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Article
The quantitative soil pit method for measuring belowground carbon and nitrogen stocks
Soil Science Society of America Journal
  • Matthew A Vadeboncoeur, University of New Hampshire
  • Steven P. Hamburg, Environmental Defense Fund
  • Joel D. Blum, University of Michigan
  • Michael J. Pennino, University of Maryland - Baltimore County
  • Ruth D. Yanai, SUNY College of Environmental Science and Forestry
  • Chris E. Johnson, Syracuse University
Abstract

Many important questions in ecosystem science require estimates of stocks of soil C and nutrients. Quantitative soil pits provide direct measurements of total soil mass and elemental content in depth-based samples representative of large volumes, bypassing potential errors associated with independently measuring soil bulk density, rock volume, and elemental concentrations. The method also allows relatively unbiased sampling of other belowground C and nutrient stocks, including roots, coarse organic fragments, and rocks. We present a comprehensive methodology for sampling these pools with quantitative pits and assess their accuracy, precision, effort, and sampling intensity as compared to other methods. At 14 forested sites in New Hampshire, nonsoil belowground pools (which other methods may omit, double-count, or undercount) accounted for upward of 25% of total belowground C and N stocks: coarse material accounted for 4 and 1% of C and N in the O horizon; roots were 11 and 4% of C and N in the O horizon and 10 and 3% of C and N in the B horizon; and soil adhering to rocks represented 5% of total B-horizon C and N. The top 50 cm of the C horizon contained the equivalent of 17% of B-horizon carbon and N. Sampling procedures should be carefully designed to avoid treating these important pools inconsistently. Quantitative soil pits have fewer sources of systematic error than coring methods; the main disadvantage is that because they are time-consuming and create a larger zone of disturbance, fewer observations can be made than with cores.

Publication Date
10-1-2012
Publisher
ACSESS-Alliance of Crop, Soil, and Environmental Science Societies
Digital Object Identifier (DOI)
10.2136/sssaj2012.0111
Document Type
Article
Rights
Copyright ©2012 by the Soil Science Society of America, Inc.
Comments

This record is for the author's post print version of this work. URL for the publisher's version: https://www.soils.org/publications/sssaj/abstracts/76/6/2241#

Citation Information
Vadeboncoeur MA, Hamburg SP, Blum JD, Pennino MJ, Yanai RD, Johnson CE. 2012. The quantitative soil pit method for measuring belowground carbon and nitrogen stocks. Soil Science Society of America Journal 76: 2241-2255