The Challenge of Predicting Nitrogen Availability from Soils

Nitrogen (N) is often a limiting nutrient in farm fields, but most commercial soil testing labs do not report N availability as part of a routine soil nutrient analysis. Why is this? Do any tests exist that reliably reflect soil N availability? This talk will present the challenges of evaluating soil N status and discuss some emerging soil N tests that hold promise for helping predict N availability from soil. Over the past several years, more than 50 on-farm corn N-rate field trials were conducted across Ohio and several measures of soil N availability were examined relative to corn response to N. This talk will present results of this study and reflect on what is needed to reliability evaluate soil N status and availability.