Year-long study tallies methane, ammonia, nitrous oxide and CO2 at Idaho feedlot
By Summit Voice
SUMMIT COUNTY — It’s long been acknowledged that greenhouse gas emissions from agriculture are an important factor in the global warming equation. By some measures, the livestock sector accounts for 18 percent off all greenhouse gas emissions — as measured in CO2 equivalent — more than the transportation sector.
And livestock production generates an even larger share of the most potent gasses, including 65 percent of human-related nitrous oxide — which has 296 times stronger than CO2 as a heat-trapping gas — and 37 percent of all human-produced methane 23 time more potent than CO2) and 64 percent of ammonia, a key ingredient in acid rain.
Recently, scientists with the U.S. Department of Agriculture took an even closer look at emissions from livestock to try and calculate how large-scale dairies contribute to the emission of greenhouse gases. This research was conducted by Agricultural Research Service (ARS) scientists at the ARS Northwest Irrigation and Soils Research Laboratory in Kimberly, Idaho.
ARS soil scientist April Leytem led the year-long project, which involved monitoring the emissions of ammonia, carbon dioxide, methane and nitrous oxide from a commercial dairy with 10,000 milk cows in southern Idaho. The facility had 20 open-lot pens, two milking parlors, a hospital barn, a maternity barn, a manure solid separator, a 25-acre wastewater storage pond and a 25-acre compost yard.
Concentration data was collected continuously for two to three days each month, along with air temperature, barometric pressure, wind direction and wind speed. After this data was collected, Leytem’s team calculated the average daily emissions for each source area for each month. The results indicated that, on average, the facility generated 3,575 pounds of ammonia, 33,092 pounds of methane and 409 pounds of nitrous oxide every day. The open lot areas generated 78 percent of the facility’s ammonia, 57 percent of its nitrous oxide and 74 percent of the facility’s methane emissions during the spring.
In general, the emission of ammonia and nitrous oxide from the open lots were lower during the late evening and early morning, and then increased throughout the day to peak late in the day. These daily fluctuations paralleled patterns in wind speed, air temperature and livestock activity, all of which generally increased during the day. Emissions of ammonia and methane from the wastewater pond and the compost were also lower in the late evening and early morning and increased during the day.
“Livestock are one of the most significant contributors to today’s most serious environmental problems. Urgent action is required to remedy the situation,” said Henning Steinfeld, chief of the UN Food and Agriculture Organization’s livestock branch.
A report from the FAO suggests that emissions from livestock production will become even more of a factor as people in developing countries consume more meat.
With increased prosperity, people are consuming more meat and dairy products every year. Global meat production is projected to more than double from 229 million tons by 2050, while milk output is set to climb from 580 to 1043 million tons.
Suggested remedies include:
Controlling access and removing obstacles to mobility on common pastures. Use of soil conservation methods and silvopastoralism, together with controlled livestock exclusion from sensitive areas; payment schemes for environmental services in livestock-based land use to help reduce and reverse land degradation.
Increasing the efficiency of livestock production and feed crop agriculture. Improving animals’ diets to reduce enteric fermentation and consequent methane emissions, and setting up biogas plant initiatives to recycle manure, could all help to reduce the direct emissions of greenhouse gases, especially methane.
Improving the efficiency of irrigation systems and introducing full-cost pricing for water together with taxes to discourage large-scale livestock concentration close to cities.