Submitted to: Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 8/15/2001
Publication Date: 9/15/2001
Citation: Morris, D.R. 2001. Soil slurry vs. moist field soil for substrate induced respiration studies. American Society of Agronomy Abstracts. CDR S03-Morris 131-225-P.
Technical Abstract: To estimate organic matter oxidation potential, soil induced respiration studies using a 14C-labelled organic substrate applied to field moist soil have been used. An experiment was conducted to determine if using a soil slurry method (SM) is more efficient than using the field moist soil method (FM). A 14C-carboxy labelled benzoate was applied to field moist soils and soil slurries of four Florida Everglades soils (4 to 83% organic matter) at rates from 0.5 to 14.6 uM g-1 soil. All soils were incubated from 15 to 180 min. Both methods were very sensitive as oxidation of the substrate could be detected at the lowest concentration and at the shortest incubation time. With FM, activities of all substrate rates were linear up to 120 min indicating incubation times should not exceed 120 min. With SM, activities increased throughout the 180 min incubation and did not achieve a maximum. At 120 min, averaged across substrate rates, SM resulted in 87% less CO2 evolved compared to the FM, probably because of substrate dilution. Due to the lower quantity of CO2 evolved per unit of substrate with SM, and ease of handling dry radioactive waste compared to liquid waste, it appears FM may be the better method for detecting soil oxidation potential.