HomeMy WebLinkAboutThe Lucknow Sentinel, 1986-11-26, Page 45Soil Erosion: A concern for everyone
The problem of soil erosion - the Ross
of soil resources - has been a concern
for farmers for many years. ,"gut how
much does the non -farmer know about
this growing problem? Not enough?
This was the sentiment expressed by
Senator erbert O. Sparrow, former
chairman of the task force on soil
erosion, at Soil Conservation Day held
in August of this year.
Sparrow noted that unless we
undertake a concerted effort to combat
the effects of soil erosion, we will see
the end of Canadian agriculture in 30
years. Soil erosion also has serious en-
vir • nmental effects, reducing water
quality for wildlife and man.
The fertile characteristics of the
relatively thin topsoils was developed
over thousands of years under the
protective cover of forests. When
pioneers arrived and removed the tree
cover to create fields for growing food,
the soil was left open to erosion by
wind and water.
The evidence of erosion is around us
everyday in the form of brown, silted
rivers; snow drifts discoloured by soil
in winter and field corners filled with
topsoil washed by rain.
Unfortunately once soil is washed or
blown away it cannot be replaced in the
short term. In effect our supply of top-
soil is limited to what exists today.
Looking at land suitable for agriculture
across Canada, there was an average of
15 inches of topsoil 100 years ago.
Today an average of 6 to 7 inches re-
mains.
Erosion has a variety of consequences.
The siltation of streams and rivers
chokes aquatic life and destroys the
spawning beds of fish. Soil particles
carry pesticides and other substances
that reduce the quality of water. On
agricultural land the loss of topsoil
means the loss of productivity. For
consumers this will mean a jump in the
cost of food in the future.
The causes of erosion are many. The
amount of rainfall, the type of soil,
slope of fields, drainage and vegetative
cover are all factors in erosion by
water. Farm management techniques
including tillage techniques that expose
the soil to wind and water are also
problems. ecause the Maitland Valley
Watershed is dominated by agriculture,
the M.V.C.A. has become involved in
the problem of soil erosion.
In 11985 the Joint Agricultural Soil and
Water Conserytion Program was init-
iated by a number of Conservation
Authorities including the M.V.C.A.
and the Ontario Ministry of Agricul-
ture and Food.
Vafeys & PeopPe - Fa!! 1906 - Page 5
The objectives of this program are to
reduce soil erosion, improve soil and
crop management practices, conserve
the soil, improve water quality and
maintain viable agricultural industry.
The emphasis of the program is on
tillage, crop rotation and field manage-
ment practices.
The benefits of soil conservation
extend bey, nd the farm itself to the
Maitland Valley Watershed as a wh:•?le.
Program serves farmers
In 1985 the Joint Agricultural Soil and
Water Conservation Program was
initiated by a number of Conservation
Authorities and the Ontario Ministry
of Agriculture and Food.
The objectives of this program are to
reduce soil erosion, improve soil and
crop management practices, conserve
the soil, improve water quality and
maintain a viable agricultural industry.
The emphasis of the program is on
tillage, crop rotation and field manage-
ment practices.
Personnel with the Joint Agricultural
Soil and Water Conservation program
will:
- provide you with access to conser-
vation tillage equipment for plot exper-
imentation on your farm
- provide free technical assistance
- prepare a soil and water conserva-
tion plan for your farm
- provide individual landowners with
financial and technical assistance in the
design of soil conservation structures
continued on page 8
What is Conservation Tillage?
The term, conservation tillage describes
a popular method of improving on-
farm soil and water conservation.
However, no clear definition of "con-
servation tillage" prevails. Some feel
that any tillage system other than the
conventional moldboard plow system
is conservation tillage. Others
assume that the use of a chisel plow in
their tillage program every second or
third year immediately classifies that
system as conservation tillage.
What is Conservation Tillage?
