Figure 1: Sensitivity analysis of predicted P uptake by cottonwood, smooth brome, and switchgrass using the NST 3.0 model showing the effect on predicted P uptake of varying individually the maximum nutrient influx rate at high concentration ( ), root growth rate ( ), root radius ( ), and initial root length ( ) values while holding all remaining model parameters constant. Each parameter has been varied from a 50% reduction (0.5 change ratio) to a doubling (2.0 change ratio).