Planting new fields of alfalfa is expensive, but putting off seedings can be costly in its own right, says Bruce Anderson, forage specialist with University of Nebraska Extension.
Alfalfa stands usually reach peak production by year two or three, Anderson notes. “By year four or five, yields of many dryland fields are much lower than (they were in) their peak years because subsurface moisture that plants were using during the early years is all gone. This is most noticeable during drought years when regrowth is almost zero after the first or second cut. Yield decline in irrigated fields is slower but usually is a ton or more lower by year five or six.”
Trying to squeeze another year out of your alfalfa stand is costly in two ways, Anderson warns. First and most obvious is the lower yield of your old field compared to yields from younger fields. A second loss, though, is the lost rotation benefit received by crops like corn following alfalfa.
“Not only will alfalfa reduce your nitrogen fertilizer needs by 100-150 lbs over the next couple years, much research has shown that corn after alfalfa often yields 10-20 bu more per acre than it will even with extra fertilizer. This rotation benefit could be especially valuable this year if corn prices stay high.”