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Forage Extension Program
What is an Adequate Alfalfa Stand?
by Dennis Cash, MSU Extension
Specialist
Winterkill or “old age” afflicts thousands
of acres of alfalfa in Montana each year. Both irrigated
and dryland producers face the dilemma of maintaining
an unproductive stand or rotating out of alfalfa for
several years – and each of these options can
be very costly. Many sub-economic alfalfa or alfalfa/grass
hay stands are maintained, but all producers should
prepare for proper rotations and flexibility of their
forage acre base.
What is an economic stand? Most of the answer to this
question lies in the goals of the individual producer.
For cash hay growers in irrigated valleys, where alfalfa
is a short rotation crop with other cash crops, a dense
stand is very important for three to five years. Varieties
grown in these situations typically have small crowns,
and respond to dense seedlings and high management.
At the other extreme, a productive dryland stand may
have fewer than two vigorous plants per square foot.
Dryland varieties such as ‘Ladak 65’ and
the “creeping” varieties have broad, deep
crowns that are adapted for production in extreme cold
and dry climates.
For irrigated production, stands should generally have
the following numbers of plants per square foot:
Fall, seeding year……..15-25
First hay year…………10-15
Second hay year……….6-10
Third + hay year……….3-6
Counts should be taken when the spring alfalfa growth
is 3 to 4 inches tall. These numbers were generated
in the Midwest with many different varieties, and are
reasonable guidelines for irrigated alfalfa in Montana.
For dryland alfalfa ten years or older, one or two plants
per square foot are acceptable as long as yields are
good, and there are no objectionable weeds that reduce
hay quality.
A second method of assessing stands has been developed
in Wisconsin. By counting the number of stems per square
foot, a better estimate of stand productivity is generated.
In their tests with numerous varieties, the following
yield data were generated:
| Stems per square
foot |
Tons/A |
% |
10 |
1.3 |
22 |
20 |
2.3 |
37 |
30 |
3.3 |
53 |
40 |
4.3 |
69 |
50 |
5.3 |
84 |
60 |
6.3 |
100 |
Again, these numbers have not been tested in Montana,
but this method will provide a reasonable estimate of
stand and yield potential. For large crowns of Ladak
65, we have found that a single plant (per square foot)
had over 40 stems, so its yield potential is certainly
better than one with only 20 stems.
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