166-12 Biochar Affects An Eroded Calcareous Soil.

See more from this Division: A05 Environmental Quality
See more from this Session: Biochar Effects On the Environment and Agricultural Productivity: I
Tuesday, November 2, 2010: 1:45 PM
Hyatt Regency Long Beach, Beacon Ballroom B, Third Floor
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James Ippolito1, Rodrick Lentz1, Robert Dungan1 and Mary Stromberger2, (1)USDA-ARS-Northwest Irrigation and Soils Research Laboratory, Kimberly, ID
(2)Colorado State University, Fort Collins, CO
Erosional effects due to furrow irrigation in the Intermountain West have caused loss of shallow surface soils and exposure of calcareous subsoils.  When cultivated, these subsoils tend to produce lower crop yields and result in lost revenue for the producer.  Therefore, we explored the potential of biochar or biochar+manure to improve the fertility status of exposed subsoil. 

In a microcosm study conducted at 20oC, increasing amounts of Dynamotive biochar (0, 1, 2, or 10% by weight) were added to a calcareous soil (pH 8.3) containing either 0 or 2% manure.  Both materials were thoroughly mixed into soil, microocosms were bought to field capacity twice per week with reverse osmosis water, and then destructively sampled at 1, 2, 3, 4, and 6 months.  Soil NO3-N, pH, plant-available nutrients (as measured by DTPA), total C, organic C, total bacterial population (RT-PCR assay), and substrate induced respiration (measured via CO2 evolution) response were measured.

In general, increasing biochar application rate caused a decrease in soil NO3-N concentration, and an increase in total C and N content, organic C content, soil pH, bacterial population, and plant-available Fe, Mn, and Ni content.  The reduction in soil NO3-N concentration, coupled with the increase in organic C content, suggested that N immobilization was occurring.  Increases in plant nutrients suggested biochar contained these elements and may serve as a micronutrient source when added to calcareous, exposed subsoil.           

Over time, however, the soil NO3-N concentration generally increased, while the total C content and plant-available Fe, Mn and Ni content decreased.  These temporal effects appeared to result from normal nitrification and soil nutrient sorption processes, and were not biochar related.  When added to manure-amended soils, biochar application results were similar to the biochar only applications.  Findings suggest that biochar may improve the short-term micronutrient status of eroded calcareous soils and can increase the soil C content, yet excessive biochar applications may cause immobilization of soil NO3-N.

See more from this Division: A05 Environmental Quality
See more from this Session: Biochar Effects On the Environment and Agricultural Productivity: I