Diversification for sustainable and resilient agricultural landscape systems

This virtual issue comprises papers that address diversification for providing sustainable solutions at different scales from cropping and grassland to food systems. The authors investigated processes in case studies at the landscape scale where synergies and trade-offs between social and environmental objectives become the most tangible. Contributions from all continents highlighted regional specificities related to diversification and include research from natural and social sciences, with inter- and transdisciplinary approaches including synthesis of knowledge (reviews), empirical studies with experiments as well as assessments with interviews in case studies: Model-based design of crop diversification, the role of digitalization for achieving sustainability in the European context, ecological engineering for rice pest suppression in China, the role of cereal species mixtures in Ethiopian smallholder farmers, diversified planting in arid irrigation areas in northwestern China, integration of legumes in European and Canadian cropping systems, screening of native forage legumes for northern Swedish grassland systems, cropping system diversification of smallholder farmers in south-central Bangladesh, identification of how farmers imagine diversified landscapes in southern Idaho in the US, farm diversification affecting impacts from COVID-19 across Europe, the role of diversified farming in Mato Grosso Brazil, diversification and soil management measures in Germany, value chain formation for the scaling of crop diversification, and the design process with farmers and scientists for the transition toward legume-supported farming in Europe. A key finding from these examples is that agricultural intensification has led to the simplification of cropping systems and landscapes in terms of species diversity and ecosystem function. To instead move towards sustainable transformation, all system levels (i.e. from the plot, farm, landscape, governance and overall food systems) need to interact and reinforce each other for diversification to deliver the desired outcomes

Rapid testing leads to the underestimation of the scrapie prevalence in an affected sheep and goat flock

To obtain a more detailed understanding of the prevalence of classical scrapie infections in a heavily affected German sheep flock (composed of 603 sheep and 6 goats), we analysed 169 sheep and 6 goats that carried the genotypes susceptible to the disease and that were therefore culled following discovery of the index case. The initial tests were performed using the Biorad TeSeE ELISA and reactive results were verified by official confirmatory methods (OIE-immunoblot and/or immunohistochemistry (IHC)) to demonstrate the deposition of scrapie-associated PrPSc in the brain stem (obex). This approach led to the discovery of 40 additional subclinically scrapie-infected sheep. Furthermore, peripheral lymphatic and nervous tissue samples of the 129 sheep and 6 goats with a negative CNS result were examined by IHC in order to identify any preclinical infections which had not already spread to the central nervous system (CNS). Using this approach we found 13 additional sheep with PrPSc depositions in the gut-associated lymph nodes (GALT) as well as in the enteric nervous system. Moreover, in most of these cases PrPSc was also deposited in the spleen and in the retropharyngeal and superficial cervical lymph nodes. Taken together, these results show a 30.3% infection prevalence in this scrapie-affected flock. Almost 7.4% of the infected animals harboured PrPSc exclusively in the peripheral lymphatic and nervous tissue and were therefore missed by the currently used testing strategy

Agro-economic prospects for expanding soybean production beyond its current northerly limit in Europe

Soybean is one of the five crops that dominate global agriculture, along with maize, wheat, cotton and rice. In Europe, soybean still plays a minor role and is cultivated mainly in the South and East. Very little is known about the potential for soybean in higher latitudes with relatively cool conditions. To investigate the agronomic potential and limitations of soybean for feed (high grain yield) and food (high protein content, e.g., for tofu production) in higher latitudes, an organic soybean cropping system experiment was carried out from 2015 to 2017 in northeastern Germany. The objectives were: (1) to identify food- and feed-grade soybean cultivars that are adapted to a central European climate in terms of protein, grain yield, and yield stability, (2) to explore the effect of irrigation on soybean protein and grain yield under relatively dry growing conditions, and (3) to determine the agro-economic potential of soybean cultivation for both feed and food markets. Three soybean cultivars were tested with and without irrigation. The soybean feed-grade cultivars 'Sultana' and 'Merlin' were better adapted to the growing cycle and temperature, providing higher and more stable yields (average 2700 kg ha(-1)) than the food-grade cultivar 'Protibus' (average 1300 kg ha(-1)). Irrigation increased soybean grain yields by 41% on average. In the year with sufficient precipitation, no additional irrigation was necessary. Gross margins of organic soybean ranged between 750 (sic) ha(-1) for the rainfed food-grade soybean and 2000 (sic) ha(-1) for the irrigated feed-grade soybean and were higher than other crops. We demonstrated a large agro-economic potential for soybean as a novel grain legume crop to diversify cropping systems and increase the production of protein crops in central Europe.Peer reviewe

