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Grasslands
Old Fields
O
ld fields are those which contain annual plants, perennial broadleaf plants, or a
mixture of the two, as well as perennial grasses. Old fields,
which include crop stubble fields allowed to lie fallow, are fairly abundant,
especially where agriculture has been practiced. These land types
occur when land goes out of cultivation for a period of time. Some
people quit farming, others let fields lie fallow for a year or two,
and still others enroll idle acres in federal conservation programs.
Old fields may appear to be wastelands but they actually are capable
of supporting many kinds of birds and small mammals. For example,
foxes, coyotes, hawks, and owls hunt in old fields, pheasants and songbirds live in them, and deer bed there.
Federal conservation programs pay landowners not to produce crops
on those acres but to establish permanent vegetative cover to
protect the soil from erosion; reduce water, air, and land
pollution; and provide wildlife habitat. If your land qualifies, you can
apply for cost-sharing programs that may help pay for seedbed
preparation, fencing, liming materials, fertilizer, seed, and
seeding operation, and pesticides. For more information, contact
your county Conservation District.
Land managers should decide whether to keep fields idle or
convert them to grassland. This chapter explains the benefits to
wildlife that occur when fields are left idle and natural succession is managed.
The Role of Succession
- A Land Aging Process
Old fields left idle are one of the early stages in the five
steps of the natural cycle of succession that, over time, turns bare
ground into a forest. Bare soil is the starting point. The first
plants to establish themselves in bare soil are annual plants which
live one growing season and then die, such as ragweed, pigweed,
smartweed, lambsquarter, foxtail, pokeweed, barnyard grass (wild
millet), and mare's tail. These plants provide seasonal nesting and
brood-rearing habitat for pheasants, quail, bluebirds, and other songbirds, and insects
for food.
 ragweed |
 pigweed |
 barnyard grass |
 lanbsquarter | |
The next successional stage is biennials and perennials. Perennials are
those non-woody plants that grow back year after year. These include
goldenrod, asters, milkweed, daisy fleabane, other forbs, and many
kinds of grasses and clovers bush, ladino, common white,
alsike, and others. Biennials are those plants that grow one year
and produce seed the next year. They include sweet clover, mullein,
curly dock, wild mustard (yellow rocket), shepherd's purse, black
mustard, foxglove, and the thistles. Small mammals such as mice, rabbits, and skunks now begin to use the
habitat, along with foxes, hawks, and owls, an abundance of
butterflies, meadowlarks, bobolinks, Savannah sparrows, and other
songbirds.
After a few years, sumac, dogwood, blackberry, autumn olive,
buckthorn, and other shrubby plants begin to invade the habitat. It
now becomes more attractive to raccoons, opossums, deer, and
songbirds such as cardinals, gray catbirds, and juncos.
As succession continues, red maple, cottonwood, birch, aspen, and
chokecherry are tree species most likely to invade. During the early
stage of this forest development, young seedlings provide browse for rabbits and deer. The increasing
amount of vertical structure attracts thrushes, woodpeckers, blue
jays, and orioles. As the forest grows over time, more shade-tolerant trees like sugar maple and beech
invade. Squirrels, ild turkeys, deer, and wood ducks are
examples of wildlife that eat the nuts produced by these trees,
which also furnish den cavities for screech owls, squirrels,
raccoons, woodpeckers, nuthatches, and chickadees.

 
Managing
Succession
You can manage your land for any stage of succession, or you can
create as much diversity as possible by managing for
several stages at once. How you manage your old field depends on
three items:
- the goals of your overall plan
- the size, shape, and other conditions of your
property
- what "tools" you
choose.
There are at
least three "tools" to maintain idle
fields.
Prescribed burning is the well-planned and
controlled use of fire to speed up or set back natural succession.
In forests, a very hot fire will set back succession, but a cool
fire in a young forest can actually advance succession. To fully
understand the results of burning habitat on your land, consult with
a wildlife biologist or other professional. Also, be sure to check
with the local fire department to see what regulations apply.
Remember that prescribed burning can be dangerous and should be done
with the help of a trained professional. For more information see
the
Prescribed Burning page within this
section.
Chemicals such as herbicides and
fertilizers are often used to maintain openings in forests, to
control the invasion of woody plants in the early stages of
succession, or to promote the growth of desirable plant species by
eliminating their competition. This
should be used only as a last resort!
The use of herbicides, if
applied properly, changes habitat but generally does not have a
toxic effect on wildlife. The use of fertilizers tends to increase
plant growth and nutrition.
