Energy assessment for variable rate nitrogen application

Abstract

Based on material flows, energy flow assessment evaluates environmental sustainability and energy use efficiency on a production system.  As precision agriculture was developed to optimize agricultural production, energy assessment has become an interesting approach to analyze these systems.  A method was developed to propitiate energy evaluation on site-specific data from variable rate nitrogen application on precision agriculture management.  It provides maps of energy indicators (energy balance, energy return on investment and energy embodiment) from input and output energy flows.  Variable and fixed nitrogen applications were evaluated on a wheat production on Paraná state, Brazil.  An optical sensor was used to generate variable rate nitrogen prescriptions.  Energy balance and profitability was higher on precision agriculture management because it provided nitrogen savings without compromising yield.  Besides, less energy was embodied on the final product.  All energy indicators pointed to the fact that variable rate technology was more sustainable than traditional management.

Keywords: precision farming, nitrogen, energy indicators, energy balance