A composite superabsorbent resin(HA-PAA) for agricultural application was prepared by the surface cross-linking reaction of sulfonated humic acid and poly acrylic acid.N

N′-methylenebisacryamide dissolved in methanol solution was used as surface cross-linking agent.The effect of the ratio of sulfonated humic to poly acrylic acid

the concentration of cross-linking agent

and volume ratio of methanol to deionized water on water absorbency was investigated.In contrast with poly acrylic acid

the surface structure of HA-PAA was analyzed by microscopic investigation

and water-absorbing mechanism was explored.The experimental results showed that HA-PAA with 10%(mass) humic acid possessed better water absorbency and electrolyte resistance.Compared with the sample of poly acrylic acid

the water retention of HA-PAA in sand was also studied.The water retention of the sand was enhanced greatly when mixed with 0.2% HA-PAA.HA-PAA can be used as water-managing and growth-improving materials for agriculture and horticulture purposes in desert-prone areas.