1797 Environment & Ecology 32 (4B) : 1797—1803, October—December 2014 Website: environmentandecology.com ISSN 0970-0420 Effect of Integrated use of Vermicompost, FYM, PSB and Azotobacter on Physico-Chemical Properties of Soil under Onion Crop Sumit Rai, Priyanka Rani, Maneesh Kumar, Avinash Kumar Rai, Sanjay Kumar Shahi Received 21 April 2014 ; Accepted 28 May 2014 ; Published online 14 June 2014 Abstract A field experiment was conducted during rabi season (2009) to find out the effect of integrated application of organic manures (FYM and vermicompost), inorganic fertilizers and biofertilizers (PSB and Azotobacter) on physico-chemical proper- ties, available NPKS content of soil and nutrient con- centration of onion (Allium cepa L.). There were six treatments comprised varied levels of FYM, vermicompost, chemical fertilizers, PSB and Azoto- bacter. The experiment was laid out under random- ized block design (RBD) and the treatments were trip- licate during the experiment. Significantly improve- ment in physico-chemical properties viz. pH, electri- cal conductivity, bulk density and water holding ca- pacity of soil under onion crop were recorded at all three growth stages i.e. 30 DAT, 60 DAT and at har- vest observed in the plots received 50% N through vermicompost + 25% N through urea + PSB + Azoto- bacter (T 6 ) as compared to other treatments. Similar S. Rai*, P. Rani, M. Kumar, A. K. Rai Department of Soil Science & Agricultural Chemistry, Insti- tute of Agricultural Sciences, Banaras Hindu University, Varanasi 221005, (UP), India S. K. Shahi Department of Agricultural Chemistry and Soil Science, Udai Pratap Autonomous College, Varanasi 22102 (UP), India e-mail: sumit.rai101@yahoo.in *Correspondence significant effect was observed on availability of NPKS in soil and nutrient content (N, P, K and S) of onion plants. On the basis of results obtained it can be concluded that the integrated use of organic ma- nures (vermicompost and FYM) along with chemical fertilizers and biofertilizers (PSB and Azotobacter) can subsitute the nitrogen requirement of plant and improved the physico-chemical properties, availabil- ity in soil of N, P, K and S and their concentration in onion tissues significantly over the sole use of chemi- cal fertilizer. Keywords INM, Vermicompost, FYM, Azotobacter, Onion. Introduction Onion (Allium cepa L.)is a prominent bulb crop used by both vegetarians and non-vegetarians due to its nutritional and characteristics flavouring properties hence cultivated extensively in India. Onion is stimu- lant, diuretic and having expectorant and anti bacte- rial properties. Onion bulb is a rich source of minerals like phosphorus, calcium and carbohydrates, protein and vitamin C. Onion has got good medicinal value as it contains several flavnoids which acts against carcinogenic agents to prevent cancer in animals and human beings. It prevents heart disease by lowering blood cholesterol and lipid level [1]. The demand for organic food is steadily increasing both in developed and developing countries, with annual average growth