Soil aggregate size distribution and particulate organic matter content from Arctic LTER moist acidic tundra nutrient addition plots, Toolik Field Station, Alaska, sampled July 2011.

Abstract: 

Soil aggregate size distribution, aggregate carbon and nitrogen, and light fraction carbon were determined for mineral soils in moist acidic tundra. Soil was sampled in control, and N+P plots of the Arctic LTER Moist Acidic Tundra plots established in 1989 and 2006.

Project Keywords: 

Data set ID: 

10489

EML revision ID: 

6

Short name: 

2011_MAT_89_06_NP_aggs_soil_JCM

DOI: 

10.6073/pasta/2b83870b06b2179669dd
People

Keywords: 

Arctic LTER keywords: 

Dates

Date Range: 

Friday, July 1, 2011 to Sunday, July 31, 2011

Publication Date: 

Thursday, December 12, 2013

Methods: 

In July 2011, soil samples were collected from control, and N+P plots from within a set of treatments in Moist Acidic Tundra plots established in 1989. A set of Control and N+P plots established on an adjacent hillslope in 2006 with both equivalent (high) and half (low) the fertilization rate of the 1989 plots were also sampled. At the time of sample collection we separated the soil into organic horizon, organic/mineral interface, and the upper 5cm of the mineral soil, and measured the depth of each layer. Field-wet mineral soil samples were broken up along fault lines and pushed through an 8 mm sieve; rocks (> 2 mm in size), live roots, and dead organic matter were removed, and what remained was air-dried. Soils were then transported to the Natural Resource Ecology Laboratory at Colorado State University for further fractionation and laboratory analysis. The sieved air-dried soils were separated into the following four water-stable aggregate size classes using techniques developed by Elliott (1986) and modified by Six et al. (1998): large (>2000 mm) and small (250-2000 mm) macroaggregates, microaggregates (53-250 mm), and a silt + clay fraction (<53 mm). Total organic carbon and nitrogen of all aggregate fractions were quantified by dry combustion using a Leco TruSpec CN analyzer (Leco Corporation, St. Joseph, Michigan). Microaggregates contained within small macroaggregates (250-2000 mm) were isolated using the method of Six et al. (2000). A 10-g subsample was placed on top of a 250-mm sieve along with fifty glass beads (4 mm diam.), shaken on a reciprocal shaker so that the macroaggregates were broken up with the aid of the beads, and washed onto a 53-mm sieve. This separation yields the following three fractions: the material remaining on the 250-mm sieve was considered to be coarse POM; aggregates passing through the 250-mm sieve but retained on the 53-mm sieve are considered occluded microaggregates isolated from macroaggregates; and material passing through the 53-mm sieve is considered clay and silt particles not associated with stable microaggregates. Occluded microaggregates were dried (65˚C), weighed, finely ground, and analyzed for total organic carbon content by dry combustion using a Leco TruSpec CN analyzer (Leco Corporation, St. Joseph, Michigan). Density separations were completed for small macroaggregates (250-2000 mm). Sodium polytungstate (SPT) was used to create a high-density solution to separate light from heavy fractions (HF) using the method of Six et al. (1998). Prior to each LF/HF density separation, aggregate fractions were dried (60ºC) then cooled to room temperature in a desiccator. Sub-samples (5 g) were added to 50-ml centrifuge tubes containing 25 ml of SPT at a density of 1.85 g cm-3, gently mixed in order to avoid aggregate disruption, topped off to 40 ml with SPT, and placed under vacuum (138 kPa) to remove air trapped within aggregates. Tubes were then centrifuged (1250 g) for 60 min to separate light from heavy fractions. Floating material, which comprises the LF, was aspirated onto a 20mm nylon filter and rinsed. Samples were dried, weighed, and analyzed for carbon content using a Carlo Erba (Milan, Italy). The silt and clay fraction was separated from sand by dispersing the HF with sodium hexametaphosphate (0.5% solution by weight), then passing the dispersed fraction through a 53 mm sieve. The carbon content of the <53mm fraction was quantified by dry combustion using a Leco TruSpec CN analyzer (Leco Corporation, St. Joseph, Michigan).

References

Elliott ET (1986) Aggregate structure and carbon, nitrogen, and phosphorus in native and cultivated soils. Soil Science Society of America Journal 50, 627-633.
Six J, Elliott ET, Paustian K, Doran JW (1998) Aggregation and soil organic matter accumulation in cultivated and native grassland soils. Soil Science Society of America Journal 62, 1367-1377.
Six J, Elliott ET, Paustian K (2000) Soil macroaggregate turnover and microaggregate formation: a mechanism for C sequestration under no-tillage agriculture. Soil Biology and Biochemistry 32, 2099-2103.

