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Higher yields of biodiversity-friendly farming do not yet outweigh costs
Intensive agriculture is under pressure because of its adverse effects on biodiversity and the living environment. The solution is often sought in more biodiversity-friendly farming practices. But while these bring many benefits, they do not always prove to be economically profitable. In a new study, scientists conclude that this could be a barrier for farmers to adopt more extensive forms of farming. Their advice: support farmers financially.
Less intensive use of agricultural land will benefit biodiversity and ecosystem services, such as an attractive landscape, cleaner air and water and crop pollination. The latter, in particular, should also be profitable to farmers, because enhanced crop pollination is expected to result in higher yields. However, an international team of scientists, led by Wageningen University & Research, shows that those higher yields do not always outweigh the extra costs of extensive management. Their study was recently published in PNAS scientific journal.
Extensive management of grassland improves sunflower pollination
The scientists investigated biodiversity, agricultural production and net farm profit at several locations in southwest France. They inventoried flower availability and wild bee diversity in 21 agricultural grassland plots (the harvest of which intended for fodder) located right next to sunflower fields. The grasslands were managed in different ways: some more extensively, others more intensively. The scientists linked the numbers of observed flowers and bees to the pollination and yield of the neighbouring sunflower fields.
Jeroen Scheper, researcher at Wageningen University & Research and first author of the study: "We saw more species of flowers and bees in the extensively managed grasslands, where harvesting was less frequent. We also saw a greater diversity of wild bees in the neighbouring sunflower fields. This enhanced pollination and increased sunflower yields. More biodiversity-friendly management resulted in an up to 17% increase in revenue on sunflower fields.”
Costs constraint for widespread adoption
On the other hand, more biodiversity-friendly management of grassland also results in reduced harvest yields. For example, harvesting permanent grassland twice a year instead of three times gave a 41% decline in gross margin. The researchers saw that the costs of yield reduction consistently exceeded the extra income from the sunflower fields. Thus, overall farmer profit was highest in grasslands that were managed most intensively.
“Our results suggest that profitability may be a key constraint for the adoption of biodiversity-friendly farming in France,” Scheper explains. “But apart from ecosystem services for the farmer, a biodiversity-friendly farming system also provides benefits for society. Such as an attractive landscape, carbon storage and cleaner air and water. For the widespread adoption of biodiversity-friendly forms of agriculture, farmers should be rewarded financially through additional public or private funding.”
The new insights are important in the light of the European Green Deal, and the transition to more biodiversity-friendly forms of agriculture in the Netherlands. It is still unknown how the budget available for this purpose will be spent.
Southwest France ideal area for research
The scientists selected the southwestern part of France for their research, because of the ideal conditions of this area. Scheper: "In the Netherlands, grasslands that are extensively managed are often found close to nature reserves, or are part of it. That will make it harder to isolate the effects of grassland management. Besides, you will hardly find adjacent fields with insect-pollinated production crops, such as sunflowers. This combination is much more common in France."
Although farmers in the Netherlands do not grow sunflowers, the principle works the same here: more extensive management of agricultural land will lead to many benefits for society, but also result in extra costs for farmers.