| Autor: |
Hensen, A.1 hensen@ecn.nl, Groot, T.T.1, van den Bulk, W.C.M.1, Vermeulen, A.T.1, Olesen, J.E.2, Schelde, K.2 |
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| Zdroj: |
Agriculture, Ecosystems & Environment. Feb2006, Vol. 112 Issue 2/3, p146-152. 7p. |
| Abstrakt: |
Abstract: The greenhouse gas emissions from agricultural systems contribute significantly to the national budgets for most countries in Europe. Measurement techniques that can identify and quantify emissions are essential in order to improve the selection process of emission reduction options and to enable quantification of the effect of such options. Fast box emission measurements and mobile plume measurements were used to evaluate greenhouse gas emissions from farm sites. The box measurement technique was used to evaluate emissions from farmyard manure and several other potential source areas within the farm. Significant (up to 250g CH4 m−2 day−1and 0.4g N2Om−2 day−1) emissions from ditches close to stables on the farm site were found. Plume emission measurements from individual manure storages were performed at three sites. For a manure storage with 1200m3 dairy slurry in Wageningen emission factors of 11±5g CH4 m−3 manureday−1 and 14±8mg N2Om−3 manureday−1 were obtained in February 2002. Mobile plume measurements were carried out during 4 days at distances between 30 and 300m downwind of 20 different farms. Total farm emissions levels ranged from 14 to 95kg CH4 day−1 for these sites. Expressed as emission per animal the levels were 0.7±0.4kg CH4 animal−1 day−1 for conventional farms. For three farms that used straw bedding for the animals1.4±0.2kg CH4 animal−1 day−1 was obtained. These factors include both respired methane and emission from manure in the stable and the outside storages. For a subset of these farms the CH4 emission was compared with monthly averaged model emission calculations using FarmGHG. This model calculates imports, exports and flows of all products through the internal chains on the farm using daily time steps. The fit of modelled versus measured data has a slope of 0.97 but r 2 =0.27. Measurements and model emission estimates agree well on average, for large farms within 30%. For small farms the differences can be up to a factor of 3. CH4 emissions during winter seem to be underestimated. [Copyright &y& Elsevier] |
| Databáze: |
GreenFILE |
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