U.S. flagAn official website of the United States government
                    Here's how you know **Official websites use .gov**
                            
                            A **.gov** website belongs to an official government organization in the United States.
 **Secure .gov websites use HTTPS**
                            
                            A **lock** (                            
                              A locked padlock                                                      
                            
                            ) or **https://** means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.


Menu Agricultural Research Service
						
                    U.S. DEPARTMENT OF AGRICULTURE
 Soil and Water Management Research: St. Paul, MN
 close



    Research

                    Research Projects
                                    Publications
                                    Collaborations
                                    News
                                    Software
                People

                    Staff Listing
                                    CareersSearch small
                    Search
            
            ARS Home
                                About ARS
                                Contact Us




ARS Home Midwest Area St. Paul, Minnesota Soil and Water Management Research Research Publications at this Location





- ARS National Programs
- Search for a scientific manuscript
- Search for a research project
- ARS Software
- Programs and Projects
- Collaborations
- Subjects of Investigation
- Publications

Title:   Author  item
                                            Venterea, Rodney

                                                         - *Rod*item
                                            Baker, John
  Submitted to: ASA-CSSA-SSSA Annual Meeting Abstracts
                                    Publication Type: Abstract Only
                                    Publication Acceptance Date: 7/1/2008
                                    Publication  Date: 10/5/2008
                                    Citation: Venterea, R.T., Baker, J.M. 2008. Effects of Soil Physical Non-Uniformity on Chamber-Based Gas Flux Estimates [abstract]. ASA-CSSA-SSSA Annual Meeting Abstracts. Paper No. 31.Interpretive Summary:
                                Technical Abstract: Chamber methods for measuring trace gases fluxes are prone to errors resulting in large part from alteration of near-surface concentration gradients. There is little information available for estimating the magnitude of such errors that simultaneously accounts for soil physical properties, chamber deployment methods, and flux-calculation options. The current study employed numerical modeling to examine how variations in these factors influence flux-estimate errors. Errors varied among profiles and flux-estimation techniques, resulting in potentially important biases. A theoretically-based flux model which assumes physical uniformity performed relatively well in non-uniform soils provided that precautions were taken. Errors using the theoretical model for non-uniform soils were minimized with larger effective chamber heights (h) and shorter deployment times (DT), as was the case for all flux-models. Recent studies that have recommended minimizing h and extending DT in order to enhance non-linearity of chamber data need to be reevaluated in light of these findings. Site-specific selection of chamber and flux-calculation methods should consider the physical characteristics of the soil profile as well as measurement error. It is also shown here that random measurement error can result in skewed flux-estimate errors. Techniques presented here can be used to develop soil- and method-specific error estimates, provided that errors from other sources are minimized.


Return to top


Connect with ARS Sign up


ARS Home
                            USDA.gov
                            Plain Writing
                            Policies & Links
                            Civil Rights Statements
                            FOIA
                            Accessibility Statement
                            Privacy Policy
                            Non-Discrimination Statement
                            Quality of Information
                            USA.gov
                            WhiteHouse.gov