Farming landscapes with more crop diversity and smaller field sizes, practices that favour biodiversity, have higher yields.
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A scientific team led by the Basque Centre for Climate Change-BC3 and with the participation of the Doñana Biological Station of the Spanish National Research Council (CSIC) has determined in a new study that agricultural landscapes with more crop diversity and smaller field sizes, especially those that rely on pollinators, have higher yields than those with less diversity and larger field sizes. The paper has been published in the Journal of Applied Ecology.
To reach this conclusion, the team has analysed a unique dataset resulting from the Survey on Crop Areas and Yields (ESYRCE), by the Ministry of Agriculture, which includes the annual monitoring of 12,300 permanent plots of 25 hectares located in different parts of Spain. The data analysed are from 2001 to 2019.
“Despite the fact that biodiversity conservation and crop productivity seem incompatible, agricultural landscapes represent important opportunities for biodiversity conservation outside traditional protected areas,” explains Ainhoa Magrach, a researcher at the Basque Centre for Climate Change – BC3. With these data, the team has shown that there are possible synergistic strategies that are good for both biodiversity conservation and increasing crop yields.
Recent studies have shown that increasing field sizes and reducing crop diversity, practices associated with agricultural intensification, have a negative effect on biodiversity. But these practices would also be less productive, contrary to what might appear to be the case. “We have found that agricultural landscapes with more crop diversity and smaller field sizes have higher production, especially in crops that depend on pollinators,” explains Ignasi Bartomeus, a researcher at the Doñana Biological Station. “That’s because more margins and more diversity of management practices help beneficial insect populations to thrive.
These organisms, on which many crops depend to produce fruit, need different requirements throughout their life cycle, so landscapes that have a great heterogeneity of crops seem to be beneficial for them in terms of resource availability and, therefore, could also be beneficial for crop yields. In many cases, also a decrease in field size is accompanied by an increase in the density of grassy areas and hedgerows, a habitat for many of the most important wild pollinators. Furthermore, smaller crop fields would also benefit the ability of pollinators to feed on crop fields because the distances to nests outside the fields are shorter.
“By reconciling experimental results that biodiversity can help crop production with real data from Spain, we open the door to changing the way we grow food and transition to more sustainable agriculture,” says Bartomeus. This study could help to improve the administrative measures that are promoted, for example, by the European Union through the Common Agricultural Policy (CAP), whose measures tend to favour an increase in crop sizes, and encourage conservation practices that do not conflict with yield production, such as decreasing the size of fields and increasing crop diversity in agricultural landscapes. “This study demonstrates how important it is to accurately measure agricultural processes and not to rely on sensations, as the data can help us decide which strategies to follow in the future,” Magrach concludes.