A dynamic optimization model which introduces an intertemporal nitrate-nitrogen carry-over function in the optimization procedure is used to derive and evaluate optimal nitrogen application rates, average yield, and the net present value of return associated with precision farming and conventional whole-field farming practices for irrigated cotton production in the Southern High Plains of Texas for a 10-year planning horizon. The results allow cotton producers to adopt decision rules concerning nitrogen application rates for a long-term planning horizon. The results of the study also indicate that the nitrogen-cotton-water price ratios vary the optimal nitrogen application rates.