Basic HTML Version
Methodology – Random Site Selection
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Irrigation District:
Western
Eastern
Bow River
Lethbridge Northern
St. Mary River
Taber
Raymond
Magrath
United
Mountain View
Leavitt
Aetna
Ross Creek
Rocky View
Wheatland
Newell
Cypress
Forty Mile
Warner
Cardston
Willow
Creek
Vulcan
Lethbridge
Taber
Figure 4.
Counties included in the weed survey.
Random Site Selection
The random selection of sites used the grid established by the Dominion Land Survey System
in western Canada.
A dataset with the locations of all irrigated fields was provided by Larry Kwasny, GIS Program Coordinator
Basin Water Management. A random sample was selected from all quarter sections (65 ha) that had a field with
greater than 16 cultivated hectares within each target irrigation district and municipality or county. A list that
contained ten times the allocated number of sites was developed for each irrigation district and county.
Ownership of the land was determined using the Alberta land titles database
. Sites were qualified, in the order
that they were listed, until the required number of fields had been obtained. A site qualified if the person who
farmed the land answered yes to all of the following questions.
1. Will you grant permission for a surveyor to count weeds on the selected quarter section during July or
early August?
2. Is there a field in the quarter section seeded to a selected crop?
3. Is the field at least 16 hectares in size?
4. Have you farmed the identified field for a minimum of five years (including 2009)?
5.
Is the identified field accessible by road?
6.
Is the field irrigated?
7.
Do you agree to complete a questionnaire on management practices used on the identified field in the
fall?
If a field in a quarter section did not qualify but the producer was willing to participate, an attempt was made to
qualify a field in another quarter of the same section. This step was followed only if the land was farmed by the
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McKercher, R.B. and B. Wolfe
. 1986. Understanding Western Canada
=
s Dominion Land Survey System.
Division of Extension and Community Relations, University of Saskatchewan, Saskatoon, SK.
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Government of Alberta.
2009. SPIN2 Spatial Information System. [Online] Available:
[4 September 2009]