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ARS Home » Southeast Area » Tifton, Georgia » Southeast Watershed Research » Research » Publications at this Location » Publication #363493

Research Project: Enhancing Environmental Quality and Ecosystem Services in Southeastern U.S. Coastal Plain Agricultural Watersheds

Location: Southeast Watershed Research

Title: Conservation tillage effects in the Atlantic Coastal Plain: An APEX examination

Author
item Bosch, David - Dave
item DORO, LUCA - Texas A&M Agrilife
item JEONG, JAEHAK - Texas A&M Agrilife
item WANG, XIUYING - Texas A&M Agrilife
item WILLIAMS, JIMMY - Texas A&M Agrilife
item Pisani, Oliva
item Endale, Dinku
item Strickland, Timothy - Tim

Submitted to: Journal of Soil and Water Conservation Society
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/30/2019
Publication Date: 5/13/2020
Citation: Bosch, D.D., Doro, L., Jeong, J., Wang, X., Williams, J., Pisani, O., Endale, D.M., Strickland, T.C. 2020. Conservation tillage effects in the Atlantic Coastal Plain: An APEX examination. Journal of Soil and Water Conservation Society. 75(3):400-415. https://doi.org/10.2489/jswc.75.3.400.
DOI: https://doi.org/10.2489/jswc.75.3.400

Interpretive Summary: This research supports the Conservation Effects Assessment Project (CEAP) by utilizing well documented field data in conjunction with the Agricultural Policy/Environmental eXtender (APEX) model to quantify long-term conservation effects. In this study, field data collected at a research site located near Tifton, Georgia were used to evaluate APEX and to quantify long-term benefits of implementing conservation-tillage in the Atlantic Coastal Plain region of the US. Fourteen-years of crop yield, surface runoff, subsurface flow, and sediment transport data were quantified comparing conventional tillage (CT) to strip tillage (ST). No treatment differences were found for either cotton or peanut yields. Surface runoff from the CT was found to be 1.7 times that of the ST, while subsurface runoff from the ST was found to be 1.7 times that of CT. Total water loss (surface and subsurface) was nearly equivalent for the two systems, 30% of annual rainfall. Satisfactory model performance was found for APEX surface runoff simulations. Mixed results were found for model performance of crop yield while model simulations of subsurface runoff and sediment yield were less than satisfactory.

Technical Abstract: The Conservation Effects Assessment Project (CEAP) was established to develop a scientific understanding and methodology for estimating environmental benefits and effects of conservation practices on agricultural landscapes at watershed, regional, and national scales. Field observations and computer-based simulation of the effects of agricultural conservation are important components of CEAP. This research supports the CEAP effort by utilizing well documented field data in conjunction with the Agricultural Policy/Environmental eXtender (APEX) model to quantify long-term conservation effects. In this study, field data collected at a research site located near Tifton, Georgia were used to evaluate APEX and to quantify long-term benefits of implementing conservation-tillage in the Atlantic Coastal Plain region of the US. The objectives of this research were to: 1) quantify differences in crop yield, hydrology, and sediment transport for conventional and conservation tillage systems in the Atlantic Coastal Plain; 2) develop a calibrated APEX simulation for these tillage systems; and 3) quantify the performance of the APEX model with respect to crop yields, hydrology, and sediment yield. Fourteen-years of crop yield, surface runoff, subsurface flow, and sediment transport data were quantified comparing conventional tillage (CT) to strip tillage (ST). No treatment differences were found for either cotton or peanut yields. Surface runoff from the CT was found to be 1.7 times that of the ST, while subsurface runoff from the ST was found to be 1.7 times that of CT. Total water loss (surface and subsurface) was nearly equivalent for the two systems, 30% of annual rainfall. Satisfactory model performance was found for APEX surface runoff simulations. Mixed results were found for model performance of crop yield while model simulations of subsurface runoff and sediment yield were less than satisfactory. The APEX modeling framework provides a useful tool for assessing crop yield and hydrologic differences between tillage management systems in the Atlantic Coastal Plain. Additional refinement of modeling approaches may be necessary to adequately represent subsurface flow and sediment transport in these same systems.