March 15, 2012

As cool-season grass pastures start to green up, we should begin thinking about fertilizing.

As with any crop, grass growth is stimulated by nitrogen fertilizer. But with the cost of nitrogen fertilizer at 60 cents or more per pound this spring, does it pay to fertilize pasture?

Our answer this year would be “Yes.” Our Nebraska research shows that you get about one pound of additional calf or yearling gain for every pound of nitrogen fertilizer applied. With grazingland becoming more scarce and the value of cattle gains exceeding a dollar per pound, boosting yield with fertilizer should be especially valuable this year.

However, this assumes that the amount applied is within our general recommendations and is based on the potential amount of extra grass growth expected. And this will depend on available moisture. More importantly, it also assumes that your grazing management will efficiently harvest this extra growth.

If your animals graze continuously on one pasture throughout the season, much of the extra growth is wasted. They trample, foul, bed down on, and simply refuse to eat much of the stemmy grass and consume less than one-third of the extra grass.

To make fertilizer pay, cross-fence pastures to control when and where your animals graze. Give animals access to no more than one-fourth of your pasture at a time. Graze off about one-half of this growth before moving to another subdivision. Maybe even save one subdivision for hay.
If your pastures aren’t subdivided, fertilizer dollars might be better spent on cross-fences and watering sites.

Following these suggestions can help ensure that more of the added pasture growth is eaten and you see more profits from your fertilizer investment.

Bruce Anderson
Extension Forage Specialist