Towards an efficient and risk aware strategy for guiding farmers in identifying best crop management
This work addresses the problem of costly crop losses for farmers in selecting management practices, though it is incremental as it builds on existing bandit algorithms with domain-specific modifications.
The study tackled the challenge of identifying optimal fertilizer practices for farmers by developing a bandit algorithm that minimizes crop losses during field trials, outperforming an intuitive strategy by increasing protection against worst outcomes in most cases.
Identification of best performing fertilizer practices among a set of contrasting practices with field trials is challenging as crop losses are costly for farmers. To identify best management practices, an ''intuitive strategy'' would be to set multi-year field trials with equal proportion of each practice to test. Our objective was to provide an identification strategy using a bandit algorithm that was better at minimizing farmers' losses occurring during the identification, compared with the ''intuitive strategy''. We used a modification of the Decision Support Systems for Agro-Technological Transfer (DSSAT) crop model to mimic field trial responses, with a case-study in Southern Mali. We compared fertilizer practices using a risk-aware measure, the Conditional Value-at-Risk (CVaR), and a novel agronomic metric, the Yield Excess (YE). YE accounts for both grain yield and agronomic nitrogen use efficiency. The bandit-algorithm performed better than the intuitive strategy: it increased, in most cases, farmers' protection against worst outcomes. This study is a methodological step which opens up new horizons for risk-aware ensemble identification of the performance of contrasting crop management practices in real conditions.