Grain legume yields are as stable as other spring crops in long-term experiments across northern Europe

Grain legumes produce high-quality protein for food and feed, and potentially contribute to sustainable cropping systems, but they are grown on only 1.5% of European arable land. Low temporal yield stability is one of the reasons held responsible for the low proportion of grain legumes, without sufficient quantitative evidence. The objective of this study was to compare the yield stability of grain legumes with other crop species in a northern European context and accounting for the effects of scale in the analysis and the data. To avoid aggregation biases in the yield data, we used data from long-term field experiments. The experiments included grain legumes (lupin, field pea, and faba bean), other broad-leaved crops, spring, and winter cereals. Experiments were conducted in the UK, Sweden, and Germany. To compare yield stability between grain legumes and other crops, we used a scale-adjusted yield stability indicator that accounts for the yield differences between crops following Taylor's Power Law. Here, we show that temporal yield instability of grain legumes (30%) was higher than that of autumn-sown cereals (19%), but lower than that of other spring-sown broad-leaved crops (35%), and only slightly greater than spring-sown cereals (27%). With the scale-adjusted yield stability indicator, we estimated 21% higher yield stability for grain legumes compared to a standard stability measure. These novel findings demonstrate that grain legume yields are as reliable as those of other spring-sown crops in major production systems of northern Europe, which could influence the current negative perception on grain legume cultivation. Initiatives are still needed to improve the crops agronomy to provide higher and more stable yields in future.Peer reviewe

Diversification improves the performance of cereals in European cropping systems

In the face of climate change, cropping systems need to achieve a high performance, providing food and feed and adapting to variable environmental conditions. Diversification of cropping systems can support ecosystem services and associated biodiversity, but there is little evidence on which temporal field arrangement affects the performance of crop yields (productivity and stability), partly due to a lack of long-term data and appropriate indicators. The objectives of this study were to quantify the effect of cropping system diversification on yield stability, environmental adaptability, and the probability of diversified systems to outperform less diverse cereal-based systems in Europe. Spring and winter cereal yields were analyzed from long-term field experiments from Sweden, Scotland, and France. We investigated diversification through (i) introduction of perennial leys, (ii) increasing the proportion of ley in the rotation, (iii) varying the order in which crops are positioned in the rotation, (iv) introduction of grain legumes, and (v) introduction of cover crops. The results showed that cereal crops within cropping systems incorporating perennial leys outperformed systems without leys in 60–94% of the comparisons with higher probabilities at low fertilizer intensities. The yield stability of oat did not differ, but mean yields were 33% higher, when grown directly after the ley compared to oat grown two years later in the crop sequence under similar management. Durum wheat grown in a cropping system with grain legumes had higher yields in lower-yielding environmental conditions compared to rotations without legumes. Diversification with cover crops did not significantly affect yield stability. We conclude that diverse cropping systems can increase cereal productivity and environmental adaptability and are more likely to outperform less diverse systems especially when introducing perennial forage legumes into arable systems. Effects of diversification on cereal yield stability were inconsistent indicating that higher productivity is achievable without reducing yield variability. These novel findings can support the design of more diverse and high-performing cropping systems

Re-designing organic grain legume cropping systems using systems agronomy

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 re-design 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 re-design 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 re-design 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 re-design 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.Peer reviewe

