الفهرس 
REVIEW OF LITERATUREOnly 14 pages are availabe for public view
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Abstract
Rice (Oryza sativa L.) is one of the most important grains in the world. It is not only a stable food, but also contributes to major economic activities and a key source of income and employment for the rural population.
In Egypt approximately 8 million feddan of land are used for growing crops. This area is doubled because of crop intensification and rotation between summer and winter crops. Assuming that 2 ton of crop residues (dry basis) were left on each feddan each season, the total will be 24 million ton annually. Traditional crop residue management removes probably most of it by grazing and mostly by burning. This practice causes many problems; firstly it causes air pollution which affects the health of human beings, secondly, it kills the macro and micro-organisms in the soil which convert energy and nutrients from crop residues and thirdly, it produce some toxic gases and maximize denitrification losses of all nutrients that get into the anaerobic soil layers. The organic matter content in the Egyptian soil does not exceed 2% due to high temperature, dry climate, shortage of organic fertilization and green manure and high cropping intensity, accordingly to support soil fertility, incorporating organic materials in the soil either as raw material or as compost, must be practiced (El-Agamy et al. 2007).
Application of the organic fertilizers, either animal manure, compost or rice husk could increase the soil organic carbon which increases aggregation, water holding capacity, cation exchange capacity (CEC), infiltration rate, hydraulic conductivity and decrease bulk density. Furthermore, organic matter content serves several advantages like conservation and slow release of nutrients, improve of soil physical conditions, provide micronutrients and other grows factors not normally supplied by inorganic fertilizers and may also enhance microbial growth and nutrient turnover in soil.
Rice is semi-aquatic plant and about 10 billion m3 of irrigation water is being used in rice production in the rice growing governorates, Egypt. This amount represents about 18% of Egypt’s share of Nile water which amounting 55.5 billion m3. The limitation of water resources and the remarkable increase in population should force research workers to find ways for saving some of this water without significant reduction in yield. Moreover because of continued population growth and economic development, the demand for fresh water to meet industrialization and domestic needs is growing rapidly. It is expected that, in the near future less water will be available for rice cultivation (Tuong and Bouman 2002).
It is estimated that about 6000 m3 of irrigation water is needed for each feddan of rice. Increasing demand for irrigation water recently appeared in Egypt for the new land reclamation programs which cover an area of 3-4 million feddan, these areas are located in Tushka, East Owwynat, Darb El-Arbaeen, Peace Canal and other cultivable areas (Mahrous, 2005). Accordingly, saving rice irrigation water is a necessary demand to cover the water requirement of these projects. This could be achieved through either developing of new rice varieties which requires less water (short duration or drought tolerant varieties) or through developing improved agricultural practices for rice cultivation. One of these practices is water management by use of organic fertilizers which increases water holding capacity and increases irrigation intervals without any drastic effect on plant growth and grain yield.
The objective of this investigation was to study the effect of organic fertilizers such as (compost rice straw, farmyard manure and rice husk) and some irrigation treatments on water use efficiency and productivity of Hybrid1 and Sakha 101 rice cultivars.