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Part I
INTRODUCTION
History of Weed Survey Activities in Alberta
The first indication of the relative importance of seven serious weeds in Alberta was obtained from reconnaissance
surveys in 1930 and 1931
In these surveys, estimates of the prevalence and distributions of species were obtained
from government officials and weed inspectors through interviews and questionnaires. Groh and Frankton
published the results of their reconnaissance survey in 1949. They listed the frequency of occurrence of weeds in
various areas of the province. In a questionnaire survey conducted during the 1960's by Ale
,
the extension staff
was asked to estimate the density and area infested with 40 species of weeds based on their knowledge of their
specific districts. These estimates for municipalities were presented on maps for each species. Although this survey
provided information that was of great value at the time, researchers and extension specialists recognized, by the
mid-1970's, a need for quantitative data based on weed counts in fields of producers.
In 1973, Dew initiated the first provincial survey in a series to identify the weeds occurring in annual cereal and
oilseed crops. The survey was a co-operative endeavour between the Canadian Department of Agriculture (Lacombe
Research Station) and the Agricultural Fieldmen of the Alberta Department of Agriculture. Fieldmen were asked to
survey one site per township each year. If this goal had been met, the results from more than two thousand
observations each year would have been obtained. Unfortunately, this goal was never achieved in any year but the
combined results from the five years of surveying provided the first quantitative data on the kinds and numbers of
weeds occurring in 3109 fields. These fields were distributed among 58 municipalities in the province but some
areas were under represented in the survey. For example, only 17 fields were surveyed in the Fort Vermilion area.
The major difference between Dew’s survey and subsequent surveys in the series was the time at which weed counts
were done. Counts were done after crop emergence and before postemergent herbicide application in fields seeded
to wheat (spring or durum), barley, oats, rapeseed, and flax. Weeds were counted in 1.0 square yard quadrats at five
representative locations in the field. The data collected from 1973 to 1977 were summarized in a Weed Survey
Series Report by Thomas and Wise (1985)
An intensive weed survey was carried out in the Fort Vermilion area, identified as Improvement District #23, of
northern Alberta in 1985 and the results were summarized in a Weed Survey Series Report by Thomas, Wise and
Clayton (1986)
The Improvement District was divided into two areas based on the common types of farming
operations. One area was characterized by mixed farming where 72 fields were surveyed and the other area was
dominated by the production of cereals and oilseeds where 61 fields were surveyed. This survey was meant to
serve as an example of the type of project that could be initiated in the rest of the province. Three major changes
were made to the survey protocol used previously by Dew. The Fort Vermilion survey applied a stratified random
sampling design for determining the location of fields rather than the grid design of Dew. An approximately equal
number of fields were randomly located in the two farming operation areas. Weed counts were done after
postemergent herbicide application instead of before application. Instead of the five large quadrats used by Dew, 20
smaller quadrats, which were 0.25 m
2
in size, were located in an “inverted W-pattern” at a set location in the field.
1
Mason, J.M.
1932. Weed survey of the prairie provinces. National Research Council of Canada. Rep. No. 26,
Ottawa, ON. 34 pp.
2
Groh, H. and C. Frankton
. 1949. Canadian weed survey. 7th Report. Canada Department of Agriculture,
Ottawa, ON. 144 pp.
3
Alex, J.F.
1965. Survey of weeds of cultivated land in the prairie provinces. Exp. Farm, Res. Branch, Canada
Department of Agriculture, Regina, SK. 68 pp.
4
Thomas, A.G. and R.F. Wise.
1985. Dew
=
s Alberta weed survey 1973-1977. Weed Survey Series Publication
85-3, Agriculture Canada, Regina, Saskatchewan. 134 pp.
5
Thomas, A.G., R.F. Wise and G. Clayton.
1986. Fort Vermilion area of Alberta weed survey in cereal and
oilseed fields 1985. Weed Survey Series Publication 86-4, Agriculture Canada, Regina, Saskatchewan. 98 pp.