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Harvard Forest Data Archive
Soil Characteristics in the Clearcut Site at Harvard Forest 2012Related Publications
- Lead: Christopher Williams
- Investigators: Myroslava Khomik
- Contact: Christopher Williams
- Start date: 2012
- End date: 2012
- Status: completed
- Location: Prospect Hill Tract (Harvard Forest)
- Latitude: +42.546
- Longitude: -72.174
- Elevation: 403 meter
- Release date: 2015
- EML file: knb-lter-hfr.227.2
- DOI: digital object identifier
- Related links:
- Project Website
- Leaf Gas Exchange in the Clearcut Site at Harvard Forest 2010-2012
- Vegetation Cover in the Clearcut Site at Harvard Forest since 2010
- Study type: short-term measurement, modeling
- Research topic: ecological informatics and modelling; forest-atmosphere exchange; physiological ecology, population dynamics and species interactions
- LTER core area: primary production, disturbance
- Keywords: carbon, decomposition, litter, nitrogen, ph, soil moisture, soil organic matter
Soil properties (C:N ratio, pH, soil moisture, bulk density, litter layer thickness) were measured at the clear cut site in December 2012. Measurements were taken inside the large PVC collars that were used to measure soil respiration at the sites during the 2012 growing season. The collars were removed for storage thereafter. 15 locations in total were sampled: 3 collars were in trenched plots, and 12 on untrenched soil. Soil properties were collected in order to help interpret spatial variability in the corresponding soil CO2 fluxes measured at the site.
Soil samples were collected on Dec 4th and Dec 5th, 2012. Both days were warm (about 10oC), but Dec 4th was foggy and sometimes light drizzle, while Dec 5th was part cloud. There was snow on the ground the week before.
Where possible 3 small cores were taken for bulk density (bd) analysis and gravimetric water content (GWC) and one larger core (about 10 cm thick) in the center for root analysis (this latter core was frozen in our lab at Clark University for later processing, for roots).
Before coring the LFH horizon was removed/collected completely into a ziplock bag. Soil moisture was measured in three replicates outside of the collar using the Hydrosense moisture probe (%VWC), just like we did when we measured soil respiration during the growing season. Later we compared the GWC and VWC from the two different methods. Cores that were taken for bulk density analysis were also analyzed for CN ratio, by grinding the dried mineral soil to a fine powder, placing few mg into a small aluminum weighing boat and burning in a CN-analyzer that is in Torrey Labs (we prepared the samples and Manisha analyzed them for us). 15 collars were sampled, 3 of them were in trenched plots.
Soil pH, moisture (VWC and GWC), bulk density (with CN analysis on those mineral soil samples). pH was measured with a portable pH/moisture meter - KEL soil tester from the Harvard Forest supply room. VWC was measured without Hydrosense probe. Set volume cores were taken of the mineral soil just below the LFH-litter layer. The LFH-litter horizon inside the collar was collected (the height of that layer was noted and the diameter of the collars is known); a 15-20 cm core of roots was also taken. Sample processing was done in Torrey labs.
Soils were dried in ovens at 105C in glass jars for 24-48hours, until constant weight. Leaves were dried in ovens, in coin envelopes, at 60oC for 24-48hours. All drying was done at Harvard Forest Labs. Dried soil samples were sieved to remove roots and any loose organic matter.
All samples (leaves and soils) were ground individually using a mortar and pestle to a fine homogenous powder. Each ground sample was packed in triplicate and weighed on the Sartorius micro-balance (Sartorius) to 3 decimal places (once packed in the tin weighing boats): for leaves packed about 2mg; for soils packed about 10mg per replicate.
The samples were analyzed on CHNOS Elemental vario micro-cube analyzer (Elementar Analysensystem, GmbH). The machine burns the sample and elemental ratio is determined as the area under the curve produced by the machine, from the signal. All is relative to internal standards (Acetanilide with known C:N % ratio); CN analysis completed by Manisha Pattel at Harvard Forest Lab.
The output in the report that we should use is the % N and %C (these are % of mg weight that was put in - i.e. the final packet.weight)
Dimensions of Corer Used for Bulk Density Determination
Internal diameter (mm): rep1 = 41.32, rep2 = 41.35, rep3 = 41.31, average = 41.33, standard deviation = 0.02
Height (mm): rep1 = 30.18, rep2 = 30.32, rep3 = 30.24, average = 30.25, standard deviation = 0.07.
Corer volume = 40572.16 mm3.
This dataset is released to the public under Creative Commons license CC BY (Attribution). Please keep the designated contact person informed of any plans to use the dataset. Consultation or collaboration with the original investigators is strongly encouraged. Publications and data products that make use of the dataset must include proper acknowledgement.
Williams C. 2015. Soil Characteristics in the Clearcut Site at Harvard Forest 2012. Harvard Forest Data Archive: HF227.
hf227-01: soil characteristics
- collar: collar identification. CC indicates untrenched, T indicates trenched.
- lfh.thickness: thickness of LFH horizon (unit: centimeter / missing value: NA)
- lfh.dry.weight: weight of dried LFH-horizon inside the collar (unit: gram / missing value: NA)
- lfh.c: estimated C-content of LFH horizon - taken as 50% of dry weight (unit: gram / missing value: NA)
- soil.water: water content of mineral soil sample in grams (unit: gram / missing value: NA)
- soil.ph: pH of soil (unit: dimensionless / missing value: NA)
- gwc.mean: average % gravimetric water content of soil samples (g of water per g of dry soil) (unit: dimensionless / missing value: NA)
- gwc.sd: standard deviation of % GWC (unit: dimensionless / missing value: NA)
- bd.mean: average mineral soil bulk density (unit: gramsPerCubicCentimeter / missing value: NA)
- bd.sd: standard deviation of soil bulk density (unit: gramsPerCubicCentimeter / missing value: NA)
- vwc.mean: average volumetric water content around the collar, measured with the Hydrosense (%) (unit: dimensionless / missing value: NA)
- vwc.sd: standard deviation of %VWC (unit: dimensionless / missing value: NA)
- soil.repl: soil replicates used to calculate all of the above averages and standard deviations
- soil.n.per: average % soil nitrogen (unit: dimensionless / missing value: NA)
- soil.c.per: average % soil carbon (unit: dimensionless / missing value: NA)
- soil.n: average soil nitrogen content (unit: milligram / missing value: NA)
- soil.c: average soil carbon content (unit: milligram / missing value: NA)
- cn.mean: average carbon to nitrogen ratio, calculated from %N and %C (unit: dimensionless / missing value: NA)
- cn.repl: number of replicate samples used to calculate all of the C- and N- averages and standard deviations (unit: number / missing value: NA)
- soil.n.per.sd: standard deviation % soil nitrogen (unit: dimensionless / missing value: NA)
- soil.c.per.sd: standard deviation % soil carbon (unit: dimensionless / missing value: NA)
- soil.n.sd: standard deviation soil nitrogen content (unit: milligram / missing value: NA)
- soil.c.sd: standard deviation soil carbon content (unit: milligram / missing value: NA)
- cn.sd: standard deviation carbon to nitrogen ratio, calculated from %N and %C (unit: dimensionless / missing value: NA)