The Impact of Different Levels of Azocompost on Growth Medium Chemical Characteristics, Growth and Nutrition of Zinnia elegans

Excessive accumulation of azolla in the wetlands of Guilan is currently an environmental problem. To this aim, a study was conducted to investigate the effect of Azolla compost on the growth medium of Zinnia ornamental plant. The treatment was a sandy loam soil and Azolla compost was replaced with 10, 20, 30, 40 and 50% by volume. The research was performed based on a completely randomized design with three replications and 54 pots. The chemical properties of the substrate including electrical conductivity, acidity, nitrogen content and phosphorus and potassium levels were measured. Growth indices including fresh and dry weight of leaves, stems, roots and flowers, and leaf chlorophyll content were also measured. Nutrient concentrations of nitrogen, phosphorus and potassium in the leaves of zinnia plant were measured. The results showed that the highest growth rate was observed in 20 and 30 % treatments of Azolla compost and the lowest growth rate was observed in control treatments. Azolla compost increased the concentration of nitrogen, phosphorus and potassium in the leaves, which indicated an increase in the quality of plant nutrition. Higher amounts of compost (40 and 50%) reduced plant growth indices compared to 20 and 30% compost treatments, but in the same treatments, plant growth was significantly higher than the control. In general, it can be concluded that Azolla compost can be used as a suitable organic matter in zinnia medium.