In general, as unprocessed seaweeds have low levels of N, P and K, their role as a nutrient fertiliser is somewhat limited. The spreading of seaweed on land is therefore not the optimum use of such a valuable resource and, in its unprocessed form, is best used in other areas of agriculture.
However, certain scientific studies indicate that extracts of seaweed may have a potential role in enhancing nutrient uptake and use efficiency in crops, thus providing a means of reducing the levels of fertilisers that need to be applied. Seaweed extracts are classified as ‘plant biostimulants’ and are described in EU Regulation 2019/1009 laying down rules on the making available on the market of EU fertilising products as inputs that stimulate a crop’s natural nutrition processes thus improving the crop’s nutrient use efficiency.
There are a number of products already on the market that provide such a function.