Researchers at the Basque Centre for Climate Change (BC3), with the collaboration of the Doñana Biological Station – CSIC, have determined in a new study that small fields and more crop-diverse landscapes, especially pollinator-dependent crops, have higher yields than those with less crop diversity and larger crop-size. The article has been published in the Journal of Applied Ecology.
To reach this conclusion, the research team has analyzed a unique dataset, the result of the Spanish Survey on Cultivar Area and Yield (ESYRCE) led by the Spanish Ministry of Agriculture, that includes the annual monitoring of 12.300 permanent 25-ha plots over two decades across Spain.
"Despite it seems that biodiversity conservation and crop yield are incompatible, agricultural landscapes provide important opportunities to conserve biodiversity outside traditional protected areas", explained Ainhoa Magrach, a researcher at the BC3. With this data, the team has demonstrated that there are synergic strategies good for both biodiversity conservation and crop yields.
Recent studies have demonstrated that an increase in field sizes and a decline in crop diversity, practices related to agricultural intensification, could harm biodiversity. But these practices are also less productive, contrary to what it may seem. "We have found that agricultural landscapes with higher crop diversity and larger field sizes have higher crop yields, especially in the case of pollinator-dependent crops", explained Ignasi Bartomeus, a researcher at the Doñana Biological Station – CSIC. "This is because more field margins and higher diversity in management practices help thrive populations of beneficial insects".
These organisms, on which many crops depend to produce fruits, need different requirements across their life cycles, so landscapes with higher crop heterogeneity could be beneficial for them in terms of resource availability and, therefore, for crop yields. In many cases, a reduction in field size also comes with an increase in grasslands and shrub areas, the habitat of many important pollinator species. Furthermore, smaller field sizes would also benefit the ability of wild pollinators to forage within crop fields given that the distance to nesting sites, usually located outside of crop fields, is shorter.
"With these experimental results, indicating that biodiversity could help improve crop yields with real data at a national level, we open the door to change the way we grow our food and make a transition to a more sustainable agriculture", said Bartomeus. This study could help improve administration measures, such as the European Union's Common Agricultural Policy (PAC), which measures tend to favour increasing field sizes. It could encourage the implementation of conservation practices that do not clash with crop yields, such as the reduction of field sizes and the increase in crop diversity in agricultural landscapes. "This study shows how important measuring accurately agricultural processes are and how we can not rely on feelings, since data could help us to decide what strategies we must follow in the future", concluded Magrach.
Ainhoa Magrach, Ángel Giménez-García, Alfonso Allen-Perkins, Lucas A. Garibaldi, Ignasi Bartomeus. Increasing crop richness and reducing field size provide higher yields to pollinator-dependent crops. Journal of Applied Ecology. https://doi.org/10.1111/1365-2664.14305
Estación Biológica de Doñana – CSIC
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