Comparative Analysis and Characterization of Varying Molar Ratios of Urea Formaldehyde (UF) Modified Rice-Straw as Slow – Release Fertilizer

Abstract

A comparative analysis and characterization of varying molar ratios of urea formaldehyde (1:2, 1:2.5 and 1:3) modified Rice-straw was done. The swell index, cold water insoluble nitrogen (% CWIN) at 250C and hot water insoluble nitrogen (% HWIN) at 980C were determined. Also, the slowly available nitrogen and the activity index (AI) were evaluated. The result from these characterizations shows that rice-straw has a good water retention capacity due to its high swell index of 1535% facilitating the slow release of nutrients. All the various formulations of urea formaldehyde in this work have their % CWIN values above the 60 % minimum, 78 % for UF 1:2, 80 % for UF 1:2.5 and 84 % for UF 1:3 while the activity indices stood at 17.9 %, 41.3% and 25% for UF 1:2, UF1:2.5 and UF 1:3 respectively. UF modified Rice-straw with molar ratio 1:2.5 whose AI is 41.3% which is within the good quality level and has the highest amount of slowly release nitrogen is therefore adduced to be a better slow- release fertilizer than the rest.