Location:2008 Annual Report
1a. Objectives (from AD-416)
Objective 1.Develop, implement, enhance, and maintain an object modeling system (OMS) and a library of modules for building agricultural system models at field to watershed scales for a variety of applications. [Contributes to Problem Area #1, Effectiveness of Conservation Practices, Product #5 of the new National Program (NP) 201 Action Plan (FY 2006 - 2010)] Objective 2.Develop, verify, and evaluate field to watershed modeling tools and techniques that quantify environmental outcomes of conservation practices in major agricultural regions, including modeling and decision aids for drainage water management systems. [Contributes to Problem Area #1, Effectiveness of Conservation Practices, Product #5 and Problem Area #3, Drainage Water Management Systems, Product #4 of the new NP 201 Action Plan (FY 2006 - 2010)] Objective 3.Develop improved space-time scaling and model parameterization approaches for landscape processes in new agricultural system models from field to watershed scales. [Contributes to Problem Area #1, Effectiveness of Conservation Practices, Product #5 of the new NP 201 Action Plan (FY 2006 - 2010), and to Goal 1.7.2 of NP 201 to develop methods to determine input model parameters, values, and state variables for multiple scales to account for the effect of management practices].
1b. Approach (from AD-416)
Objective 1. Hypothesis: The OMS framework can be used to develop customized, modular field to watershed ag system models with interchangeable components for assessing the effects of conservation practices. Experimental Design: OMS represents an ARS-led effort in partnership with the NRCS, USGS, and university collaborators (e.g. CO State University). Enhancing OMS functionality includes the development of improved capabilities for: 1) model building 2) code testing, data connectivity, and database integration; 3) geospatial output visualization and model parallelization; and 4) uncertainty, sensitivity analysis and parameter estimation. Objective 2 Hypothesis 2-1: A new prototype regionalized model can provide improved estimates of the effects of conservation practices on environmental responses at the field to watershed scales. Experimental Design: The overall goal is to develop an OMS-based modular simulation model with interchangeable components that can address regional soil and water conservation and water quality need from field to watershed scales. Specific task areas for Objective 2 are: 1) Identify regions and define process modules for a selected regional area; 2) Obtain needed scientific model components; 3) Develop a prototype regionalized watershed model and perform a preliminary evaluation; 4) Modify existing modules or identify and develop additional modules; 5) Evaluate the prototype watershed model with various conservation practices; and 6) Transfer the prototype model to NRCS. Hypothesis 2-2: An agricultural systems model, RZWQM2, can simulate and quantify the effects of BMPs under tile drainage for different Midwest climate and soil conditions. Experimental Design: In a collaborative research effort with the National Soil Tilth Laboratory (Ames, IA). Field experiments will be conducted in Iowa. RZWQM2 will be used to quantify controlled drainage and cover crop effects on drainage volumes, nitrate losses in drainage flow, and crop growth. Objective 3 Hypothesis: Soil, water and plant properties can be scaled over space and time to identify scale-appropriate behaviors and model parameters across agricultural landscapes. The resulting perameters can be used to improve the modeling of spatial interactions between land areas containing differential management and conservation practices. Experimental Design: The prototype regionalized watershed model will be used to assess the propogation of uncertainty in model structure, parameter values, and inputs to water quantity and quality effects up to watershed scales. Scale-dependence and uncertainty of model parameters will be evaluated as follows: 1) Characterize the spatial and temporal variability of measured system variables in the prototype watershed model; 2) Relate key model parameters to spatial surrogates; 3) Generate high resolution inputs to detailed process modules and upscale the results; determine effective parameter values over the range of scales of interest; and 4) Quantify parameter uncertainty and its impacts on model output uncertainty using a suite of object-based tools developed for parameter estimation.
