super absorbent polymer (abbr. sap), also named potassium polyacrylate, is a high molecular polymer with strong water absorption. after filled with water, sap will release the water slowly to roots when soil is dry, and repeatedly absorb water when rain to keep the plant with plenty of water, sap has the capacity of absorbing 300-500 times of water, and it can save 65%--95% of water. it is mainly used in agriculture plants.