I. Title of the Best Practice

II. Overview of the Best Practice

A. Characteristics of initiatives to reduce Methane and Nitrous Oxide emissions from agriculture

The UK inventory of greenhouse gases shows that in 1997, 36% of the UK's methane emissions and 52% of nitrous oxide emissions came from agriculture. Agricultural emissions are predicted to fall although their significance in terms of the UK's total emissions may grow with further pressure on overall reduction targets, and because emissions from other sources are predicted to decline more rapidly than from agriculture.

1. Decreased Nitrous oxide emissions through reducing Nitrogen surpluses in agricultural systems and encouraging efficient use of resources
Nitrous oxide (N2O) is emitted from the nitrogen in fertilisers and animal manures as a result of the soil processes nitrification and denitrification. These processes are part of the natural nitrogen (N) cycle, and agricultural systems are dependant on them to recycle nutrients and break down organic material added to the soil. N is the primary nutrient needed for crop growth, and is added in chemical fertilisers and manures applied to soil by farmers. Most agricultural systems operate at a N surplus, with inputs exceeding crop offtake. This means that a pool of N is built up which is available to be lost, either as N2O or in other potentially pollution forms such as ammonia, a contributor to acid rain and terrestrial eutrophication, or nitrate, which is leached into water. The N surplus in England and Wales averages at 100 kg N/ha agricultural land.

The UK Government is actively encouraging farmers to reduce their N surpluses through matching fertiliser applications to crop needs, and more efficient management of the N in livestock manures. This involves re-educating farmers to think of livestock manures and slurries as a nutrient and soil-conditioning resource, rather than as a waste product. These improvements, together with reductions in fertiliser applications as a result of reducing cereal price support, are estimated lead to a 12% decrease in fertiliser applications over the next 10 years.

A variety of measures exist to reduce N surpluses, ranging from compulsory management restrictions in Nitrate Vulnerable Zone areas to voluntary guidelines and advice provided by MAFF and its agencies.

2. Decreased methane emissions through improved diets and productivity in intensive cattle production
Methane is emitted from the digestive systems of ruminant animals such as cattle and sheep, and from their manures. The amount of methane emitted from the digestive process enteric fermentation is strongly influenced by the diet of the animal. Diets which are high in complex carbohydrates and roughage, typically forage-based diets, are difficult to digest and emit more methane. Diets with high levels of simpler carbohydrates and starch, typically grain-based diets, are easier to digest and emit less methane.

The methane emitted during enteric fermentation represents a loss of feed energy to the animal, and livestock scientists have been developing more efficient diets in order to enhance animal productivity long before concerns over methane's greenhouse potential arose. Methane emissions per litre of milk have decreased by an estimated 30% during the past 40 years in the EU, as a result of improved diets and productivity. In the UK, where total milk production is controlled by a quota, productivity increases have resulted in declining dairy cow numbers as fewer animals are required to produce the national milk quota, which in turn results in decreased manure production and associated environmental problems.

B. Reasons for inclusion as Best Practice
Both the initiatives described above are appropriate to be considered as Best Practice because they have real and lasting impacts on agricultural greenhouse gas emissions, and make important contributions to the overall environmental and economic sustainability of a country's agriculture.

Controlling N surpluses reduces N2O emissions at source, rather than attempting to control individual processes within complex biological systems. All sources of N pollution are reduced at the same time. The initiative encourages farmers to focus more closely on efficient resource use, particularly with respect to animal manures and slurries, which has numerous indirect benefits. Reducing N surpluses has already resulted in reduced N2O emissions and is projected to continue to do so.

Reducing CH4 emissions from enteric fermentation by improving diet is non-intrusive and results in dramatic increases in productivity. This measure is particularly relevant for countries which are in the process of intensifying their agricultural systems and require increased productivity levels to feed growing urban populations. Emissions from the UK dairy herd have decreased by 8% from 1990 to 2000, and are projected to continue to decrease at a similar rate, as a result of improved productivity.

C. Problems and their solutions
Reducing N surpluses requires several adjustments to normal farm management practice, and depends on a combination of legislation and guidance. The UK Government has invested considerable funds in providing educational and advisory material to the farming community. Imposition of new legislation on a hard-pressed sector often results in resistance from the industry, although care is always taken to demonstrate the necessity of the legislation and to emphasise the possible benefits of efficiency increases of compliance.

Improving productivity in dairy herds has been largely industry driven, and requires investment for research and development. However, the benefits to the farming sector overcome initial cost barriers very quickly. Intensification of the dairy sector, and associated moves away from grazed systems and into partly housed systems, has a suite of environmental impacts including biodiversity, resource use and welfare implications.

III. Categorizing the Best Practice

N2O: Reducing Nitrogen surpluses
1. Classifications
( X ) Regulatory approach
( ) Practical action
( ) Social network mechanism

2. Social actions involved
( ) Citizens
( X ) Central Government
( ) Local Government
( X ) Business

3. Sector(s)
( ) Energy
( ) Household
( ) Transportation
( ) Industrial enterprises
( ) Other (Non-Industrial) Business
( X ) Agriculture/land use/forestry
( ) Other

4. Target greenhouse gas(es)
( ) CO2
( ) CH4
( X ) N2O
( ) HFC
( ) PFC
( ) SF6
( ) Other

CH4: Improving dairy herd productivity
1. Classifications
( ) Regulatory approach
( ) Practical action
( X ) Social network mechanism

2. Social actions involved
( ) Citizens
( ) Central Government
( ) Local Government
( X ) Business

3. Sector(s)
( ) Energy
( ) Household
( ) Transportation
( ) Industrial enterprises
( ) Other (Non-Industrial) Business
( X ) Agriculture/land use/forestry
( ) Other

4. Target greenhouse gas(es)
( ) CO2
( X ) CH4
( X ) N2O
( ) HFC
( ) PFC
( ) SF6
( ) Other

IV. List of Attachments

Code of Good Agricultural Practice for the Protection of Air
Guidelines for Farmers in NVZs
Farm Waste Management Plan
Managing Livestock Manures (3 booklets)

V. Contact

Dr I Davidson
Scientific Advisor
Rural and Marine Environment Division
Ministry of Agriculture, Fisheries and Food
Rm 148 Nobel House
17 Smith Square
London SW1P 3JR
UK
tel: (00 44) 171 238 5585
Fax: (00 44) 171 238 6700
email: i.davidson@env.maff.gov.uk