Seaweed, or sea bamboo, is a type of algae that has been growing in our oceans for millions of years. For centuries humans have utilised it for glass making, animal feed, medicine and fertilisers. Modern science has taken these practises further and developed processed products in the pharmaceutical, industrial, nutritional and agricultural industries.
Four kelp species are found around the South African coast, with Ecklonia maxima being the most familiar and only found at the southern tip of South Africa growing in the strong currents along the coastline. Ecklonia maxima is often found washed up on beaches following heavy storms.
The kelp does not extract its nutrients from the soil but directly from the water around the plant. The plant anchors itself by attaching to a rock or even other kelp, via a holdfast. These holdfasts are an important part of the sea-ecology and prevent soil erosion on the seabed. From this root-like structure, single long stipes rise to the surface waters, where a large tangle of blades occur near the water surface to aid with photosynthesis. The stipes are hollow and full of gas to help it float. Thick fronds grow from a bulb near the surface.
Kelp forests provide a source of food and shelter to a variety of oceanic species including fish, crayfish, sea cucumbers, limpets and other filter feeders. The slimy mucus that is found on the kelp is rich in organic compounds that encourage the growth of bacteria, which in turn forms the building blocks of the food chain within the kelp forest ecosystem.
This sea bamboo species is one of the fastest growing plants on earth and can grow up to 15 cm a day and can easily reach heights of 15 metres. The high nutrient content in the ocean and the robust wave action cause the kelp to absorb the required nutrient elements and grow very fast simultaneously. Due to this unique survival mechanism, Ecklonia maxima has a very high concentration of growth regulator, auxin.
Ecklonia maxima, was discovered by Klaus Rotmann, a Namibian who registered the first kelp company in South Africa in 1971 which is now known as Taurus and based in Gansbaai. Today Taurus is the largest concession holder of kelp in the country. Afrikelp is a major shareholder in Taurus and process the harvested liquid kelp for use by farmers across the world.
Fresh kelp fronds (leaves) are harvested at sea in Gansbaai and surrounding areas by boats. Kelp that is freshly harvested is used for two main purposes. Fresh fronds are sold as abalone feed to local abalone farms. A raw concentrate containing auxin is also extracted from the kelp, which Afrikelp uses to manufacture a natural growth stimulant that is used in farming to improve the quality and quantity of agricultural crops.
All plants, on land and sea, naturally contain the growth hormones auxin and cytokinin which are always in flux to help plants grow. By spraying kelp on plants, it keeps the balance between these two hormones in check to help with root growth, flowering and fruit set and helps fruit colour more evenly. The bio stimulant thus positively influences cell and tissue development through the plant’s own hormonal action and gives plants increased access to additional nutrients by stimulating root growth of crops.
Although a chemical or synthetic version of these hormones is available, plants take a while to adapt to it. Trials done by Afrikelp showed that the number of roots on the crops treated with the kelp products were always more than those found on the control group of plants. With more roots, crops can absorb more nutrients and is therefore more resilient against disease and harsh environmental conditions. This means that the use of these products can mitigate stress in plants caused by drought, disease or other environmental factors.
“Using the kelp extract on plants or to treat roots, is not only a good idea because it’s a natural bio stimulant that helps plants to extract nutrients from the soil more efficiently, but it can effectively assist food production. The use on crops will support natural root development and growth while improving the nutrient and water efficiency, leading to a more viable farming environment,” says Kobus Lindeque, Managing Director Afrikelp.
Great care is taken so make sure that the harvesting of kelp does not upset the ecology. Furthermore, harvesting is heavily regulated by government and there are only a few concession holders. “We take great care to sustainably harvest the kelp to ensure the maintenance of healthy kelp forests.”
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