Progress 04/01/23 to 03/31/24
Outputs
Target Audience:
Nothing Reported
Changes/Problems:Iowa State University initially hired a graduate student for this project, but the student subsequently dropped out. We then re-advertised the position for both students and post-docs. We have now hired a highly qualified post-doc, Rizwan Shahid, who will begin in June 2024. As a result, progress on the ISU side experienced some delays. However, we anticipate significant progress in the next project year. What opportunities for training and professional development has the project provided?Iowa State University hired a graduate student for this project and the student dropped out. At that time, we re-advertised the position for students and post-docs. We hired a highly qualified post-doc, Rizwan Shahid, and he will begin June 2024. Dr. Shahid has extensive experience calibrating and applying ecosystem process models and he will be able to make up for lost time on modeling objectives given our original plan was to train a student. How have the results been disseminated to communities of interest?
Nothing Reported
What do you plan to do during the next reporting period to accomplish the goals?We will conduct further scenario analysis to assess the impacts of adding cover crops, transitioning from conventional tillage to conservation/no-tillage, and switching between manure and mineral fertilization. Additionally, we will consider "4R" practices in our scenario analysis. Our goal is to identify the best combination of management practices that provide the most significant environmental benefits (reducing nitrate leaching and N2O emissions) while maintaining or increasing crop yields for economic benefits. We will develop and test the proposed SWAT-DNDC model at both site and watershed scales. Furthermore, we plan to compare the SWAT-DNDC model with the DayCent-based SWAT model to evaluate their strengths and weaknesses, facilitating potential model development.
Impacts
What was accomplished under these goals?
The National Laboratory for Agriculture and the Environment collected data on nitrous oxide gas emission and nitrate loss in tile drainage from corn-soybean rotations under long-term conservation practices. In 2023 the field was in the soybean phase of the rotation and allowed evaluation of multiple winter cover strategies including rye cover crop, harvested rye cover crop and winter camelina-soybean double cropping systems. In 2024, field data collection continued in the corn phase of the rotation allowing evaluation of 4R nitrogen management on gas emissions. Data will contribute to the long-term dataset used to calibrate and validate the SWAT-DNDC model. Field data collection also included high temporal resolution nitrous oxide emission data from automated chamber systems that can be used to evaluate model capacity to estimate emissions during peak emission events. The University of Maryland developed an enhanced version of the SWAT model incorporating the latest DayCent-based N2O module. Additionally, we improved the nitrate loss simulation with tile drainage to better reflect the impacts of water table dynamics. The enhanced DayCent-based model was applied to two different SWAT projects. For the South Fork Watershed, we created a SWAT project using detailed data on crop rotation, manure application, and tillage practices collected from the watershed. We used the SSURGO soil map, a DEM with 10 m resolution, and a field farm-based land use map. The model was calibrated using data from five monitoring stations with daily streamflow and nitrate loading. We also developed a SWAT project with a single HRU for the Kelley site, incorporating detailed local weather data, crop rotation, fertilization, and the timing and amount of applications. The model was calibrated using monitored tile drainage water, nitrate loading, crop yield, and N2O emissions. The SWAT model includes two tile drainage modules: one simplified and one more physically based. After autocalibration with daily stream data, we determined that the simplified module better simulated drained water. Model calibration and validation indicated satisfactory performance for both drainage water discharge and nitrate loading at both site and watershed scales. N2O emissions and crop yields at the Kelley site were also simulated satisfactorily.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2024
Citation:
Luo, X., Risal, A., Qi, J., Lee, S., Zhang, X., Alfieri, J.G. and McCarty, G.W., 2024. Modeling lateral carbon fluxes for
agroecosystems in the Mid-Atlantic region: Control factors and importance for carbon budget. Science of The Total
Environment, 912, p.169128.
- Type:
Journal Articles
Status:
Published
Year Published:
2023
Citation:
Tijjani, S.B., Qi, J., Giri, S. and Lathrop, R., 2023. Modeling Land Use and Management Practices Impacts on Soil Organic
Carbon Loss in an Agricultural Watershed in the Mid-Atlantic Region. Water, 15(20), p.3534
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