University of Missouri nitrogen recommendation for sunflower was changed to the following:

Fertilizer N/acre = yield goal (lbs/acre) X 0.06 - warm season organic matter adjustment

The warms season organic matter adjustment is an estimate of nitrogen released by the soil during the growing season and ranges from approximately 20 to 80 lbs nitrogen/acre depending on soil type and the amount of organic matter in the soil. The new recommendation increases our estimate of sunflower nitrogen need based on research and recommendations in neighboring states.

Rice recommendations are variety specific so they need to be updated regularly as new varieties are introduced. The rice varieties covered by the current MU recommendations include Bengal, Cheneire, CL161, Cocodrie, Francis, and Wells. All these varieties have a recommended rate of nitrogen application of 150 lbs N/acre. MU also recommends all nitrogen be applied preflood except on slow flooding fields, fields with water management problems or on varieties prone to lodging. In these situations apply N in a three-way split application with 90 lbs N/A pre-flood, 30 lbs N/A at ½-inch internode elongation and again 10 to 14 days later. The MU recommendations assume rice follows soybean in rotation. These changes are based on research by Gene Stevens and David Dunn at the Delta Center and recommendations in neighboring states.

These changes have been approved but it will take some time before they are implemented in the soil test reporting software. You can track changes MU fertilizer recommendations at http://www.nmplanner.missouri.edu/recommends.asp. Expect to see significant changes to other aspects of the MU fertilizer recommendation system for agronomic crops over the next year.

John Lory,
573-884-7815