Through the Participatory Modeling Process (PMP), the project team collaborated with stakeholders to develop farm/forest scale Soil & Water Assessment Tool (SWAT) models for priority production systems in the Florida and Georgia region. The SWAT models were calibrated/validated with project-supported and literature-derived data as well as remote sensing data.
Three representative management systems (MS1-3) for each production system were co-developed by the PMP. The representative management systems were designed to encompass the range of practices currently implemented by producers in the region.
* For each production system values are relative within each management system.
Farm/forest-scale enterprise budgets were also developed for each production and management system based on interviews with growers and Extension personnel. Production inputs (e.g., irrigation and fertilizer) and crop yields from the SWAT models were used to evaluate the net returns for each production and management system.
Results from the farm-forest scale modeling laid the groundwork for Participatory Modeling Process members (i.e., stakeholders and project team members) to collaboratively develop a suite of baseline and future scenarios that were simulated at the watershed scale (Regional Scale Modeling).
Model results for the Santa Fe River Basin in Florida showed large differences in net returns and water quality and quantity impacts across priority production and management systems.
For row crop rotations, MS1 (which uses soil moisture sensors for irrigation scheduling, reduced nitrogen application rates, and a rye cover crop) decreased nitrate leaching 50%-60% and increased net recharge 33-100% as compared to MS3 (which uses calendar-based irrigation, higher nitrogen rate, and no cover crop), while maintaining approximately the same producer net returns. Adding carrot to the corn-peanut rotation increased nitrate leaching by 65-100% and decreased net recharge by 10-40%, but increased net returns by 90-100%.
Reducing nitrogen application rates also reduced nitrate leaching for both hay (90% reduction for MS1 compared to MS3) and pasture (50% reduction for MS1 compared to MS3), with relatively small changes in net recharge and net returns.
Across agricultural production systems, the corn-carrot-peanut rotation had the highest net returns but the highest nitrate leaching and low net recharge. Hay operations had low to negative net returns but provided high net recharge and low nitrate leaching. Cow-calf pastures had similar net recharge to the more efficient row crop systems (MS1 and MS2), generally lower nitrate leaching, and low to negative net returns.
Forest production systems in the Santa Fe River Basin generally produced lower nitrate leaching than row crop and forage production systems. They also produced relatively low net recharge, especially for longer rotation production systems without thinning. Shorter rotations generally had higher net returns, and the inclusion of pine straw raking substantially increased net returns.
Farm-Forest scale economic-environmental tradeoffs in the Santa Fe River Basin. Numbers with Land Use shapes refer to the Management System.
Key Findings
- Improved agricultural and forest management practices have good potential to increase net recharge and reduce nitrate leaching.
- Adding carrot to the corn-peanut rotation increased nitrate leaching by 65-100%, decreased net recharge by 10-42%, and increased net returns by 90-100%.
- Converting from high-input row crop production (MS3) to low-input hay production or short rotation forest production with thinning has the highest potential to reduce leaching and increase net recharge.
- Potential “win-win” scenarios include:
- Moving from corn-peanut MS3 to corn-carrot-peanut MS1 reduced leaching by ~20%, increased net recharge by ~20% and increased net returns by ~92%.
- Converting from long- to short-rotation production forest and adding a thinning operation increased recharge by ~30% and increased net returns by ~500%.
