Effects of Late Hemp Straw Harvesting on Fiber Quality
2010
Ilze Baltiņa, Zaiga Zamuska

As the hemp plant growing period is 120 -150 days or more, taking into account Latvian climatic conditions sowing often can only begin in early May or even in the middle, then picking up can be held up till the second part of September. For the successful separation of the fiber from wooden part of the plant traditionally there is required retting during which the crop is spread on the ground and left for several weeks. Latvian autumns often have high levels of precipitation, which complicates the machinery works on the field.The aim of the work is to determine possibility of the hemp straws withstand on the field during the winter period. At Riga Technical University the research about the influence of crop withstanding on the field to hemp fibre quality is caried out. For the experiments there were used fibers from 2009. Weather of the winter 2010 was different according to meteorological dates from other years. It can be characterized by the low temperatures and high snow cover on the fields. Spring has come late and harvesting could only occur in the middle of May. Subsequent summer was not typical for Latvia weather, too. The temperature was exceeded for 2.6 C and precipitations were 50% more than average. Analysis of the data shows that during exposure of hemp stalks on the field the relationship between bast and wooden part was gradually destroyed, therefore shives is easier to separate from the fibers. At the same time division of complex fibers on a smaller and shorter fiber bundles occurs. As a result the obtained fibers are thinner, more soft and flexible. On the other hand the degradation greatly reduces strength and extension of fibers. The breaking load of fibres till spring is reduced by 38%, but till august by 75%. Increases breaking load coefficient of variation.According to this hemp fibre usage both for apparel and household textiles, and technical textiles. In the spring fibers became more grey and dark, but in the summer under the sun - light grey.


Keywords
hemp, hemp fiber, quality, strength, flexibility, linear density, length, harvesting time

Baltiņa, I., Zamuska, Z. Effects of Late Hemp Straw Harvesting on Fiber Quality. Material Science. Textile and Clothing Technology. Vol.5, 2010, pp.194-198. ISSN 1691-3132.

Publication language
Latvian (lv)
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