Long-term Assessment of Nitrogen Management Practices on Grain Yield, Nitrogen Uptake and Use Efficiency in Irrigated Corn.
Kefyalew Girma, Kyle Freeman, Brian Arnall, Roger Teal, Starr Holtz, and William Raun. Oklahoma State Univ, 051 Agricultural Hall, Stillwater, OK 74078
Crop management strategies that improve Nitrogen Use Efficiency (NUE) obviously increase farm profits while reducing the deleterious effects on the environment associated with fertilizer N loss from the soil system. Effective N management should include several critical factors that are very interrelated. A study was conducted at the Panhandle Research and Extension Center, Goodwell, OK to evaluate the effects of multiple nitrogen management practices including N rate, source, time of application, methods of fertilizer and residue incorporation over a long period of time on grain yield, N uptake and NUE in irrigated corn in Oklahoma. Fourteen treatments that contained the aforementioned N management practices were evaluated in a Randomized Complete Block Design with three replicates. Results of the individual year and averages of all years showed that grain yield and N uptake were improved compared to checks. Both N recovery and efficiency of use were high for the 118 kg N ha-1 rate. Generally the use of either urea or anhydrous ammonia did not affect the response variables.