Location: Agroecosystems Management ResearchTitle: Modeling nitrate removal from drainage with saturated riparian buffers
Submitted to: ASA-CSSA-SSSA Annual Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 6/12/2023
Publication Date: 11/2/2023
Citation: Katuwal, S., Rogovska, N.P., Malone, R.W. 2023. Modeling nitrate removal from drainage with saturated riparian buffers [abstract]. ASA-CSSA-SSSA Annual Meeting.
Technical Abstract: Artificial subsurface (“tile”) drainage in row crop agricultural production systems of Midwest US contributes to nitrate in surface waters and hypoxia in the northern Gulf of Mexico. A saturated riparian buffer (SRB) is a relatively low cost and relatively new conservation practice designed to reroute a fraction of tile drainage to an edge-of-field riparian buffer as shallow ground water flow via perforated distribution pipes. As water flows through the buffer, nitrate is removed by plant uptake and/or denitrification occurs before entering the stream. On average (n = 47 site-years across Iowa, Illinois, Indiana, and Minnesota) SRBs have shown to remove 6.4 ± 6.3 kg N/ha-yr, with their efficiency being affected by buffer soil properties, site design, and climatic conditions. Estimation of a saturated buffers’ potential in nitrate loss reduction for the large potential variety of buffer characteristics and design is not feasible on a large scale. Therefore, the effectiveness of SRBs on the removal of nitrates from drained agricultural fields was evaluated using models such as SWAT and DRAINMOD. A saturated buffer site installed at Bear Creek (42.2112°N, 93.4707°W), Iowa, has been continuously monitored since 2012 for field and buffer tile discharge and nitrate concentrations. This long-term data will be used to model nitrate loss from field and buffer using SWAT model. The goal is to use field-tested models to predict potential of nitrate loss reduction from SRBs on a wider scale in Iowa. The results of this research will improve our understanding of saturated buffer impacts on nitrogen dynamics in drained agriculture and thus aid farmers and conservationists in decision support for choosing the best management practices for reducing nutrient losses from drained agricultural lands.