Biodiversity in intensive agriculture

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 (Image: Pixabay CC0)
(Image: Pixabay CC0)

A study with BOKU participation shows that biodiversity in intensive agriculture is not economically profitable for farmers. Measures for more sustainable agriculture can increase the number and diversity of wild bee species in grassland and thus increase pollination and crop yields in neighboring fields. However, this does not pay off economically in intensive agriculture, scientists show in the scientific journal "PNAS" using the example of sunflowers.

Implementing biodiversity-friendly practices in agriculture can protect biodiversity while increasing production, writes a team of researchers led by Jeroen Scheper of Wageningen University (Netherlands). But the economic profitability of these measures is unclear, they say, which is why farmers tend to be hesitant. And not without good reason, because at least for crops in intensively managed agricultural landscapes, for which pollination is only moderately important, it does not pay off.

For the study, which also involved Jochen Kantelhardt from the Institute of Agricultural and Forestry Economics at the University of Natural Resources and Applied Life Sciences (Boku) Vienna and Stefan Kirchweger from the STUDIA research facility in Schlierbach (OĆ), 21 grassland plots in southwestern France bordering sunflower fields were investigated. Specifically, the scientists monitored bees and flowering plants in the meadows, which were managed at different intensities, in the spring and summer of 2015 and determined the effects on yield in the adjacent sunflower fields. The following year, the authors interviewed farmers to collect data on farm management and income.

Costs higher than benefits

It was found that reduced harvest intensity in grassland increased the number of rare wild bee species and also increased wild bee diversity, crop yield, and revenue in neighboring sunflower fields. Cover crops increased by up to 17 percent due to better pollination performance, depending on the reduction in grassland harvest frequency. "However, the cost of reduced grassland forage yields exceeds the economic benefits of improved pollination in all scenarios," Kantelhardt told APA. If mowing was done only twice instead of three times per year, the contribution margin of permanent grassland management in the French study region decreased by 41 percent.

The results obtained are likely to apply to many of the intensively managed agricultural landscapes in Europe, since crops such as oilseed rape and sunflowers are only moderately dependent on pollinators and also alternate in crop rotation with other crops that are not dependent on pollination. However, in the case of highly pollinator-dependent permanent crops, such as those found in fruit growing, the balance could well be different.

The findings would underscore that profitability is often a major barrier to transitioning to biodiversity-enhancing agricultural practices and that the transition requires additional public or private incentives. "The positive effects often do not offset the detrimental ones under current conditions. Farmers do benefit from pollination services, but just not to a sufficient degreeĆ. This is where external incentive providers such as the state are currently needed to financially support such extensification measures with appropriate programs," says Kantelhardt.


(Text APA)