- J. Sadler Richards, Conservation Management Systems, Ecologistics
Limited, Waterloo, Ontario
Evaluation Summary (Tech. Transfer Report Summaries)
Associated SWEEP/LSP Research
View / Download Final Report [2512 KB pdf]
Completed: July, 1990
moldboard plow, conservation tillage, modified moldboard
plow, residue management
The erosion of agricultural land and the associated pollution
of Lake Erie with sediment and phosphorus have been identified as
major agronomic and environmental problems in Ontario. Of the several
methods available to control soil erosion and phosphorus movement,
conservation tillage systems are rated among the best. A need exists
for a conservation tillage system that will maintain crop yield
and provide adequate residue cover.
Fall weather conditions in Ontario often prolong harvest and
fall primary tillage is done in excessively wet soil. Under these
conditions the moldboard plough has been and will likely continue
to be the implement of choice for many farmers. The main problem
in using the moldboard plough is that the implement tends to bury
almost all residue from the previous crop. As a result the potential
for controlling soil erosion is considered poor. Little work has
been done to improve this performance.
In order to understand and determine the potential for using
the moldboard plough as a conservation tillage tool, two approaches
were examined. The first included documenting the relative amounts
of residue cover obtained after ploughing cereal and grain corn
stubble with three commercially available shapes and makes of moldboards.
The second approach, incorporated into the same research trial,
involved studying the residue management capabilities of different
configurations of the modified moldboard plough as first used by
Vyn, Daynard and Ketcheson.
The modified moldboard trial was located on three different sites
in Essex county. Site 1 was located on cereal stubble on a clay
soil located near Comber, Ontario. Sites 2 and 3 were located on
grain corn stubble on clay loam soils near Harrow, Ontario.
The trial was set up as a split-plot design consisting of four
replications. The main plot treatments included three of the most
popular commercially available shapes and makes of moldboards and
moldboard ploughs. The three plough makes selected were Overum,
White and John Deere. The subplot treatments consisted of three
modifications (cuts) to the moldboard shape and one control (full
Soil surface residue cover data were collected at four different
times within the project time frame. They included: before ploughing
(Fall '88); after ploughing (Fall '88); after spring run-off (early
Spring '89); and after planting (Spring and Summer '89). Prior to
treatment implementation it was found that, in general, Site 2 had
13 percent less residue cover than Sites 1 and 3. All sites had
an average residue cover above 80 percent.
In general, the third cut on all three types of ploughs left
the greatest amount of residue in fall after the ploughing treatments
were implemented in spring, after run-off, at all sites.
As a result of abnormal weather in Essex county in the spring
and summer of 1989 the seedbed was prepared twice at Sites 2 and
3. This probably caused some residue to be destroyed, buried or
moved out of the plot area, thus influencing the amount of residue
left after planting. The amount of soil surface residue left after
planting for all sites was well below the Ontario benchmark of 20
percent cover needed for erosion control.
When after-planting soil residue cover was measured it was found
that on Site 1 the third cut on the moldboards for all three plough
makes and the second cut on the White plough left significantly
more residue cover. At Site 2 the White first cut treatment and
at Site 3 the John Deere second cut treatment left significantly
more residue than other treatments.
Moldboard draft was measured using a unit designed and built
by the Ontario Centre for Farm Machinery and Food Processing Technology
(OCFMFPT) that was mounted between the tractor hitch and the plough.
Two load cells measured the pull in the left and right lower links
of the tractor's 3-point hitch. It should be noted that for each
plough make one side of the linkage to the tractor (right hand link
for the Overum, left hand link for the White and John Deere) pulled
with greater pounds force than the other side of the linkage regardless
of the moldboard shape. The magnitude of the difference in pull
varied somewhat between moldboard cuts and was not always greater
as more cuts were made relative to the pull recorded for full size
Volumetric soil moisture content was measured using a device
called IRAMS and a Campbell Pacific Nuclea Portaprobe. The moisture
content was measured on the day of ploughing (all sites) and the
day of planting (Sites 2 and 3). The volumetric soil moisture content
on the day of ploughing and the day of planting were quite similar
among treatment plots within each site. As a result the potential
effect of soil moisture content on other parameters measured was
considered equal across all treatments.
The soil surface conditions after ploughing were visually assessed
after all ploughing treatments were implemented. The conditions
tended to be relatively even and smooth for all moldboard treatments
except the third cut treatment across all three sites.
Soybean plant emergence and vegetative growth stage data were
collected at the cereal stubble site (Site 1) but heavy rains and
crusting experienced in Essex county may have influenced these site-specific
After one year of study the following conclusions were made:
Soil residue cover left after ploughing and spring run-off
tended to increase as a greater portion of the moldboards was
Soil surface smoothness after ploughing tended to decline
as a greater portion of the moldboards was removed.
At a furrow width of 16 inches, maintenance of a 6 inch ploughing
depth became more difficult as a greater portion of the moldboards
Although the magnitude of the increase in residue cover left
on the soil surface after ploughing with modified moldboards
was substantial at two of the three sites, the actual amount
of residue cover remaining after ploughing and spring run-off
tended to be slightly less or within 20 to 30 percent.
For the Overum and John Deere ploughs, the specific draft
tended to decline as a greater portion of the moldboards was
removed. Specific draft of the White plough tended to increase
at the two of three sites.
(From Technology Transfer Report Summaries - A. Hayes, L. Cruickshank,
A one year modified moldboard plow trial was conducted comparing
three makes of plows. Since standard plows were designed to bury
all surface residue, each plow was modified by removing a portion
of the moldboard bottom to retain surface residue. The objective
of the trial was to document the potential for a modified moldboard
plow to attain a minimum of 20% of the soil surface covered with
residue after planting.
The reasons for using the moldboard plow in this study are as
follows: (i) it is a low cost modification; (ii) it is easily integrated
with most operations; and (iii) no significant loss in yield is
Three makes of plows were evaluated in the study with three cuts
to each plow. Numerous measurements were taken in each plot - after
primary tillage, secondary tillage and after planting. The trials
were conducted on clay loam and clay soils in three locations and
two different crops.
Although after primary tillage 20-30% residue levels were attained,
none of the plows were able to meet the minimum 20% after-planting
guidelines necessary to qualify them as conservation tillage systems.
modified moldboard plow fails to achieve the minimum 20%
residue cover after planting
the smaller the moldboard the rougher the soil surface after
study reveals some of the changes in draft which may be encountered
when modifying the moldboard plow
Future Research: ( ) indicates reviewers suggestion
for priority, A - high, C - low.
Thursday, May 19, 2011 01:46:34 PM