Heavy Spring Rains Threaten Nitrogen Availability to Corn

Brian Lang, northeast crops field specialist

Problem

Rainfall across most of northeast Iowa averaged 3.2 times the normal amount in May 2004.  Most farmers had applied their 2004 nitrogen fertilizer prior to the heavy spring rains.  By June, many farmers were uncertain if remaining nitrogen would be sufficient enough to meet the seasonal needs for thousands of acres of corn.

Response

In June, Extension Crops Specialists responded to this problem by providing information over radio, agricultural magazines, newspapers, and email on management techniques that help determine remaining seasonal nitrogen needs during early June.  In addition, Extension Crop Specialists and Watershed Project staff conducted some nitrogen fertilizer trials and shared the initial nitrogen test results with clients to help interpret nitrogen losses under different management situations like crop rotation, manure use, flooded/saturated soils, etc.

Impact

By mid-June, Extension Crop Specialists shared 2004 nitrogen loss data with clients.  For most clients, it was recommended to side-dress 40 to 60 pounds per acre of additional nitrogen to fill the void of the nitrogen lost in the spring.  October yield estimates from the Extension fertilizer trials suggest that these recommendations are resulting in about a 20% yield increase for a net profit of $25 to $30 per acre.  One such farmer/client near Garnavillo who farms 3,000 acres of corn contacted me about this subject on June 23.  He responded by following my recommendation and it provided him with approximately $85,000 net return.

Oct. 4, 2004
103 - Nutrient Management

Page last updated: July 8, 2006
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