Graduate Studies

 

Date of Award

11-24-2023

Document Type

Dissertation

Degree Name

Doctor of Philosophy (Ph.D.)

Department

Agronomy

First Advisor

Sam Wortman

Abstract

Renewed interest in industrial hemp (Rosales, Cannabinaceae, Cannabis sativa L.) production in the United States, driven by recent legislative changes, including the Agriculture Act of 2014 and Agriculture Improvement Act of 2018, has sparked opportunities across various industries, from textiles to pharmaceuticals. With a specific focus on the High Plains climate, this research aims to inform growers about the feasibility of integrating industrial hemp into or nearby existing corn and soybean fields, crucial for those considering starting or expanding their production. The research is structured into three primary studies: 1. Herbicide Drift Sensitivity (Chapter 2): Assessing the risk of physical herbicide drift (through physical movement of droplets) from corn and soybean fields adjacent to hemp. Results underscore the high sensitivity because of hemp exposure to herbicides commonly used in these crops, indicating a high risk of biomass reduction and economic losses. 2. Hemp Tolerance to ACCase Inhibitors (Chapter 3): Evaluating the response of different hemp cultivars to Group 1 (ACCase inhibitor) herbicides. The study reveals varying levels of cultivar sensitivity, with hereby assessed cultivars displaying minor effects even when exposed to herbicide doses exceeding typical usage. These insights are crucial for developing tailored management strategies and understanding the interaction between ACCase inhibitors and hemp. 3. Volunteer Hemp Management in Soybean (Chapter 4) and Corn (Chapter 5) Cultivation: Investigating the response of early-stage volunteer hemp to weed control methods widely used in Nebraska in these crops. This study contributes to the strategic development of herbicide programs, enhancing the effectiveness of volunteer hemp control within standard soybean and corn rotations. Together, these studies provide essential insights for growers, outlining the opportunities and challenges of incorporating hemp into existing crop rotation systems. The results assist in informed decision-making choices regarding the use of herbicides in adjacent crops, managing risks with anticipated herbicide application (limited to ACCase inhibitors), and decision-making for comprehensive volunteer hemp control strategies in subsequent crop rotations.

Comments

Copyright 2023, Milos Zaric

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