Journal of Agricultural, Biological and Environmental Sciences | Year-2014 | Volume 01 | Pages 65-69 © 2014 Jakraya JOURNAL OF AGRICULTURAL, BIOLOGICAL AND ENVIRONMENTAL SCIENCES Journal homepage: www.jakraya.com/journal/jabes ORIGINAL ARTICLE Effect of Nitrogen, Farm Yard Manure, Azotobacter Interaction on Rhizospheric Population of Azotobacter and Yield of Maize in Mollisol of Uttarakhand Debashis Dutta*, Vinod Kumar and Sobaran Singh Department of Soil Science, G.B. Pant University of Agriculture and Technology, Pantnagar -263145, Uttarakhand, India. Corresponding Author: Debashis Dutta Email: debashisdutta74@gmail.com Received: 27/10/2013 Revised: 07/12/2014 Accepted: 09/12/2014 Abstract A field experiment was conducted to find out the interaction of nitrogen doses (0, 20, 40, 60, 80, 100 and 120 Kg N hac -1 ), farm yard manure (10 tons ha -1 ) and Azotobacter inoculation on the rhizospheric population of Azotobacter and yield of maize. The Azotobacter population in the rhizosphere of maize plant 10.33 to 36.33 (cfu X 10 3 ), 9.66 to 36.66 (cfu X 10 3 ), and 7.66 to 32.66 (cfu X 10 3 ), per gram of soil respectively at 30, 60, and 90 days after sowing of maize. The Azotobacter population in the rhizosphere of maize significantly increase due to inoculation over the un-inoculated control. Addition of farm yard manure (FYM) also increases the native population of Azotobacter remarkably during the active plant growth stage. The maximum Azotobacter was recorded due to application of 60 Kg N Ha -1 + Azotobacter + FYM treatment combination at 60 days after sowing. Azotobacter inoculation and Azotobacter inoculation with FYM application increases the yield of maize at level of nitrogen .The maximum yield obtain due to addition of 120 Kg N ha -1 was statistically at par with the yield resulted due to application of 60 Kg N ha -1 + FYM + Azotobacter inoculation. Keywords: Azotobacter, FYM, Nitrogen, Rhizosphere, Maize. 1. Introduction The amount of nitrogen available to plants in the soil is usually small and, therefore, in most countries, and especially in developing countries, a prerequisite for increasing yields of agricultural crops is the improvement of the nitrogen supply. The use of nitrogen from mineral fertilizers is one of the most effective methods of overcoming the nitrogen deficiency of soils but the conversion of N-N to ammonia is a high energy budgetted chemical process. The sharply rising energy price makes it increasingly difficult to meet the global requirement in nitrogenous fertilizers. But nitrogen shortage can be offset by biological fixation. The inoculation of crop plants with bacterial preparations is generally necessary because many soils lack specific microorganisms shown to or believed to stimulate productivity. Legume crops are frequently inoculated with preparations of Rhizobium to promote effective nodulation and efficient nitrogen fixation. Azotobacter chroococcum has also been widely used to inoculate crop plants to promote nitrogen fixation in agricultural crops and conclusions have been drawn that seed inoculation of non-legumes with Azotobacter chroococcum increases the yield of field crops by about 10% and of cereals by about 15 % - 20 % (Hussain et al., 1987). Azotobacter has the ability to proliferate and colonize the rhizosphere of farm crops most effectively if seeds are inoculated with this bacterium (Brown et al., 1962; 1964). The potentiality of Azotobacter strains inoculation of maize seeds and the interaction with FYM and different levels of nitrogen was investigated in the Mollisol of Uttarakhand. 2. Materials and Methods The field experiment was conducted during Kharif season 1999 at Crop Research Centre, G.B. Pant University of Agriculture and Technology, Pantnagar, Uttaranchal (290 0 N and 7903 0 E). The soil of experimental site had loam texture, pH 6.9, organic C 1.26%, Total N 0.15%, available P 2 O 5 47 Kg ha -1 , available K 2 O 258 Kg ha -1 and CEC 15 c mol (p + ) Kg -1 soil and is classified as Aquic Hapludoll. The experiment was conducted in randomize block design with 16 treatments, each replicate thrice. The treatments consisted of : (i) Control (C) (ii) Azotobacter inoculation (AZO) (iii) Farm Yard Manure at 10 ton ha -1 (FYM) (iv) Azotobacter inoculation +