3. Progress Report
The Object Modeling System (OMS) was further enhanced to better support visual assembly of spatially distributed models for different space-time scales. Major system improvements were: 1) flexible simulation management; 2) self-contained packages for run-time model deployment; 3) development of a component and scientific model library management system; 4) improved data file handling for input parameter sets; 5) time series-based I/O that now uses the flexible CSV format; and 6) development of an OMS component that allows visualization and manipulation of GIS data using NASA World Wind geospatial technology. Required JAVA-based scientific components (e.g., water balance, infiltration, groundwater recharge, runoff and stream flow dynamics, nutrient cycling, and plant growth) for an OMS-based regionalized prototype watershed model were obtained from the J2000 and SWAT models and implemented under the OMS science module library. Implementation and integration of the above modules has shown OMS to be a viable and robust platform for identifying and incorporating the most effective practical approaches for CEAP regionalized model customization. [Contributes to Problem Area #1, Effectiveness of Conservation Practices, Product #5 and Problem Area #3, Drainage Water Management Systems, Product #4 of the NP 211 Action Plan (FY 2006 – 2010)] Recent work relating soil hydraulic parameters of different soil textural classes and water infiltration and storage to pore-size distribution index or saturated hydraulic conductivity is being extended to estimate effective parameters of a heterogeneous field. These relationships are being tested using measured data to determine how basic soil physical parameters can be used to robustly estimate soil hydraulic properties needed by physically-based models. Soil water infiltration measurements at steady state were collected using 30-cm diameter rings at 150 locations on a farm in Ault, CO. The measurements were clustered or “nested” within ten unique landscape positions and were subsequently analyzed for spatial patterns of variability using fractal geometry. Fractal analyses revealed distinct changes in the apparent fractal dimension (or Hurst exponent) with the scale of analyses, where the Hurst exponent reached a maximum at about 200 m. A manuscript on this topic was submitted to the Vadose Zone Journal. Investigation of the interrelationships between wheat phenology, thermal time, and landscape position was completed, including analysis of seven years of Drake Farm experimental data defining relationships between plant properties and terrain/soil attributes. Plant phenology was more related to thermal time in wetter years than in drier years, and thermal time was more related to landscape position and terrain attributes in wetter years than drier years. [Contributes to Problem Area # 2.4: Site Specific Technologies to Conserve Water, Nutrients, and Energy, Product #7 of the NP 211 Action Plan (FY2006-2010); Problem Area #6 Water Quality Protection Systems, Product #3; and Goal 1.7.2 of NP 211].
1. Enhanced Object Modeling System (OMS) Delivered to NRCS. Modular frameworks for model development like OMS are well-suited for comprehensive projects like CEAP that require complex simulation component technology integrated into a common, collaborative, and flexible system. In order to provide such a system, the OMS application programming interface (API) was enhanced to allow flexible simulation management, self-contained model run-time execution (i.e., OMS-based models can be run without full installation of the OMS framework), and improved data file handling for input parameter sets and simulation output based on the generic CSV format. OMS was also extended to transfer and retrieve science modules to and from the OMS component library residing under the USDA Colab project management environment, and a prototype OMS component that allows visualization and manipulation of geospatial data was developed using NASA World Wind geospatial technology. The OMS was officially transferred to the NRCS on February 26, 2008, and will streamline development of customized, modular field to watershed agricultural system models to be delivered to the NRCS to address regional soil and water conservation and water quality needs. A journal paper describing space-time data structures in OMS is currently under preparation. [Contributes to problem Area #1, Effectiveness of Conservation Practices, Product #5 of the new National Program (NP) 201 Action Plan (FY 2006-2010)]
