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United States Department of Agriculture

Agricultural Research Service


Location: Agricultural Systems Research Unit

2010 Annual Report

1a.Objectives (from AD-416)
1. Streamline the procedure and training scientists for developing, testing, and improving stand-alone OMS-compatible science process modules of different agricultural systems derived from existing models or knowledge base for the OMS library, and integrating models from them.

2. Streamline the procedure and help scientists for testing and improving the modules and models created from them for a variety of applications. 3. Enhance the GPFARM-range modules and model for use in simulating a variety of range management practices, effects of climate change on forage, and soil carbon storage. Add modules for parameter estimation and scaling and improve root growth and water and N uptake components.

1b.Approach (from AD-416)
Procedures for building and testing modules and models will be streamlined and progressively improved. This will require storing in OMS of test datasets for testing the modules and models against. Active assistance will be provided to ASRU and other ARS modelers for creating, testing and improving OMS modules for a variety of agricultural systems, as well as auxiliary components (e.g., land unit delineation, parameter estimation, scaling, sensitivity and uncertainty analyses) needed for important applications, integration of these components into a running model, and showing the plug and play capability. A friendly, step-by-step, users manual and a tutorial developed for this purpose will be further improved. They will also be trained on how to test the modules and models against some data. The existing modules for a range-livestock model will be expanded to include components for effects of climate change on forage growth and quality of different forage species, and for soil carbon in the root zone. Continuing modifications will be made in OMS in response to users’ requirements and suggestions.

Functionalities in OMS will be gradually progressively updated to make it an ARS advanced framework for developing, maintaining, and delivering models/tools at different scales for resource analysis, conservation planning, optimizing agricultural cropping and management practices, and practice design, from basic science components in a library. The components are readily updated or replaced as new knowledge becomes available.

3.Progress Report

Range modeling activities continued within the joint CSU-USDA water limited agriculture project. Building on the foundation of the previous year, several aspects of the GPFARM-Range model were enhanced, according to the tasks outlined for year two, namely, the inclusion of (i) the prediction of climate change effects on forage growth and (ii) the effect of soil and nitrogen dynamics. With respect to the first task, forage response to climate change has been formulated in terms of species-dependent changes in stomatal resistance and relative growth rate with changing [CO2]. Data for these formulations were from the Agricultural Research Service’ Crops Laboratory in Fort Collins. The formulations have been incorporated into the GPFARM-Range code and limited testing is in progress. The inclusion of soil carbon and nitrogen dynamics in the model was major activity in this second year. With the support of a Senior Technician at the ARS, seven new modules were added to the GPFARM-Range model to simulate various aspects of soil carbon and nitrogen of rangelands. At the time of this report, the major aspects of programming and output have been completed. But these modules must now be rigorously tested. The appropriate data set is not immediately available for testing; some components (e.g. soil carbon data on the different carbon pools) are lacking in rangelands even though total soil carbon is often measured. It is suggested that a comprehensive test of the enhanced GPFARM-Range model must be carried out before any release to users.

The climate change predictability of the GPFARM-Range model has now become operational and is undergoing limited testing. A manuscript is in preparation on this aspect. The soil carbon and nitrogen dynamics aspect has been programmed but no testing could be carried. Two major tasks are needed to accomplish the testing (i) assembly of the relevant data sets from literature sources or otherwise for each of the new modules, and the calibration validation of the different modules within the program as well as validation of the overall enhanced GPFARM-model.

The ADODR monitored the activites of this project via meetings, conference calls, and site visits.

Last Modified: 4/16/2014
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