Hypothesis: New methods of fertilizer application in agriculture can increase the efficiency of irrigation and improve the exploitation of water and soil resources. Using controlled release systems based on superabsorbent polymers (hydrogels) is one of the appropriate solutions to reduce the wastage of water and nutrients. Hydrogels are able to absorb water from irrigation and rainfall, prevent its deep subsidence and increase the efficiency of water consumption
Methods: In this study, the biodegradable compounds of carboxymethyl cellulose
ß-yclodextrin and crosslinker adipic acid were used to make hydrogel. The synthesized hydrogel was investigated in terms of swelling capacity in distilled water, NaCl and CaCl2 salt solutions and pH changes
Findings: The water absorption process reached the maximum value (78 g/g) within 60 min and then remained almost constant. The highest amount of water absorption was obtained in a solution with pH 7 (1350 g/g). By increasing the concentration of sodium chloride salt solutions from 0.1 M to 0.3 M, the amount of swelling decreased from 48 g/g to 30 g/g and in calcium chloride salt from 21 g/g to 4 g/g, respectivelyThe information obtained from FTIR spectroscopy showed that the produced hydrogel has high porosity and a suitable equilibrium swelling ratio. The morphology of the synthesized hydrogel with TEM and SEM images showed that the synthesized hydrogel has a network structure and a completely porous surface, which increases the absorption of water and nutrients. The thermal stability evaluation (TGA) also showed that the synthesized hydrogel was resistant up to a temperature of 80°C, and with the increase in temperature to 650°C, the weight of the tested sample changed by 62.34%, and from 650°C onwards, the weight of the sample remained constant. This increase in degradation temperature and constant weight of the hydrogel sample indicates an increase in the strength of the bonds in the synthesized hydrogel