Production of Slow Release Urea Fertilizer by Three Methods of Rotary Drum Coating, Insitu and Two-Stage Hydrogel Synthesis and Evaluation Their Performance in Tomato Greenhouse Cultivation

Today, in order to increase the efficiency of fertilizer use and reduce environmental pollution, the production and consumption of slow-release fertilizers is considered. The objective of the current study was to apply three methods of rotary drum (A), insitu hydrogel synthesis (B) and two-stage (C) to reduce the solubility rate of urea fertilizer using starch as a cheap and environmentally friendly source and evaluation the comparative efficiency of these samples on the growth and nutritional responses of tomatoes. At first, fertilizers were synthesized in three methods. Then, the effects of synthesized samples (A,B and C) were compared with un-coated urea granules on morphological characteristics of tomatoes. A factorial based on completely randomized blocks design were utilized with three replications in 2020 in greenhouse conditions, at 180 and 420 kg/ha of each fertilizer treatment. The results showed that urea release rate after 6 hours from synthesized (A, B and C) fertilizers was reduced 87.33, 32.08 and 29.22%, respectively compared to un-coated urea. Comparison of coating methods showed that the highest amount of dry weight (roots and shoots), stem length, chlorophyll content and number of leaves and lateral branches were observed in C fertilizer treatment. Nitrogen use efficiency and apparent nitrogen recovery in C fertilizer treatment increased 36.54 and 27.04% compared to urea, respectively. The use of starch as a natural biopolymer in the structure of these fertilizers reduces nitrogen loss and environmental pollution.