How does the quality of ERU compare to SSURGO?
Decision Zones are based upon proprietary research known as an Environmental Response Unit (ERU), which factors in both soil type attributes and irrigation/drainage data. The Soil Survey Geographic Database (SSURGO) is a collection of digital soil survey data performed by the US Government's National Cooperative Soil Survey performed by the Natural Resources Conservation Service.
Quality differences between ERU and SSURGO:
- Using the LiDAR elevation data as ground truth, we found a significant improvement in the prediction of slope by ERU 1.2 versus SSURGO.
- We used soil test measurements of organic matter, sand, silt, and clay to select the approach that best predicted the SSURGO soil map unit to assign to the ERU polygon. The soil attributes come from the SSURGO database, not the soil test values.
- Analysis shows that ERUs generally provide about a 50% improvement in capturing spatial yield variability versus SSURGO.
- Before implementing ERU 1.2, we used the expert knowledge and experience of our field agents and agronomists to validate the effectiveness of ERUs on customer fields and surrounding landscapes where they had direct experience.
- Certified services agents (CSAs) should work with the grower to review individual fields to determine if ERUs or SSURGO maps will best address the growers needs.
What are Decision Zones?
How does the Corn Crop Model work?