Publications
- Athearn, K. (2019). Carrot production budget. [Data set]. North Florida Research and Education Center, University of Florida Live Oak, FL. https://svaec.ifas.ufl.edu/agribusiness/farm-enterprise-budgets/
- He, F. (2019). Risk and profitability analysis for sustainable agricultural practices to protect water resources [Unpublished master’s thesis]. Food and Resource Economics Department, University of Florida. https://ufdc.ufl.edu/UFE0055839/00001/pdf
- He, F., Borisova, T., Athearn, K., Hochmuth, R., & Barrett, C. (2022). Choosing nitrogen application rate recommendation given Florida’s regulatory water policy. American Society for Horticultural Science, 57(11), 1387-1396. https://doi.org/10.21273/HORTSCI16656-22
- He, F. (2023). Farm-scale and regional economic implication of agricultural land management decisions in the Floridan Aquifer region (30490241) [Doctoral dissertation, University of Florida]. University of Florida ProQuest Dissertations Publishing. https://original-ufdc.uflib.ufl.edu/UFE0059749/00001
- He, F., Lee, D., Borisova, T., Graham, W., Athearn, K., Dukes, M., Merrick, J., & Hochmuth, R. (2024). Farm-scale economic and environmental tradeoffs of land use and land management decisions. Agricultural Water Management, 301. https://doi.org/10.1016/j.agwat.2024.108925
- Graham, W., K. Athearn, W.L. Bartels, T. Borisova, P. Carton de Grammont, C. Court, F. He, R. Hochmuth, U. Koirala, D. Lee, J. Love, N. Reaver, R. de Rooij, K. Rowles, A. Smith, K. Schlatter, & D. Kaplan (In prep) . Environmental-Economic Tradeoffs of Agricultural and Silvicultural Production Management Decisions at the Farm and Forest Scale. Journal of Environmental Management
- Koirala, U., Damian, A., Smith, A., Athearn, K., Kastner-Wilcox, K. R., Hancock, G., … Hancock, D. (2022). FACETS enterprise crop budgets for NE Florida and SW Georgia. [Data set]. Ag Data Commons. https://doi.org/10.15482/USDA.ADC/1528358
- Lee, D., Merrick, J., Rath, S., Dukes, M., Kaplan, D., & Graham, W. (2024). Groundwater impacts of adding carrot to corn-peanut rotations in North Florida. Agricultural Water Management, 294. https://doi.org/10.1016/j.agwat.2024.108713
- Lee, D., J. Merrick, S. Rath, M. Dukes, D, Kaplan, W. Graham (2004) SWAT model instances for "Groundwater impacts of adding carrot to corn-peanut rotations in North Florida. https://www.hydroshare.org/resource/e992c4484f864ef8bccdc2924ed6e9ba/
- Rath, S., Zamora-Re, M., Graham, W., Dukes, M., & Kaplan, D. (2020). Quantifying nitrate leaching to groundwater from a corn-peanut rotation under a variety of irrigation and nutrient management practices in the Suwannee River Basin, Florida. Agricultural Water Management, 246(1). https://doi.org/10.1016/j.agwat.2020.106634
- Rath, S. (2021). Agricultural water security through sustainable use of the Floridan Aquifer: An integrated study of water quantity and water quality impacts (28497245) [Doctoral dissertation, Department of Environmental Engineering Sciences, University of Florida]. ProQuest Dissertations & Theses Global. https://ufdc.ufl.edu/UFE0057461/00001/pdf
- Reaver, N., Graham, G., Rath, S., Zamora-Re, M., Dukes, M., & Kaplan, D. (2021). SWAT model instances for “quantifying nitrate leaching to groundwater from a corn-peanut rotation under a variety of irrigation and nutrient management practices in the Suwannee River Basin, Florida”. HydroShare. https://doi.org/10.4211/hs.0a7735b121f845f7ab0d1ac6348d9980
- Zamora-Re, M., Rath, S., Dukes, M., D., & Graham, W. (2020). Water and nitrogen budget dynamics for a maize-peanut rotation in Florida. ASABE, 63(6), 2003-2020. https://doi.org/10.13031/trans.13916
Meet the Team
Wendy Graham, University of Florida
Damian Adams, University of Florida
Kevin Athearn, University of Florida
Tatiana Borisova, University of Florida
Fei He, University of Florida
David Kaplan, University of Florida
Unmesh Koirala, University of Florida
Dogil Lee, University of Florida
Sagarika Rath, University of Florida
Nathan Reaver, University of Florida
Rob de Rooij, University of Florida
In general, model results for the Lower Flint River Basin (LFRB) in Georgia showed large differences in net returns and water quantity impacts across crop rotations, and relatively smaller differences across management systems within each crop rotation. The cotton-cotton-peanut rotation had higher net returns and higher net recharge than the corn-cotton-peanut rotation. For both rotations, MS1 that used soil moisture sensor (SMS) scheduled irrigation along with more frequent application of fertilizer at lower rates had lower net returns than MS2 or MS3 that used less efficient irrigation and less frequent application of fertilizer at higher rates. Forest production systems in the LFRB had a large range in net returns ($5 to $75/acre/year) and a moderate range in net recharge (8-17 inches/year) depending on the tree species and management system. Restored longleaf and production loblolly showed the highest net recharge potential while production longleaf had the lowest net recharge. Net returns were highest for management systems with pine straw production (i.e., slash MS2p and longleaf MS2) while MS1 across all forest types and restored longleaf had the lowest net returns.
