Water Resources Research Act Program

Details for Project ID 2017CA375B

Suitability of alfalfa forage crops for winter groundwater recharge

Institute: California
Year Established: 2017 Start Date: 2017-03-01 End Date: 2019-02-28
Total Federal Funds: $11,165 Total Non-Federal Funds: $28,085

Principal Investigators: Helen Dahlke

Project Summary: Agricultural groundwater banking (ag-GB), where farmland is flooded during the winter using surface water to recharge the underlying groundwater, is a promising technology currently tested on alfalfa. The main goal of this research is to conduct field studies over two years to increase knowledge of the response of alfalfa forage crops to winter irrigation (Dec-Feb) for groundwater recharge. The researchers plan to conduct replicated field experiments on two commercial alfalfa fields provided by volunteering landowners and one field at the Kearney Agricultural Research and Education Center to test the effect of modest and high amounts of winter water application on alfalfa yield over the season on different soils and under different climate conditions. The effect of fall dormancy rating on alfalfa response will be evaluated. In addition, we will quantify how winter flooding affects growing season water balance and irrigation demand. Each site will be instrumented with several soil moisture sensor profiles to quantify the amount of water going to deep percolation during winter recharge and to estimate potential benefits of ag-GB for the growing season irrigation demand. Plant physiological parameters (e.g. total yield, wet and dry matter, weeds, and alfalfa density) will be determined in each treatment area using a flail-type forage harvester. The proposed research is important to estimate the risks and benefits of ag-GB to alfalfa, the costs and benefits of implementing ag-GB on alfalfa land, and the need for economic incentive tools.