Characterization of a chitosan‐based sustained release nanofertilizer formulation used as a soil conditioner while simultaneously improving biomass production of Zea mays L

Slow release nanofertilizers are of interest for reducing soil nutrient losses and preventing land degradation associated with established fertilizer use due to use of fertilizers. Chitosan nanoparticles (CN) were prepared following polymerization of chitosan with methacrylic acid and later incorporated with potassium (CNK). CN as well as CNK were characterized using Fourier‐transform infrared spectroscopy (FTIR), transmission electron microscopy, field‐emission scanning electron microscope, and atomic force microscopy (AFM) techniques. The slow potassium release property of CNK was elucidated employing membrane diffusion studies. Zea mays plant were tested in pot trials using different doses of K‐formulation with potassium incorporated or otherwise and compared with suitable controls. Soils amended with reduced potassium rates (75% CNK) significantly increased the fresh‐ and dry‐biomass accumulation by 51 and 47%, respectively, in relation to positive control (100% KCl). The use of 75% CNK improved physical properties of soil by way of enhanced porosity, higher water conductivity, and enhanced friability that favoured root growth. These along with reduced dry density induced the plants to uptake higher quantities of nutrients and develop double the root biomass relative to control. Further, no deleterious effect of the nanoformulation was apparent and the treatments showed better carbon‐cycling activity. Increased fluorescein diacetate (FDA) hydrolysis in these treatments demonstrated higher soil microbial activity in relation to control. CNK was hypothesized to condition the soil by cohesive bonding of soil particles, stabilizing the soil aggregates by coating them, and preventing their degradation amidst disruptive forces such as repeated watering. Sustained nutrient release synchronize with crop demands, reduced fertilizer requirement and increased productivity.