Time and Rate of Urea Application for Corn Influence Soil Enzyme Activity.

The timing and rate of fertilizer N application can influence soil enzyme activity. Experiments were conducted in 2014 and 2015 to compare single and split applications for differing rates of fertilizer N on an irrigated Hubbard-Mosford loamy sand complex at Becker, MN and under non-irrigated conditions on a Normania loam soil at Lamberton, MN and on a Nicollet clay loam soil at Waseca, MN. Soil enzyme activity was used as a sensitive indicator of ecological stability and its influence by the application of N fertilizer was to monitor the impact of intensive corn production on soil health. Soil enzymes can impact organic matter decomposition and nutrient cycling, thus influencing corn yield potential. This underscores the need to recognize the impact of how different N fertilizer rates and timing of application are impacting different soil enzymes. Enhanced understanding of site-specific soil and weather characteristics that influence such responses could increase corn yield and N uptake while reducing the potential for N losses to the environment.