“Nature organisations have an uneasy relationship with modern agriculture. I think many of them would ideally like to free up more land for nature and allocate the remainder to extensive, nature-inclusive agriculture. What I think that’s missing is that highly productive agriculture is part of the solution. The more you produce per hectare, the more space is left for nature.”

Andrew Balmford, Professor of Nature Conservation at the University of Cambridge (UK) is quite outspoken about the importance of high-yielding agriculture for nature. He recently published the results of a multi-year study that aimed to answer the question of what is best for biodiversity and climate: concentrating activities (land sparing) or spreading them out (land sharing). The conclusion was that biodiversity and climate benefitted most from high-yielding agriculture, where as much as possible is produced on the smallest area of land.

How did you arrive at those results?

“It was a very long haul. Six PhD students and very many colleagues have worked on the project. In an article in 2005, we tried to outline a framework for balancing food production and nature conservation: land sparing versus land sharing. Based on this work, we began collecting data in a large number of countries on agricultural yields and on the abundance of many species of birds, plants and insects. In all, our group and others have worked on just under 2,500 species.”

“It was quite complicated to collect this data. In some places, yields were measured using containers, but these were not the same size everywhere. Elsewhere, farm areas were expressed relative to the area of a circle with a radius equal to a piece of rope. But it turns out the length of the rope and thus the area of the circle differed from place to place. Counting species also took a lot of time and effort. You have to make counts of all the birds at a site, often just from their calls, and do so at many places and over several seasons. It’s equally demanding to count insects, or plants. In any case, it was a huge job for my PhD students.”

In your article you write that most species are ‘losers’ when food production increases, but that there are also some winners. How does this work?

“Many species – most of them it turns out – are associated with particular habitats If you disturb these even a little for food production, these species decline and often disappear. Those are the real losers. On the other hand, there are opportunistic species that thrive on agriculture, such as meadow birds and field herbs. In between, there is a category of species that can still tolerate a slight disturbance of their habitat.”

“In our three-compartment model, which has now also been used in the UK’s National Food Plan, we distinguish between areas with high-yield agriculture, those with low-yield agriculture and natural areas. Low-yield agriculture refers to fields and meadows that yield much less than conventional agriculture. Often the yields are very low compared to the 10,000 or more kilograms per hectare that can be achieved in conventional agriculture.

Critics argue that intensifying food production actually leads to more land being taken up. The infamous rebound effect.

“The rebound effect depends very much on the type of crop a farmer grows. If it requires a lot of labour or capital, or if price elasticity is low, as is the case for cereals and other staple foods, then expansion is much less likely than when it comes to high-demand products, and those where increasing yields is linked with labour savings or better use of capital assets. Moreover, there are a number of ways to counteract the rebound effect. The first is spatial planning – making some areas out of bounds to agricultural expansion. In the first decade of this century, this played an important part in slowing deforestation in the Amazon region. Market constraints also played role here: farmers who expanded their land by deforestation found it harder to obtain a loan from the bank. Because they could not expand, farmers invested more in measures to increase yields. These Brazilian policies were quite effective, but with the arrival of the new president, those measures have been weakened and it is cheaper now to cut down forests again.”

“Other ways to prevent the rebound effect are the strategic use of supporting measures – focusing important contributions to farming such as agricultural extension agents, new roads in already-cleared but low-yielding regions and away from frontiers of deforestation. And finally, you can think of certification. For example, you can now buy ‘shade coffee’, coffee grown on plots where there are also trees. If I could choose though, I would rather buy ‘sun coffee’ grown on plots with the highest possible yield, provided the producers also undertook to protect blocks of forest elsewhere on their land.”

Another point of criticism is that high-yield agriculture produces quite a bit of environmental pollution, which in turn has an effect on biodiversity.

