High performance of chitosan-co-polyacrylamide-TiO2crosslinked glutaraldehyde hydrogel as soil conditioner for soybean plant (Glycine max)

Abstract

Research on hydrogels as soil conditioners has been developed based on hydrogels copolymerized with composite materials in the form of chitosan and TiO2 to overcome low physical properties and low swelling of polyacrylamide. The aims of the study are synthesis, characterization, application of hydrogels, and determination of the physical and chemical properties of soil and the growth of soybean plants. Synthesis of chitosan-co-polyacrylamide-TiO2 crosslinked glutaraldehyde hydrogel was prepared by the chemical crosslinking method. The characterization of hydrogel was performed by using Fourier Transform Infra-Red (FTIR) and Scanning Electron Microscope (SEM). FTIR spectrum shows the functional groups of chitosan co-polyacrylamide-TiO2 crosslinked glutaraldehyde which includes OH functional groups (3408.22 cm-1), NH (1602.85 cm-1), C=O (1502 cm-1), CN (1600.92 cm-1), and Ti-O (619.15 cm-1). The SEM image shows the formation of pores and cavities in the hydrogel. The application of hydrogels in soybean plants shows differences in physical and chemical properties of soil and plant growth. The use of all variations of hydrogel had no significant effect on soil physical properties including temperature, humidity, and bulk density. Meanwhile, hydrogels with TiO2 concentration of 60 ppm influence significantly to the chemical properties of soil such as organic carbon, cation exchange capacity (CEC), and level of nitrogen, phosphorus, and potassium in the soil. The optimum number of leaves, plant height, total dry weight are 68 leave blades, 207 cm, and 20.6 g, respectively. This optimum condition was found in the use of KTiKPAG60 hydrogel. The results showed that chitosan-co-polyacrylamide-TiO2 crosslinked glutaraldehyde has the potential to be a soil conditioner.