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A.1 Cultivars grown at four sites under natural light and retted for two and three weeks, respectively

A.1.1 Two weeks retting

Figure 66 shows the effect of cultivar on fibre properties for the three hemp cultivars grown at Addo under natural light and which had been retted for two weeks (see Table 24). Five specimens per sample from each cultivar were tested and the testing protocol as described under section 3.2.2.2.2 (a-b) was followed. No climatic data on conditions of dew retting such as temperature and humidity was recorded by the ARC-IIC.

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Figure 66. Fibre yield, linear density and bundle strength for cultivars grown at Addo under natural light and retted for two weeks.

Fibre yield

Linear Density

Bundle strength

161 | P a g e According to the results given in Figure 66, it appears that:

 The average fibre yield of the three cultivars differed significantly, Novosadska, with a fibre yield of 23%, performing the best of the three cultivars. According to the published literature, hemp fibre yield can vary between 23 and 35% [62, 165], the levels achieved here are therefore rather on the low side.

 The average fibre linear density of the three cultivars differed significantly, with Fedora-19 having the lowest linear density, i.e. being the finest.

 Only the bundle strength Fedora-19 differed significantly from the other two.

A.1.2 Three weeks retting

Figure 67 shows the fibre yield (%), linear density (tex), bundle strength (cN/tex) and its CV (%) of the different cultivars grown at different sites under natural light and retted for 3

weeks.

Figure 67. Fibre properties of hemp cultivars grown at different sites under natural light and retted for 3 weeks. [Nov=Novosadska; Fut=Futura-77; Fer=Ferimon-12; Fed=Fedora-19; Fedr=Fedrina-74; Fel=Felina-34; QAM=Qamata]

0 10 20 30 40 50 60 70 80

Nov Fut Nov Fer Fed Fel Fedr Fut Nov Fed Fel Fedr Fut Fel

ADDO LIBODE MTIZA QAM

Fi bre Y ie ld (% ) Li ne ar de ns it y (t e x) B und le s treng th (c N /t e x) C V (% )

Fibre properties of hemp cultivars grown at different sites under natural light and retted for three weeks

Fibre yield Linear density

162 | P a g e Figure 68 shows the effect of cultivar and planting site on the various fibre properties. The results of the ANOVA are given in Appendix 2 Table 3, where the incomplete experimental design is clearly evident, meaning that no meaningful statistical results were possible.

Figure 68. Effect of cultivar and planting site on fibre yield, linear density, bundle strength and CV of bundle strength (3weeks retting)

163 | P a g e Main conclusions:

The main conclusions which can be drawn from the results plotted in Figure 67 are the following:

 Qamata produced the lowest fibre yield, with the highest yield being obtained with Fedrina-74 planted at Libode. The fibre yield levelsachieved here are lower than the minimum of 23% reported in the literature [62, 165], all the cultivars therefore failing to meet the internationally accepted minimum standards in terms of fibre yield. Since the main trading item in hemp fibre crop production is the fibre, the low levels of fibre yield achieved here will negatively affect the economic viability of the primary fibre production industry, unless it is to some extent compensated for by high biomass yields per hectare.

 Significant inconsistencies were present in the linear density for Novosadska, being, for example 68 tex when grown at Addo compared to 12.6 tex when grown at Mtiza and 14.8 tex when grown at Libode. These discrepancies are probably due to the different times of harvesting and the degree of retting, both of which are known to affect fibre linear density. The cultivar that produced the finest fibres, i.e. lowest linear density, the Futura-77 grown at Addo.

 Felina-34 grown at Libode produced the strongest fibres, with a bundle strength of

66.8 cN/tex, the weakest being Futura-77 grown at Addo, with a strength of 20.1 cN/tex. The variations in strength values are due to sampling processes (such as

variation in degree of retting, defects on tested fibres and number of single fibres contained in test specimen).

 The CV of the collective strength of bast fibre bundles tended to show the opposite trend to bundle strength, a higher bundle strength tending to be associated with a

164 | P a g e lower CV, which is not unexpected. Felina-34 and Fedora-19 exhibited the lowest CV values when grown at Libode, while Novosadska and Futura-77 exhibited the lowest CV values when grown at Mtiza and the highest values when grown at Addo.

 The cultivar that came closest to meeting the minimum requirements for the fibre properties investigated here, namely fibre yield (high value), linear density (low value), bundle strength (high value) and CV of bundle strength (low value), was Novosadska grown at Libode.

 The significant differences in fibre properties of the same cultivar grown in different sites of the same region having similar soil types and climatic conditions can probably be attributed to two factors, namely low seed germinating viability arising from planting old seeds, and the lack of technical agronomic expertise in hemp cultivation and the retting process that affect sample processing to obtain more uniform elementary fibres for testing of physical properties.

A.2 Effect of retting period and lighting (natural and artificial) on fibre properties.

A.2.1 Ferimon-12 cultivar

The effects of the retting period and lighting conditions (natural or artificial) on the fibre properties of the Ferimon-12 cultivar grown at Addo (2-4 weeks retting) and Libode (3 weeks retting) are shown in Figures 69 and 70.

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Figure 69. Effect of retting period and light on fibre physical properties of Ferimon-12 [N=natural day light; I = artificial lighting + natural day light; 2, 3, 4 = retting period in weeks].

According to Figures 69 and 70, it appears that a retting period of around 2 to 3 weeks was optimum, although the differences were not necessarily all that large or always consistent. It also appears that the results for the two different lighting conditions did not differ in a consistent manner in terms of the three fibre quality parameters covered, which is contrary to the expectations that the extra artificial light exposure would stimulate plant growth, thereby resulting in higher fibre yields.

0 10 20 30 40 50 60 N I N I I 2 2 3 3 4

ADDO ADDO LIBODE ADDO ADDO

Fi bre Y ei ld (% ) Li ne ar D ens it y (t ex ) B und le S treng th (c N /t ex )

Ferimon-12 grown at two sites (normal and artificial lighting) and retted for 2-4wks

Fibre Yield (%) Linear Density Bundle Strength

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Figure 70. Effect of retting period (2 to 3 weeks) on fibre yield, linear density and bundle strength for the Ferimon-12 cultivar grown at Addo under natural plus artificial light.

167 | P a g e A.2.2 Effect of lighting conditions (natural and artificial) for cultivars grown at Addo.

Figure 71 shows the effect of different lighting conditions (natural or artificial), on the fibre properties of the three cultivars grown at Addo and retted for 2 weeks.

Figure 71. Effect of natural and artificial light exposure on the fibre yield and physical properties of three cultivars grown at Addo [N=natural day light; I = artificial light + natural day light; 2 = retting period in weeks].

According to the analysis of the results, plotted in Figure 71, it appeared that adding the artificial light did not affect the fibre properties of the different cultivars in a consistently beneficialmanner.

B) Overall effect of planting site, cultivar, retting period and lighting conditions on