CQESTR Simulation of Management Practice Effects on Long-Term Soil Organic Carbon

Authors

• Y. Liang, University of Arkansas, Fayetteville
• H.T. Gollany, USDA-ARS Columbia Plateau Conserv. Research Center
• R.W. Rickman, USDA-ARS Columbia Plateau Conserv. Research Center
• S.L. Albrecht, USDA-ARS Columbia Plateau Conserv. Research Center
• R.F. Follet, USDA-ARS Soil Plant Nutrient Research Center
• W.W. Wilhelm, USDA-ARS Agroecosystem Management Research Unit
• J.M. Novak, USDA-ARS Coastal Plains Soil, Water and Plant Res. Center
• C.L. Douglas Jr., USDA-ARS Columbia Plateau Conserv. Research Center

Document Type

Article

Date of this Version

4-30-2007

Citation

Soil Science Society of America

Comments

Soil Sci. Soc. Am. J. 72:1486-1492 doi:10.2136/sssaj2007.0154

Abstract

Management of soil organic matter (SOM) is important for soil productivity and responsible utilization of crop residues for additional uses. CQESTR, pronounced “sequester,” a contraction of “C sequestration” (meaning C storage), is a C balance model that relates organic residue additions, crop management, and soil tillage to SOM accretion or loss. Our objective was to simulate SOM changes in agricultural soils under a range of climate and management systems using the CQESTR model. Four long-term experiments (Champaign, IL, >100 yr; Columbia, MO, >100 yr; Lincoln, NE, 20 yr; Sidney, NE, 20 yr) in the United States under various crop rotations, tillage practices, organic amendments, and crop residue removal treatments were selected for their documented history of the long-term effects of management practice on SOM dynamics. CQESTR successfully simulated a substantial decline in SOM with 50 yr of crop residue removal under various rotations at Columbia and Champaign. The increase in SOM following addition of manure was simulated well; however, the model underestimated SOM for a fertilized treatment at Columbia. Predicted and observed values from the four sites were signifi cantly related (r2 = 0.94, n = 113, P < 0.001), with slope not signifi cantly different from 1. Given the high correlation of simulated and observed SOM changes, CQESTR can be used as a reliable tool to predict SOM changes from management practices and offers the potential for estimating soil C storage required for C credits. It can also be an important tool to estimate the impacts of crop residue removal for bioenergy production on SOM level and soil production capacity.