Many of you have already pondered this question and some of you have applied fertilizer on introduced forages, such as bermuda and old world bluestems. There seems to be a perception among some forage producers that you cannot afford to apply fertilizer.
The real answer to this question depends on many factors such as your goals for the enterprise, soil type, fertility status of the soil, weather and so on. Another question could be how many cows or other livestock are needed for an economical enterprise? Perhaps you have the wrong enterprise if profit is the primary goal.
The tables below show some potential costs based on average yields from Midland bermuda grown on sandy loam upland soils in southern Oklahoma. Notice the assumed yield increase from nitrogen is 30 pounds of additional forage (dry matter basis) per acre per pound of nitrogen. Your response may be better or worse depending on soil type and weather.
Do these numbers tell us all we need to know? Do you not fertilize because according to these numbers leasing grass without fertilizer provides grass at the least cost per ton or per cow? First, your grass yields may be (probably will be) different, your cost for fertilizer could be different, etc. For instance, if 34-0-0 is $150 per ton and you apply 50-0-0 the cost for land and fertilizer is $60.96 per cow when land is $10 per acre and $75.46 when land is $15 per acre. We have not considered the increased protein content of fertilized grass, cost of upkeep on extra acres etc. Other livestock, such as stockers, may show economical responses to fertilizer at even higher rates. Again, productive potential of the land, cost of land, values of fertilizer and products to be sold all influence potential profits.
The most important consideration, if profit is your primary goal, is which production level generates the desired net profit. You will need a complete budget to adequately answer the question about fertilizing or not fertilizing. Grass cost is just one piece of the entire enterprise budget and you are encouraged to estimate potential returns from all possible expenses before purchasing inputs or making changes with any enterprise.