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41.
Harper LA Sharpe RR Parkin TB De Visscher A van Cleemput O Byers FM 《Journal of environmental quality》2004,33(4):1189-1201
Ammonia (NH(3)) emissions from animal systems have become a primary concern for all of livestock production. The purpose of this research was to establish the relationship of nitrogen (N) emissions to specific components of swine production systems and to determine accurate NH(3) emission factors appropriate for the regional climate, geography, and production systems. Micrometeorological instrumentation and gas sensors were placed over two lagoons in North Carolina during 1997-1999 to obtain information for determining ammonia emissions over extended periods and without interfering with the surrounding climate. Ammonia emissions varied diurnally and seasonally and were related to lagoon ammonium concentration, acidity, temperature, and wind turbulence. Conversion of significant quantities of ammonium NH(4)(+) to dinitrogen gas (N(2)) were measured in all lagoons with the emission rate largely dependent on NH(4)(+) concentration. Lagoon NH(4)(+) conversion to N(2) accounted for the largest loss component of the N entering the farm (43% as N(2)); however, small amounts of N(2)O were emitted from the lagoon (0.1%) and from field applications (0.05%) when effluent was applied nearby. In disagreement with previous and current estimates of NH(3) emissions from confined animal feeding operation (CAFO) systems, and invalidating current assumptions that most or all emissions are in the form of NH(3), we found much smaller NH(3) emissions from animal housing (7%), lagoons (8%), and fields (2%) using independent measurements of N transformation and transport. Nitrogen input and output in the production system were evaluated, and 95% of input N was accounted for as output N from the system. 相似文献
42.
Roles of land use resolution and unit-area load rates in assessment of diffuse nutrient emissions 总被引:1,自引:0,他引:1
In contrast to its counterparts in Europe and North America, the Australian National Pollutant Inventory (NPI) includes estimates of aggregated emissions of nutrients (total nitrogen and total phosphorus) from catchments and facilities. Sparse or inadequate data limit the extent to which nutrient exports may be estimated from direct observations. The paucity of data for calibration and simulation limits the use of sophisticated models in most Australian catchments. Therefore, a simple unit-area load model-Catchment Management Support System (CMSS)-was selected to estimate aggregated catchment emissions for the NPI. Estimates from models like CMSS are sensitive to spatial and categorical resolution of land uses identified within the catchment and to nutrient generation rates selected for each land use category. Using three Hawkesbury-Nepean subcatchments, we show that while high spatial resolution of land use mapping is useful, only four or five major land use categories with carefully selected generation rates were required to estimate potential nutrient exports sufficiently well and to determine subcatchments contributing most. Nutrient emission estimates proved to be highly dependent on selection of generation rates so a bootstrap technique was adopted to reduce subjectivity and to improve estimates of confidence limits. This led to a specification of new generation rates for Natural, Unimproved pasture, Rural and Urban land uses and to establishment of uncertainty limits. 相似文献
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Koala Conservation Policy Process: Appraisal and Recommendations 总被引:1,自引:0,他引:1
Tim W. Clark Nicole Mazur † Steven J. Cork ‡ Steve Dovers § and Ronnie Harding 《Conservation biology》2000,14(3):681-690
46.
Tim Mansfeldt 《Umweltwissenschaften und Schadstoff-Forschung》2000,12(3):122-123
Ohne Zusammenfassung 相似文献
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The Kyoto Protocol of 1997 demands an emission reduction of climate-affecting gases in various industrial sectors. In this context CO2 is one of the relevant gases and waste management is one of the relevant sectors. Referring to the situation in Europe, waste incineration is one of the major sources of CO2 in the waste management sector. The Kyoto Protocol, however, only covers CO2-emissions originating from fossil fuels, whereas the incineration of renewable materials, e.g. wood, is considered to be climate-neutral since it does not make any net contribution to the CO2 inventory of the atmosphere. Unlike the situation with municipal waste, there is little if any information on the CO2-emissions caused by the incineration of hazardous waste in specialized plants, and the renewable fraction in these materials. The present paper focuses on this gap of knowledge. Taking the full-scale hazardous waste incineration plant in Biebesheim, Germany, as an example, a carbon balance was set up for the whole-plant taking into account all other material flows. Afterwards the determination of the proportion of renewable materials in the hazardous waste incinerated by means of the radiocarbon method (14C) is reported. On the basis of the results, optimization potentials are discussed. 相似文献
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Xu S Hao X Stanford K McAllister TA Larney FJ Wang J 《Journal of environmental quality》2007,36(6):1914-1919
Composting may be a viable on-farm option for disposal of cattle carcasses. This study investigated greenhouse gas emissions during co-composting of calf mortalities with manure. Windrows were constructed that contained manure + straw (control compost [CK]) or manure + straw + calf mortalities (CM) using two technologies: a tractor-mounted front-end loader or a shredder bucket. Composting lasted 289 d. The windrows were turned twice (on Days 72 and 190), using the same technology used in their creation. Turning technology had no effect on greenhouse gas emissions or the properties of the final compost. The CO2 (75.2 g d(-1) m(-2)), CH4 (2.503 g d(-1) m(-2)), and N2O (0.370 g d(-1) m(-2)) emissions were higher (p < 0.05) in CM than in CK (25.7, 0.094, and 0.076 g d(-1) m(-2) for CO2, CH4, and N2O, respectively), which reflected differences in materials used to construct the compost windrows and therefore their total C and total N contents. The final CM compost had higher (p < 0.05) total N, total C, and mineral N content (NO3*+ NO2* + NH4+) than did CK compost and therefore has greater agronomic value as a fertilizer. 相似文献