Nutrient release from biodegradable polymer-coated multi-nutrient fertilizer granules in calcareous soils

The use of conventional fertilizers is associated with higher nutrient losses and lesser fertilizer use efficiency; hence, to increase the use efficiency by enhancing the longevity of fertilizer in the soil, coated fertilizers have been developed. The prolonged nutrient release through coated fertilizers may provide continuous plant nutrition, better growth, and improved plant performance. Biodegradable organic acids and amino acids were used as coating materials to control the rate of release of plant available nutrients thereby increasing the nutrient use efficiency. The organic acid and amino acid coated multi-nutrient fertilizer granules (MNFG) were fabricated using citric acid, humic acid , fulvic acid, salicylic acid, and glycine at 3, 5, and 10% of coating concentration by w/v and tested for their nutrient release potentials in calcareous soil. The pH, EC, free CaCO 3 , and nutrient release from coated fertilizer granules were monitored under controlled conditions, and the results revealed that coating of MNFG with 10% citric acid recorded lesser pH (7.78) and free CaCO 3 (7.85%) after the expiry of 45 days of incubation period. The reduction was marked on calcareousness (34.6%) than pH (6.71%). Higher availability of sulfur and micronutrients in calcareous soils was noted with citric acid-coated MNFG granules at 10% where the rate of release was controlled for 45 days. The results demonstrated that the profile of nutrient release from calcareous soil could be controlled by the thickness of coating, and fertilizer nutrient release which fit the crop nutrient requirement in calcareous soils was observed with 10% citric acid coating of MNFG granules.