Food safety is one of the major issues that need to be addressed to ensure that the growing world population will have access to sufficient quality food in the future. In fact, food and agriculture can be directly linked to at least three of the UN Sustainable Development Goals (SDG#2 – Zero Hunger, SDG#12 – Responsible Consumption & Production and SDG#15 – Life on Land). Despite having new forms of local food production that do not require soil, like aquaponics, for instance, most of the agriculture is still mainly reliant on healthy soils. Therefore our soils have to be preserved.
But according to our learning journey with interested parties, a significant part of arable soil in Switzerland is not anymore in the best conditions to provide a fertile ground for agricultural production. Amongst others, unhealthy soils have a lower micro-biodiversity and are more prone to pathogens and erosion. Current solutions to maintain the production may include the use of chemicals, which is mainly curing the symptoms, but not the ground cause of unsustainable productive soils. Crop rotation is as well an efficient way to regenerate the soils but it is not always compatible with the current production requirements and economic pressure that many farmers encounter.
Several types of edible mushrooms are currently grown on wood-based substrates at industrial scale in Switzerland (e.g. oyster mushrooms, shiitake, …). The Swiss mushrooms farms producing thousands tons of substrates which are containing the soil-regenerative enzymes. Indeed, literature describes the use of spent mushroom substrate (SMS) for a variety of applications, amongst which the potential to regenerate soils by fighting against pathogens. If properly mixed with native bacteria, SMS could become a soil regenerator even without crop rotation strategies. It would indeed fight against pathogens while increasing the micro-biodiversity and allow a faster recovery and an increased quality of the soils. At the moment, however, once these wood-based substrates are used, they are not valorized in the extent they could. There is therefore an opportunity to create more efficient synergies within the Swiss agricultural sector.
On the longer term and if feasibility is confirmed, other uses for SMS could be explored (enzymes production, soil decontamination,…) and combinations of activities for the mushrooms and SMS could provide access to a more circular and regenerative economic model within the agricultural sector.
What is still needed:
The principle has been prototyped and access to SMS has been confirmed both for small and large scale trials. What is needed now is a collaboration with experts in soil structure and/or research centers (such as FiBL, Lullier, UNIL, EPFL,…) to quantify the soil quality improvement in a new trial applied in Canton de Vaud. Indeed, after defining the right parameters to measure and the right tools to do so, a pilot scale trial should be conducted on the field with farmers. In parallel, information gathering on the scalability and economical viability will be needed with branch experts and technicians.