Effect of water quality and organic fertilizer type on Azolla pinnata biomass production

Abstract

Azolla pinnata is an aquatic fern with high potential as feed; however, its productivity is heavily influenced by water quality and nutrient availability under local environmental conditions. A field experiment was conducted at the College of Agriculture, University of Basra, specifically in the Aquaculture Unit (67°44'00" E, 31°32'47" N), to investigate the effect of water type (W) and organic fertilizer type (N) on the production of Azolla pinnata plants grown in water tanks. The experiment consisted of two factors: first, two types of water: (W1) reverse osmosis (RO) water, and (W2) tap water sourced from the Al-Bid'ah River. The second factor was two types of organic fertilizer: (N1) poultry manure, and (N2) livestock manure. The experiment was conducted with three replicates using a completely randomized design. Means were analyzed using the LSD test at a comparison level of P ≤ 0.05 to determine the differences between treatments, specifically the total fresh weight and total dry weight. The results indicate that treatment (reverse osmosis water) was superior to treatment (water from the Al-Bida’a river) in all studied parameters (fresh weight and dry weight). Treatment W1 recorded the highest fresh weight production with an increase of 10.49%, along with a 10.32% increase in dry weight. No significant differences were recorded between the water type W and the organic fertilizer type N in terms of fresh weight production. The results indicate that treatment (poultry manure) was superior to treatment (cow manure) in the fresh weight parameter, recording the highest fresh weight production with an increase of 2.74%. Despite the significant impact of the interaction between water type and organic fertilizer type on dry weight, the interaction between reverse osmosis water and poultry waste is better than the interaction of Al-Bida’a River water with poultry manure by 20.79%, and the treatment of Al-Bida’a water with aquatic waste by 20.79%. Reverse osmosis water mixed with poultry manure has proven very beneficial in enhancing Azolla pinnata fresh weight production under the studied conditions.