Agdell

Local identifier
R/AG/6
Years operational
1848—1990
Objective
From 1848- 1951 to study the effects of fertilizers and organic manures on four-course rotations (cereal, root, legume, fallow). Then to study the residual values of phosphorus and potassium applied in the period 1848-1951 and further applications since 1964.
Description
Agdell was the only Rothamsted Classical Experiment in which crops were originally grown in rotation. From 1848 to 1951, three different manurial combinations (none, PKNaMg and NPKNaMg plus rape cake, castor meal) were applied to the root crops of two four-course rotations. The rotations differed only in their third course - roots, barley, fallow or legume, wheat. There were only six plots and only one course of the rotation was present each year. The root crop was turnips or swedes, the legume clover or beans. From 1920, club-root (Plasmodiophora brassicae) became progressively more damaging to the root crop, especially on the NPKNaMg plots as a result of increasing soil acidity. By 1948 the produce was too small to weigh, and the four-course rotation ceased in 1951. Soil acidity was corrected and the plots were then used to evaluate the P and K reserves accumulated up to 1951. During this period the original six plots were halved and two levels of soil organic matter were established by growing leys on one half. Subsequently, the plots were further sub-divided to build up different amounts of P and K in the soil. Crop yields were then related to the reserves of P and K in the soil and the effect of adding fresh P and K. The experiment ended in 1990, only archived crop and soil samples are now available.
Data Access Statement
Other
Data license
CC BY
Data policy
Yes (not online)
Organization
Rothamsted Research
research organisation
People
Dr Margaret Glendining
data manager
Rothamsted Research
Intelligent Data Ecosystems
Dr Andrew Gregory
principal investigator
Rothamsted Research
Protecting Crops and the Environment
Dr Sarah Perryman
data manager
Rothamsted Research
Computational and Analytical Sciences

Site: Agdell Field

Type
research station field
Local code
R/AG/6
Location
Harpenden
Hertfordshire
United Kingdom
Geographic location
51.806242, -0.357553
+−
© OpenStreetMap contributors
Elevation
123 Metres
Visits permitted?
No
Soil type
luvisol
Soil description
Shallow Batcombe series, shallow flinty clay loam or very flinty loam over Clay-with-flints.
Climatic type
temperate oceanic climate
Climate properties
VariableTime periodValue (range)Units
mean total precipitation 1981 – 2010 733 (515 – 973) millimeter
mean annual air temperature 1981 – 2010 9.8 (8.51 – 10.89) degree Celsius

Design period: 4-course rotations (1848—1951)

