Comparative Evaluation of Azolla-Based Biofertilizers and Inorganic NPK Fertilizers on Soil Physico-Chemical Properties, Nutrient Dynamics and Early Plant Growth

The growing reliance on chemical-intensive fertilizers has created severe concerns about soil deterioration, nutritional imbalance, and long-term agricultural viability. Organic remedies, particularly biofertilizers like Azolla, present a promising way to restore soil health while maintaining crop output. The current study compared the effects of Azolla-based biofertilizers, alone and combined with cow dung, to inorganic NPK fertilizers on soil physicochemical parameters, nutrient dynamics, and early plant growth under pot culture conditions. A Randomized Complete Block Design (RCBD) was used, with five treatment options: control (no fertilization), Azolla, cow dung, Azolla plus cow dung, and NPK fertilizer. Soil pH, organic content, moisture content, and NPK levels were measured up to 60 days after planting, as well as seed germination and seedling growth parameters. The results showed that the combined Azolla + cow dung treatment (T3) provided the most balanced improvement in soil quality, maintaining a stable pH, significantly increasing organic carbon (up to 16%), improving phosphorus availability (36 kg/ha), and increasing potassium content while supporting favorable moisture retention. The Azolla-only treatment (T1) had the highest soil moisture levels, resulting in improved root growth and 100% seed germination. Although the NPK treatment (T4) produced the highest soil nitrogen and potassium concentrations, it did not lead to superior plant growth when compared to organic treatments. Organic amendments consistently boosted root and shoot development, indicating higher nutrient uptake efficiency and soil biological activity. Overall, the study shows that Azolla, especially when coupled with cow dung, can successfully increase soil fertility, moisture retention, and plant development, providing a sustainable alternative or supplement to synthetic fertilizers. These findings encourage the use of Azolla-based biofertilization techniques in environmentally responsible and sustainable agricultural systems.