Studies on Organic Polymer Coated DAP Fertilizer on Phosphorus and Nitrate Releasing Pattern in Calcareous Soils

An incubation experiment was carried out with DAP coated with chitosan and sodium alginate organic polymers. Treatments comprises of T1: Chitosan coated 75% DAP, T2: Chitosan coated 100% DAP, T3: Sodium alginate coated 75% DAP, T4: Sodium alginate coated 100% DAP, T5: 100% RDF (SSP), and T6: 100% RDF( DAP) which were replicated four times in completely randomized block design. Results revealed that 100% chitosan coated DAP (T2) was found to be superior than all the remaining treatments which was followed by 100% sodium alginate coated DAP (T4). Uncoated DAP and SSP high leachate P in the early stage of incubation study and there after P content was minimal in leachate. It was concluded that coated DAP had less release of P at the start of study and thereafter steady state because of the dissolution of P through the coated membrane. Similar trend was observed in nitrate releasing pattern.