“We need greater recognition for agriculture”

Can Germany help in that?

We must support them – with know-how and financial resources. Tropical countries do, however, need a completely different kind of agriculture. Applying our crop cultivation one-to-one doesn’t make sense. What we don’t need are subsidized, cheap food that floods the markets in these countries, since that destroys regional markets and regional production. These countries must triple their yields of one and a half tons per hectare. And they will only achieve that with better soil management and better management of the crops.

With a view to the necessary increase in production in the coming decades: What does that mean for the work of the farmers?

In Germany, we have already an impressive level of supply. Farmers are doing a lot right. But what could still be improved? I think that farmers are very interested in learning more about how crop rotations can be made more diverse, in other words, more crops and fewer monocultures planted. There’s still major potential here! What’s also vital is managing and building up humus. This increases the soil fertility and resilience. That has many advantages. Fertile soil retains more water and can then better provide the plants with water during dry periods.

As an agricultural scientist you look very closely at soils. How can they be sustainably improved?

It’s essentially about these questions: How much crop residue do I leave in the field? How much compost do I use? How much manure is spread in the field? How much root biomass remains in the soil as organic matter? That means all organic matter that is turned into humus through decomposition processes. Sustainable soil fertility is directly connected with the humus. Humus ensures that plants are better able to absorb nutrients. It ensures that the soil can retain much more water.

But what does that mean specifically for the work of the farmers?

One example would be expanding crop rotations in Germany, for instance. We have the problem that the crop rotations are too close together, in other words, two or three crops in the rotation. We must diversify here and introduce other parts into the crop rotation. Clover grass, a mixture of clover and grass, works well. It’s known for sustainably increasing the humus content in the soil. But clover grass isn’t economically viable for every farmer. The political course therefore needs to be set so that it also makes economic sense for farmers. Clover grass is very useful in ecological terms.

What do you think of a financial reward for farmers with soil that’s especially rich in humus?

I’m all in favor of farmers being remunerated if they use their agricultural measures to ensure that this happens. Why? Humus stores huge amounts of carbon, extracting it from the atmosphere. That’s active climate protection! And farmers must be remunerated for that. After all, every other sector is remunerated when it does something for the climate. Why not the farmers as well? We must therefore ensure that the government sets a course for that to happen. The WWF takes the view that direct payments via the EU subsidies for agriculture should be conditional upon whether or not farmers build up humus.

So-called humus certificates are an opportunity for the climate. Where do you see other need for action for climate-friendly agriculture?

Soil compaction is an urgent problem. There is a tendency with compacted soils for water to accumulate on the ground in heavy precipitation and not be able to seep away. This accumulated water runs off and causes erosion. That means soil is lost when the rainwater is washed away. To prevent that, making a very good choice of the time, for one thing, is necessary: When do I drive over the field – especially when I’m using heavy machinery? I can also try, through reduced, more conservation-friendly agriculture, so-called conservation soil cultivation, to avoid and also reduce compaction in the long term. Less plowing and harrowing would be an option. Or dispensing with them completely.

With regard to soil health, fertilization is the target of criticism. What difficulties and responsibility do you see?

The problem areas are nitrogen and phosphate, two nutrients that plants need. In the case of nitrogen, we have the major problem, however, that we currently practice a kind of agriculture in which far more nitrogen is spread across the field than the plants actually need. This is referred to as nitrogen surplus. What happens to the excess nitrogen? It ends up in the groundwater as nitrate or is lost as nitrous oxide, a gas that’s very harmful to the climate. These problem areas urgently need to be addressed.

How can nitrogen surplus be avoided?

We must move through plant breeding to varieties and cultivation systems that allow us to significantly increase the absorption of the fertilizer. We are currently in the situation in which at least fifty percent of the nitrogen that has been spread is not absorbed by the plant. That has to change, we have to adopt completely new approaches. That's a challenge for plant breeding.

Alongside a higher absorption capacity, what plant properties should the breeding research?

The climate crisis and future food security pose huge challenges for plant breeding. Even if climate change only comes in a reduced form, as now forecast, we will have a number of problems to deal with. Conventional plant breeding – in other words, breeding resistance to diseases and pests – still remains. It has to. It faces the task of the century. Given the climate crisis and food security I would even say: Breeding toward drought tolerant varieties and varieties that are also better able to absorb nutrients in adverse conditions will once again play a much more important role than we see at present.