Simulation of leaching losses in the nitrogen cycle
2006
Gerakis, A. | Rasse, D.P. | Kavdir, Y. | Smucker, A.J.M. | Katsalirou, I. | Ritchie, J.T.
The CERES (Crop Estimation through Resource and Environment Synthesis) family of crop models predicts cereal growth, development, and yield. CERES simulates nitrogen (N) as a yield-limiting macronutrient. Because N leaching is an economic and environmental concern, this study evaluated if CERES can be used to predict N leaching under different N management scenarios: background leaching in unfertilized corn (Zea mays L.), alfalfa (Medicago sativa L.) residue mineralization, and till versus no-till management. Data were collected during a 7-yr field experiment on tillage practices in a maize-alfalfa-maize succession. Sensitivity analyses were performed for decomposition rates of the different residue pools and the relative proportions of carbohydrate, cellulose, and lignin in the residues. During the last 5 yr, under corn, CERES accurately simulated nitrate leaching from the no-till lysimeters. Nitrate leaching was underestimated in the tillage treatments, possibly because CERES does not simulate tillage. The model is not very sensitive to the decomposition rates and to the composition of the residues.
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