Soil biology is central to the concept of soil health. However, measuring soil biology can be costly and difficult to translate into management recommendations. Mineralizable C (or respiration upon rewetting) has gained popularity as a soil health metric because it addresses both of these issues simultaneously. While this metric has been used extensively by researchers, more information is needed before extension agents and growers can use it reliability and in a standardized platform of soil health diagnostics.
In a recent Soil Science Society of American Journal paper, researchers used soils from 72 sites across the United States to evaluate different procedures of soil mineralizable C and its reliability. They found that methodological differences can greatly impact the final results. For example, using capillary action to rewet soil consistently suppressed total mineralizable C values. Mineralizable C was less reliable from lab-to-lab than other traditional soil metrics (e.g. pH or soil carbon). Additionally, variability in the measurement between replicates in a lab was largely soil-specific, suggesting that mineralizable C measurements are more reliable for some soils than others. These nuances and inconsistencies should be considered and communicated in grower assessments of soil health when using this metric.
Read the full article in SSSAJ. Free preview March 16 -23