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
                                            Malone, Robert

                                                         - *Rob*item
                                            WEATHERINGTON-RIC, J - BENNETT & WILLIAMSitem
                                            Shipitalo, Martinitem
                                            Fausey, Normanitem
                                            Ma, Liwangitem
                                            Ahuja, Lajpatitem
                                            Wauchope, Robert

                                                         - *Don*item
                                            MA, Q - ENVIRONMENTAL AND TURF
  Submitted to: Pest Management Science
                                    Publication Type: Peer Reviewed Journal
                                    Publication Acceptance Date: 7/31/2003
                                    Publication  Date: 5/7/2004
                                    Citation: Malone, R.W., Weatherington-Ric, J., Shipitalo, M.J., Fausey, N.R., Ma, L., Ahuja, L.R., Wauchope, R.D., Ma, Q. 2004. Herbicide leaching as affected by macropore flow and within-storm rainfall intensity variation: a RZWQM simulation. Pest Management Science. 60:277-285.Interpretive Summary: Pesticide moves to tile drains or to shallow groundwater mainly through macropores (root channels, worm burrows, cracks in soil, etc).  The effect of within storm rainfall intensity variation (natural storms) on pesticide transport through macropores, however, is uncertain.  Midwestern storms generally have higher rainfall intensity at the beginning of the storm than at the end of the storm, whereas much macropore flow research is based on constant intensity storms.  We investigated the effect of variable rainfall intensity within a storm on alachlor and atrazine transport through macropores.  It was observed that Midwestern storms increase pesticide transport through macropores up to two-fold compared to constant intensity storms.  These results indicate that experiments and models based on constant intensity storms can under predict pesticide transport under more natural conditions of variable rainfall intensity.  This research will mostly benefit scientists studying herbicide transport but will eventually help decision makers recommend farming practices that will reduce pesticide movement into the environment.
                                Technical Abstract: Pesticide transport to ground water and tile drains may increase when macropores and fractures are present in glacial till derived soil, and when rainfall intensity varies within a storm.  Most studies of pesticide transport through macropores use constant rainfall intensity.  Because field and lab data are scarce, models are an efficient way to investigate these processes.  A model that handles pesticide transport through macropores under variable rainfall intensity is the Root Zone Water Quality Model (RZWQM).  Our objective was to use the RZWQM to investigate the effect of variable rainfall intensity within a storm on alachlor and atrazine transport through macropores.  Data was used from an experiment in which atrazine and  alachlor were surface applied to 30 x 30 x 30 cm undisturbed blocks of two silt loam soils from glacial till regions.  One hour later the blocks were subjected to a 0.5 h, 30 mm simulated rain with constant intensity.  Percolate was collected and analyzed from 64 square cells at the base of the blocks.  The median Midwest storm, which has higher rainfall intensity at the beginning of the storm than at the end, was predicted (using RZWQM) to increase pesticide transport through macropores up to two-fold compared to constant intensity storms.  These results indicate that experiments and models based on constant rainfall intensity may under predict pesticide transport.  Because of variable rainfall intensity, storms are more typical of natural conditions, more field and lab studies are needed to adequately simulate macropore transport of herbicides.


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