A comparison of water-soluble fertilizer with liquid fertilizer for sport-fish pond fertilization

摘要

A finely pulverized , water-soluble fertilizer containing 10% N, 52 % P_2O_5, and 4% K_2O was compared with a standard liquid fertilizer (10% N, 34% P_2O_5, 0% K_2O) in ponds containing sunfish Lepomis spp. at the Auburn University Fisheries Research Unit, Auburn, Alabama. Our study suggests that sunfish production with water-soluble fertilizer can equal standard liquid fertilizer results at about 50% of phosphorus application rates of standard fertilization. Applications of 1-2 kg of P_2O_5/ha in water-soluble fertilizer at 2-week to 4-week intervals are sufficient to provide good sunfish production in waters with 20-40 mg/L total alkalinity, but rates of 4 kg P_2O_5/ha or more may be necessary in waters of higher total alkalinity. Low phosphorus applications to sport-fish ponds could be used with caution because phytoplankton blooms may not create enough turbidity to prevent excessive growth of undesirable aquatic macrophytes. On a nutrient basis, water-soluble fertilizers are about twice as expensive as liquid fertilizers. However, the water-soluble fertilizers can be used at a lower rate than liquid fertilizers, and they are more convenient to apply.