Inclusion of Hemp Winter Retting in a Crop Rotation in Organic Farming

Bc. Arian Majid

Master's thesis

Abstract:

Cannabis sativa or hemp is a multipurpose crop widely used in human history, but abandoned in 20th century, while recently, it is a frequently researched agricultural crop with high potential of applications across many industries. However, its practical applications remain limited. One of the main limitations is the retting process used to separate the fibres for further use. In this study, an alternative method of retting was researched, consisting of leaving the hemp stalks ret standing uncut on the field over winter. The literature overview was focused on the possible inclusion of winter retting method in crop rotations in organic farming. It reviewed the options for retting methods, environmental benefits of hemp cultivation in general and its benefits for organic farming. From the economical point of view, major possibilities of hemp applications were researched, as well as possible textile uses and the winter retting method. The overview was designed to demonstrate that hemp would be an ideal crop for organic farming crop rotations, but its practical inclusion depends on the economics of further applications. It was suggested in previous studies, that winter retting may be a way to lower the production costs, but the success of this method largely depends on reaching the textile quality of hemp fibre to be profitable for farmer. Thus, the practical experiment consisted of cultivating a hemp field using the winter retting method and taking samples of hemp stalks over winter. These samples were evaluated and one of them was further processed in order to be tested for its physical qualities. It was observed under microscope, that the resulted fibre had comparable qualities to a fibre used to make actual real hemp/cotton T-shirts. However, when measuring the physical properties using the vibroscope method, the hemp fibres had very good strength, but were lacking the desired fineness for processing on cotton mills. Using the regression analyse, it was suggested, that the elementary fibre would reach the desired quality, but the fibre bundles would need further separation. The hypothesis, that the winter retted hemp should be included in the crop rotations in organic farming, depending on the reached fibre quality in order to be profitable for farmer, was only proved partially. More research would be needed with more samples and further processing of hemp fibres into yarn and actual T-shirts.

Keywords

agriculture, Cannabis sativa, industrial hemp, hemp fibre, spring harvest

Language used: English

Date on which the thesis was submitted / produced: 14. 4. 2022

Thesis defence

• Supervisor: Ing. Perla Kuchtová, Ph.D.

Czech University of Life Sciences Prague

Faculty of Agrobiology, Food and Natural Resources

Master programme / specializace:
Agriculture and Rural Development / Organic Farming