The Use of an Automatic Spot-Sprayer in Western Tree Crops and Weed Control in a Pecan Orchard Using Preemergence and Postemergence Herbicides

Persistent Link:
http://hdl.handle.net/10150/194435
Title:
The Use of an Automatic Spot-Sprayer in Western Tree Crops and Weed Control in a Pecan Orchard Using Preemergence and Postemergence Herbicides
Author:
Rector, Ryan Jeffery
Issue Date:
2007
Publisher:
The University of Arizona.
Rights:
Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
Abstract:
Weed control is typically achieved by broadcast spraying postemergence herbicides on the entire orchard floor which wastes chemical by spraying bare ground. Growers can account for spatial variation in weed density and only spray weedy areas instead of applying herbicide to entire fields by using the automatic spot-sprayer, WeedSeeker sprayer. We conducted field experiments in flood- and microsprinikler-irrigated lemon orchards, and flood- and sprinkler-irrigated pecan orchards to measure the amount of herbicide applied, weed control, tree yield, and the economic value of adopting the WeedSeeker sprayer compared to conventional boom spray technology. The WeedSeeker sprayer reduced cumulative herbicide use by at least 36% compared to the conventional boom sprayer at all sites. Weed control obtained using the WeedSeeker sprayer was usually similar to the conventional boom sprayer. There were no effects of the treatments on yield at any location. The partial budget analysis, used to determine the economic value of adopting the technology, showed that as the area of the orchard and the cost of the herbicide increased, the time to recover the initial investment in the WeedSeeker sprayer decreased. The investment in the technology can typically be recovered in less than five years in Arizona lemon and pecan orchards.We also conducted greenhouse experiments to determine the effect of various sensitivity settings and leaf area on the operational efficiency of the WeedSeeker sprayer. The WeedSeeker sprayer did not detect and spray all broadleaf and monocot plants unless a sensitive setting was used. The WeedSeeker sprayer was more efficient when detecting broadleaf plants compared to monocot plants. Our results indicate that operating the WeedSeeker sprayer using a sensitive setting (sensitivity level 2) will result in the most efficient detection of weeds.Finally, field studies were conducted in a non-bearing pecan orchard to evaluate weed management systems using various postemergence and preemergence herbicides. Most postemergence herbicides controlled the weed species present in the orchard. Tank mixing the herbicides generally resulted in greater control compared to applying them alone. All preemergence herbicides reduced the weed emergence compared to not using a preemergence herbicide. No pecan tree damage was observed in any treatment.
Type:
text; Electronic Dissertation
Keywords:
Lemon; Pecan; Automatic Spot-Sprayer; Herbicide
Degree Name:
PhD
Degree Level:
doctoral
Degree Program:
Soil, Water & Environmental Science; Graduate College
Degree Grantor:
University of Arizona
Committee Chair:
McCloskey, William B.

Full metadata record

DC FieldValue Language
dc.language.isoENen_US
dc.titleThe Use of an Automatic Spot-Sprayer in Western Tree Crops and Weed Control in a Pecan Orchard Using Preemergence and Postemergence Herbicidesen_US
dc.creatorRector, Ryan Jefferyen_US
dc.contributor.authorRector, Ryan Jefferyen_US
dc.date.issued2007en_US
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en_US
dc.description.abstractWeed control is typically achieved by broadcast spraying postemergence herbicides on the entire orchard floor which wastes chemical by spraying bare ground. Growers can account for spatial variation in weed density and only spray weedy areas instead of applying herbicide to entire fields by using the automatic spot-sprayer, WeedSeeker sprayer. We conducted field experiments in flood- and microsprinikler-irrigated lemon orchards, and flood- and sprinkler-irrigated pecan orchards to measure the amount of herbicide applied, weed control, tree yield, and the economic value of adopting the WeedSeeker sprayer compared to conventional boom spray technology. The WeedSeeker sprayer reduced cumulative herbicide use by at least 36% compared to the conventional boom sprayer at all sites. Weed control obtained using the WeedSeeker sprayer was usually similar to the conventional boom sprayer. There were no effects of the treatments on yield at any location. The partial budget analysis, used to determine the economic value of adopting the technology, showed that as the area of the orchard and the cost of the herbicide increased, the time to recover the initial investment in the WeedSeeker sprayer decreased. The investment in the technology can typically be recovered in less than five years in Arizona lemon and pecan orchards.We also conducted greenhouse experiments to determine the effect of various sensitivity settings and leaf area on the operational efficiency of the WeedSeeker sprayer. The WeedSeeker sprayer did not detect and spray all broadleaf and monocot plants unless a sensitive setting was used. The WeedSeeker sprayer was more efficient when detecting broadleaf plants compared to monocot plants. Our results indicate that operating the WeedSeeker sprayer using a sensitive setting (sensitivity level 2) will result in the most efficient detection of weeds.Finally, field studies were conducted in a non-bearing pecan orchard to evaluate weed management systems using various postemergence and preemergence herbicides. Most postemergence herbicides controlled the weed species present in the orchard. Tank mixing the herbicides generally resulted in greater control compared to applying them alone. All preemergence herbicides reduced the weed emergence compared to not using a preemergence herbicide. No pecan tree damage was observed in any treatment.en_US
dc.typetexten_US
dc.typeElectronic Dissertationen_US
dc.subjectLemonen_US
dc.subjectPecanen_US
dc.subjectAutomatic Spot-Sprayeren_US
dc.subjectHerbicideen_US
thesis.degree.namePhDen_US
thesis.degree.leveldoctoralen_US
thesis.degree.disciplineSoil, Water & Environmental Scienceen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.chairMcCloskey, William B.en_US
dc.contributor.committeememberSilvertooth, Jeffrey C.en_US
dc.contributor.committeememberBrown, Paulen_US
dc.contributor.committeememberWright, Glenn C.en_US
dc.identifier.proquest2005en_US
dc.identifier.oclc659747584en_US
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