ESTIMATING CONFIDENCE BANDS FOR SOIL CROP SIMULATION-MODELS

A general method is described that provides confidence bands for the output from soil-crop simulation models. Stochastic data are generated for model inputs and model coefficients. These data reproduce the statistical characteristics of the climate, soil properties, and internal model coefficients including distributions, temporal, spatial and variable cross correlations, means, and standard deviations. Model output based on these inputs is then analyzed to produce means, standard deviations, and confidence bands. A typical application of the method is illustrated using a stochastic model for soils input data together with the nitrogen-tillage-residue management (NTRM) simulation model to generate confidence bands for soil NO3-N profiles in Houston County, MN.