Journal or Book Title
Proceedings of the Thirty-Sixth North Central Extension-Industry Soil Fertility Conference
Thirty-Sixth North Central Extension-Industry Soil Fertility Conference
November 7-8, 2006
Des Moines, IA
Data from 96 locations across the North Central Region was complied to evaluate the usefulness of the Illinois soil nitrogen test (ISNT) in identifying fields where corn will not respond to additional N fertilizer and predicting the yield optimizing N rate (YONR) for each field. The ISNT could not accurately predict non-responsive sites, nor could it predict YONR. Sub-setting the data based on soil drainage class and previous crop did not improve the predictive capability of the ISNT. The ISNT was related to soil organic matter and was measuring a constant fraction of total soil N. The ISNT is not a meaningful tool upon which N rate decisions should be based.
Potash & Phosphate Institute
Laboski, C. A. M.; Sawyer, J. E.; Walters, D. T.; Bundy, L. G.; Hoeft, R. G.; Randall, G. W.; and Andraski, T. W., "Evaluation of the Illinois Soil Nitrogen Test in the North Central Region" (2006). Agronomy Conference Proceedings and Presentations. 48.