title: Spot Spraying Reduces Herbicide Concentrations in Runoff.
abstract: Rainfall simulator trials were conducted on sugar cane paddocks across dry-tropical and subtropical Queensland, Australia, to examine the potential for spot spraying to reduce herbicide losses in runoff. Recommended rates of the herbicides glyphosate, 2,4-D, fluoroxypyr, atrazine, and diuron were sprayed onto 0, 20, 40, 50, 70, or 100% of the area of runoff plots. Simulated rainfall was applied 2 days after spraying to induce runoff at one plant cane and three ratoon crop sites. Over 50% of all herbicides were transported in the dissolved phase of runoff, regardless of the herbicide's sediment-water partition coefficient. For most sites and herbicides, runoff herbicide concentrations decreased with decreasing spray coverage and with decreasing herbicide load in the soil and cane residues. Importantly, sites with higher infiltration prior to runoff and lower total runoff had lower runoff herbicide concentrations.
authors.affiliation: National Centre for Engineering in Agriculture, University of Southern Queensland , Toowoomba, 4350 Queensland, Australia.
authors.forename: Alice R
authors.initials: AR
authors.lastname: Melland
authors.affiliation: National Centre for Engineering in Agriculture, University of Southern Queensland , Toowoomba, 4350 Queensland, Australia.|Department of Natural Resources and Mines, Queensland Government , Toowoomba, 4350 Queensland, Australia.
authors.forename: D Mark
authors.initials: DM
authors.lastname: Silburn
authors.affiliation: International Maize and Wheat Improvement Centre (CIMMYT), Ningxia Academy of Agriculture and Forestry Sciences , Yinchuan, Ningxia, People's Republic of China.
authors.forename: Allen D
authors.initials: AD
authors.lastname: McHugh
authors.affiliation: Sugar Research Australia Ltd., Te Kowai, 4740 Queensland, Australia.
authors.forename: Emilie
authors.initials: E
authors.lastname: Fillols
authors.affiliation: Department of Natural Resources and Mines, Queensland Government , Toowoomba, 4350 Queensland, Australia.
authors.forename: Samuel
authors.initials: S
authors.lastname: Rojas-Ponce
authors.affiliation: National Centre for Engineering in Agriculture, University of Southern Queensland , Toowoomba, 4350 Queensland, Australia.
authors.forename: Craig
authors.initials: C
authors.lastname: Baillie
authors.affiliation: Catchment to Reef Research Group, TropWATER, James Cook University , Townsville, 4811 Queensland, Australia.
authors.forename: Stephen
authors.initials: S
authors.lastname: Lewis
mesh_terms: D000383:Agriculture / Q000295:instrumentation / Q000379:methods*; D001315:Australia; D019015:Geologic Sediments / Q000032:analysis; D006540:Herbicides / Q000737:chemistry*; D007700:Kinetics; D011891:Rain / Q000737:chemistry; D031786:Saccharum / Q000737:chemistry / Q000254:growth & development; D012989:Soil Pollutants / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000737:chemistry*
chemical_list: D006540:Herbicides; D012989:Soil Pollutants; D014874:Water Pollutants, Chemical
keywords: pesticide; postemergent; pre-emergent; precision spraying; sediment−water partition coefficient; sugar cane; water quality