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Report 5 of 5:
Kelp!
- Ireland
Introduction
Seaweed though often considered more of a nuisance than anything else when decaying on our beaches is in fact one of the world’s most remarkable plants. For centuries, farmers along the Irish coast have used different kinds of seaweed, or kelp, to improve their soil and their health. Maritime plants are ten or more times richer in minerals than any known crop growing on land. This plant from the sea now has a wide reputation as a garden fertiliser for use in horticulture, farming and as a health supplement.
Like plants on land, seaweeds come in all shapes and sizes. The brown seaweeds (kelps) are usually found in cold water regions. They contain many chemicals and trace elements which is why they have always been prized by farmers for soil conditioning and supplementary animal feed mixes. Seaweed is perfectly safe for animals, humans and the soil and it remains a staple part of the Japanese diet. It does not harm birds, fish, worms, bees and all the multitude of insects and creatures which aid organic culture.
For a long time, seaweed was burnt in order to obtain the mineral content. From the residue ash, bromine, iodine and potash could be extracted. Ash deposits up to two feet high could be recovered in trenches after dried seaweed had been burnt in special kilns. The ash from kelp is very rich in soda which, until other methods were found, was used in the manufacture of glass. The same procedure was also used to recover iodine until cheaper ways of obtaining this material were discovered.
The algin molecule
Brown seaweed contains algin which is a molecule that stops water from separating and is used for thickening, stabilising and as a gelling agent in a whole range of household products. For example, alginate is used as a stabiliser in ice-cream and salad dressings, and, in fruit pie fillings, the algin stops the fruit pulp leaking into the pastry. It is also used as a foam stabiliser in beer, as well as in bakery products and pet food.
Textile printing is still the largest application of algin in the world. By thickening the dye solution, algin stops the dye running to other parts of the cloth where no colour is required, allowing very fine definition to be achieved.
There is a growing awareness of the benefits associated with the use of seaweed in soil conditioning, with golf courses and sports grounds the major uses in this sector. The alginate present in seaweed acts as a moisture retainer, particularly in loose sandy soils. This coupled with the slow release of trace elements make seaweed an attractive alternative to artificial fertilisers.
Medical uses of seaweed
The uses of algin are not confined to foods. The effectiveness of many prescription medicines is improved by controlling the rate at which they are released into the blood stream. The properties of algin as a controlled release agent are now widely recognised in the pharmaceutical industry.
Every mineral contained in the sea also appears in normal healthy human blood. Those lacking a vital bloodstream can derive benefits from seafood, especially seaweed which alone can replace any deficiencies. The sea is the richest source of iodine.
The sugar content of seaweed is not sweet enough to cause an increase in blood sugar. This makes sea vegetables an ideal food for diabetics. Kelp is an excellent source of vitamins including vitamin A, B12, C, thiamine, riboflavin, niacin, pantothenic acid and vitamin D. As such seaweed or kelp are now familiar food supplements.
Seaweed contains all the essentials for protection against the effects of stress and as an extract, for the relief of pain and in the treatment of disease. The fluid extract of seaweed can be applied to unbroken skin in the treatment of sprains and bruises. Dried seaweed powder can be mixed with vaseline or wheat germ oil for the treatment of swollen and stiff joints. In the form of a continuous fibre, algin is used as a dressing to aid wounds that are having trouble healing. Dentists also use algin to make teeth impressions.
Agricultural and garden uses
Cultivators seeking an organic fertiliser will find seaweed products to be among the finest. Seaweed fertilisers greatly aid the grower in producing bumper crops more able to resist disease. Benefits of using seaweed in horticulture and gardening include:
- Increased seed germination
- Greater resistance against frost
- Assists plants to get more nutrients from the soil
- Builds up resistance to disease
- Builds up resistance to insect pests
- Prolongs the shelf life of such crops
- Better root development
- Soil conditioning
- Fertiliser use
In fact seaweed provides maximum organic growth and protection for a minimum amount of work. It is a fine tonic and an effective plant feed, especially if it is sprayed on the underside of leaves. Any excess simply runs into the soil and acts as a feed. The spraying of crops should be carried out in the early morning or late evening because at these times, plants are able to absorb more nutrients.
Seaweed in livestock feed
Farmers who add seaweed to livestock feed report:
- Improvement in fertility rates
- Less repeat servicing
- Better heat detection
- Easier calving
- Less early calving
- Less retained after birth
- Strong lively calves
- Reduced stiffness, lameness and sore feet
- Less mastitis
- Improvement in general appearance
The raw material
For people who live near the coast, seaweed is an important natural resource that is readily available and provides food for humans, livestock and the land. It has an abundance of trace elements, minerals and growth promoting agents and decayed seaweed helps retain moisture, making seaweed attractive for use on light or sandy soils. There are estimated to be about 40 different types of seaweed out of which 8 are suitable for edible purposes.
The seaweed grows in sheltered bays and inlets along the Irish coast where the risk of pollution is very low due to the absence of heavy industry, intensive farming and busy shipping lanes. The Atlantic swell flushes out these bays and replenishes the stock of nutrients that act as feed for the seaweed plants.
Harvesting and processing
The harvesting of seaweed is dependent on the weather and tide. It is harvested by hand using hooks or sickles to cut the plant at a point between 15 and 25 centimetres above the roots. This practice ensures the regeneration of the next seaweed crop within a three, four or five year period depending on location. The seaweed is then piled onto nets and bound, before being towed behind the boat in the flowing tide to the nearest landing place awaiting collection and delivery to the factory.
The process at the factory begins with the harvested seaweed being thoroughly washed in sea-water to remove sand, silt, shells and small stones. Rotary drum dryers are used to dry the seaweed, where operating conditions are carefully monitored to ensure only seaweed meal of the highest quality is produced. Seaweed meal can be produced in varying particle sizes depending on the customer’s particular requirements.
For further information, please contact:
Intermediate Technology Development Group would like to thank Arramara Teoranta in Co.Donegal, Eire, in particular Mr. Seamus McGarvey, and G.J.Binding & Alan Moyle of Thorsons Publishers Ltd. in Wellingborough, Northamptonshire, for providing the original material on seaweed.
This document is an output from a project funded by the UK Department for International Development (DFID) for the benefit of developing countries. The views expressed are not necessarily those of the DFID.
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