v2.1 (2026-06-10) · Fernández, F. G., & Hoeft, R. G., 'Managing Soil pH and Crop Nutrients', Chapter 8, Illinois Agronomy Handbook (24th ed., 2009 baseline with subsequent revisions). University of Illinois Crop Sciences. PDF: https://dnr.illinois.gov/content/dam/soi/en/web/dnr/procurement/documents/attachmentgg-agronomyhandbookchapter8.pdf . Companion technical report: Fernández, Mallarino, Greer & Rudisill, 'Phosphorus and Potassium Recommendations for Illinois Crops' (FREC-funded re-evaluation, 2014), http://www.illinoisnrec.org/wp-content/uploads/2020/05/P-and-K-Recommendations-2014.pdf . Soil P research note: extension.illinois.edu/crops/soil-phosphorus . Grain removal update: Villamil et al. 2019, https://acsess.onlinelibrary.wiley.com/doi/full/10.2134/cftm2018.11.0090
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