Abstract
Devil’s claw (Harpagophytum procumbens) is a geophyte that occurs mainly in Central,
East and South eastern Namibia where it was previously regarded as a nuisance due to its
fruit-claws getting caught on sheep and other livestock. The species has been exploited
due to its medicinal properties leading to concerns regarding its sustainability. Efforts to
conserve it have been tried in order to understand conditions suitable for its management
but there are still poor results in the germination of the species’ seeds and an inconclusive
debate about the resting period between harvests which would be considered to be
sustainable for the plant. There is also little known about the influence of parent tuber
size, and fencing on the plant’s fruit and secondary tuber production. Moreover, the
correlation between the number and length of Harpagophytum procumbens branches and
the number of its fruits have received less research attention. There is also a lack of
knowledge on correlations between above-ground basal cover and below-ground root
mass, below-ground root mass and tuber production in Harpagophytum procumbens.
A study was carried out at Ben-Hur and Vergenoeg farms in central eastern Namibia to
investigate the above mentioned concerns.
The number and weight of secondary tubers were found to increase with parent tuber
sizes even though fruit production was found not to be influenced by age.
Harpagophytum procumbens plants that were protected from grazing produced more
fruits, and more secondary tubers that were large in size. There was a positive correlation
between above ground basal cover by other plants and below-ground root mass which
negatively correlated with the number and weight of secondary tubers, suggesting that
competition with specifically long-rooted shrubs is a threat to maximum tuber production
in Harpagophytum procumbens.
Seeds pre-treated in Effective Microorganisms (EM) resulted in a germination rate of
32%, whilst those pretreated with H2SO4 germinated to 17% compared to 5.3 % that
germinated from the control. The combination of EM and H2SO4 resulted in a lower
germination percentage than as expected.
It is concluded that fruit production in H.procumbens is neither influenced by the period a
plant is left without harvesting, nor by parent tuber size,but rather by protection of
H.procumbens from grazing. The study therefore recommends fencing for stakeholders
who wish to maximize fruit production of the species.
The study also concludes that five years of not harvesting H.procumbens produces more
and large secondary tubers than two years. It is therefore recommended that
H.procumbens should not be harvested after every two years but rather after five years
when the plant is able to produce more and larger secondary tubers. A shifting harvesting
practice is therefore recommended for sustainable management of H.procumbens.
The study further concludes that protection of H.procumbens from grazing benefits the
plant to produce more and lager secondary tubers which subsequently benefit involved
stakeholders.
The study recommends fencing of H.procumbens during their active season and allowing
animals to forage again when the plants are dormant.
The study also concludes that H.procumbens with larger parent tubers produce more and
larger secondary tubers. The study recommends that even after not harvesting
H.procumbens for five years whilst protecting the plants from grazing when they are
active, parent tuber diameter must be what determines the choice of plants to be
harvested.
It is also concluded that the presence of shrubs around H. procumbens is a threat because
their long roots negatively correlate with the number and weight of secondary tubers. It
is therefore recommended that shrubs be removed around H.procumbens, leaving grasses
which were found to coexist wit H.procumbens.
Lastly, the study concludes that sulphuric acid and effective micro-organisms enhance
germination in H.procumbens. It is therefore recommended that the two treatments be
considered to H.procumbens stakeholders who have been struggling with germination of
the species.
MOWA, M (2021). Sustainable Management Of Harpagophytum Procumbens And The Effect Of Effective Micro-Organisms And Sulphuric Acid On Its Seed Germination. Afribary. Retrieved from https://track.afribary.com/works/sustainable-management-of-harpagophytum-procumbens-and-the-effect-of-effective-micro-organisms-and-sulphuric-acid-on-its-seed-germination
MOWA, MOWA "Sustainable Management Of Harpagophytum Procumbens And The Effect Of Effective Micro-Organisms And Sulphuric Acid On Its Seed Germination" Afribary. Afribary, 28 Apr. 2021, https://track.afribary.com/works/sustainable-management-of-harpagophytum-procumbens-and-the-effect-of-effective-micro-organisms-and-sulphuric-acid-on-its-seed-germination. Accessed 19 Nov. 2024.
MOWA, MOWA . "Sustainable Management Of Harpagophytum Procumbens And The Effect Of Effective Micro-Organisms And Sulphuric Acid On Its Seed Germination". Afribary, Afribary, 28 Apr. 2021. Web. 19 Nov. 2024. < https://track.afribary.com/works/sustainable-management-of-harpagophytum-procumbens-and-the-effect-of-effective-micro-organisms-and-sulphuric-acid-on-its-seed-germination >.
MOWA, MOWA . "Sustainable Management Of Harpagophytum Procumbens And The Effect Of Effective Micro-Organisms And Sulphuric Acid On Its Seed Germination" Afribary (2021). Accessed November 19, 2024. https://track.afribary.com/works/sustainable-management-of-harpagophytum-procumbens-and-the-effect-of-effective-micro-organisms-and-sulphuric-acid-on-its-seed-germination