Controlled biofertilizer release kinetics and moisture retention in gum xanthan-based IPN

A crosslinked interpenetrating network based on gum xanthan was produced in the presence of gamma radiation and its potential as controlled release fertilizer was evaluated. Different process parameters such as gamma radiation dose, solvent amount, crosslinker and monomer concentrations were optimized to determine the maximum fluid uptake capacity of the synthesized sample. The samples were characterized using FTIR, XRD and SEM. The thermal stability was investigated using TGA, DTG and DTA techniques. The biofertilizer extracted from vermicompost was used as model agro-chemical and the presence of essential macro- and micronutrients in the biofertilizer was confirmed by chemical analysis. The in vitro release kinetics was administered by Korsmeyer–Peppas model. Release exponents were found in the range of 0.8–0.9, signifying the non-Fickian mode of diffusion where the relaxation of polymer matrix also played an important role. Further, the impact of biofertilizer control release on Cicer arietinum plant growth was investigated and it was found that there was an increase in stem and root bio-mass. The synthesized candidate polymer was found to act as a mini-water reservoir in different soil types and prolonged soil moisture for more than 50 days. Therefore, the synthesized superabsorbent with controlled release of biofertilizer can protect the environment from adverse effects of carcinogenic synthetic fertilizer leaching, along with its functionality to act as water reservoir in the fields.