Seaweed fertilizers is an efficient,green and new type of fertilizer.The main raw materials,which consist of plentiful nutriments and some speical bio-chemical components,are economic algae in the sea.In addition to the nutriments of land plants,the fertilizer also has some beneficial elements and microelements such as iodine,K,Mg,Mn and Ti.The all exist in algae as organic matters so they are not easily to be oxidized.That means that they can be absorbed and used more efficient than inorganic elements by plants.The fertilizer has plenty of active materials,such as seaweed amylose,poly-hydroxybenzene,phytohormone.These active materials take part in the transport of organic and inorganic matters in plants,enhance the absorption of nutriments by plants,improve the photosynthesis of plants,enhance the growth of root system,meliorate cell division and elongation,at the sames time.The crude amylose can enhance gas permeability of soil and conserve soil water.In this way,the fertilizer can avoid forming stiff sil,modulate soil air and conserve soil moisture.