Seaweed Extract Fertilizer: An Organic Nutrient Source
Authors: Debarati Datta1* and Sourav Ghosh2
1 PhD Research Scholar, Govind Ballabh Pant University of Agriculture and Technology, Pantnagar, Uttarakhand, India
2 PhD Research Scholar, Indian Agricultural Research Institute, Pusa, New Delhi, India

Global population is increasing at an alarming rate and thus the need of agrobased product increases. The fertilizer industry is bound to grow as it is a major component for increasing food grain production. Since, the disadvantages of fertilizers are becoming more apparent, the farmers are turning slowly but surely towards organic agriculture. With increasing demand, availability of organic fertilizers from one or two sources is not adequate. Thus, use of seaweed extract as fertilizers is one of the viable options for increasing the quality and quantity of agricultural produce.

Application of seaweed extract as a biostimulant is fast becoming an accepted practice in agriculture. Seaweeds are large plants growing in the sea, especially various marine algae like the rockweeds, kelps, sea lettuce and dulses. Seaweed extract is 100% natural, water-soluble, liquid organic biofertilizer containing micro and macro nutrients, vitamins and fatty acids formulated from soluble brown Seaweed extract derived from vegetable kelp Seaweed. It contains sufficient amount of oceanic bio-active matter such as Phycocolloid, Mannitol, Oligose, Polyphenol, Trehalase, Cytokinin, Betaine, Lignin etc which are essential for improving germination, root development, leaf quality, general plant vigour and resistance to pathogens. Seaweed extracts are allowed as fertilizer for organic farming production practices whereas synthetic chemical fertilizers are prohibited for Organic Food Production. Seaweed extracts can be manufactured in liquid and powder form and used as fertilizers for all type of crops, grasses and trees. While 'dried meal' or concentrated form are limited to soil applications due to their insolubility, foliar feeding or root zone applications through drip lines are possible with soluble extract. Seaweed extracts are now commercially available as maxicrop, seasol, SM3, kelpak , and cytokin.

Benefits of seaweed in agriculture:

  • If seeds are treated with seaweed fertilizers before they are sowed, the seeds will germinate better, have an increased growth rate and their roots will possess strength.The seaweed will encourage vigour in the plant growth cycle as it consists more than 70 nutritional deporting minerals and enzymes
  • In terms of soil structure , seaweed does not add a great deal of bulk, but its jelly like alginate content helps to bind soil crumbs together, and it contains all soil nutrients (0.3% N , 0.1% P , 1.0% K , plus a full range of trace elements ) and amino acids .
  • Being rich in bio-activators (the ingredients for healthy decomposition) seaweed is great for compost piles as it assists in speeding up the decay of other organic matter.
  • Seaweed extract also benefits in flower set and fruit production. High quality of fruit have been recorded for many of both herbaceous and woody crop species.
  • Seaweed contains large traces of potassium and natural hormones making it a hearty fertilizer that strengthens roots and increase disease resistance.
  • Its smell repels many unwanted pests and insects. A ‘fighter’ plant could be acquired if the seaweed organic fertilizers are doctored on the plant. The plant will display a higher immunity against diseases and pests such as green-fly, white fly and will have an ameliorated growth pattern.
  • Soil fungi and bacteria are known to produce natural antibiotics which hold down the population of plant pathogens, and when these antibiotics are produced in sufficient quantities they enter the plant and help it to resist disease. The production of such antibiotics is increased in soil high in organic matter, and it may be that seaweed still further encourages this process
  • As mulch seaweed stops weeds dead in their tracks and keeps soil moist. Thus, it also protects from heat stress.
  • Improves the uptake of nutrients (CEC) thus, reducing runoff loss from fertilizer and pollution.
  • It helps to preserve the freshness of flowers for days together if seaweed fertilizer is sprayed on them a day before cutting them and detaching them from the plant.
  • Liquid seaweed fertilizers contain elements called hormones. They are Auxins , Cytokinins , Gibberellins and Betaines. The auxins are a major hormonal component that increases the growth rate of the plant. It also aids the flower buds to unfold at the right time. The aging process in plants also known as the senescence, in plant taxonomy takes a backseat with the cytokinin content in the fertilizers.
  • Liquid seaweed fertilizers has alginates that has a conditioning property when applied to plants. The soil has metal content with which the alginates react and form polymers that restore moisture in the soil when it gets wet.
  • Overall, it increases yields, promotes healthier crops and fetches higher benefit cost ratio in a sustainable manner.

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