Degree Type

Thesis

Date of Award

2016

Degree Name

Master of Science

Department

Agricultural and Biosystems Engineering

Major

Agricultural and Biosystems Engineering

First Advisor

Brian L. Steward

Abstract

Weeds in row crops compete for resources available to crop plants and thus will affect crop yield and quality. However, consumers show a growing interest in organic food or foods produced with fewer agricultural chemicals. Therefore, a need exists to develop alternative weed control methods. A tine mechanism for an autonomous weeding machine was developed, and the interaction of a single tine and a rotating tine mechanism with the soil was investigated. The goal of this research was to develop a laboratory methodology for evaluating the effectiveness of a tine and rotating tine mechanism in disturbing weed plants simulated by individual wood pieces. Two experiments were performed using the tine and tine mechanism under a controlled environment. Soil in a large rotating bin was processed and sieved to a maximum size of 5 mm. The soil was then conditioned with water to produce the desired moisture content. A single tine was used in the first experiment. The experimental factors for this test were the tine diameter, tine depth and the speed that the tine moved through the soil. For the second experiment, four tines were attached to a disk that rotated about a vertical axis. The rotational tine mechanism was tested at different working depths and disk rotational speeds. All of these tests were conducted in a rotating soil bin with a controlled speed. The orientation of each simulated weed was observed in each trial. The observations were captured in a Mean Likelihood of Control (MLC) parameter which was intended to indicate the mean likelihood of simulated weed being controlled. In the first experiment, significant differences were observed in MLC across tine diameter, tine working depth and travel speed. There was evidence of a significant interaction between tine diameter and tine working depth. As for the second experiment, significant differences were observed in MLC across tine working depth and rotational speed of tine mechanism. Evidence of a significant interaction between working depth and tine mechanism rotational speed was observed. All of the factors tested were important and could be used to determine machine settings in the field.

Copyright Owner

Jafni Bin Johari Jiken

Language

en

File Format

application/pdf

File Size

81 pages

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