Sites sampled.

Download a comma delimited (csv) or Excel file (includes metadata and data sheets).

Use of the data requires acceptance of the data use policy --> Arctic LTER Data Use Policy

To cite this data set see the citation example on the LTER Network Data Portal page for this data set.

Variables Details

(Variables names are in the first line/row of the CSV file and Excel data sheet.)
Block
  • Label: Block
  • Definition: Arctic LTER blocks
  • Type: Nominal
  • Missing values: None specified
Plot Array
  • Label: Plot Array
  • Definition: Distinguished between 1989 and 2006 plots
  • Type: Nominal
  • Missing values: None specified
Treatment
  • Label: Treatment
  • Definition: Control vs +NP treatments for each plot array
  • Type: Code list
  • Codes:
    • 1989 +NP = Fertilization treatment since 1989 | 2006 Low+NP = Low fertilization treatment since 2006 | 2006 High+NP = High fertilization treatment since 2006
  • Missing values: None specified
% >2000mm
  • Label: % >2000mm
  • Definition: % >2000mm
  • Type: Physical quantity
  • Unit: percent
  • Maximum: Not specified
  • Minimum: Not specified
  • Precision: Not specified
  • Missing values:
    • -9999 = missing
% 250-2000mm
  • Label: % 250-2000mm
  • Definition: % 250-2000mm
  • Type: Physical quantity
  • Unit: percent
  • Maximum: Not specified
  • Minimum: Not specified
  • Precision: Not specified
  • Missing values:
    • -9999 = missing
% 53-250mm
  • Label: % 53-250mm
  • Definition: % 53-250mm
  • Type: Physical quantity
  • Unit: percent
  • Maximum: Not specified
  • Minimum: Not specified
  • Precision: Not specified
  • Missing values:
    • -9999 = missing
% <53mm
  • Label: % <53mm
  • Definition: % <53mm
  • Type: Physical quantity
  • Unit: percent
  • Maximum: Not specified
  • Minimum: Not specified
  • Precision: Not specified
  • Missing values:
    • -9999 = missing
% of small macroaggregate >250mm
  • Label: % of small macroaggregate >250mm
  • Definition: % small macroaggregate mass in >250mm subfraction
  • Type: Physical quantity
  • Unit: percent
  • Maximum: Not specified
  • Minimum: Not specified
  • Precision: Not specified
  • Missing values:
    • -9999 = missing
% of small macroaggregate 53-250mm
  • Label: % of small macroaggregate 53-250mm
  • Definition: % of small macroaggregate mass in occluded microaggregate fraction
  • Type: Physical quantity
  • Unit: percent
  • Maximum: Not specified
  • Minimum: Not specified
  • Precision: Not specified
  • Missing values:
    • -9999 = missing
% of small macroaggregate <53mm
  • Label: % of small macroaggregate <53mm
  • Definition: % of small macroaggregate mass in <53mm fraction
  • Type: Physical quantity
  • Unit: percent
  • Maximum: Not specified
  • Minimum: Not specified
  • Precision: Not specified
  • Missing values:
    • -9999 = missing
Total g light fraction/g small macroaggregate
  • Label: Total g light fraction/g small macroaggregate
  • Definition: Total g light fraction/g small macroaggregate
  • Type: Physical quantity
  • Unit: gramPerGram
  • Maximum: Not specified
  • Minimum: Not specified
  • Precision: Not specified
  • Missing values:
    • -9999 = missing
Total g <53mm g small macroaggregate
  • Label: Total g <53mm g small macroaggregate
  • Definition: Total g <53mm g small macroaggregate
  • Type: Physical quantity
  • Unit: gramPerGram
  • Maximum: Not specified
  • Minimum: Not specified
  • Precision: Not specified
  • Missing values:
    • -9999 = missing
mg C/g >2000 mm fraction
  • Label: mg C/g >2000 mm fraction
  • Definition: mg C/g >2000 mm fraction
  • Type: Physical quantity
  • Unit: milligramPerGram
  • Maximum: Not specified
  • Minimum: Not specified
  • Precision: Not specified
  • Missing values:
    • -9999 = missing
mg C/g 250-2000 mm fraction
  • Label: mg C/g 250-2000 mm fraction
  • Definition: mg C/g 250-2000 mm fraction
  • Type: Physical quantity
  • Unit: milligramPerGram
