Crosslinked CMC-Urea Hydrogel Made From Natural Carboxymethyl Cellulose (CMC) as Slow-Release Fertilizer Coating

Nitrogen (N) is a macronutrient that plays an important role in plant growth. The use of urea as fertilizers is very important for increasing yields and the high demand for crops. The Development of urea fertilizer is very important because around 40-70% of the nitrogen applied to plants in the form of conventional fertilizers is lost to the environment, causing environmental burdens such as eutrophication. The purpose of this study was to utilize natural materials to be used as crosslinked carboxymethyl cellulose (CMC)-urea hydrogels which can be used as slow-release fertilizer coatings and to compare which natural ingredient is better to be used as coatings. Natural material in the form of coconut (Cocos nucifera) coir and palm sugar (Arenga pinnata) gomuti powder's cellulose is taken to be synthesized into sodium carboxymethyl cellulose (Na-CMC) which is then synthesized into CMC-urea crosslinked hydrogel, then the hydrogels are tested for urea release in water. The result of this research shows that the character of coconut husk hydrogel's urea release shows a better release trend with 0.1378% urea released on the first day, release less than 0.2100% in the following days, with drastic release starting at 15th day. In palm sugar samples, 2.6899% urea was immediately released on the first day, with the relatively high release in the following days.