Improvement of yield potential of rice through combined application of biofertilizer and chemical nitrogen

Abstract

A field experiment was conducted to evaluate the suitable combination of plant growth promoting rhizobacteria (Azospirillum biofertilizer strain BM9 and BM11) along with different nitrogenous fertilizer levels (0, 20, 40, 60, 80 and 100% N) on rice variety Binadhan 4 at Bangladesh Institute of Nuclear Agriculture farm, Mymensingh in Aman season of 2006. Roots of rice seedlings were dipped in broth culture of bacterial strains in Luria-Bertani (LB) medium for half an hour before transplanting. Data were recorded on plant growth, yield, yield components and nutrient uptake. Results showed a significant increase in growth parameter like plant height, shoot dry weight, root length and dry weights, grain and straw yields, effective tillers/hill and panicle length, and nitrogen, phosphorus and potassium uptake over uninoculated under most nitrogen levels except 100% N. Number of grains per panicle and 1000 grain weights were increased considerably compared to uninoculated control. Strains BM9 and BM 11 along with 80% N produced similar grain and straw yield to that with 100% nitrogen fertilizer applied alone. Results revealed greater scope of Azospirillum biofertilizer application for supplementing fertilizer nitrogen for achieving optimum yield of rice in Bangladesh soil and environmental condition. Key words: Rhizobacteria, Azospirillum biofertilizer strain, rice growth, nitrogenous fertilizer.