Sudangrass
Sorghum sudanese (Gramineae)
Fast Facts:
Acres in Washington: 3,000 acres
Number of Growers: 53 growers
Description
of crop:
Sudangrass is a fast growing warm-season annual used for midsummer pasture,
green chop, silage or hay. It reaches a height of 3-5 ft and has a slender leafy
stem. Seedings for pasture use are made in late May or early June and will
provide three to four grazings. Sheep can be turned out when the crop is 12 to 14
inches tall and cattle when the crop is 18 to 24 inches tall. Neither should be
allowed to graze the crop below 4 inches to allow for faster regrowth. Warm
summer temperatures and adequate moisture are essential for good production.
Sudangrass and hybrids do not grow well at cold temperatures and are very frost
sensitive. Sudangrass should be cut for hay in the heading stage or for silage in
the dough stage. It can also be planted as a cover crop at the end of summer
following short season potatoes in the Columbia Basin.
When used as a cover crop, the grass is allowed to grow six to eight feet tall
and then is disked into the ground in the fall. Sudangrass is also used in fields
that have residual herbicides in the soil, because sudangrass is very tolerant to
herbicides and is one of the few crops that can be planted in such fields. Both
sundangrass and sorgum-sudangrass hybrids are heat and drought tolerant cover
crops that can be used to scavenge N, suppress certain diseases and nematodes
and build soil quality.
Key pests:
Sudangrass is essentially free from significant pest pressure. Neither insects nor
diseases are pests of this crop. Sudangrass produces the chemical dhurrin which
when incorporated into the soil can suppress populations of root-knot nematodes.
Sudangrass and sorgum-sudangrass crosses are excellent competitors against
weeds because of their height but weeds should be controlled in seeding stands to
obtain maximum production. When seeded at a high rate sudangrass will usually
smother weeds and also contains a chemical compound (sorgoleone) that
suppresses many weeds. Some weeds such as wild oat, barnyard grass and other
summer grasses can infest a field, however they are usually insignificant.
Key pesticides:
Broadleaf weeds can be controlled with 2, 4-D. Atrazine is also registered for use
on sudangrass. Pesticides are usually not used in sudangrass production.
Critical pest
control issues:
Sudangrass may have nitrate and prussic acid toxicities. They can have high
nitrate accumulations in the early stages of growth, during drought stress or just
after a frost and should not be grazed at these times. Growers should work with
reputable seed dealers since there are differences among the varieties or hybrids
for adaptation and maturity. They should use certifies seed of a low prussic acid
variety. Piper sudangrass is a good variety for Washington.
Expert contact:
Kevin Flanagan
Kappa Seeds
10882 State Road
Quincy, WA
509 787 1561
Location
of production: In eastern Washington: Benton, Columbia, Douglas,Ferry, Franklin,
Grant, Kittitas, Okanogan and Walla Walla counties. In western Washington: Skagit
county