A Snapshot of Greenhouse Gas Emissions from a Cattle Feedlot

Abstract

Beef cattle feedlots emit large amounts of the greenhouse gases (GHG) methane (CH) and nitrous oxide (NO), as well as ammonia (NH), which contributes to NO emission when NH is deposited to land. However, there is a lack of simultaneous, in situ, and nondisturbed measurements of the major GHG gas components from beef cattle feedlots, or measurements from different feedlot sources. A short-term campaign at a beef cattle feedlot in Victoria, Australia, quantified CH, NO, and NH emissions from the feedlot pens, manure stockpiles, and surface run-off pond. Open-path Fourier transform infrared (OP-FTIR) spectrometers and open-path lasers (OP-Laser) were used with an inverse-dispersion technique to estimate emissions. Daily average emissions of CH, NO, and NH were 132 (± 2.3 SE), 0, and 117 (± 4.5 SE) g animal d from the pens and 22 (± 0.7 SE), 2 (± 0.2 SE), and 9 (± 0.6 SE) g animal d from the manure stockpiles. Emissions of CH and NH from the run-off pond were less than 0.5 g animal d. Extrapolating these results to the feedlot population of cattle across Australia would mean that feedlots contribute approximately 2% of the agricultural GHG emissions and 2.7% of livestock sector emissions, lower than a previous estimate of 3.5%.

A Technique for Estimating Greenhouse Gas Exchange Adjacent Cattle Feedlots

“…The CH 4 emission rate of 171 g animal −1 d −1 was similar to other reported beef cattle feedlot rates, e.g., 154 g animal −1 d −1 [16]. Our N 2 O emission rates of 8.0 to 12.3 g animal −1 d −1 exceeded the reported the rate of 0.7 g animal −1 d −1 [17] and was less than the reported rate of 26 g animal −1 d −1 [18].…”

Ammonia deposition in the neighbourhood of an intensive cattle feedlot in Victoria, Australia

“…Underestimation may exist when using these three months data to estimate NH 3 deposition for the whole year. Firstly, due to that the mean air temperature during the three sampling periods in the study was 4 °C lower than the annual mean of air temperature and NH 3 emission rate is positively correlated with air temperature18, the NH 3 emission intensity and thus the measured NH 3 concentration during the sampling periods may be lower than the annual means, which means the annual NH 3 deposition rate at the sampling sites might be underestimated. Secondly, during the three months of sampling periods, only one month was classified into growing season and the other two months classified into un-growing season.…”

“…One possible reason for the smaller fraction of emissions deposited locally in this study could be attributed to the relatively high wind speed at our site (with an annual mean of 3 m s −1 at 2 m height). High wind speed usually favors a high NH 3 emission rate18, but may also cause fast dispersion and dilution of the NH 3 plume and thus cause low NH 3 concentration as well as low NH 3 dry deposition in the downwind areas20. The reduced NH 3 deposition in the downwind areas and the increased NH 3 emission rate from feedlot due to high wind speed then may have resulted in a relatively low fraction of locally deposited emissions.…”

“…The cattle were 1–1.5 yr of age, European breeds, mostly Angus and Angus cross, with an average body weight of 396 ± 5.3 kg. The cattle consumed an average of 10.2 kg dry matter daily of a finishing ration of barley ( Hordeum vulgare L.) and grass hay18. The area surrounding the feedlot was mainly cropland planted to wheat with sheep pasture lying to the northeast and grassland to the south (Fig.…”

“…Cattle feedlots are large NH 3 hotspots in Australia1617 with annual emissions of approximately 33,200 tonne NH 3 -N based on an emission rate of 104 g NH 3 -N head −1 d −1 and 875,000 beef cattle in Australian feedlots18. However, little is known regarding the local dry deposition of NH 3 surrounding these hotspots.…”