NEWS for North Dakotans
Agriculture Communication, North Dakota State
University
7 Morrill Hall, Fargo, ND 58105-5665
April 1, 1999
A recent study confirms long-term research conducted at North Dakota State University: stubble height has a significant influence on alfalfa yield, less on overall quality and virtually none on regrowth. Based on the data, an NDSU researcher is advising producers to cut their alfalfa as low as physically possible—ideally to a 1-inch stubble height, or as close to that height as equipment, rocks, gopher mounds and other field conditions will allow.
"The surprising thing to me is the amount of yield we lose in the first harvest with the taller stubble heights," says Dwain Meyer, NDSU plant sciences professor. "We don't actually know why. Lodging is the most logical explanation, but I just don't believe that's what it is."
NDSU researchers plan to hand-harvest some alfalfa this year to see if plant stems can explain the first-harvest yield differences they've been seeing. Meyer has been involved in research looking at how stubble height affects alfalfa since the mid-1960s. Most of Meyer's studies have compared two- and three-cut systems, but his latest trial compares three- and four-cut systems, the latter of which is possible for experienced producers using irrigation or benefitting from abundant rainfall.
The research at NDSU substantiates a point producers have long been making about quality, Meyer says. In short, taller stubble equates to higher quality alfalfa. But while that's true, he says the yield advantage from cutting alfalfa stubble shorter totally offsets the enhanced quality.
"You can't afford the loss of yield if you look at nutrients per acre," Meyer stresses.
When it comes to regrowth, the long-term research shows there is no difference among stubble heights of 1, 3 and 5 inches—all canopies regrow to similar heights. On second and third cuttings, more recovery comes from the stem tissue, Meyer says.
"After the first harvest, 95 percent of stems that initiate for the second growth come from the crown, from underground," Meyer says.
Based on two years of data, results from the current study show that fields cut to a 1-inch stubble height for the first harvest average about 0.8 tons more dry matter per acre than the 3-inch stubble height, Meyer says. The combined two-year data from the three- and four-cut systems showed an annual forage yield decrease averaging 1.64 tons per acre from the 1- to the 5-inch stubble height.
In the ongoing study looking at three- and four-cut systems, NDSU researchers have not yet evaluated how stubble height affects quality. This year, they will be evaluating faster-recovery cultivars, compared to Vernal, to see if the newer cultivars respond to stubble height differently, Meyer says.
###
Source: Dwain Meyer (701) 231-8154
Editor: Dean Hulse (701) 231-6136