201 Environment & Ecology 32 (1A) : 201—205, January—March 2014 Website : environmentandecology.com ISSN 0970-0420 Nutrient Content of Transplanted Rice Increase by Controlling Weed Through Xanthium strumarium Extracts P. K. Upadhyay, E. Kumari, A. Sen, S. K. Choudhary, R. K. Singh Received 23 September 2013; Accepted 24 October 2013; Published online 31 October 2013 Abstract To minimize problem of herbicide resis- tance as well as soil and water pollution, plant prod- ucts and plant residues are used for management of weeds because various types of allelochemicals have been found to possess capacity to control weeds and also improve or maintain soil productivity. Due to pres- ence of several allelochemical Xanthium strumarium extract has been used as a pre emergence herbicide which reduces the population of weeds and enhances the nutrients content in the plants. It was found that application of petroleum ether extract of X. Strumarium @ 2000 and 3000 mg l -1 cause significant reduction in the population of weeds which helps in reducing the crop-weed competition for nutrient applied for the crop (rice variety HUBR 2-1) as compared to control plot and at par with Anilophos a well known herbi- cide for controllling weeds in transplanted rice. Keywords Nutrient content, Herbicide, Petroblem ether. Introduction Throughout history, rice remains a staple food for two-thirds of the world’s population, especially for south-eastern Asia, where 90% of the world produc- tion of rice is grown and consumed and has become an item of commerce since the last two decades. About four-fifths of the world’s rice are produced by small- scale farmers and are consumed locally. The slogan “Rice is life” is most appropriate for the country as the crop plays a vital role in national food security providing about two third calories to the people in humid and sub humid Asia. It is grown 112 counties in world, covering every contrinent, every continent, and is consumed by 2500 million people in develop- ing countries. Among cereals rice is the major source of calories for about 40% of the world population and every third person on earth eats rice every day in one form or other (1). Since the weeds are the main enemies of the cul- tivated paddy crop, it should be eliminated in proper time. Hand weeding, which is in practice, is very ef- fective if followed in time, though it is tedious, time consuming and costly. Moreover, presently labor availability of such operation has decreased due to rapid industrialization, increased literacy and migra- tion of labor to urban areas. Weeds are naturally grown plant which are able to extract nutrients and water from the soil and are competent enough to har- vest light energy. In the growing plants, leaf area in- dex and root density increase which leads to matual interfernce in the utilization of growth factors. The population of weeds crossing over threahold level P. K. Upadhyay*, E. Kumari, A. Sen, S. K. Choudhary, R. K. Singh Department of Agronomy, Institute of Agricultural Sciences, Banaras Hindu University, Varanasi 221005, India e-mail: pravin.ndu@gmail.com *Correspondence