Design Type
Demonstration strip design
Description
The experiment tested two four course rotations in combination with different manuring treatments applied to the root break crop From 1848 to 1951, three different manurial combinations (none, PKNaMg and NPKNaMg plus rape cake, castor meal) were applied to the root crops of two four-course rotations. The rotations differed only in their third course - roots, barley, fallow or legume, wheat. There were only six plots and only one course of the rotation was present each year. The root crop was turnips or swedes, the legume clover or beans. From 1920, club-root (Plasmodiophora brassicae) became progressively more damaging to the root crop, especially on the NPKNaMg plots as a result of increasing soil acidity. By 1948 the produce was too small to weigh, and the four-course rotation ceased in 1951.
Design description
6 plots, 2 each for three fertilizer treatments, in either the legune or fallow rotation. Only one phase of the rotation each year.
Number of plots
6
Number of replicates
1
Number of harvests per year
1
Crops
CropYears grown
turnips
red clover
beans
barley
wheat
fallow
root vegetables
swedes
feed legumes
Crop Rotations
Legumes
  • 1
    root vegetables
    turnips or swedes
  • 2
    barley
    undersown
  • 3
    feed legumes
    red clover or beans
  • 4
    wheat
Fallow
  • 1
    root vegetables
    turnips or swedes
  • 2
    barley
  • 3
    fallow
    bare fallowed
  • 4
    wheat
Factor
Factor name
Factor levels
fertilizer exposure
nitrogen  (48 kgN/ha)
Applied to crop: root vegetables
Application frequency: Every 4 years
Chemical form: ammonium sulfate
Until 1912 a mixture of ammonium chloride and ammonium sulphate
phosphorous  (41.5 kgP/ha)
Applied to crop: root vegetables
Application frequency: Every 4 years
potassium  (224 kgK/ha)
Applied to crop: root vegetables
Application frequency: Every 4 years
Chemical form: potassium chloride
sodium  (16 kgNa/ha)
Applied to crop: root vegetables
Application frequency: Every 4 years
Chemical form: sodium sulphate
magnesium  (11 kgMg/ha)
Applied to crop: root vegetables
Application frequency: Every 4 years
Chemical form: magnesium sulphate
castor meal  (2242 kg/ha)
Applied to crop: root vegetables
Application frequency: Every 4 years
Supplied approximately 121 kgN/ha. Until 1936 rapeseed cake was used.
control exposure
Factor combinations
NPKNaMgR
Applied to plot 1 (fallow rotation) and plot 2 (clover/beans rotation)
fertilizer exposure: nitrogen
fertilizer exposure: phosphorous
fertilizer exposure: potassium
fertilizer exposure: sodium
fertilizer exposure: castor meal
PKNaMg
Applied to plot 3 (fallow rotation) and plot 4 (clover/beans rotation) (no nitrogen)
fertilizer exposure: phosphorous
fertilizer exposure: potassium
fertilizer exposure: sodium
fertilizer exposure: magnesium
None
No manures applied to plot 5 (fallow rotation) and plot 6 (clover/beans rotation)
fertilizer exposure: control exposure
Measurements
VariableMaterialUnitsFrequencyScaleComment
yield componentsAll cropscwtannuallyData presented in publications as means, Rothamsted Experimental Station 1970.
phosphorous contentNot specifiedlb/acrePhosphorus in crop and soil, published by Johnson and Penny 1972
potassium contentNot specifiedlb/acrePotassium in crop and soil, published by Johnson and Penny 1972

Design period: Residual Effects (1952—1990)

Design Type
Other
Description
From 1920, club-root (Plasmodiophora brassicae) became progressively more damaging to the root crop, especially on the NPKNaMg plots as a result of increasing soil acidity. By 1948 the produce was too small to weigh, and the four-course rotation ceased in 1951. Between 1952 and 1957 uniform dressings of nitrogen were applied and no potassium or phosphorous was applied. Cropping continued until 1990 to measure the residual effects of the phosphorus and potassium applied to the root crops since 1848.
Design description
In 1958 the six original plots were divided, one half sown to ryegrass the other bare fallowed. From 1959 plots were further divided into 3 for a test of phosphorous; basal N and K were applied. The 1958 fallow plots were sown with potatoes, sugarbeet and barley, each crop testing the 3 rates of P.
Number of plots
6
Number of subplots
8
Number of replicates
1
Number of harvests per year
1
Crops
CropYears grown
spring barley
spring wheat
faba beans
grass
fallow
sugar beet
potatoes
oats
winter wheat
Crop Rotation
Three-course rotation  1970—1975
  • 1
    sugar beet
  • 2
    spring barley
  • 3
    potatoes
Factors
Factor name
Factor levels
phosphate fertilizer exposure
Effects of different amounts of soil P were tested
potassium fertilizer exposure
Effects of different amounts of soil K were tested
Measurements
VariableMaterialUnitsFrequencyScaleComment
phosphorous contentNot specifiedlb/acrePhosphorus in crop and soil, published by Johnson and Penny 1972
potassium contentNot specifiedlb/acrePotassium in crop and soil, published by Johnson and Penny, 1972 and Johnson and Mitchell, 1974.
yield componentsNot specifiedt/haannuallyPublished in Johnston et al, 2013, for selected years and plots only

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