[Parameters: Topic='LAND SURFACE', Term='SOILS', Variable_Level_1='CARBON', Detailed_Variable='BIOMASS CARBON']
Broadbalk Wheat Experiment, Soil Organic Matter Network (SOMNET), U.K.Entry ID: IACR.Broadbalk
Abstract: This experiment began in 1843. The site was possibly farmed since
Roman times (i.e at least 1500 years). Map of 1623 shows field in
arable use. 1839-1843 arable crops: turnips, barley, peas, wheat,
oats. The soil is Clay-with-flint overlying chalk; see Avery & Catt,
The Soil at Rothamsted (see reference list) for full details.
The average climatic conditions at the experimental site are: Minimum
... annual temperature of 5.1 deg C, mean annual temperature of 9.1 deg C,
maximum annual temperature of 13 deg C, minimum annual rainfall of 409
mm, mean annual rainfall of 693 mm, and maximum annual rainfall of 983 mm.
There have been 5 management regimes: 1) Continuous wheat 1844 onwards
(occasional fallows). [field divided into 5 sections in 1926 to allow
regular fallowing to control weeds and into 10 sections in 1968 to
include rotations] 2) Potatoes-beans-wheat (1968-1979). 3)
Fallow-wheat-wheat (1968-1981). 4) Fallow-potatoes-wheat-wheat-wheat
(1982-1998). 5) Oats-maize-wheat-wheat-wheat (1996
onwards). Treatments (all regimes) are as follows: a) nil since 1852,
b) FYM since 1844, c) FYM since 1885 plus N2 since 1968, d) FYM plus
N4PK since 1968 (not continuous wheat), e) N0PK(Na)Mg since 1852, f)
N1PK(Na)Mg since 1852, g) N2PK(Na)Mg since 1852, h) N3PK(Na)Mg since
1852, i) N4PK(Na)Mg since 1968, j) N5PK(Na)Mg since 1985, k)
N6PK(Na)Mg since 1985. Other treatments receive NPK either singly or
in various combinations. One treatment received rape cake then castor
meal until 1988. (Na) - last applied 1973. FYM = 35 t/ha of farmyard
manure: fresh it contains about 200-250 kgN/ha, 40 kgP/ha & 210
kgK/ha. P=35kgP/ha, K=90kgK/ha (P&K both annually). Mg = 35 kgMg/ha
every 3rd year. N1, N2, N3, N4, N5, N6 = 48, 96, 144, 192, 240 & 288
kg N/ha/year as ammonium nitrate (N applied as ammonium sulphate to
most plots until 1967). FYM and N will not be applied to oats in new
oats-maize-wheat-wheat-wheat rotation. Of the 10 sections, 5 are in
continuous wheat; straw has been incorporated in one since 1986, one
has never received herbicides (fallowed every 5 years), one receives
no fungicides. 5 sections are in the 5 year rotation. All sections
have received chalk regularly since the 1950's.
Variables measured can be found in the Parameters section of this
record. Frequency of measurements varies for each variable (Daily for
weather, periodically for others, rarely for some). For detailed sampling
methodology, see SOMNET site, or publications listed in references
section on this record.
This information was compiled for the GCTE-SOMNET Database, Pete
Smith, Pete Falloon, David Powlson, and Jo Smith. Soil Science
Department, IACR-Rothamsted, UK.
Data Set Citation
Dataset Originator/Creator: Paul R. Poulton
Dataset Title: Broadbalk Wheat ExperimentOnline Resource: http://www.rothamsted.bbsrc.ac.uk/aen/eusomnet/expts/broadbal.html
Start Date: 1843-01-01
Vertical Resolution: 23 cm
Temporal Resolution: varies by parameter measured
AGRICULTURE > AGRICULTURAL CHEMICALS > FERTILIZERS
AGRICULTURE > AGRICULTURAL PLANT SCIENCE > CROP/PLANT YIELDS
AGRICULTURE > AGRICULTURAL PLANT SCIENCE > CROPPING SYSTEMS
AGRICULTURE > ANIMAL SCIENCE > ANIMAL MANURE AND WASTE
AGRICULTURE > SOILS > CARBON > BIOMASS CARBON
AGRICULTURE > SOILS > CARBON > CARBON DIOXIDE EVOLUTION
AGRICULTURE > SOILS > CARBON > TOTAL CARBON
AGRICULTURE > SOILS > NITROGEN > AMMONIUM NITROGEN
AGRICULTURE > SOILS > NITROGEN > BIOMASS NITROGEN
AGRICULTURE > SOILS > NITROGEN > NITRATE NITROGEN
AGRICULTURE > SOILS > NITROGEN > TOTAL MINERAL NITROGEN
AGRICULTURE > SOILS > NITROGEN > TOTAL NITROGEN
AGRICULTURE > SOILS > ORGANIC MATTER
AGRICULTURE > SOILS > SOIL BULK DENSITY
BIOSPHERE > VEGETATION > BIOMASS
BIOSPHERE > VEGETATION > NITROGEN
LAND SURFACE > SOILS > CARBON > BIOMASS CARBON
LAND SURFACE > SOILS > CARBON > CARBON DIOXIDE EVOLUTION
LAND SURFACE > SOILS > NITROGEN > AMMONIUM NITROGEN
LAND SURFACE > SOILS > NITROGEN > BIOMASS NITROGEN
LAND SURFACE > SOILS > NITROGEN > NITRATE NITROGEN
LAND SURFACE > SOILS > NITROGEN > TOTAL MINERAL NITROGEN
LAND SURFACE > SOILS > SOIL BULK DENSITY
ATMOSPHERE > ATMOSPHERIC CHEMISTRY > NITROGEN COMPOUNDS > MOLECULAR NITROGEN > NITROGEN DEPOSITION
ISO Topic Category
Quality Width of smallest plot is 4 m
Length of smallest plot is 23 m
Width of largest plot is 6 m
Length of largest plot is 320 m
Slope: 2% on 2/5 of experiment . Shape: Uniform
Details of direction of cultivation: Parallel to long-axis of plots
Width of Bare Strip around plot: 1-1.5m paths.
