Fellow: Heather Dose
Advisor: Ann-Marie Fortuna, Ph.D., Assistant Professor, Department of Soil Science, North Dakota State University.
Degree Progress: Ph.D. in Soil Science with expected graduation in spring 2016.

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). Yet, the effects of tile drainage on losses of reactive nitrogen (N) are largely unknown for these types of soil. Sodic soils, due to the structural limitations of excess sodium, have a high potential of being saturated. 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. 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 measure nitrogen losses and plant uptake under tile drained and undrained conditions. Specifically, we will determine potential leaching rates of nitrate-N on a common sodic soil series.

Project Objectives:

The main objective of this study is to investigate the interactions between tile drainage, nitrogen uptake and losses on a sodic soil. Specific objectives include:

• Determination of plant nitrogen uptake from a sodic soil
• Assess whether tile drainage on a sodic soil increases nitrate leaching potential

Progress:

Field plots with a tile drainage treatments (tile drained, controlled tile drained, and undrained control) were established in the fall of 2012 on an Exline soil (fine, smectitic, frigid Leptic Natrudolls) in Richland County, ND. Data on soil penetration resistance, soil enzyme activity levels for nutrient cycling, and soil chemical properties have been collected throughout the 2013 growing season.

Significance:

Soil sodicity impacts over 4 million ha in North Dakota. Increases in salt affected areas are associated with elevated groundwater tables and precipitation patterns over the last 20 years. Agricultural producers in eastern North Dakota are installing subsurface tile drainage to aid in the removal of excess soil water with a secondary benefit of removing salts. Increases in tile drainage have been linked to water quality concerns as nitrates are easily leached through the tile drain. This work will assess nitrogen uptake in crops and nitrogen leaching potential in sodic soils.