Data from Pasture Nine, Jornada Experimental Range, New Mexico, were used in regression and simulation modelling approaches to predicting perennial grass growth for use in management. These approaches served to illustrate the capabilities of timeshare computer facilities and APL (A Programming Language). Results of various regressions of the relationships of precipitation, days of soil moisture levels, and yield and cover of perennial grasses were used to heuristically develop a simulation model. Plotting the model output against the actual yields, although not statistically significant, gave promising results. The addition of parameters for evapo-transpiration could result in a valid model.