In August of 1985, the Governments of Canada and the province of Ontario
announced the beginning of a coordinated federal/provincial program to deal
with soil conservation and water quality as part of the Canadian response
to an international agreement with the United States to reduce phosphorus
loads to Lake Erie. A Five Year Implementation Plan was developed which
set out the program objectives of a 200 tonne annual reduction in P loads
due to agriculture. This target was to be met by encouraging and assisting
8,000 farmers cropping 400,000 hectares of land to adopt appropriate conservation
cropping practices. Allocating the 200 tonne objective over 400,000 ha meant
that an average annual reduction of 0.5 kg of P per ha was required.
The Technology Evaluation and Development (TED)
Subprogram of the Soil and Water Environmental Enhancement
Program (SWEEP) ran from February of 1987 until September of 1992. This
final report presents a summary of the subprogram.
The TED program was successful in responding to the research priorities
identified during a detailed planning process. The planned research was
implemented and completed on budget and on schedule making efficient use
of a range of research capabilities throughout the province. The available
research funds were equitably distributed between research institutions,
such as the University of Guelph and the private sector. A number of productive
joint ventures between research institutions, private sector contractors
and active farmers were encouraged and supported Regular review of the program
progress with the Technical Advisory Panel resulted in modifications and
research enhancements which improved the focus and overall achievement of
the program objectives. Communication of research results and opportunity
for input was provided to a wide range of interest through the use of Progress
Summary Bulletins and research conferences.
The TED subprogram of SWEEP was conceived, developed and delivered as
a cooperative venture between farmers, research scientists and administrative
personnel. Any success which the TED subprogram achieved was due to the
tremendous cooperation of individuals within these different groups.
Of the 53 research projects funded by TED, 21 (40%) were awarded in response
to the formal Request for Proposal procedure, while 32 (60%) were awarded
as a result of unsolicited proposals. Work conducted as a result of unsolicited
proposals had to be justified by a demonstrated need for the knowledge which
the work would provide.
The TED subprogram was given a mandate to focus on research conducted
at the farm scale. Nearly 78% of all the research money spent during the
TED subprogram was spent on projects which were conducted on viable commercial
farms. In addition, an additional 5.5% of the research money was spent on
studies which used a combination of farm and research station resources.
Two hundred and thirty-five farmers were directly contacted through the
TED program. Of these 235 individuals, 148 were directly involved in some
component of the TED research. One of the first projects awarded under TED
was a survey of conservation practices being tested, revised and adopted
by leading farmers in Ontario. This study was valuable to TED in refining
the farmer position on research priorities and identifying a resource group
of advisors and research cooperators.
In addition to supporting, strengthening and enlarging the network of
farmer-to-farmer communication about conservation practices, the TED program
assisted in the training and professional development of a number of technicians,
researchers and research groups.
TED identified a need for tools which would assist farmers in reducing
the risks associated with the transition from conventional to conservation
farming. Means of providing these tools were explored to some extent at
the TED Modelling Workshop held on November, 1988. An existing approach
which showed the greatest promise was developed by ROBBERT ASSOCIATES, and
derived from a five year program in Statistics Canada to develop a socioeconomic
resource framework. The promise shown by the first phase of the project
conducted under TED clearly indicates a potential for meeting the established
guidelines outlined above.
Farm Management Systems
A high priority research topic identified in the early planning stages of
TED was the management of farm-field variability. The project arose out
of the identified need to better understand the challenges involved in managing
farm fields with complex topography, soils and drainage patterns. The main
conclusions were that large amounts of soil and associated phosphorus are
being moved within fields with complex topography in southwestern Ontario,
and the amount of soil and phosphorus moved within a field does not necessarily
relate to the amount of soil and sediment delivered to streams. Therefore
the crop productivity impacts of soil movement in complex fields can be
significantly greater than the environmental and water quality impacts.
A study was undertaken to investigate an alternative farm management
system developed by a group of innovative farmers known as the Ontario Biological
Aeration Tillage Association (OBATA). Over the three field seasons of the
research, many of the OBATA treatments appeared to have little or no quantifiable
agronomic benefits. Soil fertility, structure and compaction, and microbial
biomass did not appear to differ between the OBATA and standard treatments.
Rainfall simulation indicated that the practices did result in reduced soil
and phosphorus losses when compared to conventional practices. While the
TED studies did not show the OBATA system to be agronomically superior to
the standard management system, it may be a viable alternative to conventional
agriculture, offering comparable yields and net returns, while reducing
soil erosion and phosphorus losses. Since pasture and manure management
are readily included in the OBATA system, it may appeal more to farmers
with livestock than those who grow strictly cash crops.
