Estimating Soil C, N, and P Mineralization from Short-Term CO2 Respiration

The measurement of soil carbon dioxide respiration is a means to gauge biological soil fertility. Test methods for respiration employed in the laboratory vary somewhat, and to date the equipment and labor required have somewhat limited more widespread adoption of such methodologies. A new method to measure soil respiration was tested along with the traditional alkali trap and titration method. The new method involves the Solvita gel system which was originally designed for CO2 respiration from compost, but has been applied in this research to soils with treatments of increasing dairy manure compost. The objective of this research is to: (1) examine the relationship between the CO2 release after one day of incubation from soils amended with dairy manure compost that have been dried and rewetted as determined using the titration method and the Solvita gel system; and (2) compare water-soluble organic N, as well as C, N, and P mineralization after 28 days of incubation with 1-d CO2 release from the titration method and Solvita gel system. Both 1-day CO2 from titration and the Solvita gel system were highly correlated with cumulative 28 day CO2 as well as the basal rate from 7-28 days of incubation. Both methods were also highly correlated with 28 day N and P mineralization as well as the initial water extractable organic N and C concentration.