Böhm, H., Dauber, J., Dehler, M., Amthauer Gallardo, D. A., de Witte, T., Fuß, R., Höppner, F., Langhof, M., Rinke, N., Rodemann, B., Rühl, G. and Schittenhelm, S., 2021. Crop rotations with and without legumes: a review. Legumes Translated Practice Guide 1. Available from www.legumehub.eu Legumes are indispensable for the supply of reactive nitrogen into organic farming systems due to their ability to fix atmospheric nitrogen. This reactive nitrogen is used by all arable crops in the organic rotation and forms the foundation of the protein supply for livestock. In conventional farming, legumes offer the potential to diversify crop rotations, especially those dominated by cereals. Legumes ‘break’ the sequence of cereal crops in these cropping systems. One of the most important consequences of this break-crop effect is the interruption of the life cycle of crop-specific pathogens and the associated savings in pesticides. This review summarises the current state of knowledge on crop rotations with and without legumes. It presents and evaluates the agronomic, environmental and economic effects of the cultivation of large and small legume species as main or catch crops or as components in mixtures. The focus is on relevant publications in scientific journals as well as practice and research reports from 2010 – 2020, carried out in Germany or comparable climatic conditions. From this we derive the necessary research requirements for the subject areas of crop production (conventional and organic), plant protection, economy, ecology and climate protection. This guide is based on a translation of the review published in 2020 in the Journal für Kulturpflanzen, 72 (10-11): 489–509. Fruchtfolgen mit und ohne Leguminosen: ein Review by Böhm et al. The translation was done by Jasmin Karer (Donau Soja) and Donal Murphy-Bokern.
Crop production in Europe is intensive, highly specialized and responsible for some negative environmental impacts, raising questions about the sustainability of agricultural systems. The (re)integration of grain legumes into European agricultural systems could contribute to the transition to more sustainable food production. While the general benefits from legume cultivation are widely known, there is little evidence on how to redesign specific cropping systems with legumes to make this option more attractive to farmers. The objectives of this study were to describe the constraints and opportunities of grain legume production perceived by farmers, explain the agronomic impacts of current grain legume cropping, explore technical options to improve grain legume agronomy, and to redesign current grain legume cropping systems in a participatory process with farmers. A co-design approach was implemented with farmers, advisors and scientists on 25 farms in northern Germany, that were part of two large demonstration networks of about 170 farms supporting grain legumes across Germany. We used the DEED research cycle (Describe, Explain, Explore and Design) as a conceptual framework combining on-farm research, crop rotation modelling, and on-station experiments. From it, we identified nine agronomic practices that either were novel or confirmed known strategies under new conditions, to redesign grain legume cropping systems at the field and farm level. The practices included (i) inter-row hoeing, (ii) direct seeding into a cover-crop, (iii) species-specific inoculation, (iv) cover crops to reduce leaching, (v) reduced tillage, (vi) soybean for increased gross margins, (vii) cultivars for food and feed use, (viii) flexible irrigation, (ix) grain legumes with cover crop to enhance subsequent crop yields. We also demonstrate how to complement knowledge of farmers' perceptions (Describe step) and formal knowledge from classical on-station experiments and modelling (Explain step) with on-farm research including the local views of farmers (Explore step) to identify tailored options for specific farm contexts rather than prescriptive solutions (Design step) to intensify legume production. This approach therefore contrasts with traditional methods that are often solely participatory and qualitative or model/experimental-based and quantitative. Hence, our results provide new insights in how to redesign cropping systems using a combination of participatory and quantitative approaches. While participatory approaches are common in developing countries, this study shows their potential in an industrialized context with large-scale farmers in Europe. These novel findings can be used as a starting point for further adaptations of cropping systems and contribute to making grain legume production economically and environmentally more sustainable.
Legumes Translated is a new thematic network in Horizon 2020. It supports the Agricultural European Innovation Partnership (EIP Agri) by linking research- and practice-based knowledge to support legume cropping and use. It is therefore in line with the recently announced European Protein Plan (European Commission 2018) that mentions a knowledge platform for protein crops. The overall goal is to support the production and use of grain legume crops in Europe as part of an overall change in protein sourcing and use (Donau Soja, 2017). The challenges that legumes crops can help address are well-documented: the need for more diversity in cropping with more crops that support pollinators; yield stagnation in cereal-dominated systems (e.g. Brisson et al., 2010; Watson et al., 2017); and a 29% deficit in tradable plant protein that is met by about 35 million tonnes of soybean equivalent imported from the Americas (Murphy-Bokern et al., 2017). This is a fundamental challenge to the resilience, acceptance and performance of our agri-food systems. There are indications that Europe is now on the cusp of a significant change manifest in the positive political response to the Donau Soja European Soya Declaration and the European Commission’s work on Europe’s protein balance. Thematic networks are a key element of the EIP Agri. funded from Horizon 2020. They complement both operational groups and Horizon 2020 research and innovation projects by compiling and validating existing knowledge and best practices and providing wider access to this knowledge with particular emphasis on trans-national border knowledge interaction. Legumes Translated has three underlying principles: empowerment of innovators through understanding; practice- and research-based sources of knowledge are mutually supportive; and cropping and farming system innovation must go hand-in-hand with corresponding value chain developments (especially in livestock).