Development of the publication Using Manure Nutrients for Crop Production

Antonio Mallarino and John Sawyer, Faculty, Agronomy Department


Using manure as a crop nutrient resource is important to the livestock industry and crop producers in Iowa. The reasons include economic sourcing of plant nutrients that can be used in place of fertilizers, agronomic management for minimizing environmental impacts with land application, and improving crop yields and soil quality through supply of plant essential nutrients and other manure constituents. Several recent research projects conducted across Iowa cropping systems provided new data that allowed updates to recommended manure nutrient management practices.


To develop a new Extension publication that addresses manure nutrient management for Iowa corn and soybean production systems. New research data was available that indicated some suggested practices should be adjusted for best manure nutrient use, and this needed to be incorporated into the recommendations for manure nutrient use in Iowa cropping systems.


The existing Extension publication dealing with this topic was discarded and a new publication was written as a replacement. Information was added discussing the issue of manure crop nutrient availability versus nutrient supply; manure nutrient application recommendations, revised manure crop nutrient availability values for nitrogen, phosphorus, and potassium; considerations for time of application; and example manure rate calculations for meeting crop nutrient recommendations with different manure sources. The publication was reviewed by external experts in Extension, research, and the industry before being published.

Outcome Statement: 

The publication was printed in hard copy and made into a PDF document, and is distributed through the Extension Store, the Agronomy Extension Soil Fertility web site, and the Iowa Manure Management Action Group (IMMAG) manure information web site. The publication has been used as a resource in Extension education programs, such as the Soil Fertility Workshop, and in Manure Applicator Certification education programs. Use of manure nutrient recommendations increases the short-term economic return from manure application in corn and soybean production and helps livestock and crop producers achieve long-term positive soil and environmental outcomes derived from manure use in cropping systems.


100  Corn and Soybean Production and Protection

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