Speaker
Description
Agricultural diversification is useful for agronomic, environmental, and dietary reasons, but its consequences for productivity are debated. We conducted a global meta-analysis of 226 field trials, and found (as previous meta-analyses did) that intercropping, i.e. species mixture, leads to substantial land savings over single crops when the objective is to produce a diversified set of crop products. However, if the objective of production is to maximize grain caloric output from the field, intercropping leads on average to a small yield penalty of 4% compared to the most productive single crop species comprised in the mixture, often maize. On the other hand, intercrops provide similar or greater protein yield than the most protein-productive sole crop in the mixture, especially with modest N fertilizer application. In addition, intercropping provides further ecological services, such as pest and disease control, and improved nutrient cycling. Such intercropping advantages have potential to mitigate the environmental footprint of farming and make cropping systems more sustainable. But we should not expect that in general intercrops will outperform the most productive sole crop that may be grown on a parcel of land. Results were published in the Proceedings of the National Academy of Sciences in early 2023. The presentation will present results of this study in the context of other and earlier meta-analyses, showing that the choice of metric has a critical influence on the conclusions that may be drawn from a meta-analysis or any intercropping study.
Li CJ, Stomph T-J, Makowski D, Li HG, Zhang CC, Zhang FS, van der Werf W (2023) The productive performance of intercropping. Proceedings of the National Academy of Sciences of the United States of America 120(2): e2201886120. https://doi.org/10.1073/pnas.2201886120
| Keywords | intercropping; species mixture; productivity; metrics; meta-analysis |
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