Hristov, A. N., Hanigan, M., Cole, A., Todd, R., McAllister T. A., Ndegwa, P. and Rotz, A. 2011. Review: Ammonia emissions from dairy farms and beef feedlots. Can. J. Anim. Sci. 91: 1–35. Ammonia emitted from animal feeding operations is an environmental and human health hazard, contributing to eutrophication of surface waters and nitrate contamination of ground waters, soil acidity, and fine particulate matter formation. It may also contribute to global warming through nitrous oxide formation. Along with these societal concerns, ammonia emission is a net loss of manure fertilizer value to the producer. A significant portion of cattle manure nitrogen, primarily from urinary urea, is converted to ammonium and eventually lost to the atmosphere as ammonia. Determining ammonia emissions from cattle operations is complicated by the multifaceted nature of the factors regulating ammonia volatilization, such as manure management, ambient temperature, wind speed, and manure composition and pH. Approaches to quanti...

/pdf/review-ammonia-emissions-from-dairy-farms-and-beef-feedlots1-12bcp1xe7f.pdf

Review: Ammonia emissions from dairy farms and beef feedlots1

Background:Emergence and spread of antibiotic resistance has become a global health threat and is often linked with overuse and misuse of clinical and veterinary chemotherapeutic agents. Modern ind...

Antibiotics, bacteria, and antibiotic resistance genes: aerial transport from cattle feed yards via particulate matter.

Different types of assessment tools have been developed in Europe with the purpose of determining the environmental impact of various livestock production systems at farm level. The assessment tools differ in terms of which environmental objectives are included and how indicators are constructed and interpreted. The paper compares typical tools for environmental assessment of livestock production systems, and recommends selected indicators suitable for benchmarking. The assessment tools used very different types of indicators ranging from descriptions of farm management and quantification of input to estimates of emissions of, e.g., nitrate and ammonia. The indicators should be useful in a benchmarking process where farmers may improve their practices through learning from farms with better agri-environmental performance. An example of this is given using data on P-surplus on pig farms. Some indicators used the area of the farm as the basis of the indicator—e.g. nitrogen surplus per hectare—while others were expressed per unit produced, e.g. emission of greenhouse gasses per kilogram milk. The paper demonstrates that a comparison of organic vs. conventional milk production and comparison of three pig production systems give different results, depending on the basis of the indicators (i.e. per hectare or per kilogram product). Indicators linked to environmental objectives with a local or regional geographical target should be area-based—while indicators with a global focus should be product-based. It is argued that the choice of indicators should be linked with the definition of the system boundaries, in the sense that area-based indicators should include emissions on the farm only, whereas product-based indicators should preferably include emissions from production of farm inputs, as well as the inputs on the actual farm. The paper ends with recommendations for choice of agri-environmental indicators taking into account the geographical scale, system boundary and method of interpretation. D 2005 Elsevier B.V. All rights reserved.

Environmental assessment tools for the evaluation and improvement of European livestock production systems

The global threat caused by increasing surface temperature has led to negative climate changes. One of the greenhouse gases responsible for this global warming is methane. It is emitted naturally and anthropogenically from different sources and its concentration in the atmosphere has assumed alarming proportions. Its devastating consequences on climate change and atmospheric chemistry have made it to be a focus of intense scrutiny and study. The anthropogenic sources of its emissions are generally grouped under three sectors of agriculture, energy and waste. The past emission trends of methane from these sectors are investigated through their sources while mitigation and abatement strategies are suggested. It is observed that the agricultural sector emits the highest amount of methane, followed by the energy and waste sectors, respectively.

Methane emission by sectors: A comprehensive review of emission sources and mitigation methods

Livestock manure management accounts for almost 10% of greenhouse gas emissions from agriculture globally, and contributes an equal proportion to the US methane emission inventory. Current emissions inventories use emissions factors determined from small-scale laboratory experiments that have not been compared to field-scale measurements. We compiled published data on field-scale measurements of greenhouse gas emissions from working and research dairies and compared these to rates predicted by the IPCC Tier 2 modeling approach. Anaerobic lagoons were the largest source of methane (368 ± 193 kg CH4 hd(-1) yr(-1)), more than three times that from enteric fermentation (~120 kg CH4 hd(-1) yr(-1)). Corrals and solid manure piles were large sources of nitrous oxide (1.5 ± 0.8 and 1.1 ± 0.7 kg N2O hd(-1) yr(-1), respectively). Nitrous oxide emissions from anaerobic lagoons (0.9 ± 0.5 kg N2O hd(-1) yr(-1)) and barns (10 ± 6 kg N2O hd(-1) yr(-1)) were unexpectedly large. Modeled methane emissions underestimated field measurement means for most manure management practices. Modeled nitrous oxide emissions underestimated field measurement means for anaerobic lagoons and manure piles, but overestimated emissions from slurry storage. Revised emissions factors nearly doubled slurry CH4 emissions for Europe and increased N2O emissions from solid piles and lagoons in the United States by an order of magnitude. Our results suggest that current greenhouse gas emission factors generally underestimate emissions from dairy manure and highlight liquid manure systems as promising target areas for greenhouse gas mitigation.

