When the world's population increases, so does the demand for food and fibre per unit area. As a result, the demand for chemical fertilisers rises in order to generate higher yields from a smaller area. Excessive use of chemical fertilisers is harmful to one's health and pollutes the atmosphere. As a result, many plant extracts have been used in agriculture in recent years. The use of natural seaweeds as fertiliser has enabled traditional synthetic fertilisers to be gradually phased out (Hong et al., 2007).