Project Number: 5356-11120-002-00
Project Type: Appropriated

Start Date: Oct 01, 2006
End Date: Sep 30, 2011

Objective:
1.) Determine crop and tillage management impacts on carbon (C) and nitrogen (N) cycling and related soil biophysical properties. 1.a.) Determine tillage and cropping system effects on soil organic and inorganic N and C dynamics, and greenhouse gas emission. 1.b.) Evaluate performance of modified CQESTR to estimate tillage, crop rotation, and amendment effects on long-term C sequestration. Determine guidelines for biomass removal for energy production and its impacts on important soil properties and processes across Inland Pacific Northwest precipitation zones. 2.) Determine impacts of cropping and tillage systems on water quality and maintenance of the soil resource base. 3.) Develop conservation cropping and tillage systems that improve agroecosystem performance (production, stability and sustainability) and minimize adverse environmental impacts to air, water, and soil resources. 3.a.) Develop and evaluate tillage and crop residue management practices for successful conservation systems.

Approach:
Transitional soil microbial communities will be identified in fields undergoing changes in management from conventional tillage to reduced or no-till systems. Microbial activity will be estimated by CO_2 flux. Populations of viable microorganisms will be estimated by most-probable-number assay or plate counts. Communities will be analyzed by substrate utilization patterns using the BIOLOG system. From these microbial analyses we will calculate microbial diversity, overall microbial populations, microbial activity and community profiles. The effects of different C substances will be examined in controlled plot experiments. Greenhouse-gas fluxes from three cropping system scenarios will be determined using GRACEnet protocols. Development and refinement of CQESTR will include recalibration, revalidation, compilation of data inputs and default parameters relevant to soils, and compilation of management and climatic conditions for participating ARS locations. Based on experimental results across the Inland Pacific Northwest, biomass removal guidelines will be formulated. Two small watersheds, one in a no-till four-year rotation and the second in conventional-till winter wheat¿fallow, will be used in a paired design to determine impacts of cropping and tillage systems on soil and water quality. Temperature and moisture profiles will be used to characterize the effects of tillage methods, timings, depths, and soil types on heat and water flow in order to evaluate and develop management practices for summer fallow systems. Replacing 5356-12000-008-00D 10/01/2006. Associated with Pullman, WA, project 5348-11120-004-00D.