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ARS Home » Pacific West Area » Kimberly, Idaho » Northwest Irrigation and Soils Research » Research » Publications at this Location » Publication #296366
Title: Hardwood biochar influences calcareous soil physicochemical and microbiological status

Author
item Ippolito, James
item STROMBERGER, M.E. - Colorado State University
item Lentz, Rodrick
item Dungan, Robert - Rob

Submitted to: Journal of Environmental Quality
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/25/2013
Publication Date: 1/24/2014
Publication URL: http://handle.nal.usda.gov/10113/58619
Citation: Ippolito, J.A., Stromberger, M., Lentz, R.D., Dungan, R.S. 2014. Hardwood biochar influences calcareous soil physicochemical and microbiological status. Journal of Environmental Quality. 43(2):681-689.

Interpretive Summary: A hardwood-based, fast pyrolysis biochar was applied (0, 1, 2, and 10% by weight) to a calcareous soil, with changes in soil chemistry, water content, microbial respiration, and microbial community structure were monitored over a 12-month period. Increasing biochar application rate improved the soil water status, increased plant-available iron and manganese, soil carbon content, soil respiration rates, bacterial populations, and decreased soil nitrate-nitrogen concentration. The 10% biochar application rate caused the greatest change in microbial community structure, a physiological response to stress, and a drastic reduction in soil nitate-nitrogen, and thus would not be recommended for production agricultural settings.

Technical Abstract: 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-month period. Increasing 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 iron and manganese, soil carbon content, soil respiration rates, bacterial populations, and a decrease in soil nitrate-nitrogen concentration. Biochar rates of 2 and 10% altered the relative proportions of bacterial and fungal fatty acids, and shifted the microbial community towards greater relative amounts of bacteria and less fungi. The ratio of fatty acid 19:0 cy to its precursor, 18:1'7c, was higher in 10% biochar rate soil than 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 nitate-nitrogen (85-97% reduction compared to the control), all of which were sustained over time.