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Modern agriculture has been focused on improving and optimizing production, neglicting supporting and regulating ecosystem services. Meta-analysis has been a useful tool to demonstrate the potential of cereal-legume intercropping to deliver multiple ecosystem services and providing guidelines for their intercrop design. However, detailed guidelines for the design and management of such systems remain unclear, especially for the understudied vegetable-based intercropping systems. whether such premises apply to vegetable-based intercropping systems remains unknown. Given the diversity of vegetable crops, we propose a ‘relay’ of crop-specific meta-analyses to capitalize on vegetable intercropping research. Each ‘leg’ in the relay analyzes relevant performance criteria from the perspective of one focal crop, and over the course of subsequent legs the network of interactions among the different crops is built. We argue that this approach provides crop-specific guidelines and identify designing principles that are applicable under a range of different environmental conditions. We started the ‘relay’ meta-analysis focusing on cabbage (Brassica oleracea ssp.) and the delivery of the provisioning services productivity, product quality (grade and pest injury in cabbage products), and yield stability across different companion species, spatio-temporal configurations, and management inputs. We identified 72 studies across 62 field sites, comprising 564 data records. We show that intercropping did not significantly compromise cabbage productivity (-6 % on average) or grade (1%) and significantly reduced pest injury (53 %) relative to sole cabbage systems. Effects on yield stability remained unknown as trials were rarely conducted for more than two years, pointing to the need for long-term experimentation. Greater productivity was associated with short companion species with a low growing habit or types sown at or after planting of the cabbage crop thus limiting competition with cabbage at early development stages. The decrease in pest injuries was associated with intercropping patterns involving strong inter-plant interactions (i.e. mixed, row and additive) and companion species that supported biodiversity such as living mulches. Overall, beneficial effects of intercropping tended to be more evident in organic or no input production systems, possibly due to synthetic inputs overriding potential regulating effects and/or promote imbalance between the intercropped species. Cabbage growers and agricultural advisors can use these guidelines for designing intercrop systems specific to their local conditions. A more holistic understanding vegetable intercroping systems interactions can be achieved by implementing the database structure developed here with other crops and agro-ecosystem services

Description of SUREVEG project in the Netherlands. Start of the trail.

In legume-Rhizobium symbioses, specialised soil bacteria fix atmospheric nitrogen in return for carbon. However, ineffective strains can arise, making discrimination essential. Discrimination can occur via partner choice, where legumes prevent ineffective strains from entering, or via sanctioning, where plants provide fewer resources. Several studies have inferred that legumes exercise partner choice, but the rhizobia compared were not otherwise isogenic. To test when and how plants discriminate ineffective strains we developed sets of fixing and non-fixing strains that differed only in the expression of nifH – essential for nitrogen fixation – and could be visualised using marker genes. We show that the plant is unable to select against the non-fixing strain at the point of entry, but that non-fixing nodules are sanctioned. We also used the technique to characterise mixed nodules (containing both a fixing and a non-fixing strain), whose frequency could be predicted using a simple diffusion model. We discuss that sanctioning is likely to evolve in preference to partner choice in any symbiosis where partner quality cannot be adequately assessed until goods or services are actively exchanged.

Johne's disease is an infectious gastrointestinal disease in ruminants caused by Mycobacterium avium subsp. paratuberculosis that causes diarrhea, emaciation, decreased milk production and eventually death. The disease is transmitted in utero and via milk and colostrums to calves, and fecal-orally to all age classes. Financial losses due to the disease are estimated to be over $200 million in the US dairy industry. The goal of this study was to evaluate the cost effectiveness of control measures based on diagnosis with a sensitive ELISA, EVELISA. An agent-based, discrete time model was developed to simulate Johne's disease dynamics in a US dairy herd. Spatial aspects of disease transmission were taken into account by using six spatial compartments. The effects on disease prevalence were studied with and without transmission routes included in the model. Further, using the model, cost effectiveness of ELISA-based Johne's disease control was evaluated. Using the parameters we collected and assumed, our model showed the initial prevalence of Johne's disease (33.1∈±∈0.2%) in the farm increased to 87.7∈±∈1.7% in a 10 year-simulation. When ELISA-based control measures were included in the simulation, the increase in prevalence was significantly slowed down, especially when EVELISA was used. However, the level of the prevalence was still higher than the initial level after 10 year simulation even with the ELISA-based diagnostic intervention. The prevalence was further reduced when quarterly ELISA testing was included. The cost analysis showed that the quarterly ELISA and EVELISA testing could bring $44.8 and $51.5/animal/year more revenues, respectively, to a dairy farm.