Many governments (including UK) are encouraging regenerative agriculture via policies that support or encourage reduced tillage and cover/catch crop utilisation in agricultural rotations, however, success in northern climates has been mixed. Reduced tillage practices have been shown to benefit the soils physical attributes, but the practice is often unviable in the far north of Scotland due to wetter, colder weather and shorter growing seasons. Cover/catch crops include a multitude of species and species mixtures that are primarily grown to benefit the soil, but adoption levels are lower further north for the same reasons. These practices maintain and redistribute nutrients in the soil profile, improve soil structure, improve water holding capacity of soil, and increase soil carbon. These management interventions may also impact biodiversity within the soil and the wider agroecosystem including supressing pests, diseases and weeds. Winter cover crops are usually sown from August through to mid-September in Scotland after the main crop harvest and are destroyed in February / March prior to drilling follow-on crops. Without winter cover crops or weeds as cover the soil remains bare and exposed over the winter period which can lead to significant damage (compaction, erosion, leaching). Cover crops in some circumstances have been shown suppress pests such as nematodes and to increase the yield of follow-on crops. There is also evidence of wider impacts of regenerative agriculture on other soil trophic groups such as earthworms, collembola (springtails) and mites. Data relating to the effectiveness of cover crops in northern regions is limited, and changes in daylight and often rapid drops in temperature in the autumn, as well as slug damage can lead to failure of the cover crops to thrive. We hypothesise that different plants traits will lead to successful cover crop implementation in the different environments and will have differential impacts on the soil trophic layers and above ground pests.
The project will have four objectives: 1) determine the main factors/traits limiting cover crop establishment and driving impacts on soil physical and biological health (impact on soil organism abundance and diversity) depending on location, rotation and cover crop type and utilising farmer networks to evaluate the experience of farmers experimenting with cover crops in norther climates; 2) Identify cover crops that are resistant/tolerant of pests (e.g slugs, geese, crows etc) and reduce weed burden; 3) Identify the potential for cover crops as a strategy to manage problematic pests (e.g. leatherjackets (crane fly larvae)) and weeds; 4) Establish traits that could be used in breeding to increase the stability and effectiveness of cover crops in Northern environments while increasing positive bio-diversity.
The student will begin by conducting a Rapid Evidence Assessment on the effects of tillage and cover crops on soil and above-ground ecological networks, based on published literature from similar climate regions and establish links with farmer networks to increase understanding or barriers. The student will then design a strategy for sampling the impacts of a small number of cover crops, across the trophic layers using both manual mapping/scoring, imaging and image analysis, and molecular methods. The student will be able to utilise cover crops trials on the three sites to assess species and species mixtures effectiveness of cover crops in managing weeds and pests, soil health and impact on follow on crops. Complementary trials in three locations include long-term comparison of cover-crops in barley rotations (south of the Forth), more complex rotations under different tillage systems (Grieves House and the CSC), and overwintering cover crops grown between consecutive spring barley crops in an otherwise grass dominated rotation (UHI Orkney). In addition, the student will have access to contained environment phenotyping, including imaging and image analysis methods & genotyping facilities at the James Hutton Institute for investigating potential traits for breeding underlying genetic drivers.
This 4 year studentship opportunity is open to UK students and provides funding to cover stipend, UK tuition fees and consumable/travel costs.
Students must meet the eligibility criteria as outlined in the UKRI guidance on UK and international candidates. Applicants will have a first-class honours degree in a relevant subject or a 2.1 honours degree plus Masters (or equivalent).
This project is based at the Dundee site of the James Hutton Institute, UK.