  • Maximum: Not specified
  • Minimum: Not specified
  • Precision: Not specified
  • Missing values:
    • -9999 = missing
mg C/g 53-250 mm fraction
  • Label: mg C/g 53-250 mm fraction
  • Definition: mg C/g 53-250 mm fraction
  • Type: Physical quantity
  • Unit: milligramPerGram
  • Maximum: Not specified
  • Minimum: Not specified
  • Precision: Not specified
  • Missing values:
    • -9999 = missing
mg C/g <53 mm fraction
  • Label: mg C/g <53 mm fraction
  • Definition: mg C/g <53 mm fraction
  • Type: Physical quantity
  • Unit: milligramPerGram
  • Maximum: Not specified
  • Minimum: Not specified
  • Precision: Not specified
  • Missing values:
    • -9999 = missing
mg N/g >2000 mm fraction
  • Label: mg N/g >2000 mm fraction
  • Definition: mg N/g >2000 mm fraction
  • Type: Physical quantity
  • Unit: milligramPerGram
  • Maximum: Not specified
  • Minimum: Not specified
  • Precision: Not specified
  • Missing values:
    • -9999 = missing
mg N/g 250-2000 mm fraction
  • Label: mg N/g 250-2000 mm fraction
  • Definition: mg N/g 250-2000 mm fraction
  • Type: Physical quantity
  • Unit: milligramPerGram
  • Maximum: Not specified
  • Minimum: Not specified
  • Precision: Not specified
  • Missing values:
    • -9999 = missing
mg N/g 53-250 mm fraction
  • Label: mg N/g 53-250 mm fraction
  • Definition: mg N/g 53-250 mm fraction
  • Type: Physical quantity
  • Unit: milligramPerGram
  • Maximum: Not specified
  • Minimum: Not specified
  • Precision: Not specified
  • Missing values:
    • -9999 = missing
mg N/g <53 mm fraction
  • Label: mg N/g <53 mm fraction
  • Definition: mg N/g <53 mm fraction
  • Type: Physical quantity
  • Unit: milligramPerGram
  • Maximum: Not specified
  • Minimum: Not specified
  • Precision: Not specified
  • Missing values:
    • -9999 = missing
mg C/g occluded microaggregate
  • Label: mg C/g occluded microaggregate
  • Definition: mg C/g occluded microaggregate within small macroaggregate
  • Type: Physical quantity
  • Unit: milligramPerGram
  • Maximum: Not specified
  • Minimum: Not specified
  • Precision: Not specified
  • Missing values:
    • -9999 = missing
mg N/g occluded microaggregate
  • Label: mg N/g occluded microaggregate
  • Definition: mg N/g occluded microaggregate within small macroaggregate
  • Type: Physical quantity
  • Unit: milligramPerGram
  • Maximum: Not specified
  • Minimum: Not specified
  • Precision: Not specified
  • Missing values:
    • -9999 = missing
mg LF C/g LF
  • Label: mg LF C/g LF
  • Definition: mg LF C/g LF
  • Type: Physical quantity
  • Unit: milligramPerGram
  • Maximum: Not specified
  • Minimum: Not specified
  • Precision: Not specified
  • Missing values:
    • -9999 = missing
mg small macroaggregate <53 C/g <53
  • Label: mg small macroaggregate <53 C/g <53
  • Definition: mg small macroaggregate <53 C/g <53
  • Type: Physical quantity
  • Unit: milligramPerGram
  • Maximum: Not specified
  • Minimum: Not specified
  • Precision: Not specified
  • Missing values:
    • -9999 = missing
mg LF C/g small macroaggregate
  • Label: mg LF C/g small macroaggregate
  • Definition: mg LF C/g small macroaggregate
  • Type: Physical quantity
  • Unit: milligramPerGram
  • Maximum: Not specified
  • Minimum: Not specified
  • Precision: Not specified
  • Missing values:
    • -9999 = missing
mg <53 C/g small macroaggregate
  • Label: mg <53 C/g small macroaggregate
  • Definition: mg <53 C/g small macroaggregate
  • Type: Physical quantity
  • Unit: milligramPerGram
  • Maximum: Not specified
  • Minimum: Not specified
  • Precision: Not specified
  • Missing values:
    • -9999 = missing
mg iPOM C/g small macroaggregate
  • Label: mg iPOM C/g small macroaggregate
  • Definition: mg iPOM C/g small macroaggregate
  • Type: Physical quantity
  • Unit: milligramPerGram
  • Maximum: Not specified
  • Minimum: Not specified
  • Precision: Not specified
  • Missing values:
    • -9999 = missing