Diversification improves the performance of cereals in European cropping systems

International audienceAbstract In the face of climate change, cropping systems need to achieve a high performance, providing food and feed and adapting to variable environmental conditions. Diversification of cropping systems can support ecosystem services and associated biodiversity, but there is little evidence on which temporal field arrangement affects the performance of crop yields (productivity and stability), partly due to a lack of long-term data and appropriate indicators. The objectives of this study were to quantify the effect of cropping system diversification on yield stability, environmental adaptability, and the probability of diversified systems to outperform less diverse cereal-based systems in Europe. Spring and winter cereal yields were analyzed from long-term field experiments from Sweden, Scotland, and France. We investigated diversification through (i) introduction of perennial leys, (ii) increasing the proportion of ley in the rotation, (iii) varying the order in which crops are positioned in the rotation, (iv) introduction of grain legumes, and (v) introduction of cover crops. The results showed that cereal crops within cropping systems incorporating perennial leys outperformed systems without leys in 60–94% of the comparisons with higher probabilities at low fertilizer intensities. The yield stability of oat did not differ, but mean yields were 33% higher, when grown directly after the ley compared to oat grown two years later in the crop sequence under similar management. Durum wheat grown in a cropping system with grain legumes had higher yields in lower-yielding environmental conditions compared to rotations without legumes. Diversification with cover crops did not significantly affect yield stability. We conclude that diverse cropping systems can increase cereal productivity and environmental adaptability and are more likely to outperform less diverse systems especially when introducing perennial forage legumes into arable systems. Effects of diversification on cereal yield stability were inconsistent indicating that higher productivity is achievable without reducing yield variability. These novel findings can support the design of more diverse and high-performing cropping systems

A cropping system assessment framework-Evaluating effects of introducing legumes into crop rotations

Methods are needed for the design and evaluation of cropping systems, in order to test the effects of introducing or reintroducing crops into rotations. The interaction of legumes with other crops (rotational effects) requires an assessment at the cropping system scale. The objective of this work is to introduce a cropping system framework to assess the impacts of changes in cropping systems in a participatory approach with experts, i.e., the integration of legumes into crop rotations and to demonstrate its application in two case studies. The framework consists of a rule-based rotation generator and a set of algorithms to calculate impact indicators. It follows a three-step approach: (i) generate rotations, (ii) evaluate crop production activities using environmental, economic and phytosanitary indicators, and (iii) design cropping systems and assess their impacts. Experienced agronomists and environmental scientists were involved at several stages of the framework development and testing in order to ensure the practicability of designed cropping systems. The framework was tested in Vastra Gotaland (Sweden) and Brandenburg (Germany) by comparing cropping systems with and without legumes. In both case studies, cropping systems with legumes reduced nitrous oxide emissions with comparable or slightly lower nitrate-N leaching, and had positive phytosanitary effects. In arable systems with grain legumes, gross margins were lower than in cropping systems without legumes despite taking pre-crop effects into account. Forage cropping systems with legumes had higher or equivalent gross margins and at the same time higher environmental benefits than cropping systems without legumes. The framework supports agronomists to design sustainable legume-supported cropping systems and to assess their impacts. (C) 2015 The Authors. Published by Elsevier B.V.Peer reviewe

Grain legume production in Europe for food, feed and meat-substitution

Partial shifts from animal-based to plant-based proteins in human diets could reduce environmental pressure from food systems and serve human health. Grain legumes can play an important role here. They are one of the few agricultural commodities for which Europe is not nearly self-sufficient. Here, we assessed area expansion and yield increases needed for European self-sufficiency of faba bean, pea and soybean. We show that such production could use substantially less cropland (4–8%) and reduce GHG emissions (7–22% current meat production) when substituting for animal-derived food proteins. We discuss changes required in food and agricultural systems to make grain legumes competitive with cereals for farmers and how their cultivation can help to increase sustainability of European cropping systems.</p