The Manage Water Quality Database: Addition and Analysis of Drainage Nutrient Concentration Data.

As major nutrient-related water impairments and lawsuits continue to generate headlines, there is an increasing need to better understand factors impacting nutrients transported from areas where agriculture is heavily underpinned by tile drainage. This in-progress study builds on the momentum of the previously established “Measured Annual Nutrient loads from AGricultural Environments” (MANAGE) database to better answer questions about how and why nutrients are transported in subsurface drainage. For this work, peer-reviewed literature were reviewed for drainage P and N concentration data to create a new MANAGE “Drain Concentration” table that supplements the MANAGE “Drain Load” table released in 2015. These newly compiled drainage nutrient concentration data will be statistically analyzed to determine the impacts of controllable factors (e.g., crop selection, tillage, 4R practices) and uncontrollable factors (e.g., precipitation, soil drainage class) on nutrient concentrations in drainage waters. Early results of the project will be presented here. Eventually, the MANAGE Drain Concentration table will inform new insights about controllable and uncontrollable factors impacting drainage nutrient concentrations as well as yield consequences of in-field practices impacting these nutrient concentrations. Ultimately, this work aims to improve targeting and increase implementation of appropriate nutrient loss reduction practices to improve water quality across the Mississippi River Basin.