Producing enough food to provide adequate nutrition for the growing world population without destroying the planet in the process is one of the greatest challenges of our time. The world population is expected to reach nearly 10 billion people by 2050 and already more than 811 million people go to bed hungry.
Organic farming is seen as a potential solution. The EU’s Farm to Fork Strategy puts agriculture at the heart of its ambition to transition to a more sustainable food system and includes a target to achieve 25% organic farmland in the region by 2030. The EU action plan for organic farming also sets out a strategy to stimulate demand for organic products, marking what the Commission has described as “a new era for the transformation of our food and agricultural systems towards organic and agroecology”.
Organic farming – which, among other practices, does not use chemical inputs that are harmful to wild insect populations – could be good news for biodiversity. However, concerns about declining yields – and therefore the need for more cropland – have sparked debate over whether organic can bring environmental gains while still producing enough to feed the world.
Researchers have now set out to answer the question of whether organic farming is still the best use of land.
In a recent study, published in Ecology Letters, a team from Xi’an Jiaotong-Liverpool University, University of Liverpool, University of Göttingen, Wageningen University, Center for Ecological Research and from China Agricultural University, has developed a method to help farmers and policymakers decide whether switching from conventional to organic farming will increase biodiversity while maintaining productivity. It claims to be the first international meta-analysis that quantifies the trade-off between yield and biodiversity in the same land areas.
“Our global land use meta-analysis helps identify the best strategy for both farmers and the Earth,”stressed Dr Yi Zou, land use expert in Xi’an Jiaotong-Liverpool and corresponding author of the study.
Land sharing versus land saving
Concern that the need for additional land from organic farming could negate the resulting biodiversity gains has led to the discussion of ‘land sharing’ as opposed to ‘land preservation’.
What do we mean by that?
A member of the research team, Dr Jenny Hodgson, explained: “In the land-saving strategy, agricultural land is used intensively for high-yield agriculture to leave as much land as possible to maintain high biodiversity in natural land.
“On the other hand, in the land sharing strategy, agricultural land is managed extensively and kept respectful of biodiversity; however, more land is generally required to achieve the same total production as in intensive agriculture.
Researchers analyzed land yield and biodiversity in 75 international studies to calculate a threshold where increased biodiversity from organic farming and land sharing is beneficial despite the additional land it requires.
Importantly, they found the response to be largely context-specific. The study showed that the threshold depends on the amount of biodiversity already present on the additional land that would need to be converted to agriculture to compensate for yield losses due to the decline in productivity of organic systems.
“Our results show that, on average, switching to organic farming would be a more effective strategy if uncultivated land is less than 2.4 times richer in biodiversity than cultivated land. Of course, this value is context-dependent and varies from region to region,”detailed Shanxing Gong, the first author of the study. “A shift to organic farming and land sharing is likely to be the optimal use of land in areas where species richness is lower in remaining uncultivated habitats.”
Cultivated Crops Add Complexity… But Organic Offers Benefits for All
The math is even more complicated because the impact of organic farming on biodiversity and yield depends on the species measured and the crops grown, the study found.
In cereal crops, such as oats, wheat, barley and maize, the overall yield loss is similar to the biodiversity gain after a switch to organic farming. In particular, there is a significant increase in the number of plant and invertebrate species, while birds are less affected.
In contrast, in non-cereal crops, such as coffee and vegetables, switching to organic farming does not show a significant yield loss, but there is an increase in biodiversity.
This means that certain types of produce can be grown organically without needing more land to achieve the same yield.
“Depending on the crop, it is possible to switch to organic farming for a higher biodiversity gain with very little or no yield loss,”Dr. Zou clarified. “Under these conditions, switching to organic farming is a win-win situation.”
The researchers stressed that this threshold is only a guide, as other factors such as surrounding landscapes and variation in organic treatment can also affect the benefits of organic farming. For example, moderate-intensity fertilization of non-grain organic crops can improve both yield and biodiversity, it was noted.
“Our study is only the beginning of understanding this trade-off. We need to incorporate other factors into the study such as the abundance of protected species, farmer incomes and vital ecosystem services such as pollination, carbon uptake and soil protection,”Gong commented.
Dr Zou added: “We want to encourage more studies comparing the yield and biodiversity trade-off in developing countries, as most of the existing studies have been collected from developed countries.”
So, is organic farming better for biodiversity? The answer depends on what you are trying to grow and where are you trying to grow it.
‘Biodiversity and yield trade-offs for organic agriculture‘
Authors: Shanxing Gong, Jenny A. Hodgson, Teja Tscharntke, Yunhui Liu, Wopke van der Werf, Péter Batáry, Johannes MH Knops, Yi Zou