Increased Profits and Conservation through Adaptive Management.

Nitrogen (N) management remains a critical component in corn production.  Significant financial penalties occur when yield is limited or excess fertilizer is purchased.  Despite the strong financial incentives to optimal N rates, optimizing N fertilization remains a change due to the complexity of N transformation and loss mechanisms in the soil.  The On-Farm Network was created to address problems like this by providing an infrastructure to collect large data sets that can used to improve N management.  Nitrogen assessments are made on approximately 600 - 1,000 fields each year in Iowa.  These results are used to identify differences in N management practices based on the outcome of each field.  Protocols, logistical support, an overall sampling/collection strategy, data analysis, and report generation are some of the logistical elements coordinated by the network.  In addition, group meetings that that foster participatory learning are held which has been one of the key requirements to change behavior.  Distinctions between management practices have been identified with statistical significance that are not part of the current guidelines.  The large number of factors that differentiate N management make it too complex for a general guideline approach.  The majority of growers that have participated have changed their N management and increased their profits.  A system that incorporates collection of feedback data and uses this information to adapt N management practices at a local level is required for broad scale impact.