Key Findings
- MS1 had slightly lower yields than MS2 and MS3. The differences were small.
- Soil Moisture Sensors (MS1) reduced average irrigation applied by close to 4 in/yr compared to UGA checkbook method (MS2) and by more than 7 in/yr compared to MS3 in both crop rotations modeled (corn-cotton-peanut and cotton-cotton-peanut).
- Annualized net recharge was higher for cotton-cotton-peanut rotation than for the corn-cotton-peanut rotation because cotton has less water demand relative to corn.
- Net returns were highest for MS2 in both crop rotations. MS1 had comparatively lower returns than MS2 and MS3.
- For forests, production loblolly and restored longleaf showed the highest net recharge potential while production longleaf had the lowest net recharge.
- Net returns were highest for management systems with pine straw production (i.e., slash MS2p and longleaf MS2) while MS1 across all forest types and restored longleaf had the lowest net returns.
Publications
- Haas, H. (2020). Importance of capturing forest dynamics in hydrological modeling (30272471) [Master’s thesis, Department of Forestry and Wildlife Science, Auburn University]. Auburn University ProQuest Dissertations Publishing. https://www.proquest.com/pqdtglobal/docview/2779135343/BBF54721E93047D8PQ/1?accountid=10920&sourcetype=Dissertations & Theses
- Hancock, GA. (2019). An economic analysis of adoption of conservation practices in Georgia cotton and peanut production [Unpublished master’s thesis]. Department of Agricultural & Applied Economics, University of Georgia. https://getd.libs.uga.edu/pdfs/hancock_guy_a_201908_ms.pdf
- Koirala, U., Adams, D., Smith, A., Athearn, K., Kastner-Wilcox, K. R., Hancock, G., … Hancock, D. (2022). FACETS enterprise crop budgets for NE Florida and SW Georgia. [Data set]. Ag Data Commons. https://doi.org/10.15482/USDA.ADC/1528358
- Karki, R., P. Srivastava, D.D. Bosch, L.Kalin, J. Lamba, and T.C. Strickland. (2020). Multi-variable sensitivity analysis, calibration, and validation of a field-scale SWAT model: Building stakeholder trust in hydrologic/water quality modeling. Transactions of the ASABE. https://doi: 10.13031/trans.13576
- Karki, R., P. Srivastava, and T. Veith. (2020). Application of the Soil and Water Assessment Tool (SWAT) at the Field-Scale: Categorizing Methods and Review of Applications. Transactions of the ASABE.
- https://doi: 10.13031/trans.13545
- Tadych, D (2020). Investigating Soil Parameters Effect on Crop Yields and Hydrology at Field Scale in the Southeast US Using the Soil and Water Assessment Tool [Unpublished master’s thesis]. Department of Biosystems Engineering, Auburn University.
Meet the Team
Latif Kalin, Auburn University
Henique Haas, Auburn University
Guy Hancock, University of Georgia
Ritesh Karki, Auburn University
Amanda Smith, University of Georgia
