A Computer Program to Analyze Multiple‐Season Crop Model Outputs

Management‐oriented simulation models of the growth, development, and yield of annual crops are useful tools for screening management options on the computer. Until recently, a limitation of these models has been the inability to simulate more than one cropping season at a time. The capability to simulate long‐term field experiments with such models now exists, in which the simulated soil water, N, organic C, and crop residue outputs from one model run become the input conditions for the next. Simulations of crop rotations can produce large quantities of data, especially if the simulation experiment involves replications across different years. Computer software was written to perform simple analyses of such simulation experiments. The major purpose of the software is to allow the user to investigate the stability and profitability of crop sequences. The program calculates summary statistics for model output variables; these are presented to the user in tabular and graphical forms. Net monetary returns or gross margins can also be calculated, and price and cost variability can be taken into account in the analysis. The program allows rapid, preliminary analysis of a particular crop sequence from replicated simulation experiments and can help the user to assess whether the sequence warrants further evaluation. The program can also be used to summarize the results from historical long‐term field trials. The analyses performed constitute a first step in investigating the sustainability of a particular cropping sequence for a specified length of time.