“A very important point. In arguing for land sparing, we’re not calling for a continuation of industrial farming but rather for identifying high-yield systems that cause the least possible damage in terms of so-called externalities like soil erosion and fertiliser runoff, but also in terms of animal welfare. So what farm systems might be most promising? We are agnostic about that. You can think of the use of modern genetic techniques and precision agriculture, but also of co-cultures with rice and fish farming, as in Asia, or the push-pull maize cultivation, which is applied in the Great Lakes region in Africa. This involves growing plants in amongst the crop which repel insect pests, and plants in the field margin that attract those same insects. So, you don’t always need high-tech solutions to increase yield instead of expanding your acreage.”

“A few years ago, we also studied the trade-offs between high yields and external environmental effects, measured per unit of product. Contrary to our expectations, we found the external harms of high-yielding systems quite often turned out to be much lower than those of more extensive systems, such as organic farming. In terms of nitrogen and phosphate losses, from different dairy systems, for example, the difference was a factor of two. So if you want to reduce pollution, you should probably avoid organic milk.”

Earlier you mentioned compartmentalisation. What criteria should be used in the choice of high-yield, low-yield or natural?

“First it’s important to remember that we have ploughed or chopped down almost everything in north-western Europe at one time or another. We no longer have very much primal nature at all, so you have to ask yourself what kind of nature you want. You can, for example, create habitats to reintroduce vanished species, like the wolf in your country. One point is that many of those species already exist elsewhere; they are not yet extinct. Many people also consider the opportunistic species, such as meadow and field birds, to be nature. I wouldn’t worry too much about those. Precisely because they are crop followers, they probably occur in much greater numbers now than 10,000 years ago when we still had unspoilt nature here.

“The attractive thing about the division into three compartments is that everyone can identify with it. At least until it comes to the practical implementation, when you get to the real debate. So, in advance you have to develop criteria for choosing the least bad solution. To some extent, you can make that dependent on soil fertility and water management – with high-yielding production focused on the best agricultural land – but not entirely.”

Why not?

“In Britain, for example, we cannot concentrate food production in the south-east of England and make Scotland and Wales a nature reserve. Biologically that is not sensible, because there are also species restricted to the south-east that require intact habitats. Nor is it socially or economically sensible. People also live in the south-east and want to enjoy nature. And in Scotland and Wales they also want to be able to earn a living from farming.”

“It remains difficult, but the least difficult is to look for opportunities at the regional level to reserve blocks of five to ten square kilometres for undisturbed nature. At least in Western Europe. In the Amazon region, you would sooner think of blocks of a thousand square kilometres. So in thinking of how big spared areas might be, we are not talking about hedges and field margins, nor areas the size of Scotland or Wales.

Does high-yield farming also automatically lead to large-scale monocultures, in other words ‘industrial farming’?

Absolutely not. Economies of scale can actually be harmful. Sustainable intensification means starting from the context, including social, cultural and economic aspects. The push-pull method in Africa I mentioned earlier is a good example of sustainable intensification working within a smallholder context. Another example is the introduction of land ownership. If people have the certainty that they can continue to farm a piece of land for a long time, they are much more willing to invest in improving soil fertility than if they can be evicted from their land at any time. A good system of land tenure even contributes to combating deforestation. At the same time, one should not idealise smallholder farming. Many small farmers in Ghana, for example, would like to sell their land to a palm oil company, because then they will have money to send their children to school and to buy food.”

A word about very extensive farming. How can you reward the landowners? In Costa Rica, they are paid for the ecosystem services they provide. Is that an option?

“That is certainly an option. Costa Rica has already reforested half of its territory on this basis and is a ‘shining example’ for the rest of the world. It’s not just about government subsidies, there are also other parties willing to pay for these services. In our country, for example, some water companies pay farmers to change farm practices. Another option is carbon storage. Under REDD+, several successful projects have been carried out restoring natural habitats based on the amounts of carbon they can sequester. However, with all these kinds of initiatives, you have to remember that you can pay people to conserve or restore nature, but they also have to eat. This means that at the same time you have to invest in sustainable intensification of food production, to reduce the risk of ‘leakage’, the passing on of environmental pollution and biodiversity loss elsewhere.”

Image: Jean-Luc Benazet