If putting up hay is a part of your cattle operation, you know it can be a process that takes critical attention to detail to produce the best quality forage possible. While weather, soil fertility, and method of storage each play a role, time of cutting appears to be the biggest player in quality hay production.
All In The Timing
To start, timing of the first cutting and late season cutting can both impact hay quality and health of forage plants. For the first alfalfa cut of the season, producers want to watch for flowering, height and maturity as indicators that stands are at prime quality for cutting. For instance, this would typically occur the last week of May to early June in the Dakotas.
But, South Dakota State University Extension forage specialist Vance Owens cautions that watching for flowering only – as many producers do – can be an inaccurate indicator. He points out that if an area has had a cool, wet spring, flowering will be delayed – but plants will still be maturing and ready to be cut even without the flowers. Owens says by mid-June forage quality starts to decline, so you want to make sure you make your first cut on time.
After that first cutting, a 28 to 32 day interval is generally needed between cuttings. As fall approaches, a golden rule for alfalfa harvest, is this: Avoid cutting or grazing alfalfa while the plants prepare for winter.
Montana State University Extension forage specialist Dennis Cash explains that this means allowing alfalfa plants to regrow for four to six weeks before the average first frost date until several consecutive days of killing frost in the low to mid-20 degree range. "In Montana, this translates to: don’t cut or graze alfalfa between early August until mid-October," says Cash.
He adds, "If you want an alfalfa stand to last more than three or four years, it is important to give plants this critical fall rest period." The theory behind this recommendation is that late season cutting can interrupt the plant's winter hardening process and increase the risk of alfalfa dying or suffering winter injury.
Old Guideline Holds True
According to Cash, it is a guideline first presented 40 years ago by former University of Wisconsin professor Dale Smith in his textbook Forage Management in the North, which cited research trials from the 1930's indicating the importance of not harvesting alfalfa from September 1 to mid-October. Cash also credits his Montana colleague Ray Ditterline who has preached a similar message for over 30 years.
But, does this cutting guideline hold true for today’s newer alfalfa varieties? Most definitely, says Cash, who has conducted cutting schedule research trials with new alfalfa varieties since 2000. "We have basically reproven the concept," he says.
Cash reports that in a three year, irrigated trial in Montana, half of the alfalfa plots were managed "normally" with three cuttings – two harvests by August 1 and a third in mid-October. The remaining plots were managed "intensively" with four cuttings. They had the same three cutting dates as the first trial, plus an additional harvest September 1 during the critical fall hardening period.
In the third year, 2003, the average yield of 18 varieties was 4.37 tons in the normal plots and 2.68 tons in the intensive plots, indicating a yield reduction of 39% in plots with four cuttings, with harvest costs making the fourth cutting an even bigger loss.
"It is not that the intensively managed trial was cut an extra time – it is the timing of when it was cut," says Cash. "In our region, cutting alfalfa around that critical fall hardening period is a poor time to cut – even if that's your first cut of the season – because of the impact on plant viability. From our research new varieties don’t seem to respond any differently to this time of cutting than older varieties," he says.
He reiterates that it appears best to have cutting finished by mid-August and to stay off the alfalfa until mid-October when killing frost has occurred.
More Proof From Colorado
Based on research he has conducted in western Colorado, Tri River Cooperative Extension agent Bob Hammon concurs with Cash, and says "Timing of final cutting makes an impact on stand health."
He explains, "After cutting, initial plant regrowth up to a certain point is not fueled by photosynthesis, but by the carbohydrate reserves in the roots." Based on this, he explains that if alfalfa is cut too late in the fall, root reserves are depleted for regrowth without enough time to store adequate carbohydrates in the roots for spring.
"Then in the spring, nematodes often begin to attack a plant that is already stressed," he adds.
Hammon says, "I have no doubt that the multiple stress of cutting schedules combined with stem nematodes impacts plant growth and performance. Plants may be able to handle one stress, but adding the second stress really weakens the plant."
So, should producers give up that additional cutting?While he is still in the middle of the study, Hammon says preliminary results indicate that skipping the fourth cutting can increase the following year’s first cutting yield by 20-30%.
He admits it can be difficult for a grower to look at that extra cutting and not use it, but offers this suggestion, "Look outside the box. Usually after November 1 in our region plants are dormant, and a producer can come back at that time and either make a fourth cutting if conditions are right or use it for livestock grazing." He explains that harvesting the forage when it is dormant does not deplete root reserves.
Montana’s Cash suggests the same to growers in the North. "You can maybe take two or three cuttings ahead of that critical rest period and then take an extra cutting after the killing frost. Here, that is a miserable time to put up hay, so many of our producers usually graze the fall regrowth."
As a starting point, Hammon suggests producers taking a late season fourth cutting this fall leave a small patch uncut and see the regrowth and yield results for themselves next spring.
Cash and Hammon both say these late season cutting guidelines are geared for producers who want to maximize alfalfa stand life. "If you are a cash producer who is replanting stands every three years, these guidelines may not be economical," Hammon says.