Podcast summaries

In discussion with Ken Giller
Podcast summary

31st Oct 2021

Regenerative agriculture in practice


Regenerative agriculture is having its moment in the spotlight. But behind the enthusiasm there are many complexities. Ken Giller, Professor of Plant Production Systems at Wageningen University, talks to ForumforAg about what it means in practice, whether it could be applied in Africa, and reopening the debates on gene editing and biodiversity practices. For a taster, read our short summary below, or dive into the full 30-minute Food Systems Podcast for much more. 


Where does the term regenerative agriculture come from and what does it represent today?

It originated with Robert Rodale, the father of organic agriculture, which confused me! Today there is a coalescing around regenerative agriculture because everybody wants to do better: sustainable agriculture is good but we want to go one step further.

Everything comes together around soil and biodiversity. Many companies are committing to zero carbon by 2030 in their food and supply chains and find that 70-90% of their CO2 emissions go back to farming and production. So locking carbon in the soil is very prominent in the debate. It’s a bit dangerous because it could be oversold.

How do you measure soil carbon storage?

It’s quite difficult. People often take a sample of soil from the surface. But if you practice zero till, all the organic matter accumulates on the top of the soil. If you measure at 60 centimetres deep, there’s hardly any difference between zero till and non-zero till.

Spectral sensors measure carbon in a soil sample. But that doesn’t tell you how much carbon there is in the profile. To do that you need a very detailed analysis.

Is regenerative agriculture just a combination of practices that we’ve seen before?

People talk about basic principles like reducing soil tillage, maintaining soil cover, improving soil carbon, more diverse crop rotations, and reducing agricultural inputs. With inputs, I get worried because everything is put into one bucket, agrochemicals. There’s a big difference between nutrients, which are environmentally benign if used in the right way, and pesticides, which are designed to kill things selectively.

My work focuses on Africa where we see completely degraded soil. We don’t want to reduce inputs, we need to increase inputs of nutrients. So the starting point is crucial to this debate and often ignored.

Regenerative agriculture seems accepting of mechanization and technology in general.

There’s an opportunity for technology, particularly small-scale technology. Zero tilled systems are usually highly dependent on herbicides, so how do we control weeds if we ban them? Mechanical weeding and modified forms of tillage can help to reduce the need for chemicals – a more integrated pest disease management approach.

Is there a danger of greenwashing, with everybody coming on board but it’s not clear how they’re going to get there?

Let me put two things on the table. First, we should re-open the debate around gene editing. With using the best of biology, we can reduce the need for chemicals. If you have a couple of different resistance genes in your potato, you can cut down on fungicide.

Second, the biodiversity discussion is focused on farm diversity. We end up with some practices reducing productivity and taking land out of agriculture, which is being discussed in the EU. That means our ecological footprint will be moved elsewhere. We have to think about the implications: are we pushing more cutting down of the Amazon rainforest or more clearance of land in Africa?

If you have found this short summary interesting, there’s lots more to hear in the full 30-minute conversation. It is available now on iTunes, Podbean or Spotify or on this website.

You can read Ken's paper here.

About Ken Giller

Ken Giller is Professor Plant Production Systems, within WaCASA (the Wageningen Centre for Agroecology and Systems Analysis) at Wageningen University. Ken's research has focused on smallholder farming systems in sub-Saharan Africa, and in particular problems of soil fertility and the role of nitrogen fixation in tropical legumes, with emphasis on the temporal and spatial dynamics of resources within crop/livestock farming systems and their interactions.