Soil organic carbon to clay ratio in different pedoclimatic and agronomic conditions in northeastern North America

Summary

Soil organic carbon levels are strongly influenced by pedoclimatic and agronomic environments; hence, establishing universal threshold values for SOC to differentiate soils into healthy and degraded classes is nearly impossible. Previously, SOC:clay ratio thresholds were used to classify soils into categories of “degraded”, “moderate”, “good”, and “very good”. Here, by comparing the percentage of soils under these categories, we assessed the applicability of the SOC:clay ratio as an indicator of soil carbon status on 2249 soil samples collected from Ontario (Canada) and New York (USA). Our results confirmed that the classification of soil based on SOC:clay ratio was highly clay biased, inaccurate, and not a true representation of soil degradation status. Fine-textured soils had a high perc