- R. R. Walker, Beak Consultants Ltd, Guelph, Ont., and
J. Sadler Richards, Ecologistics Ltd., Waterloo, Ont.
(Tech. Transfer Report Summaries)
View / Download Final Report [206 KB PDF]
Associated SWEEP/LSP Research
Completed: September, 1994
Note: This report consists of the executive summaries for the other seven
Pilot Watershed Study reports. The Introduction
is presented here, as well as the Evaluation
Summary from SWEEP Report #79.
This report is referred to as "Report
#77" in SWEEP Report #79. Several copies of this
report were also stamped "Report.107".
agricultural watersheds, water
quality, erosion, phosphorus, conservation tillage, watershed modelling,
soil quality, hydrology, residue management, rainfall simulation,
cooperator attitudes, program implementation
The Soil and
Water Environmental Enhancement Program (SWEEP) was initiated in
1986 with an overall mandate to:
reduce Ontario's Non-Point Source
(NPS) loadings of phosphorus to Lake Erie from agricultural sources by
200 tonnes; and
maintain or improve the productivity
of the primary agricultural sector in Southwestern Ontario by reducing
or correcting soil erosion and degradation.
Watershed Study (PWS) is a major SWEEP sub-program aimed at
evaluating and demonstrating the benefits of established conservation
farming systems at the watershed and smaller scales. Figure 1.1 shows
the overall SWEEP organizational structure
and the PWS sub-program relationship to the Program. Cooperating
agencies; Environment Canada (EC), Agriculture Canada (AC), and the
Ontario Ministry of the Environment (MOE) are identified. Beak
Consultants Limited (BEAK) is the prime contractor responsible to AC and
MOE. Ecologistics Limited (ECOLOGISTICS) is a sub-contractor to BEAK
responsible for site selection and the agronomic program of the PWS.
The PWS started in 1987 with detailed
study design, staffing, training, cooperator enlistment, and watershed
selection. Farm plans were initiated in August, 1988 and environmental
monitoring began later the same year.
Monitoring and evaluation were
conducted from late 1988 until mid 1992.
Figure 1.2 shows the location of PWS
subject areas within the Lake Erie Watershed. These are situated within
different yet common agricultural and physical settings.
The PWS has the following key
four year implementation and
test (conservation oriented systems)
and control (conventional systems) paired watershed design;
pro-active agronomic management
involving annual farm planning, cooperator compensation program,
ongoing producer extension program, availability of conservation-type
farm implements, detailed cooperator record keeping, crop scouting and
productivity analysis, and farm level socio-economic evaluation;
intensive and continuous
environmental monitoring at plot, field and watershed scales;
detailed soil survey and soil
extensive environmental monitoring
program including meteorology, hydrology and water quality; and
detailed evaluation involving the
application of two modelling systems for farm planning and systems
The paired watershed study design is a
unique approach which relies upon direct comparisons between the test
and control areas as the primary method of environmental and agronomic
evaluation. The effects of scale, at whole watershed, farm, field and
plot scales are also a fundamental aspect of the study design which
systematically addresses the relationship between producer attitudes and
adoption as well as between measurable benefits, complexity, and scale.
Objectives of the Pilot Watershed
Objective Regarding Study/Approach
To achieve a high level of adoption of
the most appropriate soil and water conservation practices among farm
operators utilizing lands in the test sub-watersheds.
Objective Regarding Effectiveness
To determine the nature and degree of
changes in relevant soil and water quality parameters and crop yields as
influenced by "basin-wide" soil and water conservation practices.
Objective Regarding Information
To prepare information about
sub-program activities and results and to transmit this to participating
farmers and other related SWEEP sub-programs.
