"Soil quality is under increasing pressure due to extreme weather conditions"
Voices on climate
Hans-Martin Krause (left) and Markus Steffens are both long-standing FiBL researchers in the Department of Soil Sciences and jointly head the Soil Fertility and Climate group. (Photo: FiBL)
Markus Steffens and Hans-Martin Krause are both long-standing FiBL researchers in the Department of Soil Sciences and jointly head the Soil Fertility and Climate group. Markus Steffens is also a lecturer in soil science at the University of Bern. Since last year, Hans-Martin Krause has been leading the DOK trial at FiBL, which has been comparing organic and conventional farming systems for over 40 years, and teaches soil fertility at Justus Liebig University in Giessen.
You have both been researching soil and climate for years. What drives you and why?
Hans-Martin Krause: I started at FiBL in 2013, measuring nitrous oxide emissions to understand how microbial processes work in the soil. This sparked my interest in microbial communities and comparing different agricultural systems. For me, it's clear that we can solve many problems by simply not doing things. But that's not possible when it comes to food – we have to produce it. And we have to do so in a way that is compatible with the environment and climate. That's why I do research on soil: it's the foundation.
Markus Steffens: There is an old saying: "He who pays the piper calls the tune". We all eat bread made from grain that has grown in the soil – but hardly anyone talks about it. Yet the soil is the basis for our food production. I have been working on the topics of soil, carbon and climate since 2004, and at FiBL since 2017. I am fascinated by how crucial humus is not only for the climate and productivity, but also for biodiversity.
What role does soil play in climate change, specifically?
Hans-Martin Krause: Soil has many functions: it regulates material cycles, stores water, provides habitat and ensures food production. But this only works if the soil quality is right. However, it is precisely this that is increasingly under pressure: heat, drought and extreme weather reduce the buffering capacity of soils. Without sufficient soil quality, we lose key functions.
Markus Steffens: We can manage our soils – to a certain extent. But climate change is fundamentally altering their properties. The most important lever is carbon. Building up humus, or at least stabilising it at a good level, helps to make production more resilient in times of climate change and can also contribute a little to mitigating it.
Repeated campaigns are promoting climate-friendly agriculture through soil-less systems such as hydroponics. Is this a sustainable solution for agricultural climate emissions?
Markus Steffens: Not really. Even in 75 years, 80 to 90 per cent of the world's food will still be produced in soil. Hydroponics may make sense for specialised crops such as herbs or tomatoes, but not for food security or landscape conservation and protection.
Depending on the calculation, up to 75 per cent of our global soil is already degraded. Arable land is becoming increasingly scarce and is under enormous production pressure. What measures are needed to make soil more climate-resilient?
Markus Steffens: More carbon in the soil – that's the basis. Rising temperatures accelerate the natural decomposition of existing humus. Therefore, we will have to continue to increase the input of organic matter into the soil in the coming years, if only to maintain the current level.
Hans-Martin Krause: And we need to think more systemically, with less economic pressure and more room for experimentation. Organic farming practices, such as composting, undersowing, and mixed cropping, can help enrich humus and thus increase carbon in the soil, thereby strengthening resilience. In the DOK long-term trial, we have seen that agricultural systems that use composting contain more humus and have a better soil structure.
So is this also a social issue? Why is it so difficult for society and politicians to recognise the value of soil and promote it accordingly?
Hans-Martin Krause: Because changes in the soil are extremely slow. Even for farmers who work directly with it, it is sometimes difficult to assess whether the quality is improving or deteriorating. Soil builds up over thousands of years, but its condition can deteriorate significantly within a few years due to poor management or be completely washed away by heavy rainfall.
Markus Steffens: And most people have no connection to the soil. Ninety-nine per cent of people don't even see our soils and their diversity.
Were there moments when you clearly recognised the importance of soil?
Hans-Martin Krause: Yes, during my studies in Venezuela. Centuries ago, the Spanish ploughed steep slopes for wheat at an altitude of 3,000 metres. Within a few decades, the formerly carbon-rich soils were destroyed. To this day, these areas remain degraded. That's when I realised that if managed incorrectly, soil can be lost in a very short time.
Markus Steffens: For me, it was during my studies. When we dug up soil profiles, I saw for the first time how different soils are. There is no such thing as "the" soil, but many. Only by understanding these differences can we protect soils and use them sustainably.
What solutions could be used to make people more aware of the value of soil again?
Markus Steffens: We protect what we love – we need to raise awareness among people about the benefits of soil, but also about the dangers.
Hans-Martin Krause: It would be very helpful if everyone had more connection to practical agriculture. That would change awareness enormously. For future political decisions, I hope that soil will not be seen purely as a production area. It fulfils so many other functions: water regulation, habitat, and carbon storage. And with political programmes on soil protection, there is a great danger that only individual aspects will be picked out.
Markus Steffens: I would like us to learn to treat the soil as a partner. This means wasting less, distributing resources more effectively and rethinking property rights. Soil is a finite resource – and it belongs not only to those who own it, but to all of us.