Mismatch between a science-based decision tool and its use: The case of the balance-sheet method for nitrogen fertilization in France

Publication date: Available online 7 October 2016 Source:NJAS - Wageningen Journal of Life Sciences Author(s): Clémence Ravier, Marie-Hélène Jeuffroy, Jean-Marc Meynard For several decades in France, the balance-sheet method has been recommended and widely used to calculate N fertilizer rates. However, despite the scientific consensus on this method and its adoption as a regulatory tool, high N losses are still frequently occurring, suggesting limits in the implementation of this method. We assumed this consensus might hide discrepancies between some scientific concepts and the ways farmers use methods and tools. We combined a systematic analysis of official reports delivered by groups of experts (Nitrate Groups) from the 20 French regions concerned by the fifth reform of the Nitrate Directive, and interviews with experts, advisors and farmers. We identified principles of the method that reveal discrepancies between the theoretical model and its use, highlighting the gap between scientific concepts and their possible implementation. Here we show three frequent controversies that create uncertainties in calculating N fertilizer rates with the model. 75% of the Nitrate Groups debated about the estimation of the target yield, showing that there is no common understanding of the concept. In practice, farmers tend to fix the target yield as the value they desire more than the average value that can be reached in their fields. Although scientists emphasized the importance o...

Source: NJAS Wageningen Journal of Life Sciences - October 9, 2016 Category: Biology Source Type: research