Submitted to: Soil Science Society of America Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 9/19/2018
Publication Date: 11/8/2019
Citation: Perez-Guzman, L., Acosta Martinez, V., Johnson, J.M. 2019. Determination of four enzyme activities simultaneously for a soil health-biogeochemical index. Soil Science Society of America Annual Meeting. Presentation.
Technical Abstract: Enzyme activities (EAs) have shown to be sensitive soil health indicators (SHI) of soil biogeochemical cycling potential and soil organic matter (SOM) dynamics as affected by management, land use and climatic variability. From the approximately 15 EAs more commonly measured, ß-glucosidase, ß-glucosaminidase, acid phosphomonoesterase, and arylsulfatase have been targeted by soil health initiatives for their important roles in C, N and C, P and S cycling. Although these EAs can be measured in air-dried soil following similar approaches which facilitate comparisons across regions, the current protocol is to measure each EA independently. This is not only time-consuming, but results in higher costs and increases the chemical waste produced from assaying the four EAs individually. Previously, we suggested a novel approach to assess multiple soil EAs simultaneously in the same soil sample by adding two or three substrates to obtain a comparable index. In this study, we report the successful simultaneous determination of the four EAs in the same soil sample using soils with a wide range of soil organic C (SOC) and texture. We also provide an optimum buffer to assay simultaneously the reactions of these four EAs. The combined assay for four EAs showed: 1) positive significant correlations with the sum of the individual EAs (r > 0.96, p < 0.001); 2) positive correlations with SOC (r > 0.91, p < 0.001); and 3) a low percentage of difference of the sum of individual EAs with the combined EAs (average of 21%). This suggested combined assay will reduce time, resources and waste while generating an index of biogeochemical potential and SOM dynamics across regions.