Assessing the Efficacy of Enzyme Assays as a Soil Health Indicator on Diverse, Long-Term, Agronomic Plots
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Date
2020-05
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The Ohio State University
Abstract
To guide land managers and policy makers, soil health indicators are needed that are temporally sensitive and reflect the ability of soils to deliver ecosystem services. This study investigated the ability of two enzyme assays, β-glucosidase (GLU) and arylsulfatase (ARS) to detect soil management treatment effects from three long-term research sites (>17 years) in North Carolina that had distinctly different soils and environments (Coastal Plain, Piedmont, and Mountain soils). Soil was collected in the 0-15cm depths and air-dried before running the assays. For both enzyme assays, there were significant differences between treatments for all three physiographic regions compared to Cornell Soil Health Assessment and Haney Soil Health Test which detected treatment effects at only one of three sites. Enzyme assays ranked treatments with known best management (no-till, organic) higher than intensive tillage and chemical treatments for all three sites. At the Mountain site, ARS and GLU had over 2.5 times the activity in the no-till organic (NTO) treatment compared to the conventional tillage chemical (CTC) treatment, compared to CASH which gave a score of 55 for NTO and 44 for CTC. GLU showed no significant difference between treatments, but when controlled for sand content (GLUS) showed significant difference with two groupings. ARS had a stronger correlation to fatty-acid methyl ester (FAME) biomarkers than GLU, and both were overall weakly correlated to FAME (r < 0.34). Overall β-glucosidase and arylsulfatase were able to distinguish between management systems and consistently rank soils with improved management as having higher enzyme activity per unit sand.
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Keywords
Soil health, Soil enzymes, Soil microbiology, Tillage, Organic, Soil quality