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United States Department of Agriculture

Agricultural Research Service

Research Project: INTEGRATED INVASIVE SPECIES CONTROL, REVEGETATION, AND ASSESSMENT OF GREAT BASIN RANGELANDS Title: Revisiting soil carbon and nitrogen sampling: quantitative pits versus rotary cores

Authors
item Rau, Benjamin -
item Melvin, April -
item Johnson, Dale -
item Goodale, Christine -
item Blank, Robert
item Fredriksen, Guinevere -
item Miller, Watkins -
item Murphy, James -
item Todd, JR., Donald -
item Walker, Roger -

Submitted to: Soil Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 31, 2011
Publication Date: June 1, 2011
Citation: Rau, B.M., Melvin, A.M., Johnson, D.W., Goodale, C.L., Blank, R.R., Fredriksen, G., Miller, W.W., Murphy, J.D., Todd, Jr., D.E., Walker, R.F. 2011. Revisiting soil carbon and nitrogen sampling: quantitative pits versus rotary cores. Soil Science. 176:273-279.

Interpretive Summary: Sequestration of carbon in soil is being proposed to mitigate anthropogenic carbon dioxide. Quantification of soil carbon is difficult and time consuming. We compared a quick rotary core methodology against traditional quantitative pits at research sites in California, Nevada, and New York. There were no statistical differences in soil carbon concentrations between the two methods suggesting the rotary core method has great utility.

Technical Abstract: Increasing atmospheric carbon dioxide and its feedbacks with global climate have sparked renewed interest in quantifying ecosystem carbon (C) budgets, including quantifying belowground pools. Belowground nutrient budgets require accurate estimates of soil mass, coarse fragment content, and nutrient concentrations. It has long been thought that the most accurate measurement of soil mass and coarse fragment content has come from excavating quantitative soil pits. However, this methodology is labor intensive and time consuming. We propose that diamond-tipped rotary cores are an acceptable if not superior alternative to quantitative soil pits for the measurement of soil mass, coarse fragment content, C and total nitrogen (N) concentrations. We tested the rotary core methodology against traditional quantitative pits at research sites in California, Nevada, and New York. We found that soil cores had 16% higher estimates of less than 2-mm soil mass than estimates obtained from quantitative pits. Conversely, soil cores had 8% lower estimates of coarse fragment mass compared with quantitative pits. There were no statistical differences in measured C or N concentrations between the two methods. At the individual site level, differences in estimates for the two methods were more pronounced, but there was no consistent tendency for cores to overestimate or underestimate a soil parameter when compared with quantitative pits.

Last Modified: 11/23/2014
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