Make legumes do the leg work (Organised by ORC)

Legumes are extremely versatile and valuable components of sustainable farming systems. Current research and best practices for fully utilising legumes on the farm will be presented and discussed by researchers and farmers.

Henry Creissen (ORC): Chair

Session summary

Dr Hannah Jones from Reading University outlined some of the key results from the LegLINK project describing some of the agronomic features of the fertility-building legume ley as well as the benefits to the environment. Although white clover, red clover, lucerne and black medic were identified as key species, the best suited legume species may differ according to site specific environmental pressures such as drought or soil pH. The importance of inoculation was also highlighted as specific species of Rhizobia bacteria are required nodule associations with specific legume species. There are often good as well as bad, parasitic, Rhizobia species present in the soil. The composition of which will often depend on the pH. Hannah also presented evidence of positive effects of the ley on subsequent grain and forage crops. A more diverse ley mixture will often release N at a slower rate providing better nutrient supply to a following wheat crop , thus increasing protein content and reducing N leaching. Forage crops were also of more consistent quality following the more diverse ley. Pollinators also benefit from a diverse ley which provides a steadier food source over the season than a simple white clover ley which flowers mainly in June.

John Newman then went on to describe his experience of growing legumes as a farmer nearer Cirencester. John has been part of several on-farm trials for the OSCAR and LegLINK projects comparing the diverse All Species Mixture (ASM) to the standard farm ley. John is particularly interested in the many benefits of diverse leys for animal health and pollinators and has been doing some simple trials investigating the potential for using the ley for grazing livestock. The cost effectiveness of different ley species is also an important factor in his system.

The final speaker, Prof Christine Watson from SRUC, outlined some insights from the Legume Futures project. The 4-year project aimed at promoting legumes in a range of farming systems across Europe to replace. There is currently an increasing need to replace imported soya as livestock feed due to increasing costs and emissions. The project could demonstrate lower N20 emissions in legume crops as well as differences among varieties. After posing the question whether grain legumes or forage legumes fix more N, Christine described the important role that legumes in permanent pasture in N fixing and soil improvement. The point was also highlighted that there is a need for adapted varieties of novel legume crops and that a lack of knowledge among growers still needs to be met.

Key conclusions

The discussion that followed the presentations brought out the following points:

  • Micronutrient deficiencies and nematode pest problems still may need to be addressed for legume establishment.
  • Farmers discussed the agronomy of establishing ley seed mixtures such as the different sized seeds, testing soil additionally for ph and calcium and underlined the need to roll after sowing the ley.
  • On the subject of whether soya could or should be grown in the uk, many participants thought that we should be making use of more adapted legumes, such as lupins, for home-grown livestock feed.
  • The better economics of growing legumes such as soya for human consumption rather than just animal feed was also suggested.

Action points

  • ORC are planning to set up on-farm field trials with new soya varieties from Germany which may also compare soya to lupins in the uk climate.
  • Although the benefits of diverse legume ley mixtures can be clearly demonstrated, the additional cost of seed should be addressed to facilitate uptake by farmers.

Individual speaker presentations and abstracts

Hannah Jones (Reading University): Legumes leys: improving fertility building, forage quality and biodiversity (3.47mb pdf file)

Some of the functions of short term leys will be discussed; how yield and quality of first wheat in the rotation can be improved; the central role these leys have in enhancing below and above ground organisms which support crop productivity; and some early work on forage yield and quality. Ley management will include mowing frequency effects, and plough incorporation depth. The infrequently used but potentially valuable lucerne has the capacity to deliver on your farm, but rhizobia soil communities in your soil will pre-determine its success, should you inoculate?

John Newman (Abbey Home Farm): Fertility building ley field labs: A farmers perspective (805kbb pdf file)

The use of legumes and fertility building are key parts of organic farming and at Abbey Home Farm we have been building up our experience in growing diverse legume mixes both for our own interest and through farmer participatory research. The drivers for this are increasing forage yield, improving nitrogen fixing, environmental resilience, benefiting pollinators and animal welfare. Defra also proposes to provide support for diverse legume mixtures as an organic option in the New Environmental Land Management Schemes under CAP reform. I will be discussing our experiences of growing a range of diverse legume and grass mixes on farm, from our own farm perspective and also focusing on our OSCAR trial plots, an EU funded project run in the UK by ORC, and a Duchy Originals Future Farming Field Lab.

Christine Watson (Abbey Home Farm): Legume Futures: Exploring the value of legumes to European agriculture (2.17mb pdf file)

Legumes have historically played a central role in Euro-pean agriculture, generating critically important inputs of nitrogen to support crop growth and providing feed for livestock in the form of forage and grain legumes. Grain legumes are now grown on only 1.8% of arable land in Europe compared with 4.6% fifty years ago. In the forage sector legumes have largely given way to heavily fertilised grassland over the same period. This sits against a growing European demand for meat and an increasing reliance on imported soya for livestock production. The Legume Futures project set out to deliver knowledge and technology for the optimisation of the use of legumes in European agricultural systems and to promote the partnerships needed to deliver the policy outcomes sought. We used a combination of case studies, modelling and new data to improve understanding of robust rotation and system design for improved legume production, quantification of the potential ecosystem services delivered by legumes and the economics of legume production across the EU. Fundamental to the integrated outcome of the project, we also addressed the policy background and options for policy support within Europe.

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