabolism with 15N isotopic tracer and ii) field experiment for two harvests in five sites to evaluate the optimal dose of N (urea) via leaf and also effect of the combined application with Mo. Under controlled condition, N metabolism, 15N recovery, biochemical and growth parameters will be evaluated. In the field experiments, nutritional parameters and biomass and sugar production will be evaluated. It is expected that the results will generate an official recommendation for the application of N and Mo via leaf in sugarcane. In addition, we seek to understand the effects of nitrogen fertilization via leaf, as well as the improvement of nitrogen metabolism with the application of Mo. In the future, the recommendation may serve to certify good practices for the use of nitrogen fertilizer in the Renovabio carbon credit program. (AU)