Table 2. Basic soil biological quality. Color/Colorimetric Number 0-1 1.0-2.5 2.5-3.5 3.5-4.0 4-5 Blue-Gray Gray-Green Green Green-Yellow Yellow Soil Respiration Activity Very Low Soil Moderately Low Medium Soil Ideal Soil Activity Unusually High Activity Soil Activity Activity Soil Activity Associated with Soil is marginal in Soil is in a Soil is well High/Excessive dry sandy soils, terms of moderately supplied with organic matter and little or no biological activity balanced organic matter additions organic matter and organic condition and and has an active matter has been population of receiving organic microorganisms matter additions *Approximate Level of CO2 - Respiration <300 mg 300-500 mg 500-1000 mg 1000-2000 mg >2000 mg CO2/kg soil/wk CO2/kg soil/wk CO2/kg soil/wk CO2/kg soil/wk CO2/kg soil/wk <9.5 lbs 9.5-16 lbs 16-32 lbs 32-64 lbs >64 lbs d d Approximate Quantity of Nitrogen (N) Release Per Year (Average Climate) <10 lbs/acre 10-20 lbs/acre 20-40 lbs/acre 40-80 lbs/acre 80->160 lbs/acre *Source: Doran, J. (2001) USDA-ARS Soil Quality Institute correlation of Solvita® and field soil respiration. Calculations based on a e-inch soil core (7.6 cm). Table 3. Soil respiration levels and interpretations. Sample Median Start End Gel Color & Soil Avg. Quantity of Site 24-hr Time Time Colorimetric Activity Respiration N Released Soil or Number Level lbs lbs/ac/yr
Table 2. Basic soil biological quality. Color/Colorimetric Number 0-1 Blue-Gray 1.0-2.5 Gray-Green 2.5-3.5 Green 3.5-4.0 Green-Yellow 4-5 Yellow Soil Respiration Activity Very Low Soil Activity Moderately Low Soil Activity Medium Soil Activity Ideal Soil Activity Unusually High Soil Activity Associated with dry sandy soils, and little or no organic matter Soil is marginal in terms of biological activity and organic matter Soil is in a moderately balanced condition and has been receiving organic matter additions Soil is well supplied with organic matter and has an active population of microorganisms High/Excessive organic matter additions *Approximate Level of CO2 - Respiration <300 mg CO2/kg soil/wk 300-500 mg CO2/kg soil/wk 500-1000 mg CO2/kg soil/wk 1000-2000 mg CO2/kg soil/wk >2000 mg CO2/kg soil/wk <9.5 lbs d 9.5-16 lbs 16-32 lbs 32-64 lbs >64 lbs d Approximate Quantity of Nitrogen (N) Release Per Year (Average Climate) <10 lbs/acre 10-20 lbs/acre 20-40 lbs/acre 40-80 lbs/acre 80->160 lbs/acre *Source: Doran, J. (2001) USDA-ARS Soil Quality Institute correlation of Solvita® and field soil respiration. Calculations based on a e-inch soil core (7.6 cm). Table 3. Soil respiration levels and interpretations. Sample Site Median 24-hr Soil or Start Time End Time Gel Color & Colorimetric Number Soil Activity Avg. Respiration Level lbs Quantity of N Released lbs/ac/yr
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