Influence of nutrient-management practices and microbial inoculants on productivity and profitability of lowland rice (Oryza sativa) in Eastern Himalayas

A field study was conducted during the rainy (kharif) season of 2016 at Umiam, Barapani, Meghalaya, to find out the effect of different nutrient-management practices and microbial inoculants on yield-attributing characters, yield and profitability of lowland rice (Oryza sativa L.) in Eastern Himalayas. The experiment consisted of 12 treat-ment combinations including 3 nutrient-management practices, viz. 100% organic, 100% inorganic [recommended dose of fertilizer (RDF)] and integrated nutrient management (INM; 75% RDF + 25% FYM), in main plot and 4 microbial inoculation treatments, viz. control, Azospirillum, Azospirillum + phosphate-solubilizing bacteria (PSB), Azospirillum + PSB + zinc-solubilizing bacteria (ZnSB) in subplots. The experiment was laid out in a split-plot design with 3 replications. The yield-attributing characters, viz. tillers/m², panicle length and filled grains/panicle were the highest with INM treatment, followed by inorganic and organic nutrient-management practices. Similar trend was observed in case of 1, 000-seed weight, but it was at par with the other nutrient-management practices. The highest grain yield (4.27 t/ha) was recorded in INM, followed by inorganic (4.08 t/ha) and organic (3.65 t/ha) nutrient-management practice. Among the microbial inoculants, the highest yield was recorded in Azospirillum+ PSB + ZnSB treatment, followed by Azospirillum + PSB and Azospirillum treatment. The highest cost of cultivation ( 28, 829/ha) was recorded under organic nutrient management, while net returns ( 48, 615/ha) were maximum in INM practice with combined application of Azospirillum+ PSB + ZnSB. Thus, INM (75% RDF and 25% organic inputs, i.e. FYM) and microbial inoculants could be used for higher productivity and profitability of lowland rice in Eastern Himalayas.