Crop diversification (CD) encompasses practices such as extending crop rotation, cover cropping and intercropping practices, and growing minor crops. It has attracted increasing interest because it can produce both private benefits for farmers, including improved crop and soil health, and reduced inputs, and public goods for society, including greater biodiversity, carbon sequestration, and climate resilience. Nevertheless, CD is not widely practiced in Europe. This paper uses a conceptual framework based upon the literature on barriers to agricultural innovation and CD to guide a systematic-like literature review of existing review articles on the barriers to CD in Europe and a review of research from the European Crop Diversification Cluster, comprising six EU research projects. We compare barriers to CD uptake and identify opportunities to accelerate CD uptake, drawing four main conclusions. First, the barriers to CD are influenced by many factors: the specific crop, cropping method, geographical region, the farmer, the supply chain or market, and the institutional environment. Second, the barriers to CD uptake are interconnected and occur at multiple points along the supply chain; addressing barriers to CD uptake therefore requires a simultaneous and coordinated approach. Third, the inclusion of farmers' perspectives in the CD cluster research revealed novel barriers and solutions demonstrating that participatory and transdisciplinary agricultural research is needed to understand the on-farm reality and its influence on CD uptake. Lastly, farmers' decision-making warrants greater attention. The results highlight that farmers' decision-making is unpredictable and likely to focus on utility rather than profit maximization.

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Compared to sole crops, intercropping—especially of legumes and cereals—has great potential to improve crop yield and resource use efficiency, and can provide many other ecosystem services. However, the beneficial effects of intercrops are often greatly dependent on the end use as well as the specific species and genotypes being co-cultivated. In addition, intercropping imposes added complexity at different levels of the supply chain. While the need for developing crop genotypes for intercropping has long been recognized, most cultivars on the market are optimized for sole cropping and may not necessarily perform well in intercrops. This paper aims to place breeding targets for intercrop-adapted genotypes in a supply chain perspective. Three case studies of legumes and cereals intercropped for human consumption are used to identify desirable intercrop traits for actors across the supply chains, many of which are not targeted by traditional breeding for sole crops, including certain seed attributes, and some of which do not fit traditional breeding schemes, such as breeding for synchronized maturity and species synergies. Incorporating these traits into intercrop breeding could significantly reduce complexity along the supply chain. It is concluded that the widespread adoption and integration of intercrops will only be successful through the inclusion and collaboration of all supply chain actors, the application of breeding approaches that take into account the complexity of intercrop supply chains, and the implementation of diversification strategies in every process from field to fork.

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Yield gaps between organic and conventional agriculture raise concerns about future agricultural systems which should reduce external inputs and face an unpredictable climate. In the UK, the performance gap is especially severe for wheat that, as a result, has a small and shrinking organic acreage. In organic wheat production, most determinants of crop performance are managed at a rotation level, which leaves cultivar choice as the major decision on a seasonal basis. Yet, conventionally generated cultivar recommendations might be inappropriate to organic farms. Furthermore, uncertainty about field-scale crop performance hinders positive developments of the supply chain of organic grains and seeds. Here, we present a field-scale evaluation of winter wheat cultivars, integrated with an agronomic crop performance survey, across a network of organic farms. The relation between crop performance and climatic patterns is explored, to capitalise past growing seasons in cultivar and management decisions on-farm. Grain yield and grain protein content were linked by a dual relation, positive across environments and negative across cultivars. Feed-grade cultivars showed a relatively high yield (4.5–5.5 t/ha) but low protein (8.5–9.3%), whereas breadmaking and historic cultivars showed higher protein (10.4–11.1%) and lower yields (3.5–4.0 t/ha). Historic phenotypes showed better weed suppressive ability than modern ones, without trade-offs with yield or quality. Multiple regressions showed that weed abundance at wheat anthesis was the main yield predictor. The effects of two different post-emergence weed management strategies were observed. Farms relying on interrow hoeing showed lower weed abundance, but a higher relative abundance of the dominant species than that of those relying on spring tine harrowing. Future wheat breeding and cultivar testing should account for crop-weed relations, weed management strategies and their effects on nutrient use efficiency. Further data collection can inform plant breeding on critical traits for low-input farming and shed light on cultivar-environment-management interactions.