Research Project: Managing Agricultural Systems to Improve Agronomic Productivity, Soil, and Water Quality

Location: National Soil Erosion Research Laboratory

2022 Annual Report

Objectives
Objective 1: Develop strategies to mitigate landscape scale attributes for improved soil and water quality and production efficiency. Sub-objective 1.1 Explore surface and subsurface hydrologic processes affecting soil quality and vulnerability on tile-drained landscape. Sub-objective 1.2 Evaluate sources and flow pathways of water and nutrients in tile-drained landscapes. Objective 2: Improve nutrient management efficiency to minimize water quality degradation and maximize agricultural production. Sub-objective 2.1 Assess the influence of combined conservation practices on soil organic matter transformations, nutrient cycling, and crop yield. Sub-objective 2.2 Evaluate soil P drawdown rates, plant phosphorus uptake, and potential changes in corn and soybean yield with elimination of phosphorus fertilizer to long-term fertility research plots. Sub-objective 2.3 Determine the critical phosphorus concentration for corn and soybean cultivars common to the Midwest using the Genetics X Environment X Management (GxExM) approach. Sub-objective 2.4 Evaluate quantity/intensity relationships and the kinetics of phosphorus release in diverse soils in working towards the long-term goal of improving soil fertility recommendations. Objective 3: Develop and refine decision support tools. Sub-objective 3.1 Develop software and database architectures to support collecting and managing observed natural resource data. Sub-objective 3.2 Develop decision support tools to explore and integrate observed field and small watershed data with spatial models. Sub-objective 3.3 Test and improve tools for assessment of climate change impacts on model predictions of soil erosion and chemical losses. Objective 4: Operate and maintain the Eastern Corn Belt LTAR network site in partnership with the Soil Drainage Research Unit, Columbus, OH and the National Center for Water Quality Research, Heidelberg University, Tiffin, OH using technologies and practices agreed upon by the LTAR leadership. Contribute to the LTAR working groups and common experiments as resources allow. Submit relevant data with appropriate metadata to the LTAR Information Ecosystem. Sub-objective 4.1 Develop water, nitrogen, and phosphorus budgets for agricultural fields under prevailing management practices in the Eastern Corn Belt. Subobjective 4.2. Evaluate relationships between soil and water quality, and greenhouse gas emissions under different cropping and management scenarios in the Eastern Corn Belt.

Approach
Objective 1: Both laboratory and field studies will be used to gain a better understanding of the hydrologic processes that control erosion at various locations in the landscape and assess sources and flow pathways of nutrients and water to streams. This will involve assessing the effect of subsurface tile drains on in-stream variability of nutrient concentration and isotopic signatures. Indoor rainfall simulation tools and a stream survey will be utilized to accomplish the listed objective. Objective 2: Regarding soil quality and phosphorus fertilizer recommendations, laboratory and field experiments will be used. Current long-term field experiments where various crop rotations and best management practices have been implemented will provide soils for detailed laboratory analysis to assess the impact of the given practices on soil quality. For phosphorus fertilizer recommendations, the approach is to construct a controlled indoor growth facility and evaluate phosphorus uptake by various crop cultivars, followed by a detailed experiment on quantifying the ability of soil to supply dissolved phosphorus to solutions using long term incubations and various types of extraction methods. Objective 3: Computer programs will be developed for automation of uploading environmental data into the proper format for use by several models, as well as convert to specified data formats, and help interpret validation data from model simulations. This includes incorporation of various future climate scenarios into different models. Objective 4: Discharge, water quality data, and producer surveys will be used to develop water and nutrient budgets for agricultural fields in the Eastern Corn Belt region. This research will link soil quality parameters and soil processes to water quality and gas flux data collected from monitored field sites.

