Location: Agroecosystems Management Research
2022 Annual Report
Objectives
Objective 1: Evaluate trends in hydrology and water quality in agricultural watersheds managed with current production practices. The research utilizes georeferenced data relating to landuse, terrain, cropping and animal production, observable use of conservation practices, and climate and meteorological data.
1.A: Document changes in land use, conservation practices, and climate as drivers of water quality trends in three Iowa watersheds.
1.B: Utilize new stream monitoring technology and terrain analyses to document stream bank movement and water quality changes along the SFIR, as related to adjacent land use and extreme weather events.
Objective 2: In collaboration with other Long-Term Agroecosystem Research (LTAR) network sites, identify practices and factors that influence the effectiveness of conservation practices.
2.A: Compare the effects of ASP cropping system as part of the LTAR Common Experiment with other C-S cropping systems on targets such as N loss to drainage.
2.B: Determine crop water use using UAV imagery.
Objective 3: Assess and improve models and remote sensing to characterize fields and watersheds.
3.A: Assess and improve modeling of Midwest conservation practices for sustainable intensification of agriculture.
3.B: Assess and improve mapping and analysis of subsurface drainage (e.g., patterns and intensity) using techniques from UAS and satellite imagery from several Midwest locations including four LTAR-drainage workgroup sites (Ames, St. Paul, W. Lafayette, Columbus).
Approach
This project will investigate the effects of agricultural management practices at field and watershed scales, investigate the dynamics of watershed hydrology, and assess and improve tools to characterize agricultural systems.
Under the first objective, watershed studies will evaluate practices that can reduce loss of nitrate-nitrogen and phosphorous from cropped fields. These practices include saturated buffers, bioreactors, and blind surface inlets to subsurface drainage. Trend analysis will be conducted on long term records in the watershed studies to gain insight on water quality and streamflow variability over time. Streambank movement in these watersheds will be monitored with remote sensing.
Under the second objective, field studies will be conducted as part of the Long-Term Agroecosystem Research network that will support research to sustain or enhance agricultural production and environmental quality in the Upper Mississippi River Basin (UMRB) region.
The third objective will employ a mix of modeling and remote sensing studies to evaluate conservation practices and subsurface drainage systems.
A breadth of watershed monitoring, remote sensing, controlled experiments in field and laboratory, and modeling techniques will be employed in the research. Publications, tools for conservation planning, and databases available to other scientists will be produced. Results are intended to enable agriculture to better manage water resources for multiple needs; particularly, in the UMRB.
Progress Report
Objective 1: Water flow and quality data, and meteorological data were obtained from the experimental watersheds, and laboratory measurements were completed for the 2021 sampling season. Sampling and analysis for the 2022 year are underway. Data from these watersheds were added to the Sustaining the Earth's Watersheds, Agricultural Research Data System database supporting the Conservation Effects Assessment Project and the Long-Term Agroecosystem Research (LTAR) network.
Research planning has begun in collaboration with the Southfork Watershed Alliance (SFWA), a producer-led watershed group that was recently funded by the State of Iowa to recruit local landowners to install new practices at locations identified using the Agricultural Conservation Planning Framework. Practices being recruited focus on tile drainage treatments, including saturated riparian buffers (SRBs), woodchip bioreactors, and blind inlets. Once the permissions from landowners are obtained, ARS scientists in partnership with SFWA will collaborate with National Resources Conservation Service (NRCS) on the surveillance of the sites to determine their suitability for installation of SRB, woodchip bioreactors, or blind inlets. NRSC will provide engineering designs for the installation of SRB on selected sites.
For installation of the saturated buffer within the riparian buffer strip, a soil sampling plan has been drafted that includes obtaining several soil cores distributed along the proposed saturated buffer at a depth of 120 cm to confirm that the soil has sufficient soil organic carbon content and the absence of coarse textured soil layers. The control box will be an Agri Drain Smart Drainage System – which will allow for automated, remote-control capabilities of data collection.
Unmanned Aerial System (UAS) Light Detection and Ranging mapping missions were flown at three South Fork Iowa River reach areas adjacent to stream flow monitoring stations during the Spring of 2022 to document stream bank movement and erosion.
Objective 2: Drainage water samples are being collected and analyzed as part of the LTAR to quantify the effect of cropping systems and nitrogen (N) management on water quality and nitrous oxide emissions. Nitrous oxide emissions are being monitored weekly. Nitrate, phosphorus (P), and potassium losses in tile drainage are being measured during flow events in the field. Preliminary 2022 water quality data collected shows nitrate-N concentrations taken from the “aspirational” cropping system (includes relay intercropping of winter camelina between corn and soybean) were no different than nitrate coming from conventional corn soybean management. Treatments with rye cover crop (CC) and unfertilized (No fertilizer N) plots had significantly lower concentration of nitrate in drainage. Cropping system had no significant effect on concentration of P and total dissolved P in drainage.
Objective 3: Data is being gathered from the Kelley field site near Ames, Iowa, to parameterize and test the Soil & Water Assessment Tool model to simulate effect of winter CC on N loss to drainage. Preliminary model runs appear promising with the model reasonably simulating N loss to drainage and crop growth compared to field observations.
UAS flights have begun at the Kelley field site to help identify subsurface drainpipe configurations. Several flights have been completed. Problems with data collection and processing are being addressed. Thermal data processing has been challenging and techniques have been modified to increase the quality of the products.
Accomplishments
1. No Accomplishments this FY.. This is the first report for this new project which just began in April 2022 and continues research from the previous project, 5030-13000-011-000D, “Agroecosystem Benefits from the Development and Application of New Management Technologies in Agricultural Watersheds”. Please see the report for the previous project for additional information.
