Reducing soil application of nitrogenous fertilizer as influenced

Introduction

Rice (Oryza sativa L.) is one of the most important crops in Bangladesh and It is the largest crop in terms of area and production in Bangladesh (BBS, 2008). Although rice is consuming large acreage, Bangladesh is still far behind than other rice producing countries. There are many reasons for this low yield. The most important of them is the indiscriminate and improper application of nutrients with unfavorable condition. Many factors determine the fertilizer use efficiency for rice crop during cultivation such as soil, cultivar, season, environment, planting time, water management, weed control, cropping pattern, source, form, rate, time of application and method of application (De Datta, 1978).Rice is mainly cultivated in flooded fields. The unique properties of flooded soils make rice nutrient management different from any other crop. Submerging rice field brings a series of physical, chemical and microbial changes in the soil, which profoundly affects growth of rice plant as well as availability, loss and absorption of nutrients due to chemical reduction of soil and decrease in concentrations of water-soluble Zn and Cu (Ghildyal, 1978). Nearly 70% of the land area of the country has been brought under rice cultivation. Out of this 70%, fine rice is cultivated in roughly 10% land. This lower coverage is primarily due to the emphasis of government policy and research on food grain production but with low input technology. Nutrient management practices determine the sustainability of the most intensively cropping systems (Flinnet al., 1982). Therefore, there is an imperative need to provide the required nutrients over and above the regular soil application through foliar application as well. Foliar application is well recognized and is being practiced in agriculturally advanced countries. In many cases aerial spray of nutrients is preferred and gives quicker and better results than the soil application (Jamal et al., 2006). Recently foliar application of nutrients has become an important practice in the production of crops while application of fertilizers to the soil remains the basic method of feeding the majority of the crop plants. Foliar feeding is an effective method for overcoming the flooded soil special condition. In case of foliar feeding, nutrients are absorbed directly where they are needed, the rate of the photosynthesis in the leaves is increased, nutrient absorption by plant roots is stimulated and foliar nutrition applied at critical times. Other advantages are low application rates, uniform distribution of fertilizer, reduction in plant stress, plant's natural defense mechanisms to resist plant disease and insect infestations, improvement of plant health and yield (Finck, 1982). Nitrogen fertilizer is more urgent for security rice production. Liquid fertilization might reduce the use of chemical fertilizer specially the nitrogenous fertilizer in soil.In this aspect, the present study was undertaken to find out the effect of liquid fertilization (Magic Growth) on performance of Kataribhog rice and to calculate how much urea can be saved by using liquid fertilization of Magic Growth without the reduction of grain yield.