Progress Report
In regard to Objective 1, several goals were achieved that help to improve our understanding of how rainfall-runoff interactions control sediment transport. We recently verified a new method to quantify the kinetic energy (KE) supplied by simulated rainfall. Raindrop KE varies with drop size and velocity. The KE supplied by raindrops to the soil can breakdown surface aggregates and dislodge soil particles that can be easily swept away as runoff develops. In moving towards these goals, it was necessary to improve the experimental methods; The indoor experimental rainfall plot has been renovated. Briefly, the experimental setup consists of a large soil box (12m long x 5m wide) set at a 5% slope, with 30cm of erodible topsoil sitting atop a layer of crushed gravel. Plastic pipes w/tiny holes buried within the gravel layer allow subsurface moisture conditions to be controlled. A calibration of the spray nozzles was performed for multiple rainfall intensities to ensure uniform rainfall application. Next, a series of rainfall experiments has been designed and planned for mid-summer, with the objective of identifying the dominant mechanisms present during a rainfall (storm) event. A storm event can be broken up into four distinct phases. Phase 1: initial (unsteady) period where rainfall and infiltration processes compete. Phase 2: pseudo- steady infiltration and evolution of the drainage network. Phase 3: pseudo-steady runoff, an induction (large flush of sediment) results from incision/ headcutting processes and bed morphology. Phase 4: pseudo-steady sediment, where headcutting and morphology begin to dissipate. The second objective looks at how rainfall intensity impacts the above-mentioned four phases and corresponding mechanisms. A gridded system is being installed above the soil surface (0.5m spacing) to establish a coordinate system for the plot. Beyond the laboratory, samples were collected within Long Term Agricultural Research (LTAR) sites to assess the impact of management on soil aggregate stability using a multi-sample water stable aggregate testing apparatus. Additional sampling across multiple LTAR sites is scheduled for late summer/fall. Soil aggregate stability has been positively related to soil structure, infiltration, and erodibility. This robust data set will encapsulate a wide range of soil types, slopes, and cropping systems, that can better inform producers which management practices promote resiliency in the face of a changing climate. For Sub-objectives 2.1 and 2.2: Work continued on field studies dedicated to studying the effects of conservation practices on soil carbon (C) dynamics and cessation of phosphorus (P) fertilizer to long-term fertility research plots by collecting soil and plant samples. Total soil C and nitrogen (N) in the top 15cm soil layer were not impacted by gypsum application or cover crop (cereal rye). In May 2022, soil samples were collected from 0-100 cm from a field experiment to study the impact of gypsum rate and frequency of application and cover crops on C distribution in the soil profile and C quality parameters (i.e., active C, the readily digestible and easily decomposed organic residue). In a different field study, neither gypsum nor cover crop affected active C, but both conservation practices increased soil microbial biomass-C. From preliminary data, gypsum nor cover crop affected corn and soybean yields. In addition, cessation of P fertilization for four years, on long-term fertility plots with two-year corn-soybean rotations under no-till, did not affect corn and soybean yield (relative to the control). P status in soils (e.g., Mehlich-3 and water- extractable P), P uptake by corn and soybean plants, and soil C and N will be determined in the future. Also, in the realm of Objective 2, we completed a nation-wide collection of soils that were additionally characterized in preparation for several experiments. Specifically, we began the process of adjusting pH to five different target values for use in the soil incubation focused on examining phosphorus water solubility and kinetics. pH adjustment is a slow process and is ongoing. The incubation should be initiated with the next couple months. Towards the same general effort, we began developing and testing different methods of soil water extraction, intended to more closely capture the soil solution that best represents the root environment. This included designing and building a special centrifuge container and several types of displacement columns. These methods will be compared thoroughly over the next several months. Among the many soils collected, about 30 were utilized in flow-through desorption experiments for the purpose of gaining a better understanding of how contact time and flow rate partly controlled P desorption quantity and kinetics. This allows close examination of the process of desorption, and how this chemical process is influenced by physical processes. One of the soils was chosen to be studied in greater detail in further P desorption kinetics experiments. The dynamics of the physical/chemical realm of a flowing system serve to bridge the gap between physical processes and chemical processes. As part of objective 2 in regards to developing better fertilizer P recommendations, corn nutrient uptake data from the indoor grow room was analyzed in detail for the purpose of determining the minimum P uptake mass required for achieving maximum grain yield (about 580 mg). This value will be critical in the long-term development of a nutrient management tool based on the nutrient uptake and soil-solution dynamics processes, as opposed to the traditional empirical techniques. Detailed analysis of nutrient uptake proved to be useful in understanding why excess P uptake caused a decrease in grain yield. Related to Objective 3, Sub-objective 3.3, downscaled climate information obtained from General Circulation Models (GCMs) obtained during the previous year’ efforts were utilized in Climate Generator and Water Erosion Prediction Project (CLIGEN and WEPP) modeling studies at 20 locations across the United States. Erosion model simulations were conducted using both tilled fallow and typical cropping management at each site. Results for both the baseline conditions and projected future climates for early (2025), mid (2055), and late (2085) 21st century were modeled. In the Subobjective 3.3 study examining effects of using adjacent Parameter-elevation Regressions on Independent Slopes Model (PRISM) grid cell adjustments were conducted. Results suggest that precipitation with adjustments from both 4-km and 800-m PRISM was comparatively greater than CLIGEN, though differences in mean values for precipitation, runoff, and soil loss were not significantly different at most locations. As part of Objective 4, a multi-location (n=22) project was initiated and completed assessing phosphorus budgets across the United States and Canada including many sites within the conservation effects assessment project (CEAP) and LTAR network. Using this large data set for both national projects, sensor data from ARS field sites continue to be uploaded to a central website where users can view the latest weather and soil moisture data. Work has also continued using a commercial water database system to catalog and quality check all data for the ARS field research sites in Northeast Indiana. Remote cameras at eleven Conservation Effects Assessment Project (CEAP) field sites transmit images every ten minutes to a server at the National Soil Erosion Research Laboratory (NSERL). A separate server archives the image data. How to use the image data to support modelling applications related to canopy and residue cover are currently being evaluated. Data is being collected, but processing algorithms have not been developed. Several sites now have image data for over 12 months under varying field and ditch conditions. Within this effort to produce and share data for modelling, work has started on adapting a research version of the USDA Annual Phosphorus Loss Estimator (APLE model) to a web-based platform. Initial work involves converting the MATLAB based model into Python, C++ and JavaScript to more easily develop alternate user interfaces to the model suitable for end users.

