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This article in JEQ

  1. Vol. 43 No. 2, p. 681-689
    Received: Aug 15, 2013
    Published: June 23, 2014

    * Corresponding author(s): jim.ippolito@ars.usda.gov
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Hardwood Biochar Influences Calcareous Soil Physicochemical and Microbiological Status

  1. J. A. Ippolito *a,
  2. M. E. Strombergerb,
  3. R. D. Lentza and
  4. R. S. Dungana
  1. a USDA–ARS, Northwest Irrigation and Soils Research Laboratory, 3793N 3600E, Kimberly, ID, 83341
    b Department of Soil and Crop Sciences, Colorado State University, Fort Collins, CO, 80523-1170


The effects of biochar application to calcareous soils are not well documented. In a laboratory incubation study, a hardwood-based, fast pyrolysis biochar was applied (0, 1, 2, and 10% by weight) to a calcareous soil. Changes in soil chemistry, water content, microbial respiration, and microbial community structure were monitored over a 12-mo period. Increasing the biochar application rate increased the water-holding capacity of the soil–biochar blend, a trait that could be beneficial under water-limited situations. Biochar application also caused an increase in plant-available Fe and Mn, soil C content, soil respiration rates, and bacterial populations and a decrease in soil NO3–N concentration. Biochar rates of 2 and 10% altered the relative proportions of bacterial and fungal fatty acids and shifted the microbial community toward greater relative amounts of bacteria and fewer fungi. The ratio of fatty acid 19:0 cy to its precursor, 18:1ω7c, was higher in the 10% biochar rate soil than in all other soils, potentially indicating an environmental stress response. The 10% application rate of this particular biochar was extreme, causing the greatest change in microbial community structure, a physiological response to stress in Gram-negative bacteria, and a drastic reduction in soil NO3–N (85–97% reduction compared with the control), all of which were sustained over time.

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Copyright © 2014. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.