An Integrated Approach to Assess the Water Efficiency of Introducing Best Management Practices: An Application to Sugarcane Mechanisation in Brazil.

Management practices reputed to be the best are being introduced widely in the agricultural sector. The identification of what these best management practices are for a given cultivation area requires thorough assessment, using indicators that reduce the risk of unintended impacts and that help manage environmental and economic trade-offs. We propose an integrated assessment that includes two indicators in water footprint sustainability assessment: water apparent productivity and ecosystem services value, thereby considering the trade-offs in the two ecosystem services of water provisioning and erosion potential. The approach was tested in Mogí-Guaçú Pardo (Brazil), a basin that has been subjected to intensive land-use changes through the expansion of sugarcane plantations. Here, regulatory changes have also promoted the introduction of the new management practice of mechanised harvesting, thereby phasing out the practice of burning the fields before manual harvest. A probabilistic approach was applied to account for uncertainty in model parameters. The results reveal that sugarcane has a comparably high economic value but is a less efficient land-use type from a water-use perspective. The total green and blue water footprint in the basin increased by 12% from 2000 to 2012, mainly due to the increase in sugarcane area (+36%). The intensification in sugarcane harvesting practices led to improved economic water-use efficiency and also lowered erosion costs. Adding the new indicators and considering trade-offs linked to new management practices and/or land-use changes allow for more robust decision making. [ABSTRACT FROM AUTHOR]