Accomplishments
1. Forces united: How physical and chemical processes combine to impact water quality through soil phosphorus release on the way to the drain. Transport of P from soils to surface waters is responsible for eutrophication and water quality degradation, worldwide. Changing climate can have an impact on how rainfall and runoff interact with the soil. ARS researchers in West Lafayette, Indiana, conducted research that shed light on how the physical manner in which water interacts with soil can have a profound impact on the chemical process of P being released from the soil, with regard to both the quantity and speed of P release. Higher flow rates through soils release a lesser quantity of P but release it faster. These results are important for improving existing P transport models as well as understanding the potential impact of climate change on water quality. Models are used to make agricultural policies that have an impact on farmer’s efficiency, economics, and water and environmental quality. It is important that these models accurately represent reality because of the profound implications. This research better informs those models so that they more accurately represent reality.

2. Successfully growing grain corn indoors under artificial conditions. When it comes to research on plants and nutrient uptake, having total control of all conditions is ideal. Current techniques all have disadvantages: greenhouse, field-grown, growth chambers, and traditional hydroponics. ARS researchers in West Lafayette, Indiana, developed a semi- automated technique for growing 96 corn plants to full maturity, indoors with 100% artificial conditions.With ideal conditions and successful simulation of light intensity, diurnal fluctuations in temperature and humidity, changing photoperiod, and the ability to precisely control nutrient bioavailability, grain yield and tissue nutrient concentrations were identical to field-grown corn. Through use of an inert rooting media that would not adsorb or release nutrients, researchers were able to utilize nutrient fertigation for controlling bioavailability and timing, which is impossible with soils. Development of the research technique was a big step forward with regard to future plant physiology and nutrient demand studies designed to focus on topics such as optimizing fertilization strategies for improving efficiency of crop production.

