Integrated nutrient-management practices effect on productivity of rice (Oryza sativa) and soil properties under rainfed lowland rice situation – A long-term study

An experiment was conducted on a fixed site at Agricultural Research Station (Paddy), Sirsi, University of Agricultural Sciences, Dharwad, Karnataka, India, during the rainy (kharif) season of 2000 to 2017 (18 years), to study the long-term effect of integrated nutrient-management (INM) practices on productivity of rice (Oryza sativa L.) and its soil health. The experiment was laid out in a split-plot design with 7 main plot treatments, viz. no manure, farmyard manure (FYM) @ 10 t/ha, vermicompost @ 5 t/ha, eupatorium @ 10 t/ha, gliricidia [Gliricidia sepium (Jacq.) Steud.] or quick stich @ 10 t/ha, sunhemp (Crotalaria juncea L.) grown in-situ @ 8.96 t/ha and paddy straw @ 5 t/ ha) and 3 subplot treatments [no fertilizer, 50% recommended dose of fertilizer (RDF) and 100% RDF]. The average of 18 years pooled data showed that, the grain yield, straw yield and net returns of rice were significantly higher with the application of gliricidia and eupatorium @ 10 t/ha compared to all other manures. Among the interactions of different organic manures and inorganic fertilizers, combinations of application of gliricidia @ 10 t/ha + 100% RDF resulted in significantly higher grain yield (6.2 t/ha), straw yield (7.8 t/ha) and net returns (`30,569/ha) followed by eupatorium + 100% RDF. The grain yield, straw yield and net returns obtained with application of green-leaf manures, viz. gliricidia alone (5.29, 6.01 t/ha and `25,443/ha, respectively) or eupatorium @ 10 t/ha alone were found to be at par with that of 100% RDF alone.