Biogeochemical Processes Influencing Formation and Stabilization of Soil Organic Matter and Soil Structure

Tom Miles

Biogeochemical Processes Influencing Formation and Stabilization of Soil Organic Matter and Soil Structure
Douglas Karlen, Research Leader, Ames, IA 50011 USDA ARS, Soil and Water Quality Research

Project Number: 3625-11120-003-00
Project Type: Appropriated

Start Date: Apr 25, 2006
End Date: Apr 24, 2011

1)Develop a mechanistic understanding of processes controlling the formation and stabilization of organic matter in soils that enhance stabilization of soil structure. a) Determine the relative contributions of biochemical compounds to aggregation and C sequestration. b) Determine the role of clay minerals and charcoal in the formation and stabilization of soil organic matter and soil structure. c) Determine the nature of reactions between smectites and pesticides. d) Determine the effects of anaerobic soil conditions on biochemical processes that influence soil nutrient cycling. e) Develop integrative methods for fractionating SOM into meaningful pools. 2) Develop tools for in situ assessment of soil organic carbon and soil structure. a) Develop a multi-function probe (electrical and thermal properties) to evaluate soil structure. b) Develop and evaluate a field mobile NIRS tool for sensing soil carbon and various soil properties.

Field plot and column leaching studies will be used to quantify the impact of adding charcoal to soils on nutrient cycling, soil productivity, C sequestration, pesticide leaching, and on the formation and stabilization of clay-humic complexes. Interactions between selected pesticides and reference clays will be investigated to elucidate bonding mechanisms between organic molecules and clay surfaces. Seasonal patterns for cycling of phenolic and organic nitrogen compounds will be compared for routinely flooded and non-flooded soils. Anticipated products will include more accurate predictions of how crop and soil management effect nutrient cycling and soil organic matter stabilization. We will develop and test electrical and thermal soil probes to characterize soil structure. A regional non-linear multivariate calibration model for a recently developed on-the-go in situ near infrared diffuse reflectance soil probe will be evaluated to determine if the system can accurately map the spatial distribution of numerous soil properties (organic C, total N, CEC, moisture, buffer pH, and extractable nutrients) at the field scale.

Project Team
Laird, David - Dave
Olk, Daniel
Logsdon, Sally

Project Annual Reports
FY 2006


Related National Programs
Soil Resource Management (202)
Global Change (204)
Water Resource Management (201)

Related Projects
Mechanisms and Forces Controlling Pesticide Retention by Soil Clay Minerals
Soil Organic Matter and Nitrogen Cycling under Continuous Rice Cropping in the Mekong Delta, Vietnam

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