3. Developed the P-FLUX dataset critical to improving phosphorus use efficiency. Phosphorus is a critical nutrient needed for crop growth, but once transported from agricultural fields can result in water quality impairment downstream. Led by ARS researchers in West Lafayette, Indiana, the P-FLUX dataset represents a collaboration between 47 scientists with data spanning 22 U.S. states and two Canadian provinces. The P-FLUX dataset was developed to summarize and compare phosphorus inputs, outputs, and budgets across diverse cropping systems in the U.S. and Canada. Data on phosphorus management practices and losses from 61 cropping systems including row crop, rangeland, forage, and bioenergy systems are contained within the dataset, which is publicly available for download through the USDA Ag Data Commons (https://data.nal.usda.gov/dataset/ltar-phosphorus-budget-summary-0). Datasets such as P-FLUX are critical for improving phosphorus use efficiency and developing management practices to mitigate environmental impacts of agricultural systems.

4. Utilized dynamic rain gauge system (DRGS) to provide simplistic, inexpensive solution to quantify raindrop kinetic energy (KE) and improved erosion prediction. Raindrop KE is the triggering mechanism in soil erosion events, as raindrops transfer KE into the soil surface, which can break apart aggregates and dislodge material that can be easily swept away as runoff develops. Traditional methods to estimate KE necessitate expensive sensors and are generally computationally intensive. Recently, ARS researchers in West Lafayette, Indiana, have verified a new, simplistic method to quantify the KE supplied by simulated rainfall, utilizing the DRGS, which consists of a 1m long bar lined with rain gauges that spins like the blade of a helicopter, collecting different sized raindrops. The mass of raindrops collected within the spinning gauges and their respective velocity have successfully been used to quantify the KE provided by a wide range of rainfall intensities. Incorporating DRGS into existing meteorological weather stations could provide spatial, event-based measures of raindrop KE, which can be used to improve watershed/sub-catchment models and erosion prediction.

