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A Grassland Nitrogen Flow Simulation Model
J. O. Reuss and G. S. Innis
Vol. 58, No. 2 (Mar., 1977), pp. 379-388
Published by: Wiley
Stable URL: http://www.jstor.org/stable/1935612
Page Count: 10
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A dynamic simulation model of nitrogen flow in a grassland ecosystem has been developed. State variables in the model include the nitrogen in the following major components; soil ammonium, soil nitrate, live roots, dead roots, soil organic matter, live tops, and litter. Belowgrown components are subdivided into four depth layers. The model includes a simple producer-decomposer submodel, but the nitrogen sections have also been incorporated into the ELM 73 ecosystem model. Temperature and soil H"2O driving variables are supplied from external sources. Nitrogen flows, plant growth, and plant decomposition are controlled by temperature, soil H"2O, phenological stage of plant development, and the nitrogen status of the various components of the system.The interaction of the nitrogen components with production and decomposition rates allows nitrogen status to act as a control variable in ecosystem processes, an important feature in a grassland model. Test conducted to date indicate that the model performs in a realistic manner. Simulation of fertilizer effects has been satisfactory, and the model has been useful in identifying critical processes where further research is necessary for an understanding of the system.
Ecology © 1977 Wiley