Lethbridge ABC Rotation

This experiment has been added by the GLTEN Curators using existing published sources.
Objective
To study and evaluate the long-term impacts of cropping systems on soil quality, productivity, and the broader environment.
Description
The ABC rotation study was initiated as part of a wider effort by the Canadian Department of Agriculture to better understand the long-term effects of cropping systems. Over time the objective of the Lethbridge ABC Rotation changed from evaluating crop rotations to understanding the impact of cropping systems on nutrient flows, soil productivity, and the stock of soil organic carbon. The current objective of the study is to determine the long-term effect of fallow frequency and fertilizer amendments on soils, crop productivity, the sustainability of the production practices, and the broader environment. Soils samples have been collected periodically for over 100 years. Soil samples are stored dry at room temperature.
Data Access Statement
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Data license
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Data policy
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Organization
Lethbridge Research and Development Centre
experimental research station
People

Site: Lethbridge

Type
research station field
Location
Lethbridge
Alberta
Canada
Geographic location
49.6996877098134, -112.775890676392
+−
© OpenStreetMap contributors
Visits permitted?
No
Soil type
chernozem
Soil description
The soils are Orthic Dark Brown Chernozems (US soil classification system: Typic Haplustolls) developed on lacustrine parent material under native vegetation of tall and short grass species.
Soil properties
VariableDepthValue (range)UnitsRef yearEstimated?Baseline?
sand content 45 Percent
silt content 30 Percent
clay content 25 Percent

Design period: Period 1 (1911—1966)

Design Type
Demonstration strip design
Description
No fertilizer was applied during this period.
Design description
The experiment was non replicated and compared three rotations (A - continuous wheat, B - fallow-wheat, C - fallow-wheat-wheat. The rotations are fully phased with 6 plots in total, 1 for rotation A, 2 for rotation B and 3 for rotation C.
Number of plots
6
Number of harvests per year
1
Crops
CropYears grown
spring wheat
fallow
oats
Crop Rotations
A: Continuous wheat
  • 1
    spring wheat
B: F-W
  • 1
    fallow
  • 2
    spring wheat
C: F-W-O  1911—1923
  • 1
    fallow
  • 2
    spring wheat
  • 3
    oats
C: F-W-W  1924—
  • 1
    fallow
  • 2
    spring wheat
  • 3
    spring wheat
Measurements
VariableMaterialUnitsFrequencyScaleComment
grain yield traitspring wheat
soil organic carbonSoil

Design period: Period 2 (1967—)

Description
In 1985, the rotation B plots were assigned to new plots because of road building encroachment. The new plots were on land previously under a wheat fallow rotation since the 1950s.
Design description
In 1967 plots were split to compare with and without nitrogen and in 1972 plots were further split to compare with and without phosphorous. All plots compare all combinations of N and P. Plots are 22.7m wide and range from 212.8 to 276 m long.
Number of plots
6
Number of subplots
24
Number of harvests per year
1
Crops
CropYears grown
spring wheat
fallow
Crop Rotations
A: Continuous wheat
  • 1
    spring wheat
B: F-W
  • 1
    fallow
  • 2
    spring wheat
C: F-W-W
  • 1
    fallow
  • 2
    spring wheat
  • 3
    spring wheat
Factors
Factor name
Factor levels
nitrogen fertilizer exposure
Introduced 1967
control exposure  (0 )
N+  (45 kg/ha)
1967—
Applied to crop: spring wheat
Application method: broadcast application method
Chemical form: ammonium nitrate
phosphate fertilizer exposure
Introduced 1972
control exposure  (0 )
P+  (45 kgP/ha)
1972—2009
Applied to crop: spring wheat
Application method: broadcast application method
Chemical form: triple superphosphate
P+  (22.5 kgP/ha)
2010—
Applied to crop: spring wheat
Application method: broadcast application method
Chemical form: triple superphosphate
Measurements
VariableMaterialUnitsFrequencyScaleComment
grain yield traitspring wheat
soil organic carbonSoil

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