Basic HTML Version
167
Part V
SUMMARY
Abstract for Poster
Half a million hectares of irrigated land are located in the South Saskatchewan River Basin in southern Alberta,
accounting for over half of the irrigated agricultural land in Canada. While irrigated fields have been included in
some provincial weed surveys, a separate weed survey of irrigated fields has not been previously conducted in
Alberta. In 2009, a survey was conducted of 571 fields of common irrigated crops including annual cereals (spring
wheat, barley, corn), annual broad-leaved crops (canola, sugar beets, dry beans, potatoes) and perennial crops
(alfalfa, grass hay). Fields were selected using a stratified random sampling procedure. In each field, weeds were
identified and counted in twenty 0.5 m x.0.5 m quadrats placed in an inverted W-pattern. The relative abundance of
each species was determined based on density, uniformity and frequency. Wild oats
(
Avena fatua
L.), kochia
(
Kochia scoparia
(L.) Schrad.), wild buckwheat
(
Polygonum convolvulus
L.), lamb's-quarters (
Chenopodium album
L.) and redroot pigweed (
Amaranthus retroflexus
L.) were the five most abundant species in the annual broad-leaved
crops. These species also were the top species in the cereal crops; however, the ranks differed. Dandelion
(
Taraxacum officinale
G. H. Weber ex Wiggers), Canada thistle
(
Cirsium arvense
(L.) Scop.), lamb's-quarters,
kochia and green foxtail (
Setaria viridis
(L.) P. Beauv.) were five most abundant species in the perennial crops. The
total weed density was lowest and the number of weed-free quadrats was highest in the annual broad-leaved crops.