SENSITIVITY ANALYSIS OF THE SOIL INPUTS FOR THE GROWTH-MODEL PEANUT

The peanut growth model, PEANUT, requires several inputs that describe the physical characteristics of the soil. A sensitivity analysis was conducted to determine the model's response to changes in the soil inp uts. For the soil water evaporation and water distribution inputs, one input was varied per simulation, while the other variables were set e qual to values previously determined for a Norfolk sandy foam soil. Se nsitivity to changes in the soil water characteristic function was obt ained by fitting the function to data for five different Norfolk soils . The effects of changes in the inputs were considered by conducting g rowth simulations with 16 years of weather data. Changes in all of the soil water parameters, with the exception of the soil water storage p arameters, had little effect on the predicted pod masses; however, a g reater effect on predicted pod mass due to changes in the sail water p arameters was present iii years with adequate rainfall in the early se ason followed by drier conditions in mid to late season.