Effects of bentonite/sodium alginate/nanocellulose composites on soil properties and their biodegradability over time

This study investigates the effects of bentonite/sodium alginate/nanocellulose (BAN) composites on soil properties. The composites, formulated with different bentonite/sodium alginate/nanocellulose ratios (50:30:20, 70:20:10 and 80:15:5) at three concentrations (1%, 2% and 3%), were applied to soil samples. Field emission scanning electron microscopy (FESEM) images showed that the composites improved soil structure, with the B50/A30/N20 ratio exhibiting improved dispersion and stability. The results showed that the application of BAN composites significantly increased the water holding capacity (WHC), with the 3% concentration showing a ∽25% increase compared to the control treatment. Soil respiration rates were highest at the 3% concentration, with a 50-100% increase in CO2 emission compared to the control treatment. Biodegradability tests showed that the B50/A30/N20 composite had the highest degradation rate (52%), while the B80/A15/N5 composite showed the lowest rate (17.13%). The total organic carbon (TOC) content was increased by up to 40-100% in the soils treated with 2% and 3% BAN, with the B50/A30/N20 treatment showing the greatest increase. The pH values were slightly acidified, with a decrease in pH and an increase in EC. In addition, treatment with the composite resulted in a significant improvement in soil aggregation, with the mean weight diameter (MWD) and geometric mean diameter (GMD) significantly increased by treatment with B50/A30/N20 (3%). The microbial populations (bacteria and fungi) were significantly higher in the treated soils compared to the untreated soils. These results indicate that BAN composites can significantly improve the physical and biological properties of the soil and thus offer potential for sustainable agricultural practices.