Nitrogen fertilizer-induced spatial variation in the size of methane oxidizing bacterial population in rainfed rice cultivars

Abstract

This study was conducted to investigate the effect of N fertilization on methane oxidizing bacteria that lead to changes in the microbial communities in rice agroecosystems. Variation in MOB population size due to rice varieties of three different soil type bare, bulk and rhizosphere was investigated in rainfed rice NDR-97 (Narendra-97), Pant Dhan-12 and Vanaprabha. The growth variables (shoot biomass and root biomass) were higher in fertilized plots than unfertilized plots. The ammonium-N, nitrate-N was higher in fertilized plot than unfertilized plots. There were significant differences in MOB population size during the study (p<0.05). The highest MOB bacterial population was found in rhizospheric soils. So that, MOB bacterial population range between 19.2xlO6 to 70.54xl06 cells g1 dry across soil type of varieties and treatment. N-fertilization reduces population size of MOB. Thus the result suggests that MOB population size were varied by different soil type and soil fertilization. This study showed significant impact of N-fertilization on MOB population. © 2012 Knowledgia Review, Malaysia.