Width of Discard Strip around ... plot: 6.0m discard strip between
Details of homogeneity of the plots: Variability within plots: most
plots are about 6.0m wide. Transects taken across several plots
indicate that soil movement has occurred and that there is a gradient
across the unplanted path extending about 1m into the plot. Soil and
crop samples are therefore taken from within the central area (4.0m) and
excluding a 1m strip on each side. Within this area, soil analysis
shows that for C, N, pH Olsen P etc. the plots are reasonably uniform,
c.v. about 10% (more for microbial biomass).
There are at least 0 replicates in the experiment. No true replication
but the experiment was divided into 10 sections in 1968 (previously
into 5 sections in 1926). Therefore, plots on sections 1 and 9 can be
regarded as replicates. Sections 2,3,4,5 and 7 could be regarded as
replicates over a five year period (i.e. the length of one rotation).
There are control plots described as follows: Nil inputs plot included
which has received no inorganic fertilizers or organic manures since
1852. Nil plot does get chalk and pesticides on a regular basis. Also
an area fenced off in 1882 and allowed to revert to natural woodland
(see SOMNET entry on Broadbalk Wilderness).
Thorough scrutiny at point of entering onto electronic database (in
1995). Some soil and crop samples from archive have been reanalysed
retrospectively; no unexplained discrepancies observed to date.
Access Constraints none
Use Constraints Link to the following location to view data use policy of SOMNET members:
Role: TECHNICAL CONTACT
Phone: +44 (0)1582 763133
Fax: +44 (0)1582 760981
IACR-Rothamsted AL5 2JQ.
Province or State: Hertfordshire
Country: UNITED KINGDOM
Role: DIF AUTHOR
Phone: (301) 614-6898
Email: Tyler.B.Stevens at nasa.gov
NASA Goddard Space Flight Center Global Change Master Directory
Province or State: MD
Postal Code: 20771
Avery, B.W. & Catt. J.A. (1995) The soil at Rothamsted. Lawes
Agricultural Trust, Rothamsted, Harpenden, U.K.
Dyke, G.V., George, B.J., Johnston, A.E., Poulton, P.R. & Todd, A.D.
(1983) The Broadbalk Wheat Experiment 1968-78: Yields and
Plant Nutrients in Crops Grown Continuously and in Rotation. Rothamsted
Experimental Station. Report for 1982, Part 2: 5-44 (and
Garner, H.V. & Dyke, G.V. (1969) The Broadbalk yields. Rothamsted
Experimental Station. Report for 1968, Part 2: 26-49.
Hart, P.B.S., Powlson, D.S., Poulton, P.R., Johnston, A.E. & Jenkinson,
D.S. (1993) The availability of the nitrogen in the crop residues
of winter wheat to subsequent crops. J. Agric. Sci. 121: 355-362.
Jenkinson, D.S. (1990) The turnover of organic carbon and nitrogen in
soil. Phil. Trans. R. Soc. Lond. B. (1990) 53-60..
Johnston, A.E. & Garner, H.V. (1969) Broadbalk: Historical Introduction. Rothamsted Experimental Station. Report for 1968, Part 2:
Johnston, A.E. (1969) Plant nutrients in Broadbalk soils. Rothamsted
Experimental Station. Report for 1968, Part 2: 93-115 (and
Johnston, A.E. (1969) Plant nutrients in crops grown on Broadbalk.
Rothamsted Experimental Station. Report for 1968, Part 2: 50-62.
Extended Metadata Properties
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Creation and Review Dates
DIF Creation Date: 1999-10-20
Last DIF Revision Date: 2006-05-11