Should Soil Testing Services Measure Soil Biological Activity?

• Published in: Agricultural & environmental letters Vol. 1; no. 1; pp. 1 - 5
• Main Author: Franzluebbers, Alan J.
• Format: Journal Article
• Language: English
• Published: The American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc 2016; Wiley
• ISSN: 2471-9625; 2471-9625
• DOI: 10.2134/ael2015.11.0009

Core Ideas Soil biological activity is a key indicator for productivity and environmental quality. The flush of CO2 possesses many qualities of a robust soil test. Field calibration is underway to relate the flush of CO2 to nitrogen availability. Health of agricultural soils depends largely on conservation management to promote soil organic matter accumulation. Total soil organic matter changes slowly, but active fractions are more dynamic. A key indicator of healthy soil is potential biological activity, which could be measured rapidly with soil testing services via the flush of CO2 during 1 to 3 d following rewetting of dried soil. The flush of CO2 is related to soil microbial biomass C and has repeatedly been shown strongly related to net N mineralization during standard aerobic incubations. New research is documenting the close association with plant N uptake in semicontrolled greenhouse conditions (r2 = 0.77, n = 36). Field calibrations are underway to relate the flush of CO2 to the need for in‐season N requirement in a variety of crops. An index of soil biological activity can and should be determined to help predict soil health and soil N availability.