/pdf/greenhouse-gas-emissions-from-dairy-manure-management-a-2dadl4i8sp.pdf

Greenhouse gas emissions from dairy manure management: a review of field-based studies

Standardization of flux chamber and wind tunnel flux measurements for quantifying volatile organic compound and ammonia emissions from area sources at animal feeding operations

Researchers and practitioners have used wind tunnels and flux chambers to quantify the flux of volatile organic compounds (VOCs), ammonia, and hydrogen sulfide and estimate emission factors from animal feeding operations (AFOs) without accounting for effects of air velocity or sweep air flow rate Laboratory experiments were conducted using a small rectangular wind tunnel (305 cm length, 152 cm width, 51 cm height) The objectives of the research were to (1) quantify the effect of wind velocity on VOC flux rates, (2) compare and contrast a two-film model with different wind speed corrections, and (3) provide insight into methods for either selecting appropriate wind tunnel velocities or conducting post-sampling wind velocity corrections to simulate field emission rates Fluxes were measured on standard solutions and on manure/wastewater from beef cattle and dairy AFOs Volumetric air exchange rates were varied between 06 and 44 exchanges per minute, corresponding to calculated longitudinal air velocities of 0003 to 023 m s-1 Exhaust air was sampled using stainless steel sorbent tubes and analyzed for eleven volatile organic compounds comprised of seven volatile fatty acids (VFAs: acetic, propionic, isobutyric, butyric, isovaleric, valeric, and hexanoic) and four heavier molecular weight semivolatile organic compounds (sVOCs: phenol, p-cresol, indole, and skatole) using gas chromatography/mass spectrometry Sulfur-containing VOCs were quantified using a portable total reduced sulfur meter Flux rates for VOCs with small dimensionless Henry's law constants (ie, those found at AFOs) increased with increasing air velocity The two-film model with an experimentally derived reference gas-film transfer coefficient was found to reliably predict VOC flux at velocities between 0003 and 023 m s-1 However, the two-film model did not reliably predict VOC flux with other air velocity correction formulae, an indication that flux is a function of wind tunnel geometry and turbulence factors, and not just average air velocity or sweep air flow rate These results corroborate other studies that show that air velocity is a major factor affecting VOC fluxes from AFOs, verifying that an air velocity correction factor is required for estimating accurate VOC emission factors using wind tunnels and flux chambers

Effect of Wind Tunnel Air Velocity on VOC Flux from Standard Solutions and CAFO Manure/Wastewater

Chemical Composition of Pen Surface Layers of Beef Cattle Feedyards1

Ammonia emissions from cattle feedlots pose the potential to react with other compounds such as oxides of nitrogen and sulfur, which lead to detrimental environmental effects. Ambient ammonia (NH3) concentrations were measured continuously at a beef cattle feedyard for 12 months beginning in March 2007. Concentrations were measured every 5 min, 24 hours per day, at a sample intake height of 3.3 m using a chemiluminescence analyzer. On-site weather data were collected concurrently. Modeled emissions of NH3 were compared with the mass balance of N for the feedyard. Mean annual NH3 concentrations were 0.57 ppm, with a monthly average low of 0.37 ppm in December 2007 and a monthly average high of 0.77 ppm in August 2007. Flux densities were calculated using a backward Lagrangian stochastic model (WindTrax 2.0.7.8). Mean annual flux density was 70.7 µg m-2 s-1 (2.2 kg m-2 year-1). Mean monthly flux density ranged from 42.7 to 123.1 µg m-2 s-1 (0.11 to 0.32 kg m-2 month-1) in November and April 2007, respectively. Both concentration and flux density had a diel distribution with minima during the nighttime hours and maxima during the early afternoon. On an annual basis, 48.8% of fed N was volatilized as NH3. The inverse modeled daily ammonia production per head was 85.3 g NH3-N (head fed)-1 d-1.

R. W. Todd

Papers

Standardization of flux chamber and wind tunnel flux measurements for quantifying volatile organic compound and ammonia emissions from area sources at animal feeding operations

Effect of Wind Tunnel Air Velocity on VOC Flux from Standard Solutions and CAFO Manure/Wastewater

Chemical Composition of Pen Surface Layers of Beef Cattle Feedyards1

Continuous Ammonia Emission Measurements from a Commercial Beef Feedyard in Texas

Methane emissions from southern High Plains dairy wastewater lagoons in the summer