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Alfalfa Harvest Management
5/5/2004
Ron F. Meyer
Area Extension Agent
(Agronomy)
Colorado State University Extension
Golden Plains
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There is no optimum alfalfa cutting schedule for all growers in
all locations. Several factors should influence the selection of a
cutting schedule. These include the quality of the hay desired, weather
conditions, the anticipated length of the growing season, harvest costs,
desired stand life, and the alfalfa market.
The purpose of producing
high-quality alfalfa hay is to take greatest advantage of the plant’s
nutrient potential as a livestock feed. Therefore, hay intended for use
as a maintenance feed for beef cows can be of much lower quality than that sold
to dairies or used to grow weaner calves or yearlings. Hence, the growth
stage at which alfalfa is cut should reflect the intended use for the
hay. The dairy industry is demanding higher and higher quality. At
one time premium hay had 54 percent TDN; the dairy market is now insisting much
more TDN. Hay intended for this market must be cut early (late-bud stage
at the latest) for the necessary quality to be achieved. Conversely, hay
intended for beef cattle or horses can be cut later, at 10- to 30-percent
bloom, to maximize yields with acceptable quality for these livestock
classes.
Alfalfa fields are sometimes harvested on a calendar basis,
using a fixed interval and a fixed number of cuttings per season. The
advantage of this method is that the number of cuttings per season is
predetermined. This facilitates planning—it allows advanced
irrigation scheduling, the cutting of other fields, and other activities.
The problem with this method is that it does not account for weather or
dormancy differences among alfalfa cultivars. Weather, primarily
temperature, has a significant effect on alfalfa development and will cause
plant maturity on a given date to vary from year to year. The dormancy of
a variety also influences its development. In general, a less dormant
variety matures more rapidly than a dormant variety. Also, plants from
different dormancy classes respond differently to temperature and
photoperiod. Dormant varieties are more responsive to photoperiod than
are less dormant varieties.
Another method of scheduling alfalfa
harvests uses the growth stage of alfalfa to indicate the appropriate time to
cut and the number of cuttings per season. The grower selects a specific
alfalfa growth stage (such as bud, late-bud, 10-percent bloom, etc.) at which
harvest will begin. This method takes into account the effects of
environmental and varietal differences and results in more consistent,
predictable forage yield and quality than when harvesting on a calendar
basis.
A relatively short growing seasons may restrict a harvest
schedule. Therefore, consider both calendar date and stage of growth when
deciding on a harvest strategy. Modify harvest timing to fit three or
four cuttings into the season.
In addition to time of harvest, seasonal
changes in temperature and photoperiod (day length) impact forage yields and
quality. In general, first-cutting forage yields tend to be higher than
those of subsequent cuttings, regardless of the total number of cuttings per
season. However, when the first cutting is taken at a vary early growth
stage (early-bud or sooner), second-cutting yields may be higher. The
final cutting of the season, in the fall, normally yields less than previous
cuttings because the alfalfa growth rate has slowed in response to cooler
nighttime temperatures and shorter day lengths. In contrast to yield, the
nutritional quality of the fall cutting is typically the
highest.
Cutting Height - Leave a stubble height of 3 to 4 inches when
cutting alfalfa. Studies from central and northern United States have
shown that average annual yields of dry matter, protein and digestible dry
matter decrease as cutting height increases from 3 to 9 inches. Maximum
yields were obtained at the 3-inch cutting height. Raising the cutting
height more than 3 inches high did increase forage quality, but it caused a
significant decrease in production that more than offset the slight increase in
quality.
Source: Intermountain Alfalfa Management - University of
California #3366 |
Page Created and Maintained by: Perry D. Brewer, Area
Extension Agent (Technology Education/Youth)
5/12/2004 |
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Colorado
State University, U.S. Department of Agriculture, Kit Carson, Phillips,
Washington and Yuma counties cooperating. Extension programs are
available to all without discrimination. Where trade names are used, no
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