New research launched into managing legume mixes
Recent research has identified the most potentially beneficial mixtures of legume species to use for fertility building leys.
This is based on the mixes achieving multiple functions such as fertility building, weed control and biodiversity conservation.
In the Defra-funded Legume LINK project, 12 legume species were grown in a series of field trials, and results were fed into ecological computer models determining the effects of inter-plant competition. The modelling helped assess which species will dominate in any given mixture. This was then used to establish the properties of the resulting plant community, such as regrowth, residue break-down, weed suppression, soil fertility, and yield of the following crop.
This method has predicted that the top four mixes are various combinations of black medic (BM), red clover (RC), white clover (WC) and lucerne (LU) with the top two base mixes being BM+LU+RC and BM+LU+RC+WC. These combinations have turned out to be good for all agronomic functions including the decomposition properties after incorporation in the soil. Other species can then be added in to the base mix to bring other benefits such as increasing the value for insect pollinators and increasing the reliability of establishing the ley.
On-farm trials that have formed part of the project across the UK, representing a range of soil and climatic conditions, have also shown these four species to be among the best performers in comparison with other legume species. The optimal proportions of various components such as seed rates still need to be determined, and some species might be better substituted for others based on particular requirements in the growing system. The Legume LINK project will be publishing a species matrix which farmers and advisors can refer to when making such decisions.
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To read more about the Legume LINK project and the use of legumes to help fix nitrogen please click here.