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ARS Home » Pacific West Area » Pullman, Washington » Northwest Sustainable Agroecosystems Research » Research » Publications at this Location » Publication #321765

Research Project: Mitigating Agricultural Sources of Particulate Matter and Greenhouse Gas Emissions in the Pacific Northwest

Location: Northwest Sustainable Agroecosystems Research

Title: Evaluating measures to assess soil health in long-term agroecosystem trials

Author
item MORROW, JASON - Washington State University
item Huggins, David
item CARPENTER-BOGGS, LYNNE - Washington State University
item REGANOLD, JOHN - Washington State University

Submitted to: Soil Science Society of America Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/15/2015
Publication Date: 4/22/2016
Citation: Morrow, J.G., Huggins, D.R., Carpenter-Boggs, L., Reganold, J.P. 2016. Evaluating measures to assess soil health in long-term agroecosystem trials. Soil Science Society of America Journal. 80:450-462.

Interpretive Summary: Monitoring and assessing soil health is an important component of any land management system with a vision of sustaining soil resources. Soil organic matter characteristics are key to soil health and responsive to tillage and crop management. We evaluated organic matter characteristics from five field experiments ranging from 2- to 30-years old representing diverse agricultural systems across the inland Pacific Northwest. Characteristics measured included soil organic carbon, total nitrogen, microbial biomass carbon and nitrogen, carbon mineralization, oxidizable carbon, and membrane nitrogen. We further evaluated these characteristics and the Haney Soil Health Index relative to seven criteria we propose as a framework to judge the effectiveness of assessing soil health. Mineralization, membrane nitrogen, and the Haney Soil Health Index were highly variable and subsequently not highly sensitive to management. Oxidizable carbon coupled with membrane nitrogen provided complimentary information important to soil health. Based upon the seven criteria to gauge soil health, oxidizable carbon scored the highest and should be considered by the NRCS, Conservation Districts, scientists, and land managers as a component for soil health assessment within the Inland Pacific Northwest.

Technical Abstract: Monitoring and assessing soil health is an important component of any land management system with a vision of sustaining soil resources. Soil organic matter(SOM)characteristics are key to soil health and responsive to tillage regime and crop management. As metrics of soil health, we evaluated surface SOM properties from five field experiments ranging from 2- to 30-years old representing diverse agroecosystems across the inland Pacific Northwest (iPNW). The SOM properties measured included soil organic Carbon, total nitrogen, non-hydrolyzable carbon and nitrogen, microbial biomass carbon and nitrogen, carbon mineralization (Cmin), permanganate oxidizable carbon (POXC), ion exchange membrane nitrogen (IEM N). We further evaluated these SOM soil health metrics and the Haney Soil Health Index (SHindex) relative to the following seven criteria we propose as a framework to judge the effectiveness of soil health tools: (1) evidence based, (2) sensitive to change, (3) logistically feasible, (4) cost effective, (5) accurate and precise, (6) performed in-situ or on undisturbed samples, and (7) valued for management decisions. Measures of the active SOM, particularly one-day Cmin, IEM N, and SHindex, were highly variable and subsequently not highly sensitive to management. POXC displayed sensitivity to more stabilized SOM, indicated by strong correlations to non-hydrolyzable carbon (r = 0.84) and non-hydrolyzable nitrogen (r = 0.80), and coupled with IEM N provided complimentary information important to soil health. Using these seven criteria to gauge soil health metrics, POXC scored the highest and should be considered as a component for soil health assessment within the iPNW.