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
 close



Research
                Research Home
                            National Programs
                            Research Projects
                            Scientific Manuscripts
                            International Engagement
                            Scientific Software/Models
                            Databases and Datasets
                            Office of Scientific Quality Review
            Media
                News & Features
                            Multimedia
                            Briefing Room
                            Down on the Farm
                            Press Room
                            Science in Your Shopping Cart
                            Scientific Discoveries
                            Tellus
                            Under the Microscope
            About ARS
                About ARS Home
                            Staff Directory
                            Labs and Research Centers (Map)
                            Headquarter Offices
                            Organizational Chart
                            Employee Services (REE Employees Only)
                            Office of Outreach, Diversity, and Equal Opportunity
            Work With Us
                Work With Us Home
                            ARS Vacancies at USAJOBS
                            Careers at ARS Information
                            Scientific Collaborations
                            Extramural Agreements
                            1890 Faculty Research Sabbatical ProgramSearch small
                    Search
            
            ARS Home
                                About ARS
                                Contact Us




ARS Home 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
                                            Ma, Liwangitem
                                            Malone, Robert

                                                         - *Rob*item
                                            Heilman, Philip

                                                         - *Phil*item
                                            Ahuja, Lajpatitem
                                            Meade, Terryitem
                                            ANAPALLI, SASEENDRAN - COLORADO STATE UNIVERSITYitem
                                            Ascough Ii, Jamesitem
                                            KANWAR, R. - IOWA STATE UNIVERSITY
  Submitted to: Geoderma
                                    Publication Type: Peer Reviewed Journal
                                    Publication Acceptance Date: 6/28/2006
                                    Publication  Date: 5/16/2007
                                    Citation: Ma, L., Malone, R.W., Heilman, P., Ahuja, L.R., Meade, T.G., Anapalli, S.S., Ascough Ii, J.C., Kanwar, R.S. 2007. Sensitivity of tile drainage flow and crop yield on measured and calibrated soil hydraulic properties. Geoderma 140:3(2007) 284-296. Published on-line 5/16/2007.  doi:10.1016/j.geoderma.2007.04.012Interpretive Summary: Process-based agricultural systems models require detailed description of soil hydraulic properties that are usually not available. The objectives of this study were to evaluate the sensitivity of model simulation results to uncertainty in measured soil hydraulic properties and to compare simulation results using measured and default soil parameters. To do so, we measured soil water retention curves and saturated soil hydraulic conductivity (Ksat) from intact soil cores taken from a long-term experimental field near Nashua, Iowa for the Kenyon-Clyde-Floyd-Readlyn soil association. The soil water retention curves can be well described using the pore size distribution index ('). Measured ' values from undisturbed soil cores ranged from 0.04 to 0.12 and the measured Ksat values ranged from 1.8 to 14.5 cm/hr. These hydraulic properties were then used to calibrate the Root Zone Water Quality Model (RZWQM) for simulating soil water content, water table, tile drain flow, and crop yield (corn and soybean) by optimizing the lateral Ksat (LKsat) and hydraulic gradient (HG) for subsurface later flow. The measured soil parameters provided better simulations of soil water storage, water table, and N loss in tile flow than using the default soil parameters based on soil texture classes in RZWQM. Sensitivity analyses were conducted for ', Ksat, saturated soil water content ('s) or drainable porosity, LKsat, and HG using the Latin Hypercubic Sampling (LHS) and for LKsat and HG using a single variable analysis. Results of sensitivity analyses showed that RZWQM simulated yield and biomass were not sensitive to soil hydraulic properties. Simulated tile flow and N losses in tile flow were not sensitive to ' and Ksat either, but they were sensitive to LKsat and HG. Further sensitivity analyses using a single variable showed that LKsat in the tile layer was a more sensitive parameter compared to LKsat in other soil layers, and HG was the most sensitive parameter for tile flow under the experimental soil and weather conditions.
                                Technical Abstract: Process-based agricultural systems models require detailed description of soil hydraulic properties that are usually not available. The objectives of this study were to evaluate the sensitivity of model simulation results to uncertainty in measured soil hydraulic properties and to compare simulation results using measured and default soil parameters. To do so, we measured soil water retention curves and saturated soil hydraulic conductivity (Ksat) from intact soil cores taken from a long-term experimental field near Nashua, Iowa for the Kenyon-Clyde-Floyd-Readlyn soil association. The soil water retention curves can be well described using the pore size distribution index ('). Measured ' values from undisturbed soil cores ranged from 0.04 to 0.12 and the measured Ksat values ranged from 1.8 to 14.5 cm/hr. These hydraulic properties were then used to calibrate the Root Zone Water Quality Model (RZWQM) for simulating soil water content, water table, tile drain flow, and crop yield (corn and soybean) by optimizing the lateral Ksat (LKsat) and hydraulic gradient (HG) for subsurface later flow. The measured soil parameters provided better simulations of soil water storage, water table, and N loss in tile flow than using the default soil parameters based on soil texture classes in RZWQM. Sensitivity analyses were conducted for ', Ksat, saturated soil water content ('s) or drainable porosity, LKsat, and HG using the Latin Hypercubic Sampling (LHS) and for LKsat and HG using a single variable analysis. Results of sensitivity analyses showed that RZWQM simulated yield and biomass were not sensitive to soil hydraulic properties. Simulated tile flow and N losses in tile flow were not sensitive to ' and Ksat either, but they were sensitive to LKsat and HG. Further sensitivity analyses using a single variable showed that LKsat in the tile layer was a more sensitive parameter compared to LKsat in other soil layers, and HG was the most sensitive parameter for tile flow under the experimental soil and weather conditions.


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