Encapsulation of Urea Into Bio-Based Adhesive to Improve Its Degradation Rate in Soil and Studying Its Release Mechanism

Abstract

Urea is the most widely used fertilizer, supplying 46% nitrogen, the most essential nutrient for plant growth. However, its nitrogen delivery system is exposed to high losses associated with high ammonia volatilization, leaching, and surface runoff. This research formulated a new type of slow-release urea fertilizer by encapsulating urea powder in a biodegradable adhesive. The formulation was evaluated for its degradation rate in soil, nitrogen release profile, and associated release kinetics. After an hour of incubation in distilled water, LRU-e-LAO-g-GA exhibited a nitrogen release rate of only 2.9%, which is very small compared to 98% for commercial urea. The LRU-e-LAO-g-GA releases 76.14% N within 25 h of incubation in water, which was relatively less than a slow-release coated fertilizer. The degradation rate test in the soil results indicates that all U-e-LAO-g-GAs were entirely degraded in the soil. The amount of urea encapsulated in the LAO-g-GA positively affects its N release and degradation rate in soil. As its urea loading concentration increases from 70% to 80%, its degradation rate rises from 83.8% to 91.8%. The study results suggest that the newly developed slow-release urea fertilizer has a promising future for the sustainable growth of modern agriculture.