Refining Sample Guidelines for Soil Health Assessment

Although soils are known to be spatially and temporally dynamic, the effects of sampling time and depth on soil health assessment are poorly understood, and soil testing protocols for soil health monitoring remain limited. 

A team of scientists from Arkansas investigated how soil sampling time (spring, summer, fall, and winter) and sampling depth (0–5, 5–10, and 10–15 cm) affect various soil health indicators and scores across ten long-term field trials with contrasting tillage, cover crops, and nutrient management practices under diverse cropping systems. Biological soil health indicators and integrated scores were determined for two well established frameworks: Haney Soil Health Test (HSHT) and Cornell’s Assessment of Soil Health (CASH).

Findings indicate that soil sampling approach influences not only measured soil health values but also the ability to detect crop- and soil-management-induced differences. Soil health indicator values and scores were highest in surface soils and declined with depth, while higher values were observed in summer and winter, especially for soil respiration, β-glucosidase activity, and HSHT soil health score.