The overall PWS reporting has been
sub-divided into the following categories:
Study Area Selection, Description and Climate (SWEEP Report #69)
Implementation of Conservation Systems (SWEEP Report #70)
Evaluation of Conservation Systems, Social Factors (SWEEP Report #71)
Evaluation of Conservation Systems, Soils and Crops (SWEEP Report #72)
Evaluation of Conservation Systems, Hydrology (SWEEP Report #73)
Evaluation of Conservation Systems, Water Quality (SWEEP Report #74)
Modelling (SWEEP Report #75)
Executive Summary (SWEEP Report #76)
Each report is a stand alone document
including a summary, descriptions of objectives, methodologies,
observations, discussion, and summarized listings of relevant data where
applicable. The Executive Summary is a compilation of summaries with
emphasis on conclusions and recommendations extracted from the seven
(From Technology Transfer Report
Summaries - A. Hayes, L. Cruickshank, Co-Chairs)
Watershed Study (PWS) was designed to evaluate the environmental
benefits as well as the agronomic and socio-economic implications of
conservation farming systems when applied over whole agricultural
watersheds. The study design and evaluation program was based upon the
use of paired test and control watersheds. The control watershed
cooperators were encouraged to continue with conventional farming
practices while the test watershed cooperators were encouraged to adopt
conservation farming systems during the course of the study.
Over 75 cooperating farms were
involved in the study over a four year period. Three pairs of watersheds
(test vs. control) were selected to be representative of three
different, yet common farming environments in terms of crop rotations,
soils and topography within the Lake Erie Watershed. The study areas
were selected at the earliest stage of the PWS and are located in Essex
County, (east of the town of Essex) an area representing primarily cash
cropping with row crops/grain rotations on flat poorly drained clay
soils; in the headwaters of Kettle Creek, (north of St. Thomas)
representing rolling landscapes with mixed farming involving row
crops/grain rotations and swine production on silty loam soils; and in
the headwaters of the Gordon Pittock Reservoir (north of Woodstock)
where row crop/grain rotations are maintained along with swine and dairy
operations on an undulating landscape.
Implementation of Conservation
As a proactive and targeted program
the PWS identified specific geographic areas where soil
degradation/water quality problems were of interest and where adoption
of soil conservation measures by local cooperators would have the
greatest impact on soil erosion control and sediment delivery to water
courses. Within the PWS an incentive package was required to promote
change (i.e. the adoption of conservation practices) and general
cooperation within the time frame of the study so that objectives could
be realized. The incentives were formulated on the basis of access to
information, experience, specialized equipment and financial grants.
Cooperators signed agreements with the PWS that outlined the
responsibilities of each party. The agreements were amended annually and
included changes to conservation farm plans by test cooperators or
confirmed the maintenance of records by control watershed cooperators.
During the project approximately 89% of eligible landowners/managers
participated in the program (e.g. 65 out of a possible 73 in the final
To meet the objectives of the PWS
conservation farm plans were developed with the test cooperators which
identified the management techniques that would be used to maintain soil
productivity and improve water quality in the associated test
watersheds. The approach involved the integration of watershed computer
modelling used to predict the impacts of current watershed management
practices with farm and field level conservation planning. This
integration effectively made the watershed modelling tool into a
planning tool that could be used to estimate the potential combined
effects of individual farm plans on the watershed before any work was
done on the ground. With this information a unique opportunity to adjust
plans in order to meet watershed soil erosion and sediment delivery
targets was available. A two level approach was used that involved
first, a background analysis step and second, a field discussion step.
Indicators of Adoption and Cooperator
The incidence of conservation
practices in the test watersheds increased positively during the study.
The study time frame represented the early adoption phase which is often
characterized by a relatively steep participant learning curve. Within
the first three years of the study approximately 81% of identified
conservation crop and tillage actions and 52% of conservation structures
were completed by the test cooperators. The shift in acreage that was
moldboard ploughed versus no tilled was also dramatic.
Documented changes in cooperator
attitudes toward soil and water conservation resulted in several
conclusions including the following:
Implementation of erosion control
measures resulted in test cooperators perceiving less erosion
occurring on their farms in 1992 relative to 1988. Conversely, control
cooperators saw the same amount or slightly more erosion happening on
their farms over the same time period. Control cooperators likely
became sensitized to erosion problems as a result of the PWS, but did
not receive encouragement to implement measures within the watershed
boundaries to alleviate the problem.
Test cooperators were generally
neutral or slightly positive about practice effects on crop yields.
They were almost always more positive with respect to effects on
profitability. This bodes well for future adoption as cooperators
appeared to be acknowledging the net financial benefits of
implementation of even the less familiar practices.
In general, cooperators agreed that
five to ten years was a realistic time frame for achieving a
satisfactory comfort level with conservation planting equipment. This
took into consideration extremes in weather, shifting weed
populations, fine-tuning equipment to variable soil textures and
moisture conditions, and the application of conservation planting to
all crops in the rotation. Some suggested a three-year time frame may
be adequate for developing confidence in no-till wheat production.
