Nowadays, more attention is being paid to alternative crops and hemp is certainly one that has been gaining its share of the attention. The agronomic characteristics of hemp and the diverse renewable resources it produces, have triggered renewed interest in the crop. This presents new opportunities for producers and researchers alike.

While the country’s producers are not yet allowed to grow and industrialise hemp, it is legal to cultivate 2ha of hemp for research purposes. This is subject to having obtained a research permit from the South African Health Products Regulatory Authority, which is said to be a slow process.

The new cultivars, SA Hemp 1 and SA Hemp 2, have been developed by the Agricultural Research Council and show great promise in terms of uniform maturity, biomass, stem and fibre yields.

Kwena Mokgohloa, a researcher at the Agricultural Research Council (ARC) says that fast-tracking the development of certain critical components of the value chain, has become imperative for the country if it is to benefit from industrial hemp cultivation. “Of these components, adapted cultivars and reliable seed systems are probably the most relevant at this stage,” he adds.

South African researchers began conducting trials in 1996 and the first research permit for cannabis was awarded to the ARC. The council has since identified varieties, mostly from Europe, that will grow well in the country’s climate. Various stakeholders from the private and public sectors have invested in the ARC’s hemp research and development programme over the years.

The many applications of hemp

Seeds derived from hemp trials at the Agricultural
Research Council.

Hemp has the potential to become a household name. It has even trended in the fashion industry, where it refers to the durable soft fibre from the cannabis plant stem, which is considered stronger and longer lasting than cotton.

Many commercial products can be produced from hemp, including paper, insulation material and bio-composites, construction material and textiles. Several innovative hemp fashion brands have entered the clothing industry, while the crop’s high nutritive value makes it excellent for human consumption in the form of hemp milk, seed and oil, as well as animal feed.

Mokgohloa sheds some more light on how hemp is obtained. “One normally obtains hemp fibres by stem retting to separate the fibres from non-fibre components, known as hurd. Hemp hurd is the woody and lignified inner tissues, or core, consisting of 70% stalk, which is considered a by-product of fibre production.”

He adds that hemp is a relatively high-yielding crop with great agroecological plasticity, low or no pesticide requirement, and modest fertiliser demand. Its versatility allows it to be grown under a wide range of agroecological conditions.

Cultivation methodology

“When it comes to environmental conditions, the choice of cultivar becomes an essential aspect. This relates both to increasing fibre production and enhancing co-products such as the core, from a perspective of the full use of biomass in a cascade approach,” says Mokgohloa.

“In this crop, even more than in other fibre species, the germplasm plays a crucial role in successful cultivation. This relates not only to environmental adaptability and production potential, but also to final quality and end use. Fibre chemical composition in particular, as well as the ratio between core and bark, depend directly on genotype and maturation time.”

Furthermore, fibre hemp includes dioecious (plants species that include ginkgos, willows, cannabis and African teak) and monoecious varieties belonging to different geographical areas with different biological and morphological characteristics. The monoecious varieties exhibit both male and female reproductive organs on the same plant. With intervention and plant breeding, these hemp varieties will revert to their natural dioecious state.

Availability of propagation material

The availability of improved propagation material (or seed systems) and advanced cultivation methods, are among the key success factors of commercial hemp cultivation. The ARC and other stakeholders will therefore continue to pilot research and development for the establishment of hemp seed systems, to ensure a sustainable supply of quality propagation material.

According to Kwena, the ARC will optimise protocols for South African conditions and strains to develop certified seed supply systems for the industry. He believes mass propagation techniques using cuttings and tissue culture, including feminisation to produce only female seed, and auto-flowering for open field production techniques, will be optimised to develop a mass-production system to provide good-quality planting material, with known cannabinoids.

Phenological sensitivity in cultivars

Due to hemp’s sensitivity to temperature and photoperiod, cultivars that originate from a latitude further north, tend to flower earlier when grown in lower latitudes. However, early flowering results in the reduction of fibre yield and quality.

Kwena remarks that, based on the results of the study conducted by the ARC, the cultivars Novasadska, Kompolti and Futura 77 were found to be well adapted in South Africa for commercial hemp fibre production.

“The recommendation of these varieties is based on their uniform maturity as well as biomass, stem and fibre yields,” he says. “It is also worth noting that a much wider range of cultivars is currently available around the world. However, many of these cultivars have not yet been tested under South African conditions.”

South African growers should first determine the performance of imported cultivars on a small scale, before establishing large commercial plantings.

Developing new hemp cultivars

“The ARC has developed two new cultivars called SA Hemp 1 and SA Hemp 2. Although these two cultivars are not yet registered, they were tested and compared with the three cultivars recommended for the South African climate. They outperformed them or performed at least on par in terms of uniform maturity, biomass, stem and fibre yields,” says Kwena.

SA Hemp 1 and SA Hemp 2 are in the process of being registered as cultivars. Predictions are that these two cultivars could play a key role in commercial hemp production in South Africa, once the registration process is complete. – Carin Venter, Plaas Media

For more information, phone Kwena Mokgohloa on 072 831 0520
or email mokgohloak@arc.agric.za.