Water Resources Research Act Program

Details for Project ID 2016TN117B

Measuring Water Table Flucations under Different Irrigation Regimes in Western Tennessee Agroecossystems

Institute: Tennessee
Year Established: 2016 Start Date: 2016-03-01 End Date: 2017-02-28
Total Federal Funds: $5,000 Total Non-Federal Funds: $10,000

Principal Investigators: Christopher Wilson, Jon Hathaway, Shawn Hawkins

Abstract: The soil water balance is a prime control of the structure and function of agroecosystems, driving the dynamics of both the crops and soil microbial communities. However, maintaining the optimal level of soil moisture is increasingly a challenge, as weather patterns more frequently shift between extensive flooding and deep droughts. Exacerbating these complications are the stresses from encroaching urban areas in formerly agriculturally dominant landscapes. These projected changes, along with volatile corn prices, have prompted many farmers to consider irrigation in western Tennessee in hopes of maintaining high yield crops. In fact, there has been a ten-fold increase in the number of center-pivots between 2007 and 2012 in Tennessee, with the number of acres under irrigation increasing by about 40,000 each year. Irrigation has been shown to stabilize and even increase crop yields. In western Tennessee, this can translate to an extra 50 bushels per acre of corn or 300 additional pounds of cotton per acre. But, is irrigation truly sustainable? This is difficult to say, as the few measurements and predictions of water table fluctuations under irrigation schemes that are currently being made are insufficient for management level decision-making (i.e., are not adequate to be paired with economic models). As a result, a critical gap in our current monitoring and modeling capabilities is the lack of understanding about the interactions of soil moisture, infiltration, and pedology at different spatial and temporal resolutions and under different management practices. Such knowledge is important to quantify sufficiently water table fluctuations, especially in regions exhibiting high heterogeneity in landscape characteristics, to help us understand how irrigation impacts the available water resources and develop sensible water allocation plans for the region.