Managing Cover Crops Profitably - Valley Crops Home

as buckwheat, cowpeas, sorghum-sudangrass
hybrid, or another crop adapted to your conditions.
As with other cropping systems, plant a
winter annual cover crop on fields that otherwise
would lie fallow.
Where moisture is sufficient, many vegetable
crops can be overseeded with a cover crop, which
will then be established and growing after vegetable
harvest. Select cover crops that tolerate shade and
harvest traffic, especially where there will be multiple
pickings,such as in tomatoes or peppers.
Cover crop features: Oats add lots of biomass,
are a good nurse crop for spring-seeded legumes,
and winterkill, doing away with the need for
spring killing and tilling. Sorghum-sudangrass
hybrid produces deep roots and tall, leafy stalks
that die with the first frost. Yellow sweetclover
is a deep rooting legume that provides cuttings of
green manure in its second year. White clover is
a persistent perennial and
good N source.
In Zone 5 and cooler,
plant rye, oats or a summer
annual (in August) after snap
bean or sweet corn harvest
for organic matter production
and erosion control,
especially on sandy soils. Incorporate the following
spring, or leave untilled strips for continued
control of wind erosion.
If you have the option of a full year of cover
crops in the East or Midwest, plant hairy vetch in
the spring, allow to grow all year, and it will die
back in the fall. Come back with no-till sweet or
field corn or another N-demanding crop the
following spring. Or, hairy vetch planted after
about August 1 will overwinter in most zones
with adequate snow coverage. Allow it to grow
until early flower the following spring to achieve
full N value. Kill for use as an organic mulch for
no-till transplants or incorporate and plant a
summer crop.
You can sow annual ryegrass right after harvesting
an early-spring vegetable crop, allow it to
grow for a month or two, then kill, incorporate
and plant a fall vegetable.
Residue from small grains
provides organic matter for
soil building. . . to prevent
erosion over winter.
Some farmers maximize the complementary
weed-suppressing effects of various cover crop
species by orchestrating peak growth periods,
rooting depth and shape, topgrowth differences
and species mixes. See Full-Year Covers Tackle
Tough Weeds (p. 38).
3 Year: Winter Wheat/Legume Interseed>
Legume>Potatoes. This eastern Idaho rotation
conditions soil, helps fight soil disease and
provides N. Sufficient N for standard potatoes
depends on rainfall being average or lower to
prevent leaching that would put the soil N below
the shallow-rooted cash crop.
1 Year: Lettuce>Buckwheat>Buckwheat>
Broccoli>White Clover/Annual Ryegrass.The
Northeast’s early spring vegetable crops often
leave little residue after their early summer harvest.
Sequential buckwheat plantings suppress
weeds, loosen topsoil and
attract beneficial insects.
Buckwheat is easy to kill by
mowing in preparation for fall
transplants. With light tillage
to incorporate the relatively
small amount of fast-degrading
buckwheat residue, you
can then sow a winter grass/legume cover mix to
hold soil throughout the fall and over winter.
Planted at least 40 days before frost, the white
clover should overwinter and provide green
manure or a living mulch the next year.
California Vegetable Crop Systems
Innovative work in California includes rotating
cover crops as well as cash crops, adding diversity
to the system.This was done in response to an
increase in Alternaria blight in LANA vetch if
planted year after year.
4 Year: LANA Vetch>Corn>Oats/Vetch>Dry
Beans>Common Vetch>Tomatoes>S-S Hybrid/
Cowpea>Safflower. The N needs of the cash
crops of sweet corn,dry beans,safflower and canning
tomatoes determine,in part,which covers to
grow. Corn, with the highest N demand, is pre-
CROP ROTATION WITH COVER CROPS 37