Assessment of Teabag Litter Decomposition as a Measure of Soil Health, Including Sensitivity to Crop Type and Management System in Agricultural Soils

ABSTRACT Soil biota contribute to soil function and health, yet accessible and cost‐effective methods for assessment remain limited. This study evaluated teabag litter decomposition as a potential biological soil health measure by examining its relationship to commonly used soil measures. In addition, litter decomposition sensitivity to crop type (annual vegetables, perennial fruit and trees and grain/forage) and agricultural management systems (conventional, organic and regenerative) was assessed. Fifty‐seven farms from across British Columbia (BC), Canada completed three replicates of teabag litter decomposition trials and provided management system and crop production data from 171 fields. In‐depth chemical, physical and biological soil health measures were taken from a subset of 35 farms across a local bioregion with similar climatic and environmental conditions (Vancouver Island). Correlation between laboratory and teabag measures and LASSO and random forest (RF) analyses were used to assess the sensitivity of commonly used chemical, physical and biological soil health measures to each other and to crop type and management system. Our focus is to determine the effectiveness of Tea Bag Index (TBI) measures ( S , k ) and the individual mass remaining of red Rooibos and green tea ( Br , Bg ), relative to standard laboratory measures, especially across varying crop types and management systems. Both LASSO and RF analyses identified the measure of the rate of biological decomposition of red Rooibos tea ( Br ) over 90 days as the most consistent and effective soil teabag measure in differentiating both crop type and management system. The decomposition of red tea ( Br ) was lowest in conventional fields and significantly higher in organic and regenerative systems, suggesting greater biological activity in these fields. This regional study demonstrated that mass remaining of red tea over a 3‐month in situ incubation period was a reliable and accurate soil health measure, providing an opportunity to significantly increase access to and reduce costs in measuring and monitoring soil health across varied environments and management systems.