Due to the complexity and heterogeneity of soil, the evaluation of soil health is extremely difficult requiring several physical, chemical and microbial assays. We intend to evaluate soil health through the use of a new assay for soil microbial activity. The assay relies on a portable kit that can be used in the field to evaluate farmer's soil. In addition, the assay is essentially real-time - less than 10 minutes. The ultimate goal of the project is to correlate the assay with crop yield.