SWAT model instances for "Groundwater impacts of adding carrot to corn-peanut rotations in North Florida". Hydroshare

Authors: LEE, DOGIL - University Of Florida; MERRICK, JASON - Natural Resources Conservation Service (NRCS, USDA); RATH, SAGARIKA - Texas A&M University; DUKES, MICHAEL - University Of Florida; KAPLAN, DAVID - University Of Florida; GRAHAM, WENDY - University Of Florida; Reaver, Nathan

Submitted to: Consortium of Universities for Advances of Hydrological Sciences
Publication Type: Other
Publication Acceptance Date: 11/22/2024
Publication Date: 11/22/2024
Citation: Lee, D., Merrick, J., Rath, S., Dukes, M., Kaplan, D.A., Graham, W.D., Reaver, N.G. 2024. SWAT model instances for "Groundwater impacts of adding carrot to corn-peanut rotations in North Florida". Hydroshare. Consortium of Universities for Advances of Hydrological Sciences. https://doi.org/10.4211/hs.e992c4484f864ef8bccdc2924ed6e9ba.
DOI: https://doi.org/10.4211/hs.e992c4484f864ef8bccdc2924ed6e9ba

Interpretive Summary: The Floridan Aquifer is a highly productive aquifer in the Southeastern US and is the primary agricultural and drinking water source for North Central Florida. Increased groundwater pumping and nitrate leaching have substantially impacted the water quality and quantity within the Floridan Aquifer. Increased carrot production in the region has the potential to exacerbate these impacts. Understanding the water quality implications of carrot production is essential for the development of best management practices that allow growers to meet yield goals while minimizing impacts. The SWAT model described and presented in this publication was used to assess the groundwater recharge and nitrate leaching impacts of adding carrot into corn-peanut rotations within the Santa Fe River watershed in Florida. Results suggest that the addition of carrot cultivation to corn-peanut rotations will generally increase both irrigation and nitrate leaching, potentially making it more difficult achieve water quantity and quality standards in the region. The model is published and described so that it is publicly available, reproducible, and so it can be used by scientists and decision makers.

Technical Abstract: The Upper Floridan aquifer underlying the Suwannee River Basin in Florida has experienced increased groundwater pumping and nitrate leaching over the last half century resulting in violation of water quantity and quality standards, largely due to row crop production. Increasingly carrot is being added as a winter cash crop to the traditional corn-peanut rotation in the region which may further increase pumping and nitrogen leaching. Establishing carrot nitrogen and irrigation best management practices is therefore critical to help growers meet yield goals while minimizing groundwater quantity and quality impacts. In this study, a carrot cultivation field experiment was conducted to evaluate the effects of a range of irrigation and nitrogen fertilizer practices on irrigation demand, nitrogen uptake and carrot crop growth and yield. Results showed that soil moisture sensor-based irrigation reduced the amount of water used for carrot cultivation by approximately 30% over the calendar-based irrigation without statistically significant reductions in yield, and fertilization rates above 224 kg ha-1 showed no statistically significant increase in yield. A field-scale SWAT carrot model was calibrated using the field experiment data and validated using previously published experimental results. The carrot parameters were then incorporated into a watershed-scale SWAT model of the Santa Fe River Basin, a tributary of the Suwannee River, and used to assess groundwater recharge and nitrate leaching impacts of adding carrot into corn-peanut rotations across all row crop lands in the watershed. Modeling results showed that adding carrot cultivation to the rotation will increase irrigation by 32-43% and decrease net groundwater recharge from row crop land by 9-28%. Moreover, it will increase nitrate leaching from row crop land by 60-100%. These results indicate that adding carrot cultivation to the conventional corn-peanut rotation will make water quantity and quality standards in the region more difficult to achieve.