There is an urgent need to transform arable farming systems in response to climate change. However, this need is not only being driven by increasing summer droughts and extreme rainfall events, but also by public demand for pesticide-free agricultural production and the pressure for more efficient production that delivers higher yields while reducing the use of auxiliary agents. Sustainably produced protein sources are an important concern for agriculture, the animal feed industry and NGOs. The domestic share of feed soybeans is only 5%, although there is potential to increase domestic production with better cultivation systems. Demand for edible Swiss-grown soybeans is high; Coop, for example, uses 100% Swiss organic soybeans to produce its tofu. The importance of soya as a protein-rich food is increasing with the dietary trend towards eating less meat.
In the search for new solutions, an innovative farmer and private soil and fertiliser consultant became aware of relay intercropping, a method that has been practised for some time by farmers and innovative researchers in North and South America. In relay intercropping, two or more crops are grown simultaneously in the same field for part of their respective growing seasons. Winter cereals are grown in wide rows so that soybeans can be sown in the gaps in spring. Motivated by the potential positive effects on soil fertility, crop yields and income, the farmer set up his own initial trials in Switzerland with wheat and soybeans. These were extended to other farms as part of this advisory project. Records of the use of auxiliary agents, crop yields and income were also kept and analysed along with farmers' experiences to provide insights and knowledge for more widespread use of this method on Swiss arable farms. The results showed that relay intercropping is technically feasible in Switzerland, but that soybean production in general poses great risks and challenges, particularly in terms of yields and costs.
