Estimating active carbon for soil quality assessment: A simplified method for laboratory and field use

Summary

This study presents a simplified method for measuring biologically active soil carbon using dilute permanganate (0.02 M KMnO₄) that is practical for both laboratory and field applications. The authors demonstrate that shaking air-dried soil in permanganate solution for 2 minutes produces consistent, management-sensitive results comparable between laboratory and field protocols (R² = 0.98). The active carbon measure was more responsive to management effects and more closely related to biological soil properties than total organic carbon, offering a practical tool for evaluating soil quality impacts of alternative farming practices.

Regional applicability

The study was conducted in the United States, but the simplified methodology and portable field kit have potential applicability to United Kingdom soil quality assessment programmes. The technique's sensitivity to management practices makes it relevant for evaluating UK regenerative and organic farming impacts, though regional soil type validation would strengthen applicability to diverse UK soil conditions.

Key measures

Biologically active soil carbon (measured by dilute KMnO₄ absorbance at 550 nm), total organic carbon, soil respiration, microbial biomass, soil aggregation, absorbance readings from hand-held colorimeter

Outcomes reported

Development and validation of a simplified dilute permanganate method for measuring biologically active soil carbon in laboratory and field settings. Comparison of active carbon measurements with total organic carbon and other soil properties across different management practices.

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