Theses and Dissertations

Advisor

Dodds, Darrin M.

Committee Member

Avila, Luis D.

Committee Member

Reynolds, Daniel B.

Committee Member

Korte, Hubert A.

Committee Member

Kruger, Greg R.

Date of Degree

12-12-2025

Original embargo terms

Immediate Worldwide Access

Document Type

Dissertation - Open Access

Major

Plant & Soil Sciences (Weed Science)

Degree Name

Doctor of Philosophy (Ph.D.)

College

College of Agriculture and Life Sciences

Department

Department of Plant and Soil Sciences

Abstract

Chemical plant protection is widely adopted in agriculture and plays a crucial role in maximizing plant production. Several developments for site-specific applications have been implemented in chemical plant protection, driven by economic, social, and environmental considerations. Spot spraying technology, which utilizes single nozzles or a limited number of nozzles to treat specific areas, is now available and gaining market penetration. However, its performance depends on carefully optimized application parameters to ensure consistent coverage and efficacy, thereby mitigating both under- and overdosing. To address concerns including reduced efficacy, resistance evolution, and environmental impacts, this work researches the effects of nozzle selection on lateral distribution quality under laboratory conditions. In 2021, the Pesticide Application Technology Lab at the University of Nebraska Lincoln was used to evaluate the effects of boom height, nozzle spacing, fan angle, and nozzle orientation in combination with different nozzle types. A new evaluation standard was developed to assess the distribution patterns in spot spray applications. The effects of varying nozzle types on spot spray herbicide application and subsequent savings were investigated in field trials with a Fendt Rogator Smart Sprayer prototype. Randomized strip trials with four replicates were set up on eight agricultural fields in corn and grain stubble between 2021 and 2023. Results indicate that nozzle type influences savings, and that boom height, nozzle spacing, fan angle, and nozzle type impact lateral distribution for single nozzle applications. This study also introduced a novel method, the In-Spot Out-Spot (ISOS) standard, which has proven to quantify spraying quality in single nozzle applications. Therefore, application equipment is a crucial factor in evaluating site specific pesticide applications, and the findings from this study should be considered when calibrating spot sprayers.

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