A series of novel multifunctional poly (acrylic acid-co-acrylamide) (PAA-AM)/organomontmorillonite (O-MMT)/sodium humate (SH) superabsorbent composites were synthesized by the graft copolymerization reaction of partially neutralized acrylic acid and acrylamide on O-MMT micropowder and SH with N,N'-methylene bisacrylamicle as a crosslinker and ammonium persulfate as an initiator in an aqueous solution. The superabsorbent composites were characterized by means of Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, and thermogravimetric analysis. The effect of the relative weight ratio of SH to O-MMT on the water absorbency was studied, and the results indicated that the best water absorbency of 591 g/g in distilled water was obtained when an O-MMT content of 20 wt % and an SH content of 30 wt % were incorporated. The superabsorbent composite possessed a good capacity for water retention; even after 30 days, 24.4 wt % of water could still be saved by the sand soil containing 1.0 wt % superabsorbent composite. The results from this study show that the water absorbency of a superabsorbent composite is improved by the simultaneous introduction of O-MMT and SH into a PAA-AM network in comparison with the incorporation of only O-MMT or SH. Also, in comparison with PAA-AM/MMT/SH, an appropriate amount of O-MMT can benefit the developed composites with respect to their water absorbency, salt resistance, and capacity for water retention in sand soil. (c) 2007 Wiley Periodicals, Inc.