The Effects of Control Release Fertilizer Packets on Nutrient Leaching

Nutri-Pak is a slow release fertilizer in a micro-pore polyethylene packet where moisture enters the packet through micro-pores located on both sides of the packet. The pressure caused by heat and vapor, releases the dissolved fertilizer through the same micro-pores and into the soil gradually providing nutrients to plants for a year. The principle objective of this study is to compare the nutrients levels in leachate samples of Nutri-Pak to a control release fertilizer and a conventional granular product. The fertilizers used for this experiment includes Nutri-Pak (12-4-12), Harrell’s (controlled release 12-4-12), and Atlantic (8-4-12). Atlantic fertilizer was used as the control in this experiment. These fertilizers were applied to Chinese Fan (Livistona chinensis) and Queen (Syagrus romanzoffiana) palms based on each manufacturer’s recommendation. In order to measure the impact of fertilizer type on nutrient loss, leachate samples were collected after each scheduled irrigation. The mean values for N, P and K leached from Nutri-Pak or Harrell’s were divided by control values for comparison. From pots containing Chinese Fans, Harrell’s lost 1.85 N, 2.59 P, and 1.88 K times that of the control. Nutri-Pak lost 0.08 N, 0.67 P, and 0.07 K times that of the control values. From Queen Palms, Harrell’s lost 2.52, 2.76, and 1.99 times the N, P and K, respectively. Nutri-Pak lost 0.06, 0.35, and 0.12 times the N, P and K, respectively. Subsequent leachate collections after 60 days indicated similar trends, however Nutri-Pak’s leaching potentials of N, P, and K were reduced. The ICP analysis showed least amount of Ca²⁺, Cu²⁺, Fe²⁺, Mg²⁺, Mn²⁺ and Zn²⁺ from Nutri-Pak compared to Harrell and conventional fertilizers. Experiment is in progress further evaluating these fertilizer types for recommendations.