When asked about their post PWS
conservation intentions, a strong majority of farmers in both the test
and control watersheds intended to increase or maintain the same
acreage under conservation practices. The primary exception to this
was the adjusted or modified moldboard plow which many said they would
either discontinue or didn't know whether they would continue.
Seventy-four percent of the test cooperators and 38% of control
cooperators said they would maintain or increase their acreage under
Watersheds were fully instrumented and
monitored from late 1988 until June 1992. Residue management in the test
watershed resulted in generally higher cover levels in test watersheds
over the course of the study. In the latter stages of the study, test
watershed cover exceeded control watershed cover by an average of 17%.
During the study monitoring period
(1989-1992) the precipitation deviated significantly from normal trends.
While above average or average precipitation was desired in order to
rigorously test the conservation systems implemented, well below normal
precipitation was experienced in 1989, 1991 and the first six months of
1992. Winter precipitation and snowfall were well below normal resulting
in minimal snow cover and modest spring melt events. Severe storms were
rare during the study period. Precipitation was near normal in 1990 on
the whole and exceeded the normal precipitation during the later summer
Test and control watershed pairs
experienced very similar weather throughout the study although total
event precipitation did differ significantly on occasion.
Streamflow was measured continuously
by the Water Survey of Canada at the watershed mouths. Surface run-off
was monitored at field scale monitoring sites from most of the
significant precipitation events. Total run-off generated from 1 metre
square plots during simulation storms was measured and recorded.
Watershed scale, field scale and plot scale run-off behaviour was
examined and compared between corresponding test and control sites.
Run-off was also related to conservation system effects using cover
(live and dead) as the primary independent variable to determine whether
run-off increases or decreases under conservation tillage.
In Essex, watershed and field scale
run-off increased under conservation systems while plot scale studies
indicated a general reduction in run-off. In Kettle Creek, watershed
scale evaluations indicated a reduction in run-off with increased cover
while plot scale evaluations indicated the reverse. The field scale
evaluations in Kettle Creek were inconclusive.
In Pittock, the watershed scale and
field scale studies were inconclusive, partly due to a lack of data.
Pittock was generally drier, producing fewer significant run-off events.
Plot scale studies in Pittock indicated a positive relationship between
cover and run-off.
Plot scale studies in Essex also
indicated that, in general for pre-plant periods, total run-off was
highest from control plots with less plant residue and run-off from the
control plots exceeded run-off from other times. In Kettle Creek test
plot run-off generally exceeded control plot run-off during pre-plant
and post tillage periods when test plot residues were highest. No
differences were observed for post harvest times when cover was similar
in both set of plots.
In Pittock, test run-off exceeded
control run-off during post tillage periods when residues differed
Pre-plant period run-off was generally
highest for all areas combined. Post tillage run-off from control plots
was generally the lowest due to high surface detention storage and
Overall, test plot run-off exceeded
control plot run-off in this aspect of the study.
Water Quality Loadings
A continuous record of water quality
loadings was generated for each watershed, for events at the field
scale, and for each rainfall simulation measurement.
In Essex, the watershed scale total
suspended solids (TSS) and total phosphorus (TP) data indicated that a
trend to improvement in the test watershed may have started in 1991 and
continued through the first half of 1992. However, this observation was
not statistically significant as test and control unit area loadings
have been very similar throughout the study. At the field scale a
definite inverse relationship between cover (live and dead) and TSS and
TP loadings has been identified. The relationship shows that as event
run-off increases the improvement in run-off water quality in the test
watershed over the control increased. That is, the benefit afforded by
cover becomes most evident during more extreme precipitation events. At
the plot scale, control plot run-off of TSS and TP is significantly
higher than the test plot run-off in the pre-plant and post tillage
Run-off loadings during the post
harvest period, when cover levels are similar, is not significantly
different between test and control plots. Rainfall simulation
measurements also indicated that run-off loadings are highest during the
pre-plant period for both test and control plots.
