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e-RA: the electronic Rothamsted Archive
Rothamsted

Broadbalk Soils

The Broadbalk wheat experiment, established in the autumn of 1843, has been cultivated since at least 1623, and probably much earlier (Avery & Bullock, 1969). In his first Rothamsted paper, published in 1847, Lawes described the soil as "a heavy loam resting upon chalk, capable of producing good wheat when well manured" . Here, details are given of the site, the soil description and standard soil weights.

Site details

Soil details

Soil texture class: Clay loam to silty clay loam over clay-with flints. The soils contain a large number of flints and are slightly calcareous. Below about 2m depth the soil becomes chalk. The experiment is under-drained and the site is free draining.

Soil texture, 0-23cm (from Gregory et al, 2010)

There is considerable variation in soil texture across the site, with clay contents ranging from 19 – 39% (Watts et al, 2006). The mean clay content for Sections 0 (straw incorporated since 1986) and 1 (straw removed, both continuous wheat) is 28.3% (Watts et al, 2006). Clay content increases with soil depth in the Batcombe Series (from Jenkinson et al, 2008):

Soil pH: The plough layer (0-23 m) is limed when necessary to maintain a minimum soil pH of 7.0 – 7.5.

For information on soil organic carbon, see SOC Open Access dataset.

For information on soil concentration of Olsen P (plant-available P), see Olsen P Open Access dataset.

Soil Moisture Characteristics:With nearly 200 plots in the experiment, there isn’t water retention information for all treatments. Water retention characteristics for contrasting plots can be found in Salter & Williams (1969). For more recent information, see Gregory et al, 2010, where retention characteristics have been fitted to the van Genuchten model.

Soil weights, Mkg/ha

The following standard soil weights should be used for Broadbalk soil, both continuous wheat and rotational sections. All weights are in 106 kg/ha of oven-dry fine soil. To convert to g/cm3 divide by depth in cm (eg 23) and multiply by 10. Data prepared by A J Macdonald and P R Poulton, February 2014.

Broadbalk standard soil weights 106 kg/ha, 0-23cm

Year
Inorganic a
Plots 03-20
FYM since 1844 b
Plot 2.2 (2B)
FYM since 1885 b
Plot 2.1 (2A)
FYM 1968-2000 c
Plot 01
1843
1865
1881
1884
1893
1914
1967
2000
2010
(2.88)
2.88
2.88
2.88
2.88
2.88
*
2.88
2.88
(2.88)
2.78
2.69
*
2.62
2.60
*
2.52
2.52
*
*
*
(2.88)
2.81
2.75
*
2.52
2.52
*
*
*
*
*
*
(2.88)
2.52
(2.63)

 

Broadbalk standard soil weights 106 kg/ha, 23-46cm

Year
Plots 03-20
Plot 2.2 (2B)
Plot 2.1 (2A)
Plot 01
All years
3.0
3.0
3.0
3.0

Broadbalk standard soil weights 106 kg/ha, 46-69cm and 69-91cm

Year
Plots 03-20
Plot 2.2 (2B)
Plot 2.1 (2A)
Plot 01
All years
3.1
3.1
3.1
3.1

Topsoil data is the mean of comprehensive measurements of soil weight made in 1865, 1881, 1893, 1914 and 2000. Figures in brackets are assumed. * indicates no samples taken. 23-46cm is the mean of all plots measured in 1865, 1881, 1893 and 1914. 46-69cm and 69-91cm is the mean of all plots measured in 1865, 1881 and 1893. See Dyer, 1902 for 1865, 1881 and 1893 data. See Watts et al, 2006 for 2000 data. 1914 data is previously unpublished.

Notes:

a Plots 03-20, receiving inorganic fertilizer only, no manure (FYM). This also includes plot 03, given no fertilizer, and plot 19, recieving rape cake/castor meal.

b Assume no further change in bulk density/soil weight on plots 2.1 and 2.2 after 2000. However, BD may increase slightly on plots in rotation as FYM is NOT applied to the oats.

c BD will increase on plot 01 as applications of FYM stopped in 2000.The increase is assumed to be at the same rate as the decrease in BD between 1968-2000.

For deeper soil layers, use the following weights, taken from Dyer, 1902:

Depth
cm
Plots
Soil weight, 106 kg/ha
Soil weight, g/cm3
91-114
114-137
137-160
160-183
183-206
206-229
All plots
All plots
All plots
All plots
All plots
All plots
3.21
3.18
3.20
3.22
3.37
3.37
1.40
1.38
1.39
1.40
1.47
1.47

Sampling and Analysis methods

For information about sampling and analysis methods go to the sections below:

Data prior to 1926 when the experiment was divided into sections and some of the more recent data are given for whole plots only. Other more recent data are available for individual plots within each section.

Further information and acknowledgements

For more details, contact the e-RA Curators.

With thanks to Andy Macdonald and Paul Poulton for help with compiling the information and text.

Key References

2012

2010

2009

2008

2006

1995

1980

1969

1902

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