The TED studies explored a range of management and species alternatives
for cover crops and developed the establishment and elimination methods
required to successfully incorporate their use into a farm system. The success
of a succeeding crop often appeared dependent on using some degree of tillage
in the spring prior to planting to provide an optimal seed bed environment
in the presence of crop residues. Pushing residue aside was also often successful.
Cover crops appear to have great potential to contribute to the reduction
in soil erosion from cropland as evidenced by the biomass and residue covers
which could be achieved over winter.
What is less clear from the research, is the link between main or cover
crop residues and yield reduction responses. The effects of residues on
soil temperature and soil moisture revealed that reduced temperature under
residues may delay development but did not necessarily reduce soybean and
corn yields. The development of the nitrogen soil test would be a useful
tool in the management of soil fertility with cover crops. Similarly, a
screening test may be of help in choosing a corn hybrid that may be better
able to emerge at cool temperatures.
"Tillage Options" was identified as one of the research priorities for TED
in the Background Paper, prepared by the Centre for Soil and Water Conservation,
and by the participants of the initial planning workshop. Eleven tillage-related
research contracts were awarded during the TED program. Studies on subsoiling
were included in the tillage options category as were development and testing
of new planting or fertilizer application equipment for conservation tillage
Several projects provided researchers and fanner cooperators with an
opportunity to test promising new planting and tillage equipment under Ontario
conditions. Minor modifications to existing technology were also tested
such as the cutoff mold board plow which appears to be a viable first step
for farmers towards conservation farming. Studies were conducted to assess
the benefits of subsoiling on soil properties and subsequent crop yields.
Overall, the TED studies did not come out in favour of subsoiling. It does
not appear to be cost effective unless a severe compaction problem exists.
A contract resulted in the publication of a booklet by OMAF, entitled
"Equipment Modifications and Practical Tips for Use". This publication contained
photographs and descriptions of a wide range of modifications to moldboard
plows, chisel plows, tandem disks, conservation seed drills, row crop planters
and edge-till systems.
The confirmation that nutrient stratification exists in systems in which
tillage does not mix or shallowly mixes fertilizer with the soil was expected.
There is no indication that this would be of concern to farm management
in terms of application rates and soil testing methods. The TED work indicated
that increased phosphorus contribution from these fields is unlikely where
conservation tillage achieves a concurrent reduction in sediment detachment.
Further, nitrogen losses from conventional, ridge tillage, and zero tillage
corn in runoff and tile drainage were similar and there was no indication
that conservation practices would lead to greater pollution of nitrogen
in waters. A sod crop dramatically reduced nitrogen losses and nitrogen
concentrations in runoff and tile waters relative to any of these corn systems,
however, which would suggest that cover crops or intercrops may play a role
in reducing nitrate leaching from soils.
The research which examined this possibility found that the cover crops
of ryegrass, oilseed radish, and red clover, scavenged nitrogen initially
but that soil nitrate levels were often as high or higher under the cover
crops during the late fall and winter. The pattern of release of the nitrogen
differed widely among the cover crops with some (oilseed radish) releasing
too early to be largely available to a corn crop while others immobilized
nitrogen to the extent of depressing corn growth early in the season in
the absence of supplemental nitrogen. There seems to be considerable opportunity
to understand the contribution of cover crops in nutrient cycling.
There was some evidence from this same study that the various cover crops
are leached of their nutrients to varying degrees by rainfall. The question
of the importance of residues in contributing to soluble P levels was raised.
The manure management studies in TED provided useful agronomic information
and tested some interesting and environmentally viable systems for manure
applications. The design, timeframe and budget of the manure studies did
not allow for full evaluation of the environmental implications of the management.
In some cases the manure was not incorporated, such as the applications
to established forages and to winter wheat in the spring. These systems
have the advantage of providing high ground covers of 50 to 100% which could
be expected to minimize runoff and soil erosion.
Other management systems, such as manure applications following winter
wheat harvest and soybeans, provide opportunities for manure incorporation.
When incorporation is accomplished by tillage which does not involve full
soil inversion by moldboard plowing, the main crop residue may provide sufficient
cover to reduce soil erosion. Some tillage was shown to be required to maximize
corn yields the following year in these studies.