2. OMS-Based Prototype Regionalized Watershed Model. In addition to needed science base improvements for ARS watershed models, a flexible modular modeling configuration is needed to efficiently build a watershed model customized to regional processes, concerns, and issues. Java-based simulation modules (80+ representing interception, snow processes, soil water balance, lateral flow and ground water movement, and runoff concentration/flood routing in channels) from the European J2000 modular process-oriented hydrological system were integrated under OMS to form a prototype regionalized watershed model. The resulting prototype model is unique in allowing for conjunctive stream flow and groundwater interaction, carried out by hydrological response units (HRUs) which are connected by a lateral routing scheme to simulate lateral water transport processes. This allows a fully distributed hydrological modeling of river basins. The prototype model under OMS was tested against the J2000 model running under the Jena Adaptable Modelling System (JAMS) for reference watersheds in the United States and Europe in order to verify the accuracy of the OMS implementation. Formal evaluation of the prototype for stream flow is being performed using data from an ARS CEAP Watershed in Indiana (Cedar Creek Watershed). [Contributes to Problem Area #1, Effectiveness of Conservation Practices, Product #5 and Problem Area #3, Drainage Water Management Systems, Product #4 of the new NP 201 Action Plan (FY 2006 – 2010)]
3. PhenologyMMS Version 1.2.2 and Unified Plant Growth Model (UPGM) Version 1.0. Improved plant growth modeling is needed to better assess the impacts of implementing conservation practices at field to watershed scales. PhenologyMMS Version 1.2.2 was released, and can be used as a stand-alone tool or incorporated into existing crop simulation models and decision support tools to simulate changes in multi-crop phenology as a result of varying levels of soil water availability. Version 1.2.2 provides the complete developmental sequences of the shoot apex correlated with different developmental events for winter and spring wheat, winter and spring barley, maize, proso millet, hay millet, and sorghum. The Unified Plant Growth Model (UPGM) has been developed and tested for corn and wheat across a range of environments, and successfully merges different versions of the EPIC-based plant growth model that exist in many agricultural system simulation models (e.g., GPFARM, WEPP, WEPS, SWAT, and ALMANAC). Using this stand-alone foundation, improvements in simulating plant growth have been made. For example, the UPGM has been re-structured and modularized (for future integration into the OMS) and new phenology and seedling emergence simulation code from PhenologyMMS is being incorporated and tested. [Contributes to Problem Area #1, Effectiveness of Conservation Practices, Product #5 and Problem Area #3, Drainage Water Management Systems, Product #4 of the new NP 201 Action Plan (FY2006-2010)]
4. RZWQM Modeling Confirms Cover Crops Reduce Nitrate Leaching. Additional field-scale model evaluation quantifying the effects of cover cropping, water table and nitrogen management, and other BMPs under tile drainage conditions is needed to further support regionalized watershed model development for Midwest conditions. This research investigated the expected reduction of nitrate losses in tile drainage with a rye winter cover crop in a corn-soybean rotation when different levels of nitrogen fertilizer were applied in the corn year. A calibrated RZWQM-DSSAT hybrid model was modified to simulate a rye winter cover in a corn-soybean rotation and simulation results were verified against field measurements. The simulation was then run at various nitrogen fertilizer application rates using a long-term climate record. Results showed that percentage reduction of nitrate losses in tile drainage caused by the cover crop remained relatively constant over a wide-range of nitrogen fertilizer application rates. This indicates that rye winter cover crops will reduce losses of nitrate in tile drainage water even at relatively low nitrogen application rates. [Contributes to Problem Area #1, Effectiveness of Conservation Practices, Product #5 and Problem Area #3, Drainage Water Management Systems, Product #4 of the new NP 201 Action Plan (FY2006-2010)].
5. Significant Activities that Support Special Target Populations
On-farm spatial data collection and transfer of information to “small farms” are enabled under the MOU with the Drake Farm near Ault, Colorado, which is a family owned and operated business. Information from this cooperative work has also been shared with other owner/operators of small farms through meetings of the Young Farmers Association.
Green, T.R., Taniguchi, M., Kooi, H. 2007. Potential Impacts of Climate Change and Human Activity on Subsurface Water Resources. Vadose Zone Journal 2007;6 531-532. DOI: 10.2136/vzj2007.0098.