Update to Corn Suitability Rating Provides Transparent System for Calculation

Tuesday, May 28, 2013

According to a recent Iowa State University press release, advances in soil science have brought on a need for an update in the Corn Suitability Rating (CSR), which is used to rate the crop-growing productivity of Iowa soil. The goal of the “CSR2” is to provide a transparent system for calculating CSR so county assessors, farmers, realtors and other interested person can readily understand the mathematics underlying the current CSR.

CSR2 updates are designed to be proportional to the existing CSR values; however, “it is not always possible given the responsibility for transparency and consistency,” according to Iowa State University agronomist Lee Burras. The CSR2 values of any given soil map unit (SMU) is a function of five parameters; the soil properties captured within a soil series classification, the specific field conditions captured by each SMU, the soil depth, local climate and environment, and expert judgment.

A secondary goal is the creation of a framework for CSR2 evolution, which is necessary to ensure rapid and transparent updates of CSR2 as new soil series and new classifications are created, according to the release.

“Advances in soil-mapping techniques and the adoption of the national soil classification system during the past 50 years provide improved methods for calculating the CSR when compared to its original formula,” Burras said.

With these updates being incorporated, those interested in understanding the mathematics within the current CSR will be able to readily do so.