Animal production is the main source of atmospheric ammonia in Europe. The volatilisation or emission of ammonia from field-applied animal manures, which accounts for approximately 40% of the total agricultural emissions, not only represents a significant financial cost to the European farmers in terms of the loss of plant available nitrogen but also results in environmental pollution.
The European expertise in ammonia emissions from field-applied manure is confined to a relatively small group of researchers. Little comparison of national datasets was conducted so far. The Concerted Action ALFAM was conceived to improve the co-operation between the various national research groups and to share the research results, so that their potential can be fully exploited.
The main objectives of ALFAM were to:
· Collate and analyse European data on ammonia emission from field-applied manure and to describe the relationships between agricultural practice, weather and ammonia losses.
· Promote the comparison of data collected in different European countries by describing standard techniques for measuring ammonia emissions and agreeing measurement protocols.
· Evaluate both the efficiency of the techniques available to reduce ammonia emissions from field-applied manure and their economic implications.
· Identify the requirements for future research and development.
· Disseminate the findings to policymakers and advisors.
Results
· An ammonia emission database was developed by using data from manure application experiments conducted in eight countries. It contains about 7000 records (Swiss contribution: about 1000) and is publicly accessible via the Internet (http://www.alfam.dk/).
· A statistical analysis of the data showed that emissions could be described mathematically by a Michaelis-Menten-type equation with the loss rate as the output variable (R2 = 80%). The variables significantly affecting ammonia emissions are soil moisture content, air temperature, wind speed, manure type, dry matter content of manure, ammoniacal nitrogen content of manure, application method (including soil incorporation) and application rate. The model is publicly available via the Internet (http://www.alfam.dk/).
· A review on different measurement techniques was conducted. It contains detailed information on methods used to measure ammonia emissions from field applied manure (soil balance or N recovery method, micrometeorological methods, enclosure methods, controlled gas release ratio methods, modelling), on sensors for measuring ammonia concentrations in air or ammonia fluxes and a descriptions of the most commonly used methods in experiments (micrometeorological mass-balance, wind tunnels, equilibrium concentration method).
· A overview was assembled on all the possible abatement strategies; namely: Dietary measures manure treatments, amendments/adsorbents/additives, low emission manure spreading techniques.
· A model has been developed to calculate the costs of manure application. Using input data from a number of European countries application costs varied from € 1.7 to 13.0 per m3 manure applied. Simulations showed that for farms with an annual manure production of 1000-3000 m3, the costs of manure application by low emission techniques were on average ca. 2 Euro per m3 higher than for surface spreading. For larger farms the difference increased, for smaller ones it decreased.
· A detailed assessment of future research and development needs was conducted.
· The results of the project were reviewed with extension and policy experts of all participating countries and with representatives of the EU commission.
· The final report of the project is available under
http://www.alfam.dk.
