Water Resources Research Act Program

Details for Project ID 2014ND284B

Where is fertilizer nitrogen going, up in smoke or down the pipe? An assessment of nitrogen transformations and water quality impacts on a tile drained sodic soil

Institute: North Dakota
Year Established: 2014 Start Date: 2014-03-01 End Date: 2015-02-28
Total Federal Funds: $5,350 Total Non-Federal Funds: $10,699

Principal Investigators: AnnMarie Fortuna

Abstract: Sodic soils have a high potential of being saturated. In response to wet growing conditions, tile drained acreage has increased exponentially during the last 10 years, a period of sustained or excess moisture. Yet, the effects of tile drainage on losses of reactive nitrogen (N) that include: nitrate leaching, denitrification and ammonia volatilization are largely unknown. Tens of thousands of ha have been tiled annually, many of which are located on soils having a high risk for salinity or sodicity (i.e. Calciaquolls and Natraquolls). Tile drainage has the potential to improve nitrogen use efficiency, net primary productivity of row crops, and reduce gaseous losses of reactive N by eliminating saturated anoxic zones that foster denitrification. However, tile drainage has been linked to greater nitrate leaching losses and reduced water quality. In sodic soils, leaching rates may be overestimated, while gaseous losses underestimated. This work will inventory nitrogen losses and plant uptake under tile drained and undrained conditions. We will calculate nitrogen use efficiency, as the percent recovered of applied 15N in plant tissues, to optimize nitrogen fertilizer rates and develop management guidelines that optimize production on a common sodic soil series. We will also determine potential leaching rates of nitrate-N on a common sodic soil series. Comparisons of field measured nitrogen losses and uptake can then be compared to model estimates.