Agdell

  • Experiment Code: R/AG/6
  • Experiment Site: Rothamsted
  • Objectives: 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.
  • Date Start: 1848
  • Date End: 1990

Key Contacts

  • Margaret Glendining

  • Role: Data Manager
  • ORCID: https://orcid.org/0000-0002-6466-4629
  • Organisation: Rothamsted Research
  • Address: West Common, Harpenden, Hertfordshire, AL5 2JQ, United Kingdom
  • Andy Macdonald

  • Role: Principal Investigator
  • Organisation: Rothamsted Research
  • Address: West Common, Harpenden, Hertfordshire, AL5 2JQ, United Kingdom
  • Sarah Perryman

  • Role: Data Manager
  • Organisation: Rothamsted Research
  • Address: West Common, Harpenden, Hertfordshire, AL5 2JQ, United Kingdom

Funding

Experimental 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.

Design

  • Period: 1848 - 1951
  • Number of Blocks: 6
  • Number of Replicates: 1
  • Number of Harvests per Year: 1

Crops

Crop Years Grown
Turnips
Red Clover
Beans
Barley
Wheat
Fallow
Root Vegetables
Swedes
Feed Legumes

Crop Rotations

Rotation Crops
Legumes ( - ) Root Vegetables > Barley > Feed Legumes > Wheat
Fallow ( - ) Root Vegetables > Barley > Fallow > Wheat

Factors

Factors are the interventions or treatments which vary across the experiment.

Fertilizer Exposure

Levels
Level Name Amount Years Frequency Crop Method Chemical Form Notes
Nitrogen 48 kgN/ha - Every 4 years root vegetables ammonium sulfate Until 1912 a mixture of ammonium chloride and ammonium sulphate
Phosphorous 41.5 kgP/ha - Every 4 years root vegetables
Potassium 224 kgK/ha - Every 4 years root vegetables potassium chloride
Sodium 16 kgNa/ha - Every 4 years root vegetables sodium sulphate
Magnesium 11 kgMg/ha - Every 4 years root vegetables magnesium sulphate
Castor Meal 2242 kg/ha - Every 4 years root vegetables Supplied approximately 121 kgN/ha. Until 1936 rapeseed cake was used.
Control Exposure -

Factor Combinations

Factor Combinations are the combination of factors applied to different plots on the experiment.

Factor Combination Time Coverage Notes
NPKNaMgR - Applied to plot 1 (fallow rotation) and plot 2 (clover/beans rotation)
PKNaMg - Applied to plot 3 (fallow rotation) and plot 4 (clover/beans rotation) (no nitrogen)
None - No manures applied to plot 5 (fallow rotation) and plot 6 (clover/beans rotation)

Measurements

Variable Unit Collection
Frequency
Material Description Crop
Yield Components cwt annually AllCrops Data presented in publications as means, Rothamsted Experimental Station 1970.
Phosphorous Content lb/acre Phosphorus in crop and soil, published by Johnson and Penny 1972
Potassium Content lb/acre Potassium in crop and soil, published by Johnson and Penny 1972

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.

Design

  • Period: 1952 - 1990
  • Number of Blocks: 6
  • Number of Replicates: 1
  • Number of Sub-plots:
  • Number of Harvests per Year: 1

Crops

Crop Years Grown
Spring Barley
Spring Wheat
Winter Field Beans, (vicia faba)
Grass
Fallow
Sugar Beet
Potatoes
Oats
Winter Wheat

Crop Rotations

Rotation Crops
Three-course rotation (1970 - 1975) Sugar Beet > Spring Barley > Potatoes

Factors

Factors are the interventions or treatments which vary across the experiment.

Phosphate Fertilizer Exposure

Description: Effects of different amounts of soil P were tested

Levels
Level Name Amount Years Frequency Crop Method Chemical Form Notes

Potassium Fertilizer Exposure

Description: Effects of different amounts of soil K were tested

Levels
Level Name Amount Years Frequency Crop Method Chemical Form Notes

Measurements

Variable Unit Collection
Frequency
Material Description Crop
Phosphorous Content lb/acre Phosphorus in crop and soil, published by Johnson and Penny 1972
Potassium Content lb/acre Potassium in crop and soil, published by Johnson and Penny, 1972 and Johnson and Mitchell, 1974.
Yield Components t/ha annually Published in Johnston et al, 2013, for selected years and plots only

Site: Agdell Field - Rothamsted

Soil

  • Type: Luvisol
    Shallow Batcombe series, shallow flinty clay loam or very flinty loam over Clay-with-flints.
There are currently no prepared datasets online for this experiment. However, there may still be data available but requiring curation. For more information please contact the e-RA curators.

Key References

2013

  • Johnston, A. E. , Poulton, P. R. and White, R. P.(2013) "Plant-available soil phosphorus. Part II: the response of arable crops to Olsen P on a sandy clay loam and a silty clay loam", Soil Use and Management, 29, 12-21
    DOI: 10.1111/j.1475-2743.2012.00449.x

1994

  • Johnston, A. E.(1994) "The Rothamsted Classical Experiments", Long-term experiments in agricultural and ecological sciences, Proceedings of a conference to celebrate the 150th anniversary of Rothamsted Experimental Station, 14-17 July 1993 Rothamsted Experimental Station, Harpenden UK, 9-37

1972

For further information and assistance, please contact the e-RA curators, Sarah Perryman and Margaret Glendining using the e-RA email address: era@rothamsted.ac.uk