Askov Long-Term Experiments on Animal Manure and Mineral Fertilizers - Sandmarken

This experiment has been added by the GLTEN Curators using existing published sources.
Local identifier
Askov-LTE Sandmarken
Years operational
1894—
Objective
Quantification of changes in carbon and nitrogen of top soil before and after conversion to grassland. The Sandmarken site was kept under well-defined arable management for 75 years and then converted to unfertilized semi-natural grassland in 1998.
Description
The experiment is on a coarse sandy soil with poor productivity, and includes replicated plots that were subjected to different fertilizer management until 1998. Since which it has been permanent grassland with no fertilizer application and no removal of plant biomass.. Quantification of the changes in topsoil C and N contents in the Sandmarken experiment have revealed that converting low-yielding arable land to semi-natural grassland can be an efficient management option for increased C storage in agricultural land.
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Site: Sandmarken

Type
research station field
Location
Askov Experimental Station
Denmark
Geographic location
55.28, 9.07
+−
© OpenStreetMap contributors
Visits permitted?
No
History
Kept under well-defined arable management for 75 years and then converted to unfertilized semi-natural grassland in 1998.
Soil type
Inceptisol (USDA)
Soil description
The soil is a coarse sand with a structureless, single-grain structure and is classified as an Inceptisol (Orchrept) according to USDA Soil Taxonomy.
Soil properties
VariableDepthValue (range)UnitsRef yearEstimated?Baseline?
clay content0 – 20 Centimetres4 Percent
silt content0 – 20 Centimetres4 Percent
find sand content0 – 20 Centimetres34 Percent
course sand content0 – 20 Centimetres57 Percent
soil density0 – 100 Centimetres1.5 gram per cubic centimetre
Climate properties
VariableTime periodValue (range)Units
Mean annual precipitation 1961 – 1990 862 millimeter
Mean annual temperature 1961 – 1990 7.7
Mean annual atmospheric ammonia & nitrate deposition 1921 – 1927 8 kg nitrogen per hectare
Mean annual atmospheric ammonia & nitrate deposition 1987 – 1989 16 kg nitrogen per hectare

Design period: Arable phase (1894—1997)