Review Publications
Wacha, K.M., Hatfield, J.L., O'Brien, P.L., Dold, C. 2021. Short-term effects of nitrogen source on soil properties and plant growth. Agrosystems, Geosciences & Environment. 4(2). Article e20176. https://doi.org/10.1002/agg2.20176.
Wacha, K.M., Huang, C., O'Brien, P.L., Papanicolaou, T.N., Hatfield, J.L. 2021. Quantifying the time-specific kinetic energy of simulated rainfall using a dynamic rain gauge system. Agricultural & Environmental Letters. 6(1). Article e20042. https://doi.org/10.1002/ael2.20042.
Gonzalez, J.M., Dick, W., Islam, K.R., Watts, D.B., Fausey, N.R., Flanagan, D.C., VanToai, T.T., Batte, M.T., Reeder, R.C., Kost, D., Shedekar, V.S. 2022. Gypsum and cereal rye cover crops affect soil chemistry: Trace metals and plant nutrients. Soil Science Society of America Journal. 886:781-794. https://doi.org/10.1002/saj2.20394.
Penn, C.J., Williams, M.R., Camberato, J., Wenos, N., Wason, H. 2022. Desorption kinetics of legacy soil phosphorus: Implications for non-point transport and plant uptake. Soil Systems. 6:6. https://doi.org/10.3390/soilsystems6010006.
De Campos, M., Penn, C.J., Gonzalez, J.M., Crusciol, A.C. 2021. Effectiveness of deep lime placement and tillage systems on aluminum fractions and soil chemical attributes in sugarcane cultivation. Geoderma. 407:115545. https://doi.org/10.1016/j.geoderma.2021.115545.
Weithorn, M., Penn, C.J., Camberato, J. 2021. A research method for semi-automated large-scale cultivation of maize to full maturity in an artificial environment. Agronomy Journal. 11(10):1898. https://doi.org/10.3390/agronomy11101898.
Penn, C.J. 2021. Letter to the editor of Chemosphere regarding Yang et al. (2021) and techniques for assessing realistic phosphorus removal in the field. Chemosphere. 286:131843. https://doi.org/10.1016/j.chemosphere.2021.131843.
Yuan, L., Zhang, X.J., Busteed, P.R., Flanagan, D.C. 2022. Simulating the potential effects of elevated CO2 concentration and temperature coupled with storm intensification on crop yield, surface runoff, and soil loss based on 25 GCMs ensemble: A site-specific case study in Oklahoma. Catena. 214:106251. https://doi.org/10.1016/j.catena.2022.106251.
Yuan, L., Zhang, X.J., Busteed, P.R., Flanagan, D.C., Srivastava, A. 2022. Modeling surface runoff and soil loss response to climate change under GCM ensembles and multiple cropping and tillage systems in Oklahoma. Soil and Tillage Research. 218. Article 105926. https://doi.org/10.1016/j.still.2021.105296.
Williams, M.R., McAfee, S.J. 2021. Water storage, mixing, and fluxes in tile-drained agricultural fields inferred from stable water isotopes. Journal of Hydrology. 599. Article 126347. https://doi.org/10.1016/j.jhydrol.2021.126347.
Pignotti, G., Rathjens, H., Chaubey, I., Williams, M.R., Crawford, M. 2021. Strong sensitivity of watershed-scale, ecohydrologic model predictions to soil moisture. Journal of Environmental Modeling and Software. 144. Article 105162. https://doi.org/10.1016/j.envsoft.2021.105162.
Williams, M.R., Welikhe, P., Bos, J.H., King, K.W., Akland, M., Augustine, D.J., Baffaut, C., Beck, G., Bierer, A.M., Bosch, D.D., Boughton, E., Brandani, C., Brooks, E., Buda, A.R., Cavigelli, M.A., Faulkner, J., Feyereisen, G.W., Fortuna, A., Gamble, J.D., Hanrahan, B.R., Hussain, M., Kohmann, M., Kovar, J.L., Lee, B., Leytem, A.B., Liebig, M.A., Line, D., Macrae, M., Moorman, T.B., Moriasi, D.N., Nelson, N., Ortega-Pieck, A., Osmond, D., Pisani, O., Ragosta, J., Reba, M.L., Saha, A., Sanchez, J., Silveira, M., Smith, D.R., Spiegal, S.A., Swain, H., Unrine, J., Webb, P., White, K.E., Wilson, H., Witthaus, L.M. 2022. P-FLUX: A phosphorus budget dataset spanning diverse agricultural production systems in the United States and Canada. Journal of Environmental Quality. 51:451–461. https://doi.org/10.1002/jeq2.20351.
Steinman, A., Hassett, M., Oudsema, M., Penn, C.J. 2022. Reduction of phosphorus using iron slag filters in the Macatawa Watershed (Michigan). Frontiers in Environmental Science. 10. Article 863137. https://doi.org/10.3389/fenvs.2022.863137.
Liu, P., Bindlish, R., O'Neil, P., Fang, B., Lakshmi, V., Yang, Z., Cosh, M.H., Bongiovanni, T., Holifield Collins, C.D., Starks, P.J., Prueger, J.H., Bosch, D.D., Seyfried, M.S., Williams, M.R. 2022. Thermal hydraulic disaggregation of SMAP soil moisture over continental United States. IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing. 15:4072-4093. https://doi.org/10.1109/JSTARS.2022.3165644.