A synthesis of meta-analyses on crop diversification at the global scale

Agricultural diversification is often presented as a major lever to improve the sustainability of agro-ecosystems. To date, no study has provided a comprehensive synthesis of existing experimental results on crop diversification. Numerous meta-analyses have been conducted in the last two decades to assess the productive and environmental benefits resulting from a diversification of cropping systems. But, these studies generally focused on one or a very limited number of strategies and most often considered only one type of outcome. We present here a meta-synthesis containing the results of 99 meta-analyses estimating 2382 effect-sizes from the results of 3736 experimental studies worldwide. We also provide an extensive appraisal of the quality of each meta-analysis and a quantification of the redundancy of primary studies between meta-analyses. Our database hence provides (i) a quantification of the impacts of a variety of diversification strategies on crop production, the environment and economic profitability at the global scale and, (ii) a quality and redundancy assessment that may be used as a reference for future meta-synthesis.