الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
This investigation was carried out during the two summer seasons of 2009 and 2010 in sandy soil on potato ”Sante” to study the effect of using 100% compost (15 t/fed.) and 50% compost + nitrogen fixing bacteria (Azotobacter, and Pseudomonas alone or together) on potato growth and yield as compared to the conventional mineral fertilization (120-75-150 kg/fed. NPK + 5 ton compost/fed.(control)). No significant differences in tubers yield per plant and per fed. were detected between mineral fertilization (control) and using 100% compost (15 t/fed); however, control treatment significantly produced a high yield per feddan than using 50% compost + any biofertilizer treatment.Using compost treatment at 15 t/fed.execeed all biofertilizer treatments in marketable yield in both seasons, without no significant differences compared with mineral fertilization (control). Compost treatment at 15 t/fed. had the highest value of haulm fresh weight and had similar effect to mineral fertilization (control) in both seasons.There were no significant differences between mineral fertilization (control) and all organic fertilizer treatments regarding number of tubers per plant. Using Azotobacter(0,3,6,9 weeks+ pseudomonas (0,6weeks) had a higher tuber dry matter value than all biofertilizer treatmentas, compost and control treatment. Compost application(15 ton/fed.) had significantly lower nitrate concentration in tuber than mineral fertilization.
Key words:Potato, compost, Azotobacter, pseudomonas, tuber yield