Baseline Soil Sampling and Analysis- GLBRC Intensive Site

Replaced by: Soil Sampling of BCSE and Scale-Up Experiment

In use from 2008-08-01 to 2009-11-30


Fall Surface Soil Sampling

Fall surface soils samples are taken to 25 cm in two depth increments: 0-10 and 10-25 cm using an 8 cm dia. Eijkelkamp root auger. At each of three sample stations per plot, one sample is taken within the row and another between rows. Soils at stations are composited by depth, to yield 3 composite samples per plot for each depth increment. Back in the lab, soils are weighed, sieved, and subsampled to provide the following measures: bulk density, total carbon and nitrogen, inorganic nitrogen, pH, gravimetric moisture, and microbial biomass. A separate 0-25 cm subsample taken by push probe and composited by plot is also sent to a university test lab for standard agronomic soil recommendations (N, P, and major cations).

Spring Surface Soil Sampling

Spring surface soil samples are taken with a push probe (2 cm dia.) to 25 cm depth. At each of the three sample stations per plot one sample is taken within the row and another between rows. Soils at stations are composited to yield 1 composite sample per plot. Back in the lab, soils are weighed, sieved, and subsampled for inorganic nitrogen and gravimetric moisture.

Deep Soil Sampling

Soil cores to 1 m depth are taken once every 5 years to follow long-term carbon change. Intact cores (6 cm dia.) are taken with a hydraulic probe (Geoprobe model RS60, Geoprobe Systems; Salina, Kansas) at each of 3 sampling stations (one core/station) in late spring / early summer. For the row crops, cores are taken between the rows. Cores are refrigerated until analyzed. Analyses include depth to major soil horizons (Ap, Bt, and Bt2 at KBS) and by specific depth intervals (0-10, 10-25, 25-50, and 50-100 cm), bulk density, organic carbon, total nitrogen, and carbonate content. The initial sampling also includes cation exchange capacity and soil texture for each depth interval composited by plot.

In situ N Availability

To follow seasonal patterns of N availability ion exchange resin strips (2.5 × 10 cm) are placed in the field on a monthly basis from March to November. Cation and anion strips are placed at each of the three sample stations and left in place for 4 weeks.


Sample Locations

Sampling locations within all plots are identical following the stratified random placement of three sample stations at plot establishment. Sampling by station increases the potential for identifying early treatment differences but care must be taken to avoid taking more than one sample from a particular spot and to avoid excessive plot disturbance. Table 1 provides suggested locations, which must necessarily be flexible to allow for the need to retake cores that encounter rocks or excessive compaction.

Table1: Location of sampling within the plot with reference to stations, taking into consideration biomass sampling locations and the need to avoid repeating exact locations each year.

Year Spring Fall Deepcore
2008 1mN, 1mE 1mN, 2mE 4mS, 1mE
2009 1mN, 1mW 1mN, 2mW
2010 1mS, 1mE 1mS, 2mE
2011 1mS, 1mW 1mS, 2mW
2012 1mN, 1mE 1mN, 2mE
2013 1mN, 1mW 1mN, 2mW 4mS, 1mW

Materials (Does not include materials for specific analyses)

  1. Eijkelkamp Root Auger
  2. Geoprobe (model RS60, Geoprobe Systems; Salina, Kansas)
  3. Plastic bags (pre-labeled)
  4. Meter Stick
  5. cm ruler
  6. 4mm sieve (treatment specific)
  7. Data Sheets
  8. Drying Oven @ 60 ° C
  9. Balance (e.g. Mettler PJ3600)
  10. Soil Grinder
  11. Pint and Quart Canning Jars (pre-labeled)

Soil Inorganic Nitrogen

Follow LTER protocol: KBS021-prot03, V1

Gravimetric Moisture

Follow LTER protocol: KBS015-prot01, V1

Bulk density

Follow LTER protocol: KBS026-prot01, V1 taking into consideration differences in soil core diameters and depth increments. For measuring bulk density in deep core samples follow LTER protocol:

Soil pH

Follow LTER protocol: KBS028-prot01, V1

Soil Organic Carbon and Nitrogen

Follow LTER protocol: KBS024-prot01, V1

Agronomic Soil Analyses (N, P, major cations)

Samples are sent to Soil and Plant Nutrient Laboratory Department of Crop and Soil Sciences, Michigan State University, East Lansing.

Microbial biomass (Carbon and Nitrogen)

Follow LTER protocol: KBS011-prot01, V1

Ion Exchange Resin Strips for Nitrogen Availability in Soil

Follow LTER protocol: KBS033-prot02, V1

Soil horizonation

Major soil horizon depths (cm) are estimated by visual differences in color and texture. Generally 3 horizons are identified, as well as any sand intrusions.

Soil texture

Follow LTER protocol: KBS000 V1 after compositing soils by plot.

Carbonate Detection

Follow LTER protocol: KBS058-prot1 V1

Cation Exchange Capacity

Composite samples by plot (25 gm) and depth increment are sent to Soil and Plant Nutrient Laboratory), Department of Crop and Soil Science, Michigan State University, East Lansing.

Hydraulic Conductivity

Calculated by modeling equations.


For annual fall sampling: Remaining soil after subsampling is dried and placed in 1 quart Mason jars after compositing by plot. Jars are labeled with sample date, depth increment, and treatment code in order of T-R- D-, where T = treatment number, R = replicate, and D = depth.

For deep core samples: Each dried individual horizon section is ground and stored in 1 pint Mason jars; cores are not composited. Jars are labeled with sample date , treatment code as T-R-S where T = Treatment #, R = Replicate #, S = Station # and depth (0-10 cm, 10-25 cm, 25-50 cm and 50-100 cm)

Date modified: Tuesday, Oct 24 2023



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