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United States Department of Agriculture

Agricultural Research Service

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Research Project: Improving the CQESTR Model Accuracy for Tropical Soils

Location: Soil and Water Conservation Research

Project Number: 2074-11120-003-02-N
Project Type: Non-Funded Cooperative Agreement

Start Date: Jul 1, 2013
End Date: Jun 30, 2016

The objective of this cooperative research project is to modify the CQESTR model for tropical conditions (i.e., the presence of amorphous clay, oxides and hydroxides of iron and aluminum, high acidity, and low cation exchange capacity). Specifically this project is conducted to: 1) evaluate possibilities of necessary adaption of CQESTR model for tropical climate areas; 2) correlate the degree of humification of soil organic matter (SOM) to the stability of recalcitrant soil organic carbon (SOC); 3) examine the impact of amorphous clay, acidity and cation exchange capacity on SOC stabilization in tropical soils; and 4) modify the CQESTR code to include algorithms for correlation between the degree of humification of SOM, amorphous clay, acidity, or cation exchange capacity and the stability of SOC.

The CQESTR model, a carbon (C) balance model developed by ARS scientists at the Columbia Plateau Soil Conservation Research Center (CPCRC) in Pendleton, will be modified. The modification of a process-based soil C model such as CQESTR requires detailed knowledge of current model structure and knowledge of proposed algorithm addition. First, we will review current available literature on the CQESTR model structure, and any available literature on properties of tropical soils related to soil organic matter decomposition. Factors controlling preservation or mineralization of soil organic matter will be examined. Second, we will develop functions and algorithms proper for tropical soil organic matter humification. Third, we will examine the model structure, and code and modify the code to accommodate the newly developed algorithms. Fourth, any changes in the program code will be documented. Fifth, new executable files will be prepared. Sixth, all accomplished tasks will be documented in a final report and a peer-reviewed manuscript will be prepared.

Last Modified: 07/26/2017
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