Managing Cover Crops Profitably - Valley Crops Home

7 to 13 Years: Flax>Winter Wheat>Spring
Barley>Buckwheat>Spring Wheat>Winter
Wheat>Alfalfa (up to 6 years) >Fallow
System sequences are:
• Flax or other spring crops (buckwheat, wheat,
barley) are followed by fall-seeded wheat
(sometimes rye), harvested in July, leaving
stubble over the winter;
• Spring-seeded barley or oats, harvested in
August, leaving stubble over the winter;
• Buckwheat, seeded in June and harvested in
October, helps to control the weeds that have
begun cropping up;
• A spring small grain, which outcompetes any
volunteer buckwheat (alternately, fall-seeded
wheat, or fall-seeded sweetclover for seed or
hay).
The rotation closes with up to 6 years of alfalfa,
plowdown of sweetclover seeded with the previous
year’s wheat or an annual legume green
manure such as Austrian winter peas or berseem
clover.
There are many points during this rotation where
a different cash crop or cover crop can be substituted,
particularly in response to market conditions.
Furthermore, with Angus cattle on the ranch, many
of the crops can be grazed or cut for hay.
Moving into areas with more than 12 inches of
rain a year opens additional windows for incorporating
cover crops into dryland systems.
9 Year: Winter Wheat>Spring Wheat>Spring
Grain/Legume Interseed>Legume Green
Manure/Fallow>Winter Wheat>Spring
Wheat>Grain/Legume Interseed>Legume>
Legume. In this rotation, one year of winter
wheat and two years of spring-seeded crops follow
a two or three-year legume break. Each
legume sequence ends with an early summer
incorporation of the legume to save moisture followed
by minimal surface tillage to control
weeds. Deep-rooted winter wheat follows sweetclover,
which can leave topsoil fairly dry. Springseeded
grains prevent weeds that show up with
successive winter grain cycles and have shallower
roots that allow soil moisture to build up deeper
in the profile.
In the second spring-grain year, using a low-N
demanding crop such as kamut wheat reduces
the risk of N-deficiency. Sweetclover seeded with
the kamut provides regrowth the next spring that
helps to take up enough soil water to prevent
saline seep. Black medic, INDIANHEAD lentils and
SIRIUS field peas are water-efficient substitutes for
the deep-rooted—and water hungry—alfalfa and
sweetclover. These peas and lentils are springsown,
providing back-up N production if the forage
legumes fail to establish.
While moisture levels fluctuate critically from
year to year in dryland systems,N levels tend to be
more stable than in the hot, humid South, and
adding crop residue builds up soil organic matter
more easily. Low-water use cover crops have
been shown to use equal or less soil water than
bare fallow treatment, while adding organic matter
and N. Consequently, dryland rotations can
have a significant impact on soils and the field
environment when used over a number of years.
When starting with dryland soil that has raised
the same crop for many years with conventional
inputs, it will take three to five years of soil-building
rotations until soils become biologically
active. This is the length of time often cited by
farmers in many regions for soil-based changes to
take place. These improved soils have higher
organic matter, a crumbly structure, and good
water retention and infiltration. They also resist
compaction and effectively cycle nutrients from
residue to following crops.
Remember, the benefits of cover crops accrue
over several years.You will see improvements in
crop yield, pest management and soil tilth if you
commit to cover crop use whenever and wherever
possible in your rotations.
42 MANAGING COVER CROPS PROFITABLY