الفهرس 
Review Of LiteratureOnly 14 pages are availabe for public view
 |  | from | 105 |  |  |
| | | from | 105 | | |
Abstract
Snap bean (Phaseolus vulgaris L.) is one of the most important vegetable crops in Egypt as well as many other countries. Production of snap bean for local consumption and exportation is of great importance. Exportation is mainly devoted to European markets which need high quality as extra fine, fine and bobby snap bean cultivars.
According to the statistic1 of 2005 in Egypt, the total area devoted for the production of green pods and dry seeds were 23835 and 39049 feddans, respectively. These areas produced total yields of 115240 and 44466 tons, orderly.
Nitrogen nutrition is known to affect growth and yield potential of vegetable crops. Nitrogen as an essential element was found to be involved in amino acids, chlorophylls and auxins metabolism as well as enzymes and protein synthesis.
Judicious application of nitrogen to the growing snap bean plants was emphasized by many investigators to attain favorable enhancing impacts on growth and yielding capacity (Elhag, 1982; Feleafel and El-Araby, 2001 and Ahmad, 2006). However, excessive and continuous nitrogen applications lead to delaying pod formation, pollution of agro-ecosystem, deterioration of soil fertility and finally increasing the cost of snap bean production (Marschner, 1995). Under these circumstances, supplementing or substituting inorganic nitrogen with organic sources, are really needed.
Addition of organic fertilizer such as composted manure in sandy soils improve the soil structure, increase nutrients availability, improve the aeration in the soil, increase cation exchange capacity and supply with adequate micronutrients. Also, it contains high organic content, improve drought tolerance and increase soil microbial activities, which lead to higher yield and quality (Singer et al., 1998 and Hafez and Mahmoud, 2004).
Response of the grown cultivars to the applied nitrogen, whether were of inorganic or organic sources, are among the important factors that greatly affected variant phases of growth and development of snap bean. Among these cultivars, Giza-3 and Paulista are widely grown in Egypt for local and export market, respectively.
However, information concerning optimum combination ratio of mineral and organic nitrogen and rate of nitrogen for these two cultivars are scant. There is a real need for more detailed study on the subject. Accordingly, the main objective of this study is to investigate the response of two snap bean cultivars to three nitrogen fertilization rates, each of them is applied in five different combinations between mineral and organic nitrogen on vegetative growth, green pods yield and its components and chemical content of snap bean.