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ARS Home » Pacific West Area » Kimberly, Idaho » Northwest Irrigation and Soils Research » Research » Publications at this Location » Publication #318456
Title: Biochar can positively influence soil moisture relations

Author
item Ippolito, James
item LEVINE, JONAH - Confluence Energy
item WILLIAMS, MORGAN - University Of California

Submitted to: Popular Publication
Publication Type: Popular Publication
Publication Acceptance Date: 12/17/2015
Publication Date: 12/31/2015
Citation: Ippolito, J.A., Levine, J., Williams, M. 2015. Biochar can positively influence soil moisture relations. Idaho Crops & Soils News. 12:3-5.

Interpretive Summary:

Technical Abstract: One major issue related to climate change is the potential to improve soil water relations in light of changes in future precipitation patterns or reductions in water availability in drier portions of the world (such as the western US). It appears that biochar may play a positive role, but that role may be soil texture related. We performed a study with a sandy (Wolverine sand from Shelley, ID), silty (Portneuf silt loam from Kimberly, ID), and clay loam soil (Danville clay loam from a subsurface horizon, from near Oakland, CA) that received either 5 or 10% by volume of lodgepole biochar in either chipped (0.25-0.63”) or fine (0-0.25”) form; a control (no biochar) was also included. Soil-biochar treatments were evenly mixed and placed into containers, volumetric moisture sensors were inserted into the soil, and then 150 mL of water were evenly applied to the soil surface. Sensor measurements were collected every 2 minutes over a 14 day drying period. Results showed that after applying the same volume of water and allowing the mixtures to dry for 14 days, the control soils always contained less volumetric water than soils receiving biochars regardless of soil texture. Specifically, the volumetric water content was between 31 and 41%, 16 and 18%, and 15 to 18% greater than the control when chipped biochar was applied to the sandy, silty, or clay loam soils, respectively. In addition, differences between the 5% and 10% rates were not always considerable to warrant the greater application rate. It is important to note that the volumetric water content still increased when fine biochar was added to the soils, but the increase was not as dramatic as with the chipped biochar. It is speculated that at the applied rates, finer biochar particles could increase connectivity between the soil surface and subsurface and increase evaporative losses as compared to larger sized biochars. Additional research is needed to prove or disprove this hypothesis, but improvements in soil water content via biochar application may be of value to arid region crop producers and producers in areas where precipitation events are variable and lacking over relatively long time periods.