Soil Fertility

Nutrient Topics

Questions? Contact John Sawyer

Professor
Extension Soil Fertility Specialist
Phone: (515) 294-7078
Email: jsawyer@iastate.edu

Antonio Mallarino

Professor, Soil Fertility
Phone: (515) 294-6200
Fax: (515) 294-2458
Email: apmallar@iastate.edu

Soil Fertility Home Page

Welcome to the Iowa State University Agronomy Extension Soil Fertility Home Page. Nutrient topics are listed on the left side. Simply click on a topic of interest and you can find information about that topic, including Extension publications, newsletter articles, conference proceedings and reports, presentations, and links to other related sites. Links also provide access to soil fertility decision aid tools, a photo gallery, and the ISU Soil and Plant Analysis Laboratory.

Current Topic

UPDATE TO IOWA PHOSPHORUS, POTASSIUM, AND LIME RECOMMENDATIONS

Antonio P. Mallarino and John E. Sawyer, Professor, Department of Agronomy, Iowa State University
September 20, 2013

This article highlights revisions to Iowa State University (ISU) soil-test interpretations and application guidelines for phosphorus (P), potassium (K), and lime in an update of Extension Publication PM 1688 "A General Guide for Crop Nutrient and Limestone Recommendations in Iowa". The printed version of this publication will not be ready until later in the fall and the online version should be posted here by early October at and on the Soil Fertility web site. Field research is conducted continuously to assure that nutrient management suggestions are up to date. This research has indicated that some recommendations should not be changed, but other recommendations needed significant changes in order to optimize nutrient management to improve the profitability and sustainability of crop production. Read on.

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