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ARS Home » Northeast Area » Orono, Maine » New England Plant, Soil and Water Research Laboratory » Research » Publications at this Location » Publication #183611
Title: CHARACTERIZING COMPOST MATURITY FOR NITROGEN AND CARBON MINERALIZATION

Author
item Griffin, Timothy
item HUTCHINSON, MARK - UNIV OF MAINE

Submitted to: American Society of Agronomy Meetings
Publication Type: Abstract Only
Publication Acceptance Date: 5/15/2005
Publication Date: 7/13/2005
Citation: Griffin, T.S., Hutchinson, M. 2005. Characterizing compost maturity for nitrogen and carbon mineralization. Northeast Branch,American Society of Agronomy Meetings, Storrs, CT. July 2005 CD-ROM

Interpretive Summary:

Technical Abstract: Improved methods for assessing manure compost maturity are needed to balance soil improvement and nutrient availability. We collected eleven separate compost samples from a single windrow over a 100 d period. Initial assessment of compost maturity used standard analyses, including total C and N, C:N ratio, and inorganic N concentration. Compost C and N lability were assessed by measuring CO2 evolution during a 24 hr period, and also using commercially available compost evaluation kits which include both CO2 and NH3 release to establish a Maturity Index. We also estimated slowly degradable C fractions in the composts using neutral and acid detergent fiber (NDF and ADF, respectively) and lignin methods developed for ruminant feed analysis. The relationship between maturity and each compost maturity index was evaluated using simple linear regression. Some widely-used parameters, like compost C:N ratio, changed very little during the sampling period. Compost CO2 evolution and the Maturity Index both showed strong linear relationships with the length of the compost process (in days), with coefficients of determination (r2) of 0.75 to 0.85. Likewise, fiber and lignin concentration increased (r2 = 0.75 to 0.80) during compost maturation as more easily available C was used by microbes. These results indicate that both commercial maturity indices and alternative (but commonly available) fiber analysis can be used to establish relative differences in compost maturity.