Speaker
Description
Introduction
In recent years intercropping (IC) has increased in prominence in research globally and produced a large legacy of empirical evidence. A bibliometric study on cereal-legume IC found 4735 articles and revealed that on a continental scale most publications originated from Asia (China 785, India 626), followed by the Americas (1003) and Europe (943) (Landschoot et al., 2024). This wealth of evidence was synthesized in meta-analytic studies, indicating the advantages but also limitations of IC systems. Recently, a global study showed that IC outperformed sole crops (SC) with respect to land use efficiency when the aim was to produce a diversity of products while IC systems are not better but close to SC if the overall highest yield is the goal (Li et al., 2023). In contrast to this strong evidence for their high potential, in Europe IC are still confined to small niches of fodder and biomass production or catch crops while there is a wide implementation gap for food crops (Timaeus et al., 2022). A current challenge is to structure the wealth of empirical research to inform strategic IC research to develop cropping systems that fit the diverse ecological, technological and economic contexts of European agriculture. As one step towards these goals, we conducted a review of IC studies following the systematic map approach of James et al. (2016). A systematic mapping approach is able to answer a broad research question and to identify research gaps and facilitate knowledge synthesis. We addressed the following research question: What is the state of experimental research on IC systems with two arable grain crops in Europe?
Materials and methods
We developed a search combining a cereal grain crop and an intercrop search string, that consisted of synonyms for each concept. These strings were combined with an exclusion string for terms that are irrelevant to our research question. To restrict the geographic scope to Europe a country filter was added. The search string was developed iteratively in the web of science (WoS) database and tested against a benchmark list of 30 articles known to be relevant for our research question. The final search string missed only one of these 30 articles and this was considered to be sufficiently comprehensive for our research question. The final search was conducted on November 24, 2023 in the WoS core collection without any time restrictions. References were exported to Zotero to remove duplicates. Screening of titles and abstracts against the eligibility criteria was done in the Rayyan software. Studies needed to include two arable grain crops and be conducted in Europe. Studies that were reviews, meta-analyses, pure modeling or social science were excluded. Full text screening was done manually by reading the pdf files and documentation in an excel database.
Preliminary results outlook
The search in WoS yielded 2080 articles. Screening these articles against eligibility criteria resulted in 661 eligible articles from which 621 could be retrieved as full texts. Full text screening resulted in 449 eligible articles. The top five countries with the most studies were Germany (75), France (49), Turkey (46), Poland (44), and UK (32). While data extraction was not yet conducted, the screening already revealed some gaps. Biodiversity conservation effects of IC were only addressed in six, strip intercropping in eight and testing of agricultural technology for IC management in zero articles. The next step is to extract metadata from the experiments describing what has been studied in detail. An analysis of knowledge gaps and knowledge clusters will be presented at the conference.
References
James, K.L., Randall, N.P., Haddaway, N.R., 2016. A methodology for systematic mapping in environmental sciences. Environ. Evid. 5, 7. https://doi.org/10.1186/s13750-016-0059-6
Landschoot, S., Zustovi, R., Dewitte, K., Randall, N.P., Maenhout, S., Haesaert, G., 2024. Cereal-legume intercropping: a smart review using topic modelling. Front. Plant Sci. 14. https://doi.org/10.3389/fpls.2023.1228850
Li, C., Stomph, T., Makowski, D., Li, H., Zhang, C., Zhang, F., van der Werf, W., 2023. The productive performance of intercropping. Proc. Natl. Acad. Sci. U. S. A. 120. https://doi.org/10.1073/pnas.2201886120
Timaeus, J., Ruigrok, T., Siegmeier, T., Finckh, M.R., 2022. Adoption of Food Species Mixtures from Farmers’ Perspectives in Germany: Managing Complexity and Harnessing Advantages. Agriculture 12, 697. https://doi.org/10.3390/agriculture12050697
| Keywords | intercropping; species mixture; diversification; agroecology; experiments |
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