SUMMER AND FIRST-CUT HAY SEASON HAVE ARRIVED

MowingAlfalfa5Forget the summer solstice as the official start of summer — it comes too late. I officially usher summer into my life when the first stems of alfalfa are ruthlessly sawed off by reciprocating knives or rotating blades. Summer is here.

Though agriculture gets blamed for its fair share of objectionable odors, freshly cut hay in dry-down mode always evens the score for the year. It’s the kind of smell that should be captured for car or home air fresheners. It might also score big as a perfume or aftershave on eHarmony.com first encounters. This isn’t the time of year to drive with windows in the upright position.

Making first-cut alfalfa is both a rewarding and challenging experience on most dairy farms. The rewards and frustrations are at the mercy of Mother Nature. A string of good drying days is as essential as sharp cutter knives — perhaps more so.

I’m sure the CEOs of Fortune 500 companies make a lot of tough and important choices, but I’ll put the decision of when to start cutting hay up against any of them. Not only is there the need to hope the weather prediction is correct in the days following cutting, there is also a lot going on with the plant itself that impacts current and future yield; feed quality; and long-term persistence. First-cutting is unlike any of the subsequent season harvests.

Farmers and scientists have been able to solve a plethora of agricultural problems over the years, but the yield-quality-persistence trade-off that comes with producing alfalfa has only partially been softened with improved genetics. Recommendations for first-cut harvest strategies become a litany of options depending on the feed needs of the individual farm and the operator’s willingness to risk downside on the competing factors of forage yield, quality and stand persistence.

A discussion of first-cut forage quality has to begin with the growing environment. At no other time during the growing season is there the likelihood for such a wide range of weather conditions: cool and wet, cool and dry, hot and wet, or hot and dry. This potential range in growing environment has a profound impact on both alfalfa growth and forage quality from year to year.

Moisture stress and/or cool temperatures result in a slower decline of forage quality and generally slower growth. Conversely, high temperatures result in a more rapid decline in digestibility and increased growth, assuming adequate moisture is present.

These plant responses to environmental conditions are interactive and the primary cause for the many possible growth and forage quality scenarios in the spring. This is what comprises the “art” of haymaking.

Plant fiber digestibility usually takes a wild ride during the course of spring alfalfa growth. First-cutting forage digestibility can be — and often is — higher than any other cutting of the season. Even small increases in fiber digestibility can make for large differences in milk production.

Though first-cutting offers the opportunity for harvesting the highest digestible fiber of the growing season, forage quality declines at a faster rate for first-cut compared to subsequent cuttings. This presents the possibility of also harvesting large quantities of very poor, low digestible forage once flowering stages are reached. To achieve a target forage quality, the spring harvest window is often narrower compared to subsequent growth cycles.

First-cutting also has some unique yield characteristics. Spring alfalfa growth almost always provides the highest percentage of total-season dry matter yield. This makes the consequences of making a first-cut timing mistake higher than for any other cutting.

Similar to forage quality, changes in initial spring growth occur more rapidly for yield than for summer and fall growth cycles. Further, growing environment dictates the rate of dry matter accumulation per acre. An average figure is reported to be about 100 pounds per acre per day during the late-vegetative to late-bud stages. If air temperatures are warm, it will be greater; if cool, less than 100 pounds.

First-cut timing sets the pace for the rest of the growing season. In other words, the first-cut harvest date may dictate how many future cuttings will be taken, the interval between those cuttings, and how late into the fall the last cutting will be harvested.

First-cutting is the only one of the year when there are no number of days since the previous harvest. The decision options are wide open, but the consequences of the decision impact the rest of the season.

Forage quality and yield considerations aside, an earlier initial harvest date often provides for a better utilization of available soil moisture for the second-cutting and expands harvest options for the remainder of the season. Conversely, cutting too early may also be more detrimental to a stand that was stressed the previous year or during the winter.

Finally, after suffering through seven months of snow, mud, jumping batteries, and putting on long underwear, it’s time to make hay. This is perhaps the best unique thing about first-cutting.

Mike Rankin, Crops and Soils Agent, UW Extension-Fond du Lac County

Stuff you can do with this post