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Legume-supported cropping systems for Europe

Legume Futures Report 3.8/6.6

Policy implications of the environmental and resource effects of legume cropping

Prepared by:

Michael Williams, Jane Stout and Susannah Cass, Trinity College Dublin, Ireland

Jenny Fischer and Hewart Bhm, Thnen-Institute for Organic Farming, Westerau, Germany.

Donal Murphy-Bokern, Germany

Tom Kuhlman, Wageningen University, The Netherlands

Fred L. Stoddard and Kristina Lindstrm, University of Helsinki, Finland

Christine Watson, Valentini Papa and Kairsty Topp, Scotland's Rural College, United Kingdom

Moritz Reckling, Sara Preiel, Andrea Bues and Peter Zander, Leibniz Centre for Agricultural Landscape Research, Germany

Marie Trydeman Knudsen, Jrgen E. Olesen, John E. Hermansen and Kirsten Schelde, Department of Agroecology, Aarhus University, Denmark

25 February 2014

Legume Futures

Legume-supported cropping systems for Europe (Legume Futures) is an international research project funded from the European Unions Seventh Programme for research, technological development and demonstration under grant agreement number 245216. The Legume Futures research consortium comprises 20 partners in 13 countries.

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The information presented here has been thoroughly researched and is believed to be accurate and correct. However, the authors cannot be held legally responsible for any errors. There are no warranties, expressed or implied, made with respect to the information provided. The authors will not be liable for any direct, indirect, special, incidental or consequential damages arising out of the use or inability to use the content of this publication.

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Citation

Please cite this report as follows:

Topp, K., Watson, C., Papa, V. Williams, M., Stout, J., Cass, S., Fischer, J., Bhm, H., Murphy-Bokern, D., Kuhlman, T., Stoddard, F.L. Lindstrm, K., Reckling, M., Preiel, S., Bues, B., Zander, P., Knudsen, M.T., Olesen, J.E., Hermansen, J.E.M., Schelde, K. 2014. Policy implications of the environmental and resource effects of legume cropping. Legume Futures Report 3.8/6.6. Available from www.legumefutures.de

CONTENTS

FOREWORD4

SUMMARY5

INTRODUCTION6

RESOURCE AND ENVIRONMENTAL EFFECTS7

Resource effects7

Reduced use of synthetic nitrogen fertiliser7

Phosphorus9

Farm-level environmental effects10

Nitrous oxide emissions10

Emission factors for nitrous oxide flux14

Leaching of nitrogen14

Impacts of legume cropping on above and below ground biodiversity17

Assessments of crop products and cropping systems17

Assessments of protein crop-based animal production20

POLICY IMPLICATIONS24

FOREWORD

Legume Futures, "Legume-supported crop rotations for Europe", is an international research project funded under the European FP7 programme. It has 20 partners in 13 countries. The project aims to develop and assess legume-supported cropping systems that improve the economic and environmental performance of farming in Europe.

Legume Futures produces information relevant to both the development of legume-supported cropping by farmers and other actors in the agricultural sector and to the policy community. This report is aimed at the policy community in particular. The purpose is to provide a synthesis of information about the environmental impact of legume crops, including both background literature information and results of research in Legume Futures. From our assessments of the economic performance of legume crops, we know the policy community will remain key to the development of legume cropping in Europe for the foreseeable future.

Kairsty Topp

SRUC Edinburgh, UK

27 February 2014

SUMMARY

Compared with other major agricultural regions of the world, Europe is characterised by a lower share of legumes in cropping systems. This is because land is preferentially allocated to cereals or to oilseeds in most of Europes cropping regions. Cereals grow particularly well in Europe generally. The demand for plant protein which current cropping cannot fully meet comes from a livestock sector scaled to meet the EUs high demand for meat. Our assessment of the environmental impact of increasing legume cropping concludes that increasing the production of protein crops would be an important contribution to the sustainable development of European agricultural and food systems. The direct farm and regional level environmental benefits combined with the indirect benefits arising from the better balance of EU agriculture and trade justify public intervention. We recommend that policy makers focus on the public benefits of increased legume cropping in the context of a wider re-balancing of European agricultural and food systems. This requires an integrated approach to policy development, which sees legumes expansion as a component of a wider effort to develop a more sustainable agriculture and food system.

