Organic agriculture refers to a farming system that enhance soil fertility through the efficient use of local resources, while prohibiting the use of agrochemicals and  the use of Genetic Modified Organisms.  Organic agriculture relies on farming practices based on ecological cycles, and minimizing the environmental impact of the food industry, preserving the sustainability of soil. Organic farming received heavy attention by the researchers and consumers recently, because of misuse and overuse of fertilizer and agrochemicals resulting in unacceptable levels of pesticides and heavy metals in the produce. Cereals grown in the world belong to the family Gramineae/Poaceae. Traditional cultivars of cereals, both tropical and temperate, are poor yielders but  the world can produce almost three times as much cereal from a given area of land today, due to the cereal improvement programs of green revolution.  The most important input inorganic fertilizer recommendations are geared to provide a well-balanced fertilizer mixture to a crop in adequate amounts of all required nutrients at the particular stage of crop to achieve its potential yield.  All Cereal crops generally have several growth stages where heavy demand for nutrients are imminent to obtain potential yields. In rice PI stage with very high growth rate of about 01 primordia differentiated every 3 hrs and each primordium consisting of several millions of independent cells, will depicts the heavy nutrient demand. At this growth stage rate of  mitotic cell division is unimaginable and happens in a split second and therefore nutrient requirement is extremely high.  Hence, a single blanket treatment of organic fertilizer, providing N in small amounts uniformly throughout the growth cycle, cannot provide all the necessary nutrients in required amounts and time. Further, split application of organic manures will lead to temporary N deficiency for the cereals, because of microbial fixation.  In tropical and subtropical countries, cereal rice, is grown extensively under flooded conditions and the anaerobic decomposition of added organic fertilizers cannot provide the necessary nutrition in time and in required amounts to the improved rice plant. Moreover, organic farming results in poor yields with the present day varieties, which are highly fertilizer responsive though there is no difference in ions derived between organic and inorganic fertilizer forms but inorganic ions are prohibited in organic farming and is only a myth. Therefore science, scientific thinking and decision making is open and what scientists should possess is the enthusiasm, dedication and intellectual judgment in order to sustain global food production in a healthy, safe and sustainable manner for the future posterity using organic farming techniques.

Key words: Organic agriculture, Cereal crops, Growth stages, Primordia, Organic fertilizer, N  deficiency 

Dr Nanda Senanayake studied at the University of Ceylon Peradeniya, Sri lanka and joined the Department of Agriculture, Sri Lanka as a Research Officer and Received M.Sc (Agron) from the University of Philippines, Los Banos in 1983 as a Research Scholar IRRI, Philippines, and Ph.D ( Plant Science) in 1990 from the University of Aberdeen, UK again as a Research fellow of IRRI, Philippines. After retirement from Department of Agriculture he joined the University of Rajarata, Puliyankulama as a Senior lecturer and retired. He has authored 03 Books on rice plant and rice cultivation and more than 70 research articles in local and international  journals and received three Presidential Research Awards.