5 Alfalfa Management
Cutting Schedule
First Cutting
Take the first cutting from fall-planted or previously
established stands when most plants have flower buds formed or when new
crown shoots have grown no more than 1 to 2 inches. Since flowering is
controlled by day length, the first growth is often ready to harvest before
flower formation, which usually occurs in late April or early May. Because
the first growth may get tall and tend to lodge, try to harvest before
lodging occurs.
Seedling stands planted in spring should not be
harvested until at least 50 percent of stems show flower formation or lodging
appears evident. Delaying harvest will allow seedling roots to develop
further.
Second and Subsequent Cuttings
Most of these cuttings should be made when 10 to
25 percent of stems have flowers present. In practice, this means harvesting
within 2 to 4 days of seeing the first few scattered flowers. It takes
only 5 to 10 days for alfalfa to advance from the bud stage of growth to
the 25 percent flower stage.
In general, regrowth will reach favorable cutting
stage every 28 to 35 days. During hot, dry weather, plants may flower
profusely prior to 30 days regrowth and before the plants reach a 10-inch
height. In such cases it is best to graze or cut the short growth when
it has been 35 to 40 days since last harvest. Once the plants have flowered
extensively, those specific stems will not make any more growth and their
continued presence tends to retard new growth even when favorable conditions
occur.
Fall Cutting Management
About four to six weeks of regrowth is needed for
plants to build carbohydrates prior to the first killing frost (24' F);
10 to 14 inches of growth is ideal. After several frosts but before the
leaves begin to wilt and drop, graze or harvest this growth to avoid waste
of good quality feed and reduce residue available for egg deposition by
the alfalfa weevil.
September Plantings
Even though weather conditions often allow 10 to
15 inches of seedling growth on stands planted in September, DO NOT harvest
the stand.
Stand Density
The following chart shows the number of plants per
square foot recommended for a productive stand. Be aware that a single
"old" plant may have 20 to 30 tillers. To get an accurate count of plants,
take a knife or small hand trowel and dig around the crown so that individual
plants can be counted by the number of tap roots.
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Nodules
Scout for nodules on seedling stands four to six
weeks after emergence. Effective and viable nodules are plump and pinkish
or beefsteak red when sliced open with a sharp knife.
Characteristic symptoms of poor nodulation or ineffective
nodules are: (a) yellowish, undirifty plants showing typical signs of nitrogen
deficiency or (b) nodules which, if present at all, appear shriveled or
wrinkled and are white, greenish, or brown on die inside.
Nodulation is usually not a problem on stands after
the first year. In dry periods, however, old plants may appear to be nitrogen
deficient as a result of leafhopper damage or diseases. During such periods
the plants often slough the nodules, which normally reappear when environmental
conditions become favorable again.
