Alternate Wheat and Fallow

Local identifier
R/WF/3
Years operational
1856—2014
Description
The Alternate Wheat and Fallow experiment was started by Lawes and Gilbert in 1856, on a 0.4 ha site on part of Hoosfield. The experiment originally had two strips which alternated winter wheat and a bare fallow in successive years. Between 1932 and 1982, a modification was introduced to allow a yearly comparison of a one-year and a three-year fallow but the effects on the yield of the subsequent wheat crop were small and since 1983 the experiment has reverted to the original design. The wheat cultivar grown has usually been the same as on Broadbalk, and the effects of fallowing on the yield of winter wheat can be roughly estimated by comparing yields from this experiment with continuous, unmanured wheat on Broadbalk (plot 03). In the first 10 years of the experiment the one-year fallow gave an extra 0.6 t ha-1, but over the next 60 years the difference was even smaller (0.14 t ha-1). Since its reversion to the original design in 1983, and with modern cultivars, average yields of the wheat after a one-year fallow have been 1.7 t ha-1. When expressed on the basis of the whole area (i.e. wheat plus fallow), the yield of 0.85 t ha-1 is slightly less than the 1.0 t ha-1 for continuous wheat on Broadbalk. Since autumn 2015, the whole experiment (both plots) has been sown to winter wheat, the same variety as is grown on Broadbalk. A small amount of N fertilizer (50 kg N ha-1) is applied in spring (mid-April), but to maintain the low soil P and K status, no other fertilizers are applied. No yields or crop samples have been taken since harvest 2015. It was in this experiment in 1935, that symptoms caused by the fungal pathogen Gibellina cerealis or 'white straw disease' were first recorded in the UK.
Farm operation data?
Sample archive?
Samples available?
 
Data Access Statement
Available to any researcher on request
Data license
CC BY
Data URL
http://www.era.rothamsted.ac.uk/Alternate
Data policy
Yes (not online)
Organization
Rothamsted Research
People
Dr Andy Macdonald
principal investigator
Rothamsted Research
Dr Sarah Perryman
data manager
Rothamsted Research
Computational and Analytical Sciences

Site: Hoosfield

Type
research station field
Location
Harpenden
Hertfordshire
United Kingdom
Geographic location
51.812632, -0.375997
© OpenStreetMap contributors
Elevation
131 Metres
Visits permitted?
Yes
Visiting arrangements
By arrangement with Dr Andy Macdonald
History
The experiment is sited on part of Hoosfield that had received no applications of fertilizers or manures since 1851.
Soil type
luvisol

Design period: Original Scheme (1856—1931)

Design description
Two half acre strips, A and B, lie side by side, one carrying wheat while the other is fallow. These treatments alternate each year. No fertilisers are applied.
Number of plots
2
Number of harvests per year
1
Crops
CropYears grown
wheat
fallow
Measurements
VariableMaterialUnitsFrequencyScaleComment
harvested surface areawheathaannuallyplot
grain yield traitwheatt/haannuallyplotAt field moisture content
harvest dateNot specifieddateannuallyplotStart and end date
forage yieldwheatt/haannuallyplotstraw yield

Design period: Revised Scheme (1932—1982)

Description
A modification was made to enable the effect of a 1 year fallow to be compared with that of a 3 year fallow.
Design description
Each original A and B strip was divided transversly into 4 equal sections. When a strip carries wheat, only 3 of the 4 sections are cropped, the fourth section being left fallow. Each of the eight sections has a triple fallow in turn with an eight year cycle having 5 fallow and 3 cropped years Between the autumn of 1956 and 1960 each strip was divided in half longitudinally. The centre two halves continued the eight year cycle while the outer plots were assigned to the Entomology department for studies wheat bulb fly. No fertilizers were used. Between 1963 and 1966 plots were split to compare varieties Squarehead's Master 13/4 (Kloka 1966), Capelle and Rothwell Perdix.
Number of plots
8
Number of harvests per year
1
Crops
CropYears grown
wheat
fallow
Crop Rotation
WFFFWFWF
  • 1
    wheat
  • 2
    fallow
  • 3
    fallow
  • 4
    fallow
  • 5
    wheat
  • 6
    fallow
  • 7
    wheat
  • 8
    fallow
Measurements
VariableMaterialUnitsFrequencyScaleComment
harvested surface areaNot specifiedhaannuallyplot
harvest dateNot specifieddateannuallyplotstart and end date
grain yield traitwheatt/haannuallyplotMeasured at field moisture content until 1957 and 85% dry matter from 1958
forage yieldwheatt/haannuallyplotMeasured at field moisture content until 1957 and 85% dry matter from 1958
fallow yearsNot specifiedThe number of consecutive fallow years

Design period: Reversion to Original Scheme (1983—2015)

Design description
The four sections for each strip were merged reverting the experiment to the original two strip design.
Number of plots
2
Number of harvests per year
1
Crops
CropYears grown
wheat
fallow
Measurements
VariableMaterialUnitsFrequencyScaleComment
harvest datewheatdateannuallyplot
harvested surface areaNot specifiedhaannuallyplot
grain yield traitwheatt/haannuallyplotMeasured at 85% dry matter
forage yieldwheatt/haannuallyplotMeasured at 85% dry matter

Design period: Low P and K Maintenance (2016—)

Description
Since autumn 2015, the whole experiment (both plots) has been sown to winter wheat, the same variety as is grown on Broadbalk. A small amount of N fertilizer (50 kg N ha-1) is applied in spring (mid-April), but to maintain the low soil P and K status, no other fertilizers are applied. No yields or crop samples have been taken since harvest 2015.
Number of plots
1
Number of harvests per year
1
Crop
CropYears grown
wheat