CN-SIM: a model for the turnover of soil organic matter. II. Short-term carbon and nitrogen development

A computer model is presented, which describes the transformations of C and N in the soil. The development has been divided into two interdependent tasks, the first is long-term simulation of soil organic carbon simulation capabilities, and the second is short-term simulations of C and N, as described in this paper. A number of existing, independent laboratory experiments, covering a range of amendments, have been used for the latter task. The amendments include a variety of different crop residues and animal manures. These experiments include measurements of 13C and 15N in various pools, and the model facilitates the simulation of these isotopes. Non-linear optimisation procedures were utilised wherever feasible, and in order to test the robustness and generality of the model, cross-validations and sensitivity analyses were performed. In general, the model yielded good to acceptable descriptions of the measured data.