Greenhouse Gas Emissions from Beef Feedlot Surface Materials as Affected by Diet, Moisture, Temperature, and Time

Abstract

Abstract. A laboratory study was conducted to measure the effects of diet, moisture, temperature, and time on greenhouse gas (GHG) emissions from feedlot surface materials (FSM). The FSM were collected from open-lot pens where beef cattle were fed either a dry-rolled corn (DRC) diet containing no wet distillers grains with solubles (WDGS) or a DRC diet containing 35% WDGS. The FSM were collected, air-dried or mixed with 3.0 L of water to represent dry or wet conditions, and then incubated at temperatures of 5°C, 15°C, 25°C, or 35°C. Static flux chambers were used to quantify GHG emissions over a 14-day period. Flux data for each diet × moisture combination were analyzed using repeated measures in time. The largest GHG emissions occurred under wet conditions at temperatures of 25°C and 35°C. Flux values for these conditions typically were significantly greater than measurements obtained on the same day at 5°C and 15°C. Mean emissions under wet conditions for CO2, CH4, and N2O were 35, 121, and 278 times greater, respectively, than emissions from dry FSM. The 0% WDGS diet produced mean CO2 and N2O flux measurements that were 1.8 and 1.5 times greater, respectively, than those obtained for the 35% WDGS diet. The 35% WDGS diet, in contrast, produced a mean CH4 emission rate that was 6 times greater than the 0% WDGS diet. Management for GHG mitigation should include design and/or maintenance of pen drainage to speed drying as well as the use of modified animal diets. Keywords: Air quality, Carbon dioxide, Confined animal feeding operations, Drainage, Emission rates, Feedlot, Greenhouse gas, Methane, Nitrous oxide, Pen design.

Effect of Using Aluminum Sulfate (Alum) as a Surface Amendment in Beef Cattle Feedlots on Ammonia and Sulfide Emissions

“…The first lab-scale study was a titration study with four alum treatments evaluated: 0, 2.5, 5, and 10% alum (g g −1 ) based on the mass of the FSM. Using methodology from previous studies in our lab [34,35], FSM was collected from three adjacent beef feedlot pens at the U.S. Meat Animal Research Center (USMARC) feedlot. Each pen was 30 m × 90 m and contained a central mound constructed from manure and soil and a 3 m concrete apron located behind each feed bunk.…”

“…Daily, the mass of the pans was recorded to determine how much water had evaporated. Water was added back to each pan to maintain the original pan mass which allowed for a uniform moisture content among all 24 pans of FSM [34,35]. Constant water content was maintained to represent an extended wet period that often occurs on feedlot pen surfaces [34,35].…”

“…Water was added back to each pan to maintain the original pan mass which allowed for a uniform moisture content among all 24 pans of FSM [34,35]. Constant water content was maintained to represent an extended wet period that often occurs on feedlot pen surfaces [34,35]. On sampling days water was added to the pan 30 min prior to sampling.…”

“…This would not be a cost-effective treatment for most producers who allow 14-23 m 2 per animal [51]. However, research has demonstrated that spatial variation exists in feedlot pens, which contributes to differences in odor and greenhouse gas emissions [34,35]. By identifying the locations in the pen that contribute the most to NH 3 emissions, perhaps alum could be applied to the specific areas of the pen, instead of the entire pen, making it a more cost-effective treatment for producers.…”

Nitrous Oxide from Beef Cattle Manure: Effects of Temperature, Water Addition and Manure Properties on Denitrification and Nitrification

“…Beef cattle feedyards produce nitrous oxide (N 2 O) from manure [1][2][3][4][5][6]. Nitrous oxide is a potent greenhouse gas (GHG) implicated in climate change due to a global warming potential (GWP) of 265-298 carbon dioxide equivalent (CO 2 e).…”