The reform of the common agricultural policy that is now being implemented includes two measures specific to protein crops: the consideration of nitrogen-fixing crops as part of the Ecological Focus Areas and limited provision for national coupled support for protein crops. In addition, protein crops are the subject of the first focus group advising the EU European Innovation Partnership on agriculture and food.

INTRODUCTION

Legumes play a vital role in European agriculture, but most of the legumes used are grown outside Europe. The EU imports 70% of its requirement for high-protein crop raw material, mostly as soya from South America. This accounted for about 14% of the world-wide production of soya bean from about 15 M ha of arable land outside the EU in 2011. Over the 50 year period 1961-2011, the production of beef, pig and poultry meat in the EU-27 has increased from 17 to 43 million t, with a particularly large increase in pig and poultry meat (See Legume Futures Report 5.3). While demand for livestock feed increased, our production of protein crops has decreased (Figure 1). Protein crops are now grown on only 1.8% of arable land in the EU, compared with 4.7% in 1961. In contrast, they are grown on about 8% of arable land in Australia and Canada. The direct human consumption of pulses has also declined. It is estimated that only 11-15% of pea and 9-14% of faba bean grown are now used for human consumption. A major underlying driver behind the reduction in the proportion of arable land used for protein crops is the increased comparative advantage in the production of starch-rich cereals.

Figure 1. Production areas of different protein crops in the EU-27 in relation to policy events (1961-2011). Data source: FAOSTAT (2013)

RESOURCE AND ENVIRONMENTAL EFFECTS

Particularly in developing public policy, it is important to distinguish between the resource and environmental effects of legume cropping. Biological nitrogen fixation, which is a distinguishing feature of cultivated legumes, has both resource and environmental effects.

Resource effectsReduced use of synthetic nitrogen fertiliser

Protein crops require almost no N fertiliser to express their yield potential while the cereal crops they normally replace typically receive 100-200 kg N/ha. As a result, the production of protein crops directly reduces nitrogen fertiliser use. Furthermore, the large quantity of nitrogen in the residues of legumes allows the saving of considerable amounts of nitrogen fertiliser in the following crops (Fig. 2).

Figure 2:The on-farm nitrogen cycle, showing the effect of legume pre-crops

The residual N combined with other precrop effects such as the reduction in root diseases that reduce nitrogen uptake can be expressed as a fertiliser nitrogen equivalent. This is reported to be as much as 120 kg N/ha (Chalk 1998; Kpke and Nemecek 2010). However, the public benefits of this depends on how well farmers take it into account when fertilising the following crops. A survey of agronomic experts for the Legume Futures project reported that the savings made in practice are significantly less (Table 1). It appears that many farmers fertilise the crop after legumes as they would after other crops and treat the legume-derived N as a bonus that supports the higher yield and protein content normally achieved in these situations. This means the full potential environmental and resource benefits of protein crops are often not realised. Forage legumes fix significantly more nitrogen than grain legumes due to their high biomass production and longer growth period.

Studies using nitrogen labelled with non-radioactive isotopes (15N labelling methods) show that only a relatively small proportion of nitrogen residue from protein crops is used by the next crop through direct take-up (Fig. 2). As much as 75% of the total residue enters the soil reserve, providing a resource for the longer-term supply of other crops. Thus there is a resource impact for the farm and an environmental impact due to reduction in fertiliser manufacture.

Table 1: Fertilisation practices for major protein crops and winter wheat in five case study regions across Europe

Crop2

Yield(t/ha)

Regional average mineral fertiliser applied (kg/ha)

Exper