Effects of Liquid Cow Manure Compost Content in Azolla Cultivation on Water Quality, Yield, Chemical Properties and Nutritional Contents

Azolla, a fast-growing aquatic fern, is an inexpensive source of biomass for biofertilizer, livestock feed, phytoremediation and biofuel production applications. The use of compost-based fertilizer to improve the cultivation of azolla can reduce production costs and enhance sustainability. While previous studies investigated the use of organic fertilizers for azolla growth, little work has been done to compare such use with chemical fertilizer use. In this work, the effects of liquid cow manure compost fertilizer, compared to urea fertilizer, on azolla growth, yield, chemical and nutritional compositions and water quality were studied. The results revealed that the optimal application of compost fertilizer enhanced azolla growth and yield greater than that of urea fertilizer. The compost also improved nitrogen, phosphate, potash and protein content in azolla. Azolla treated with the liquid compost fertilizer could effectively remove phosphate from water, but the addition of the compost increased both phosphate and ammonia content and reduced dissolved oxygen. Thus, the liquid cow manure compost fertilizer was suitable for promoting azolla growth for livestock feed and biofuel applications rather than water treatment.