Carboxymethyl tragacanth-based slow release system for urea delivery

Nitrogen is an essential nutrient for plant growth, and urea is also a nitrogenous nutrient that is widely used in agriculture due to its high nitrogen content (46%) and relatively low production cost. As urea is a neutral organic compound, it cannot be readily absorbed by the charged soil particles before hydrolysis, and thus a large fraction of urea is not absorbed by plant which causes serious environmental problems.1 Moreover, due to the high solubility of urea in the water, a fraction of urea is also lost in leaching.2 Volatilization is another harmful phenomenon that results in loss of urea.3 One of the ways overcoming on the problems mentioned above is the use of slow or controlled release fertilizers (SRFs) containing the superabsorbent polymers (SAPs).4 In the present work, we have also used a new type of low cost and eco-friendly slow release system based on the CMT with the function of superabsorbent. The CMT-based SAP is used as carrier of urea in the slow release system. To prepare of the SAP, we chemically modified the tragacanth gum by reaction with the monochloroacetic acid and then grafted acrylic acid on the CMT. We have applied the SAPs in order to water retention and slow-release of the urea fertilizer and the resulted data showed the proper effect of using these materials.

Keywords:

Carboxymethyl tragacanth , Biodegradable superabsorbent , Slow release , Urea fertilizer.