Enhancement of rice productivity and soil fertility through system integration of organic and mineral fertilizers in Vertisols

Field experiments were conducted in a Vertisol for two years to study the response of lowland rice to N from organic and mineral fertilizer tested at N equivalence. The treatments consisted of different organic materials as N fertilizer, viz composted coir pith green manure, sugarcane trash compost, vermicompost, poultry manure and farmyard manure (FYM) applied at 100% N and combination of 50% N from above organic materials and 50% N from urea besides 100% N through urea and control. The recommended dose of fertilizer (RDF) was 120:60:60 N, P2O5 and K2O kg ha−1. The results revealed that addition of organics or urea or both enhanced the growth, rice yield and nutrient status over control. The highest grain yield (4.95, 5.33 t ha−1) and straw yield (7.31, 7.73 t ha− 1) for the two years were noticed with vermicompost plus urea (50% N each) which was on par with poultry manure plus urea (50% N each). Combined use of organic fertilizer along with mineral N recorded higher concentrations of NH4-N and NO3-N in soil and increased total N uptake. Nutrient use efficiency was compared to individual application. It was more in vermicompost- amended soil followed by green manure and poultry manure.