Overview of existing excretion factors Gerard Velthof

Aim of this Task Make an overview of the different methodologies used in Europe to calculate N and P excretion factors Create a database with the excretion factors used in different reporting systems

Need for excretion factors Greenhouse gas emissions: UNFCCC Ammonia emissions Gothenborg protocol: UNECE NEC Directive: EC Manure production: EC Nitrates Directive Agri-environmental indicators, including nutrient balances: Eurostat, EEA, DG’s Models used for evaluations: GAINS, CAPRI, MITERRA

UNFCCC Countries report emissions of greenhouse gases to the UN Framework Convention on Climate Change Methods to calculate greenhouse gas emissions based on the IPCC guidelines Intergovernmental Panel on Climate Change N excretion factors needed to calculate N2O emissions from housing, manure storage and soils

IPCC Guidelines: Tiered approach Tier 1. Default excretions rates in units of N excreted per 1000 kg of animal per day Typical average animal mass values are available Tier 2. Calculation of N excretion from N intake and N retention data Typical N retention data are available Tier 3. Country-specific methodology

Example IPCC Tier 1 excretion factors

Methods in 2011 reports to UNFCCC

Excretion factors dairy cattle in NIR 2011

Excretion factors pigs in NIR 2011

Gothenborg protocol and NEC Directive Obligations to report ammonia emission to UNECE and EC EMEP/EEA air pollutant emission inventory guidebook Includes methods to calculate ammonia emission Tiered approach

EEA/EMEP Guidebook Tier 2 excretion factors Tier 1. Default NH3 emission factors in kg per animal. Tier 2. Defaults values Tier 3. Country-specific approach. More categories than Tier 2.

Comparison IPCC and EEA/EMEP factors

Nutrient balances Eurostat and OECD Both nitrogen and phosphorus Different approaches used Combination of new and existing factors, e.g. excretion factors reported for UNFCCC Excretion factors also used for other Agri-environmental indicators: ammonia and greenhouse gas emissions

GAINS model (IIASA, Vienna) Used for studies for EC, including NH3 emission Default values for excretion, except dairy cattle equation in which excretion depends of milk yield

CAPRI model (university of Bonn) Economic model used for Common Agricultural Policy Excretion is calculated as the difference between N intake and N retention of animals Based on feed statistics (FAO, Eurostat) Available feed in a region distributed over animals, based on energy and nutrient requirements

Nitrates Directive Maximum application of manure: 170 kg N per ha Estimation of manure N production (net excretion): Net excretion = gross N excretion - gaseous N losses in housing and storage Defaults: EU or country specific Calculation: farm specific Both excretion factors and N emission factors Calculated/measured manure amount or volume and N content Defaults or measurements

Nitrates Directive Guidelines to calculate manure N production are available: Ketelaars and van der Meer (1999): “Establishment of criteria for the assessment of the nitrogen content of animal manures” Used in some member states (e.g. UK and Italy), but most member states use other approaches Also recommended in HELCOM in 2003

Nitrates Directive

Differences

Causes for differences Different methodologies: from defaults to country specific approaches but even defaults differ (e.g. IPCC and EEA/EMEP) sometimes not clear (e.g Nitrates Directive) Sometimes only aggregated excretion figures for animal categories are reported Differences in age, weight, feeding systems, young animals and unit (per animal or per animal place) Lack of feed data; assumptions have to be made

Recommendations Need for a harmonized procedure to calculate excretions: Harmonization of animal categories (e.g. FSS) Recommend a set of methodologies (Tier approach) to estimate the excretion for each category To be used for all policies and reporting systems

Thank you