Herbicides such as glyphosate (Round-Up) will kill all
plants. If you disk the field without using an herbicide, quack
grass will quickly spread eliminating valuable annuals. Using a
herbicide will reduce quack grass and allow the favored annuals to
come back. Seeds of annual plants are larger than those of
perennials and are more preferred by wild-life. Important ones are
giant and common ragweed, smartweed, barnyard grass, lambsquarter,
pigweed, and foxtail. Wildlife use this food year around, but it
becomes most important in winter and early spring. Indiscriminate
use of herbicides or fertilizers, however, can have more negative
than positive effects. Seek the advice of a conservation
professional before applying chemicals.
Mechanical alterations , which include mowing, manual
cutting, disking, and plowing, are other methods for
maintaining early successional stages and for removing unwanted
vegetation. Soil type, depth, potential erosion, and the size and density of the
target vegetation are all factors to consider. Also, the mowing of
some woody species causes them to grow faster and spread more
rapidly.
Fields left alone for eight to 10 years will produce primarily
goldenrod and asters, which have limited value to wildlife. Discing
a portion of the idle field each year on a three- to five-year
rotation will restore root vigor by reducing the effects of crowded
root systems. Discing will also scatter the seed to better establish
valuable annuals. For example, if your idle field is 25 acres, disc
five acres (five one-acre blocks or strips) each year to get the
complete range of early successional annuals, biennials, and
perennials.
Site Preparation and
Stand Maintenance
Field preparation should create a bare-soil condition through
plowing or repeated discing. Eliminate quack grass with Round-Up or
a similar herbicide. After the last field tillage, the seeds of
dormant annual plants will grow into the prepared site and provide
first year food and cover. Augment, if you wish, with a cover crop
of small grain. The best soil pH for weed growth and crop growth is 6.0
to 6.5. If soil pH is above 5.5, the dormant seeds of various
clovers (which you can rotate with periodic discing) will naturally
sprout and provide two or three years of food and cover. If pH is
below 5.5, add lime.
Second-year growth will show more annuals, plus biennials and
seedling perennials. Each successive year will show a greater
percentage of perennial forbs and grasses. A once-over deep discing
during the spring of the fourth year will again create a mixed
annual-perennial crop. A heavy discing two or three times over will
set back the site even further. Continue to disc on a rotational
basis or recycle the field by plowing if grasses and perennial forbs cover more than 70 percent of the
ground surface.
 Grasshoppers
are abundant in old fields.
Planting
Options
Because plantings assist the advancement of succession, they are
usually done in combination with one or more of the other tools. The
timing of discing or other treatments determines which annual weed
varieties will dominate in an idled field. Fields treated from April
15 to June 1 will usually explode with lambsquarter, pigweed, and
ragweed. The earlier the treatment, the more ragweed will appear in
the stand. Stands prepared later in the summer will favor annual
grasses and the establishment of biennials.
You can help provide additional
wildlife food by planting a crop in the old field and not harvesting
it. A field prepared in September and lightly seeded to winter wheat
(one bushel per acre) will provide wheat seed, abundant insect life
and a late crop of ragweed seed. The mixture of unharvested wheat
and ragweed will furnish a food source and summer/fall roosting cover for pheasants, quail, and
rabbits. Some of the wheat will provide a second-year crop through
volunteer seeding. Likewise, a field planted in early spring (before
May 1) to oats (one bushel per acre) will create a similar
food/cover situation for one year. Not being winter hardy, the oats
will offer a food source for only one year.
If you plan to manage idle fields for grassland habitat, consider
planting cool season and warm season grasses. Cool season grasses
are those species which grow most rapidly during spring and early
summer and again at the end of summer and early fall when cool
nights follow warm days. These include grasses such as orchard
grass, timothy grass, June grass, and redtop, which are usually
mixed with many kinds of clovers (white and red). Warm-season
grasses grow most rapidly during the peak of summer when warm nights
follow hot days. Growth slows in fall when soil temperatures drop.
Some native grasses include Indiangrass, switchgrass, big bluestem,
and little bluestem. Whenever possible, plant native species and
follow natural patterns as dictated by the terrain and soil
conditions of your property. Questions about suitable plants,
sources of planting stock, and ground preparation are best answered
by your Conservation District wildlife biologist, local extension
agent, or NRCS staff. For more information, see the chapters on
Cool Season Grasses and Warm Season Grasses in this section.
In summary, old fields provide not only a variety of benefits to
wildlife but also help protect soil from erosion and reduce water,
air, and land pollution. There are many management options that can
assist you in maintaining your old field. Choose one that will help
meet your wildlife goals.
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