Research carried out since 1987 under TED provided substantial evidence
to reject the notion that reduced tillage systems lead to greater weed problems
and higher herbicide dosages. At the beginning of the TED program a very
strong concern was expressed by the most experienced conservation farmers
that weed management and the availability of appropriate products was, or
could become, a serious problem. By the end of the TED study it seems safe
to conclude that their concern is significantly reduced. A number of new
mixes and rates of application using currently registered materials and
usages have proven to be extremely effective in controlling weeds at reasonable
cost. An innovative farmer was able to demonstrate a 60% reduction in herbicide
use through the integrated use of a herbicide banding and interrow cultivation.
This reduction offers significant environmental and economic benefits, while
at the same time appearing to have no adverse effect on weed pressures.
The system was developed to the point where the inter-row cultivation was
performed at the same time as nitrogen fertilization which meant no additional
passes across the field. In effect, the secondary cultivation allowed the
farmer to save 60% on his herbicide bill without substantially increasing
the costs of his field operations.
No significant problems with either slugs or armyworms were reported,
despite the fact that in many of the research plots, residue cover was in
excess of 75%. However, the lack of slug problems may be attributed to the
drier than normal conditions which generally prevailed during the three
field seasons. No evidence that fusarium infections can be linked to the
adoption of soil conservation practices was found.
Attempts under TED to monitor the water quality impacts of water control
structures were unsuccessful due to weather problems. Some empirical data
are required to calibrate available models. Once these data are available
modelling should prove to be a more reliable and cost effective method of
monitoring these structures.
Some tillage and farm management practices, such as cultivation, mulch
tillage, residue management and cover crops, have the potential to increase
the rates of infiltration and percolation into cropped land. A portable
device, the Guelph Pressure Infiltrometer (GPI), was developed and used
to compare the infiltration rates from soils under conventional and conservation
tillage systems. The GPI provided rapid measurements of a number of soil
hydraulic properties and is a promising research tool for further work.
Rainfall simulations were conducted in a separate contract on a large
number of TED research sites. Although differences in surface hydraulic
properties were not specifically examined, the response of different treatments
to the simulated rainfall did show relative differences in surface infiltration
rates. The results from the simulations were highly variable, but generally
in agreement with those from the GPI study.
At a monitored upland site, surface and tile flow from a fall moldboard
plow tillage system and a no-till system were monitored and compared. Very
little surface runoff occurred during the first 12 months of the monitoring
period. It was concluded that the sandy loam soils at the site were not
susceptible to surface runoff and erosion under either the no-till or fall
plow systems. When rainfall simulations were conducted on a part of the
field that had clay loam soils, both runoff volumes and soluble orthophosphate
losses were greater from the no-till soils.
The results from a monitored lowland site indicate that conservation
tillage is not sufficient to reduce phosphorus losses from cropland located
on flat clay soils. Other measures may be necessary, such as optimizing
phosphorus fertilizer use, or controlling the flow and reusing the tile
drainage water (subsurface irrigation, creating wetlands, etc.), to keep
the nutrients in the fields. The technology and options for accomplishing
this were not investigated further.
Rated as a high priority was the examination of the nature, extent, and
possible remedies to allelopathic and phytotoxic effects related to conservation
farming and specific crop rotations. The specific compounds studied were
volatile fatty acids (VFA's) which are by products of biological fermentation,
and phenolic acids which are organic compounds initially leached from crop
residues. Corn did not consistently exhibit a yield reduction response to
the presence of crop residues on the soil surface and hence the observation
of farmers related to phytotoxicity could not be reproduced in research
trials in the field.
Studies were conducted to determine the extent of soil compaction on
lowland clay soils in southern Ontario. Results indicated that around 50
to 70% of clay to clay loam soils in Lambton, Middlesex, Kent, Essex, and
Elgin Counties have some degree of subsoil compaction. Twenty-five percent
of these are considered to be severely compacted. Subsoiling of these lands
was generally not beneficial to crop yields, and may be of use only on severely
As a progression from studies carried out in TED and Tillage 2000 examining
variability of fields and effects of landscape positions on soil loss, research
focused on shoulder slope erosion and the extent to which tillage operations
move soil up and down slopes. This research is continuing beyond the TED
The report concludes with a discussion of the TED process and the Results
of the research. Recommendations for the planning and management of future
research programs are made. In addition specific topics for future research
are suggested in the area of soil and water quality, farm management systems,
soil fertility and nutrient management, crop residue management and tillage