The Composition of the Soil Atmosphere Beneath a Beef Cattle Feedlot and a Cropped Field1
- L. F. Elliott and
- T. M. McCalla2
The soil gases beneath a feedlot and an adjacent cropped field were measured at several time intervals and soil depths for a 1-year period. The gas samples were obtained in situ with gas diffusion equipment protected by caissons installed in the feedlot and field.
During warm periods and when the feedlot was not unusually dry, average concentrations of up to 51.5% CH4 and 35.5% CO2 were detected in the feedlot soil profile atmosphere. Methane and CO2 feedlot values for the year averaged from 8–27.5% and 12.5–23%, respectively. When CH4 and CO2 values were high, O2 concentrations were minimal. High CH4 values were recorded up to 152 cm deep in the feedlot. No H2 was detected beneath the feedlot or the cropped field. Oxygen and CO2 values ranged from 12.5–21% and 0.1–5%, respectively, in the cropped field soil profile. No CH4 was detected.
Methane and CO2 concentrations beneath the feedlot were lowest in midwinter and during extended drought periods in early summer; O2 concentrations were highest during these periods. The cropped field soil profile showed the highest CO2 values in the summer when the crop was growing vigorously; O2 values were lowest during this period.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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