Green Yellow (2.5 to 3.5) (4 to 5) (0 to 1.0) (1.0 to 2.5) (3.5 to 4.0) Soil respiration activity* Moderately Unusually Very low Medium Ideal low high Dry, Soils with Soils that Soils with Soils with sandy marginal have a sufficient excessive soils that biological moderately organic organic have activity balanced matter matter little or and condition content content no organic and to and organic matter which populations matter organic of active matter has been added **Approximate level of CO2 respiration – >2,000 <300 mg 300 to 500 500 to 1,000 to mg mg 1000 mg 2,000 mg CO2-C/kg CO2-C/kg CO2-C/kg soil/week soil/week soil/week soil/week soil/week <9.5 lbs 9.5 to 16 16 to 32 32 to 64 >64 lbs lbs lbs lbs 3 in/day in/day in/day in/day in/day Approximate quantity of nitrogen (N) release per year (normal climatic conditions) 80 to <10 10 to 20 20 to 40 40 to 80 >160 lbs/acre lbs/acre lbs/acre lbs/acre lbs/acre * Under optimum soil temperature and moisture conditions. ** Doran, J., and W. Brinton. 2001. Soil quality correlation of basal respiration and N mineralization over time using intact 3-inch field soil cores under optimal temperature and moisture in the lab. U.S. Department of Agriculture, Agricultural Research Service. More accurate estimates of yearly potential mineralizable nitrogen (PMN) release with optimal re-wetting of air-dry soils can be made using the Solvita® soil CO2 burst test and calculator.
(0 to 1.0) (1.0 to 2.5) Green (2.5 to 3.5) (3.5 to 4.0) Yellow (4 to 5) Soil respiration activity* Very low Moderately low Medium Ideal Unusually high Dry, sandy soils that have little or no organic matter Soils with marginal biological activity and organic matter Soils that have a moderately balanced condition and to which organic matter has been added Soils with sufficient organic matter content and populations of active Soils with excessive organic matter content **Approximate level of CO2 – respiration <300 mg soil/week 300 to 500 mg CO2-C/kg soil/week 500 to 1000 mg CO2-C/kg soil/week 1,000 to 2,000 mg CO2-C/kg soil/week >2,000 mg soil/week <9.5 lbs 3 in/day 9.5 to 16 lbs in/day 16 to 32 lbs in/day 32 to 64 lbs in/day >64 lbs in/day Approximate quantity of nitrogen (N) release per year (normal climatic conditions) <10 lbs/acre 10 to 20 lbs/acre 20 to 40 lbs/acre 40 to 80 lbs/acre 80 to >160 lbs/acre * Under optimum soil temperature and moisture conditions. ** Doran, J., and W. Brinton. 2001. Soil quality correlation of basal respiration and N mineralization over time using intact 3-inch field soil cores under optimal temperature and moisture in the lab. U.S. Department of Agriculture, Agricultural Research Service. More accurate estimates of yearly potential mineralizable nitrogen (PMN) release with optimal re-wetting of air-dry soils can be made using the Solvita® soil CO2 burst test and calculator.
USDA_NRCS_respiration_guide.docx