Huang, Wen-Yuan

By: Huang, Wen-Yuan; Hewitt, Tracy I.; Shank, David
Timing nitrogen applications to the biological needs of a crop is an effective way to reduce nitrogen losses to the environment. However, this strategy may carry a production risk and conflict with farmers' economic objectives. A field-level production decision model was used to estimate on-farm costs associated with timing nitrogen applications for crop needs in Indiana. For risk-neutral farmer, the estimated cost is less than $1 per acre with a reduction of 11 pounds of residual nitrogen. For a risk-aversion farmer, the estimated cost is up to $37 per acre with a reduction of 96 pounds of residual nitrogen.
By: Watkins, K. Bradley; Lu, Yao-Chi; Huang, Wen-Yuan
This study evaluates the long-term profitability and environmental impacts of variable rate versus uniform nitrogen application in seed potato production with nitrogen carry-over effects included. Seed potato yields were simulated for four different areas of a field using the EPIC crop growth model. A dynamic optimization model was used to determine optimal steady-state nitrogen levels for each area and the entire field. Average nitrogen losses and economic returns were evaluated for both uniform and variable rate nitrogen fertilizer. Variable rate nitrogen application was found to be unprofitable for the field when compared to uniform nitrogen application. Nitrogen losses for the field were about the same under both strategies. The results indicate greater economic and environmental benefits may be achieved by splitting nitrogen applications, especially for areas of the field exhibiting low yield productivity.