Kristina von Bobrutzki

A comparative study among H2O-balance, heat balance, CO2-balance and radioactive tracer gas technique for airflow rates measurement in naturally ventilated dairy barns

The major problem of natural ventilation is the lack of accurate measurement methods for air exchange rates (AER) which is crucial for emissions quantification. This paper aims at comparing four methods and to recommend thereof one method for further developments. Thirty six experiments were performed to study the AERs in a naturally ventilated dairy barn through four summer seasons and three winter seasons. AERs were determined using moisture (H2O) balance, heat balance (HB), CO2-balance and radioactive tracer gas technique (TGT). The statistical analyses were correlation analysis, regression model, ANOVA and t-test. Continuous measurements of CO2 concentrations, temperature and relative humidity inside and outside the barn were performed. H2O-balance showed reliable results through winter and slightly acceptable results through summer. HB showed slightly acceptable results through summer and unsatisfactory results through winter. CO2-balance showed unexpected high differences to the other methods in some cases. TGT showed reliable results compared to all methods and is independent on physiological parameters. Therefore, TGT should be further developed. The airflow rates (AFRs), subject to TGT, were 0.12 m3 s-1 m-2, 1.15 m3 s-1 cow-1, 0.88 m3 s-1 LU-1 (LU is livestock unit of 500 kg), 395 m3 s-1 and 470 kg air s-1 through summer, and 0.08 m3 s-1 m-2, 0.83 m3 s-1 cow-1, 0.64 m3 s-1 LU-1, 275 m3 s-1 and 328 kg air s-1 through winter. AERs were 37, 81, 63 and 62 h-1 through summer, and 40, 143, 61 and 39 h-1 through winter subject to H2O-balance, HB, CO2-balance and TGT, respectively.

Ammonia emissions from a broiler farm: spatial variability of airborne concentrations in the vicinity and impact on adjacent woodland

Agricultural NH3 emissions affect air quality and influence the nitrogen cycle. In the subject study, NH3 emissions from a broiler farm and the resulting atmospheric concentrations in the immediate vicinity during three growing cycles have been quantified. Additionally, vegetation along a transect in an adjacent woodland was analysed. The emissions were as high as 10xa0kgxa0NH3u2009h−1 and the atmospheric concentrations ranged between 33 and 124xa0μgxa0NH3u2009m−3xa0per week in the immediate vicinity. Measurements of the atmospheric concentrations over 7xa0weeks showed a substantial decline of mean concentrations (based on a 3-week average) from ∼13 to <3xa0μgxa0NH3u2009m−3, at 45- and 415-m distance from the farm. Vegetation surveys showed that nitrophilous species flourished when they grew closest to the farm (their occurrence sank proportionately with distance). A clearly visible damage of pine trees was observed within 200xa0m of the farm; this illustrated the significant impact of NH3 emissions from agricultural sources on the sensitive ecosystem.

The Influence of Building Equipment and Operation on the Air Exchange Rates throughout a Naturally Ventilated Dairy Barn

Naturally ventilated barns have gained wide acceptance worldwide, due to the easy design and the low energy consumption. The inside climate and the air exchange rate (AER) of such buildings is mainly affected by the outside conditions. The AER has a great influence on emission fluxes. There is no reference method for AER estimation in naturally ventilated barns but several methods with different pros and cons and each with uncertainties have been used. The aim of this study is to evaluate the influence of side curtains of a naturally ventilated barn on AER as well as the reliability of tracer gas technique in AER quantification throughout these kinds of barns. The AER and the emission fluxes were measured in a naturally ventilated dairy barn in north Germany. The AER was estimated using two methods. The first one is the concentration decay of radioactive isotope tracer-gas Krypton (85Kr-M) with two different evaluation procedures: (1) AER obtained from the sum of impulses for all 85Kr-detectors (sum-85Kr-M), and (2) AER obtained from the arithmetic average of the single 85Kr-detectors (average-85Kr-M). The second method is the CO2-mass balance model (CO2-M). The meteorological parameters were recorded inside and outside the barn, as well as the concentrations of ammonia (NH3), carbon dioxide (CO2) and methane (CH4). Pearson correlation analysis was performed and linear regression models were fitted. On this basis, the influence of the side curtains on AER was investigated and evaluated. The AERs, derived from CO2-M, were 35.3±14.6 h-1 and 22.0±7.1 h-1 for opened and closed side curtains, respectively. The 85Kr-M resulted in higher AERs values compared to CO2-M by 0.15±0.13 for sum-85Kr- M and by 3.66±1.17 for average-85Kr- M. The emission fluxes according to CO2-M were during the summer seasons 124, 538 and 45,600 g d-1AU-1 for NH3, CH4, and CO2, respectively. During winter seasons they were 64, 348 and 42,700 g d-1AU-1.

Awassi sheep keeping in the Arabic steppe in relation to nitrous oxide emission from soil

Abstract Sheep husbandry is the main source of income for farmers in arid zones. Increasing sheep production on steppes may increase the greenhouse gas production. The objective of this study was to investigate the nitrous oxide (N2O) emissions from the steppes for Awassi sheep keeping and feed cropping in arid zones such as Syria. The methodology developed by the Intergovernmental Panel on Climate Change (IPCC) was used to estimate N2O emissions. A survey was conducted on 64 farms in Syria to gather data for analysis. Precipitation and crop yield data from 2001 to 2009 were also used for calculation and modelling. Sheep-keeping systems, precipitation, year and the region have significant effects on N2O emissions (p < 0.05). Emissions of N2O from lands with extensive, semi-intensive and intensive systems were 0.30 ± 0.093, 0.598 ± 0.113 and 2.243 ± 0.187 kg sheep−1year−1, respectively. Crop production was higher in regions with high precipitation levels, which helped to reduce N2O emissions. Using more residuals of wheat, cotton and soya as feed for sheep in the keeping systems evaluated may decrease the overuse of steppe regions and N2O emissions. Nitrous oxide emissions of N2O from sheep-keeping areas can be reduced by changing sheep-keeping systems and increasing the crop production in arid zones through artificial irrigation.

Spatial variability of ambient ammonia in the vicinity of a broiler farm.

Ammonia (NH3) emissions from agricultural sources affect the air quality in negative manner. The objective of this study was to quantify NH3 emissions from a commercial broiler farm by measuring weekly averages of atmospheric NH3 at different locations at the same time during two growing cycles. Thus, it was possible to analyze the spatial occurrence of NH3 in air and assess the environmental impact of the farm. For detecting NH3 in air, passive sampling was used at five locations in the immediate vicinity of the farm. The inside NH3 concentrations and the performance of the air volumetric flow rate were measured continuously during the growing cycles inside one broiler barn. In addition, the wind direction was detected.

Ammonia Emission from Broiler Houses and the Dispersion of this Emission in the Surroundings

The necessary ventilation of animal houses leads to emissions and air-borne pollution in the surroundings of these buildings. Ammonia can cause direct damage to plants in the immediate surroundings of livestock buildings and the odor emissions can lead to annoyances. Therefore, in Germany, guidelines exist to keep minimum distances between livestock buildings, sensitive plants and ecosystems, and living areas. To calculate the necessary distance, knowledge about the emission streams from the livestock building and about the dispersion behavior are needed. Therefore, measurements were done regarding emission streams and the dispersion process for a broiler farm.