Conservation tillage can probably be
best defined as any system that meets
or exceeds accepted residue cover
standards and controls soil erosion by
effectively reducing runoff. These
standards are met by satisfying two
main objectives: 1) retention of the
previous crop's residue on or close to
the surface as a protective mulch cover
to improve infiltration and organic
matter content, and 2) maintaining a
rough, porous or ridged surface to
induce infiltration and reduce erosion.
Residue Must be Kept on the
Soil Surface
Crop residue kept at or near the soil
surface protects the bare soil by
dissipating the energy of falling rain,
and by providing small channels and
cracks to allow better water infiltration.
Increasing the surface roughness
provides small barriers to reduce the
velocity of wind and water, and
provides a source of organic matter
that assists in improving the water
holding capacity of the soil and ultim-
ately its resistance to erosion.
Research indicates that for a medium
textured soil, 1000/lb./ac. (1,120
kg./ha.) of surface residue from the
previous crop is required, after plant-
ing, to have the .desired effect on the
control of soil erosion by water on
slopes ranging from 0 - 507o . As the
potential for erosion increases (i.e.
slopes increase or sandier soils) the
recommended cover value increases.
Examples:
Findings from a study in LaSalle
County Soil and Water Conservation
District in Illinois reveals that on aver-
age for every bushel (25 kg.) of grain
corn harvested, 56 lbs. (25 kg.) of sur-
face residue is produced. A yield of 120
bu./ac. (7,530 kg./ha.), therefore,
results in a surface residue of approx-
imately '6,720 lb./ac. (7,526 kg./ha.)
prior to any tillage operation. Every
tillage pass through until planting time
the following spring will reduce this
surface cover as shown in the following
table.
Tailor Your System Accordingly
If 1,000 lb./ac. of surface residue is the
goal for good erosion control one must
next decide which tillage tools will
achieve that goal on a particular farm
and tailor the system accordingly. No
one tillage machine, or set of
lbs. of
Residue
Per Acre
6720
336
252
151
CONVENTIONAL TILLAGE
% of Crop Residue Maintained
by
Tillage Equipment
507o Fall Moldboard Plow
75 %Overwinter Decomposition
6007o Spring Disc
80% Field Cultivate
equals
equals
equals
equals
equals
Residue
Left
lb./ac.
336
252
151
121
121 lb. ac. residue left on the soil surface prior to planting certainly is not
enough to offer any appreciable protection against soil erosion.
CONSERVATION TILLAGE
6720 X 50% Fall Mulch Tiller
3360 X 75% Overwinter Decomposition
2520 X 60% Spring Disc
1512 X 80% Field Cultivate
equals
equals
equals
equals
3360
2520
1512
1209
The remaining 1,209 lb./ac. of residue at soil surface before planting is suffici-
ent to effectively control runoff and soil movement within tolerable limits.
VINIIMMINIMONIMINIMIMMOIS
machines, is best for all conditions.
Soil textures, topography and moist-
ure conditions all differ from farm to .
farm. Likewise - crops change and
weed problems vary. The type of farm
operation may somewhat lirnit the
choice of conservation tillage systems.
In some instances, tillage alone cannot
do a complete job in controlling soil
erosion. Certain conditions may
dictate that conservation tillage be,
coupled with various other soil conser-
vation measures such as: contouring,
striperopping, rotations, grassed
waterways, terracing, etc. Fully
committed practicioners of
conservation tillage emphasize that it is
not just one machine, or one practice
that makes it work - it is a system
which they have modified and tailored
to their specific farm conditions.
Often, the system cannot be perfected
in just one or two seasons. It may take'
twice that time, or even more.
Conservation tillage requires a full
commitment on the part of the farm
operator to make it work; both in
terms of soil erosion control and
economical crop production. Anyone -
considering a conservation tillage
system on their land is advised to talk
to the real experts - the people who
have made it work successfully. Area
farmers and machinery dealers should
be able to help you assess which
machines are operating in conditions
similar to your farm. Remember -
conservation tillage, to be successful in
the long term, requires an optimistic
attitude.
(Reprinted from Talk of the Thames,
U.T.R.C.A., by Andy Graham, Senior
Soil Conservation Advisor, O.M.A.F.)