Leopold Center for Sustainable Agriculture

Completed Competitive Grant

Calibration of the late-spring soil nitrate test for manured soils

Project ID: 1992-28

Abstract

In the past, farmers have generally assumed that nitrogen fertilizers were needed on manured cornfields and questioned the value of using the late-spring soil nitrate test. In this project, Iowa farmers cooperated in studies at 111 sites to calibrate the test on manured cornfields. The value of animal manures as a nitrogen fertilizer for corn, and the possible benefits to corn producers, were also assessed. Results show that guidelines for using the late-spring test in manured cornfields need to be revised to decrease amounts of fertilizer nitrogen recommended. Widespread implementation of the late-spring soil nitrate test and the end-of-season cornstalk nitrate test should bring about more effective use of animal manue as crop fertilizer.

Lead investigator: Alfred Blackmer, ISU Agronomy

Year of grant completion: 1996

This competitive grant project was part of the Leopold Center's Initiative.

Topics: Nutrient management , Soils and agronomy