One way to make sure pasture fertilization programs are worth the money is to manage grass pastures so the grass actually gets eaten instead of wasted, suggests Bruce Anderson, University of Nebraska forage specialist. “If you fertilize pasture in spring and then let animals graze continuously on one pasture throughout the season, much of the extra growth is wasted,” Anderson says. “They trample, manure and foul, bed down on, and simply refuse to eat much of the grass. Eventually, less than one-third of the extra grass ends up inside your livestock.”
To make fertilizer pay, subdivide pastures with cross fences and control when and where animals graze. Give animals access to no more than one-fourth of the pasture at a time, and preferably less. “Then graze off about one-half of the growth before moving to another subdivision,” he says. “If your pastures aren’t already subdivided into at least four paddocks, your fertilizer dollar might be better spent on developing more cross fences and watering sites.
“With nitrogen fertilizer costing over 60 cents per pound this spring, though, does it pay to fertilize pasture?” Anderson asks. He cites Nebraska research that shows producers can get 1 lb of additional calf or yearling gain for every pound of nitrogen fertilizer applied. However, this rule-of-thumb assumes that the amount applied is within general recommendations, which are based on the potential amount of extra grass growth expected. That growth is affected mostly by moisture. It also assumes that the pasture will be well-managed so the extra growth will be harvested efficiently.