In Kettle Creek, at the watershed
scale, a similar trend, as observed in Essex, may be in effect. The 1991
and 1992 test watershed loadings tended to decrease relative to the
control loadings especially for TSS. While these results are not
statistically significant, the trend is positive. The field scale
studies show a marked improvement in run-off loadings for TSS and TP
from test fields when compared to control fields at high run-off flow
rates. In Kettle Creek, the positive benefit is shown to occur only for
high flow events.
The plot scale studies for Kettle
Creek are similar to those for Essex. Control run-off loadings for TSS
and TP are significantly higher than test plots during the post harvest
and pre-plant periods. Post tillage run-off loadings are low and not
significantly different. While improvements in test run-off loadings are
significant they are not as pronounced as in Essex. Pre-plant and
post-tillage periods generated the most run-off loadings of TSS and TP
in both test and control plots.
At the watershed scale, Pittock test
loadings of TSS and TP were lower than control in 1990 when the test
watershed achieved the highest cover values, exceeding overall cover in
the control watersheds. Test watershed cover decreased in 1991 and 1992
reflecting a lower level of cooperator enthusiasm in Pittock. A
comparison of watershed loadings between test and control after 1990 was
not statistically significant. The Pittock area received less
precipitation and much fewer field scale surface run-off events. Only
one of four microbasins had sufficient data to evaluate the effect of
cover on run-off loadings of TSS and TP. That field scale site indicated
that TSS and TP loadings were inversely related to cover, as hoped. At
the plot scale the overall loadings of TSS and TP were highest from the
control plots. This was due to high control plot loadings during the
pre-plant period. Run-off loadings of TSS and TP for the post-harvest
and post tillage periods were significantly higher from test plots
although overall loads were low during these periods.
Generally, cover was shown to reduce
run-off loadings of TSS and TP from watersheds, fields and plots.
Results at the plot and field scale are statistically significant. At
the watershed scale, general improvements in test watersheds over
control watersheds may be in effect over the last 12 to 18 months of the
study. These trends are not statistically significant. These observed
trends coincide with the management of higher crop residue levels in
test watersheds. These results are highly positive in light of the fact
that these evaluations have been conducted for a transition period and
more dramatic improvements in test watershed loadings relative to
control watersheds is likely as soil quality and farmer confidence and
familiarity are improved.
It is unfortunate that this study was
conducted over a relatively short period of time. Some trends were
beginning to emerge but the limited amount of data made it difficult to
draw any definite conclusions regarding effectiveness at the watershed
scale. Smaller scale research areas identified positive environmental
benefits. Ideally the study could have monitored the watersheds for
three years while conservation tillage was being implemented and then
for three to five years after implementation. In this study the entire
monitoring period was an adoption-transition phase in terms of soil
structure and social factors such as farmer education and farm
management. The study did not run long enough to allow for collection of
data from the watersheds during a post-transition period.
The two years of abnormal weather
(generally low precipitation amounts for the period) made it difficult
to build a large base of information for use in evaluation of the
conservation tillage system. The watersheds generally did not experience
extreme precipitation events which are necessary to test the systems in
SWEEP Report #69
- Pilot Watershed Study Report #1: Study Area Selection, Description and
SWEEP Report #70
- Implementation of Conservation Systems (PWS Report #2)
SWEEP Report #71
- Evaluation of Conservation Systems: Cooperator Attitude Change (PWS
SWEEP Report #72
- Evaluation of Conservation Systems: Soils and Crops (PWS Report #4)
SWEEP Report #73
- Evaluation of Conservation Systems, Hydrology (PWS Report #5)
SWEEP Report #74
- Evaluation of Conservation Systems, Water Quality (PWS Report #6)
SWEEP Report #75
- Watershed Modelling (PWS Report #7)
SWEEP Report #62
- Volume I - An Economic Evaluation of Soil Conservation Technologies,
SWEEP Report #63
- Volume II - Collection and Analysis of Field Data in the Pilot
SWEEP Report #64
- Volume III - Field Level Economic Analysis of Changing Tillage
Practices in Southwestern Ontario
SWEEP Report #67
- Volume VI - Watershed Level Economic Analysis of Tillage Practices in
Future Research: ( )
indicates reviewers suggestion for priority, A - high, C - low.
(A) The watershed studies should be
continued for three to five more years to evaluate the test following
the adoption period. This is consistent with the time frames for
agricultural watershed scale studies conducted elsewhere in North
Thursday, May 19, 2011 07:53:10 PM