INFLUENCE OF DIFFERENT SOURCES OF ORGANIC MANURE ON THE GROWTH PERFORMANCE AND BIOMASS PRODUCTION OF AZOLLA SP.

Azolla, a diverse and fast-growing genus of aquatic ferns, is widely recognized for its unique symbiotic relationship with the nitrogen-fixing cyanobacterium. This symbiosis enables Azolla to fix atmospheric nitrogen, making it a valuable natural source of nitrogen for agricultural ecosystems. This study evaluated the growth performance and biomass production of Azolla sp. as influenced by different sources of organic manure under controlled conditions in Niger State, Nigeria. A Completely Randomized Design (CRD) was employed with five treatments: control (no manure), cow dung, goat manure, rabbit manure, and poultry manure. Physicochemical parameters and nutrient composition of pond water, including temperature, pH, dissolved oxygen, nitrogen, phosphorus, and potassium, were monitored alongside biomass yield and relative growth rate over a 21-day period. Results indicated that organic manure significantly influenced nutrient enrichment and Azolla productivity. Poultry manure recorded the highest nutrient concentrations (N, P, K), while the control had the lowest. However, the highest biomass yield (1468 g) and growth rate (0.0949 g·g⁻¹·day⁻¹) were observed in ponds treated with goat manure, followed closely by rabbit manure (1440 g; 0.0940 g·g⁻¹·day⁻¹). Cow dung produced moderate growth, while the control recorded minimal biomass (390 g). Notably, no growth was observed in the poultry manure treatment, likely due to toxicity associated with excessive nutrient loading and ammonia accumulation. The findings demonstrate that while nutrient-rich manures enhance water fertility, optimal Azolla growth depends on balanced nutrient release and favorable water conditions. Goat and rabbit manure were identified as the most suitable organic manure sources for maximizing Azolla biomass production. This study highlights the importance of selecting appropriate organic inputs for sustainable Azolla cultivation and biofertilizer production.