Sustainable soil management & healthy food

carrots growing in the soil, shalow DOF

How does soil management affect the quality of the soil? What could be the indirect effects on the quality of our food? What if good soil management one day could eliminate the need for medicins? On the 9th of February, the symposium ‘Sustainable soil management & healthy food’, organised by  Down2Earth and the Centre for Soil Ecology NIOO/WUR, took place at Wageningen UR to discuss such questions. BY: SANNE VAN LEEUWEN.

For this day of lectures and workshops, about 80 participants had joined, all from different backgrounds, but with a common interest: the role of soil in food production and food quality. The day started off with a  talk by ass. prof. dr. E. van Kompanje on the health of our food, showing the direct link between our diet and our health. He posed that you can keep yourself healthy by eating a diet with fresh vegetables, high in omega-3 containing and fibre rich products. However, in the reflection moderated by prof. dr. J. Seidell that followed, the interesting question was raised if we are actually free in our choice of food. Even in the Netherlands, such a diet may not be accessible to everyone due to social, political or economic constraints. Why do we eat what we eat? This question spurred quite some discussion and the mixed reaction of the audience clearly showed how many different views there are on food nowadays and how complex our current system of production and consumption has become. A good wake-up and kick starter of the day.

The rest of the morning, multiple lectures on the different aspects related to the quality of our food, the relation with production and production methods were given.

Ir. Anton Nigten from Down2Earth explained about his views on the health of our cattle and our milk. For sure, the mineral composition and fat content of milk has changed significantly since the beginning of the previous century. Nowadays, farmers are advised not to feed their calves on fresh cowmilk as the increased fat and nitrogen content causes diarrhoea. A direct relation between the change in milk composition and health issues may exist with the changes in production methods. Do these changes also pose a threat to human health? And if so, what should be the solution?  Anton himself proposed that our milk now contains too much NPN (non protein nitrogen) and too little magnesium in relation to the calcium content. Adding sodium to the grasslands could help to balance the uptake of multiple minerals by cows and decrease illness like grass tetany. But critical reflection was also raised: how to scientifically prove such indirect and complex relations between grassland management, cow health and human health? Check the video below for a full explanation from ir. Nigten of his ideas (in Dutch).

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Next up was a very enthusiastic, almost overwhelming presentation of prof. dr. R. K. Sinha on the role of earthworms and the use of vermicompost (compost produced by earthworms) in agriculture. Benefits of stimulating earthworms or fertilizing with vermicompost range from increased yields to lower health risks. Scientific proof is accumulating that there is a direct link between fertilization and the quality of our crops. For example, vermicompost can significantly increase tomato yields (Gutiérrez-Miceli, 2007) and reduce the incidence of fusarium wilt (Szczech, 1999) in comparison with artificial fertilizer. To find out more, it is recommended to read the very complete article by dr. Sinha called ‘The wonders of earthworms & its vermicompost in farm production: Charles Darwin’s ‘friends of farmers’ (full citation below).

After a good lunch break, the last lecture of the day was provided by prof. dr. L. Brussaard on the quality of our soils. Starting with a broad overview of what soil quality actually means, he provided interesting examples on applied research into soil quality, such as the relation between yield and soil compaction or yield and availability of soil organic matter. Interestingly, soil quality has become a topic also in societal context, as there is now for instance the Dutch manifest ‘Organische stof: leven in de Nederlandse bodem’. As a general conclusion, he proposed that soil is a public good and is to be treated as such. A very supporting message for all proponents of agroecology and other sustainable farming practices!

”Soil is a public good and is to be treated as such” – prof. dr. Lijbert Brussaard

During the last part of the day, participants could join one of four working sessions that were held, on food quality, milk & cattle quality, crop quality and soil quality. In the soil quality session, the discussion focused on which soil related constraints are now most limiting in practice and which research questions could be posed to solve these constraints. It turned out that compaction issues and soil organic matter issues are now most urgent. Especially, research into the effects of vibrations from machinery, the decomposition of different materials in the soil and the effects of pesticides on decomposition, was assigned to be of interest for most of the participants. With both researchers and practical stakeholders together, we also discussed in what manner research should be done for the results to be successfully applied in practice. Good cooperation, realistic field experiments and clear communication were immediately mentioned as crucial points for any research result to be effectively adopted.

The day ended with a summary of all working group sessions and concluding words from chairman dr. sr. J.D. van Mansvelt. It had been an interesting day, not the least because of the diverse crowd that had participated. The mix of researchers, farmers, policy makers from the regional and the local government and consultants in agriculture and horticulture, all with their own perspectives, made for very lively discussions. Also, it was a good opportunity to hear about what is going on and who is involved in soil management and food quality. Topics that will hopefully gain attention in the coming years!

For more information, please check:
– The organisation Down2Earth (in Dutch)
– The Centre for Soil Ecology
– The video of Anton Nigten, ‘Bemesting en voedsel distributie’ (in Dutch)
– The article of R. K. Sinha, ‘The wonders of earthworms & its vermicompost in farm production
– Manifest Organische Stof: leven in Nederlandse bodem (in Dutch) Read more here or download the full manifest.
– The international movement People4Soil, who started a petition to call for attention for soil in the EU, website of the Dutch Publiek Private Samenwerking Bodem

– Gutiérrez-Miceli, F. A., Santiago-Borraz, J., Molina, J. A. M., Nafate, C. C., Abud-Archila, M., Llaven, M. A. O., … & Dendooven, L. (2007). Vermicompost as a soil supplement to improve growth, yield and fruit quality of tomato (Lycopersicum esculentum). Bioresource Technology, 98(15), 2781-2786.
– Szczech, M. M. (1999). Suppressiveness of vermicompost against Fusarium wilt of tomato. Journal of Phytopathology, 147(3), 155-161.