Submitted to: Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 10/21/1998
Publication Date: N/A
Technical Abstract: Microbial biomass is part of the active pool of soil organic matter that plays focal roles in decomposition of organic materials, nutrient cycling, and biophysical manipulation of soil structure. We asked the question "Is there something missing?" when not subtracting a control in the CHCl3 fumigation-incubation [CFI] method. We compared CFI with and without subtraction of a control against other active, passive, and total soil C and N pools in soils from Texas, Georgia, and western Canada. Relationship of potential C mineralization with CFI without subtraction of a control was much stronger (r2=0.81 among five data sets with a total of 844 obs.) than with subtraction of a control (r2=0.30). Similarly, relationship of soil organic C with CFI without subtraction of a control was better (r2=0.80) than with subtraction of a control (r2=0.38). Relationships of net N mineralization, flush of N following CFI, particulate organic C and N, mean weight diameter of water-stable aggregation, and total porosity with CFI were also better without than with subtraction of a control. CFI without subtraction of a control should be considered a more robust method to determine microbial biomass under a wide range of environments.