Description
The Sandmarken field consists of four sections (termed G1, G2, G3 and G4), and from 1894 to 1997 it was under a four-course rotation of autumn-sown cereals, root crops, spring-sown cereals and leguminous crops. each crop was present every year in a separate section. Leguminous crops were ‘whole-crop’ harvested in green condition, and cereals and root crops taken at maturity. All above ground biomass components of crops were removed at harvest, leaving only short stubble. The main treatments in the experiment were unfertilized and unmanured plots (0; termed unmanured), and plots amended with either animal manure (AM) or mineral fertilizers (NPK). In each section, the 0, AM and NPK treatments were represented by two, three and three replicated plots, respectively. The amounts of NPK increased in 1923, 1949 and 1973, see Christensen et al (2022) for details. Farmyard manure was applied in AM plots from 1894 to 1972, supplemented with liquid manure from 1923 to 1972. Since 1973, the AM treatment has relied on cattle slurry. Each treatment plot was 55 m2, with the central 24 m2 used for determining yields at harvest in the arable phase. The factor combination levels are given below with codes (historical codes in parentheses).
Number of plots
174
Number of harvests per year
1
Crops
CropYears grown
rye
oats
grass clover leys
lupins
mangolds
potatoes
turnips
root vegetables
peas
barley
Crop Rotations
1st phase  1894—1922
  • 1
    rye
  • 2
    root vegetables
    Plots divided into two subplots growing mangolds and potatoes respectively
  • 3
    oats
  • 4
    grass clover leys
2nd phase  1923—1948
  • 1
    rye
  • 2
    root vegetables
    Plots divided into two subplots growing turnips and potatoes respectively
  • 3
    oats
  • 4
    grass clover leys
    Lupins since 1943
3rd phase  1949—1972
  • 1
    rye
  • 2
    root vegetables
    Turnips and potatoes grown in alternating rotations
  • 3
    oats
  • 4
    lupins
    Peas from 1968
4th phase  1973—1997
  • 1
    rye
  • 2
    root vegetables
    Turnips and potatoes grown in alternating rotations
  • 3
    barley
  • 4
    peas
Factors
Factor name
Factor levels
farmyard manure exposure
Amount of animal manure in fresh weight. From 1894–1922, AM was farmyard manure. From 1923–1972, AM was farmyard manure supplemented with liquid manure. From 1973–1997, AM was cattle slurry.
0.5 AM
1 AM
1.5 AM
2 AM
nitrogen fertilizer exposure
Fertilizer rates differ between crops and rotations, see Christensen et al (2022) for details.
0.5 N
1 N
1.5 N
2 N
phosphate fertilizer exposure
0.5 P
1 P
1.5 P
2 P
3 P
potassium fertilizer exposure
0.5 K
1 K
1.5 K
2 K
3 K
Factor combinations
1 (a) Unmanured  1893—1997
21 replicates
2 (b) 0.5 AM  1894—1997
11 replicates
farmyard manure exposure: 0.5 AM
3 (c) 1 AM  1894—1997
21 replicates
farmyard manure exposure: 1 AM
4 (d) 1.5 AM  1894—1997
17 replicates
farmyard manure exposure: 1.5 AM
5 (s) 2 AM  1923—1997
3 replicates
farmyard manure exposure: 2 AM
8 (p) 0.5 NPK  1923—1997
15 replicates
nitrogen fertilizer exposure: 0.5 N
phosphate fertilizer exposure: 0.5 P
potassium fertilizer exposure: 0.5 K
9 (k) 1 NPK  1923—1997
20 replicates
nitrogen fertilizer exposure: 1 N
phosphate fertilizer exposure: 1 P
potassium fertilizer exposure: 1 K
10 (r) 1.5 NPK  1923—1997
13 replicates
nitrogen fertilizer exposure: 1.5 N
phosphate fertilizer exposure: 1.5 P
potassium fertilizer exposure: 1.5 K
11 (u) 2 NPK  1923—1997
4 replicates
nitrogen fertilizer exposure: 2 N
phosphate fertilizer exposure: 2 P
potassium fertilizer exposure: 2 K
12 (r1) 1.5 N + 3 PK  1923—1997
4 replicates
nitrogen fertilizer exposure: 1.5 N
phosphate fertilizer exposure: 3 P
potassium fertilizer exposure: 3 K
13 (l) 1 NP  1894—1997
10 replicates
nitrogen fertilizer exposure: 1 N
phosphate fertilizer exposure: 1 P
7 (f) 1 NK  1935—1997
10 replicates
nitrogen fertilizer exposure: 1 N
potassium fertilizer exposure: 1 K
6 (e) 1 PK  1935—1997
13 replicates
phosphate fertilizer exposure: 1 P
potassium fertilizer exposure: 1 K
14 (m) 1 N  1894—1997
4 replicates
nitrogen fertilizer exposure: 1 N
15 (n) 1 P  1894—1997
4 replicates
phosphate fertilizer exposure: 1 P
16 (o) 1 K  1894—1997
4 replicates
potassium fertilizer exposure: 1 K
Measurements
VariableMaterialUnitsFrequencyScaleComment
yield componentsNot specifiedGrain yields of spring- and autumn-sown cereals and total yields of leguminous and root crops for the period 1923–1997 were from the Sandmarken yield database
soil carbon in topsoilNot specifiedvalues reported for Sandmarken by Kofoed (1982) for the period 1923–1976
soil nitrogen in top soilNot specified

Design period: Grassland phase (1998—)

Description
Following the crop harvest in 1997, nutrient additions ceased and the arable crop rotation site was converted to permanent grassland with perennial ryegrass (Lolium perenne L.) and red fescue (Festuca rubra L.) sown in mid-March 1998. The grass was mown once or twice every year with the cut biomass left on the plot. Thus, grass productivity was not determined. The Sandmarken site has been considered since 1998 as a semi-natural grassland with no fertilizer application and no removal of plant biomass. Magnesium-enriched lime was applied in 1997 (4 Mg ha−1) before grass was sown and again in 2005 (3.5 Mg ha−1) when grass was reseeded directly into the grass sward without any other cultivation.
Crops
CropYears grown
rye grass
red fecsue

Related publications

  • Converting temperate long-term arable land into semi-natural grassland: decadal-scale changes in topsoil C, N, 13C and 15N contents (2018) Taghizadeh-Toosi et al. European Journal of Soil Science Vol. 70 Issue 2 pages 350-360
  • The Askov long-term experiments: 1894-2021 represents a unique research platform, Christensen et al. (2022)