Application Of Alternative Nutrient Sources To Improve Soil Fertility And Protecting Environment Using Nuclear Technique

Two field experiments were conducted on virgin sand soil under drip irrigation system using squash and spinach as tested crops. Squash crop was fertilized with 15N labeled ammonium sulfate fertilizer, commercial compost locally manufactured in Egypt and artificial compost prepared by author, either completely (100%) of mineral or of organic; or 50%: 50% (mineral: organic). Under all fertilization treatments, squash plant was inoculated or uninoculated with Azospirillum. Spinach plant was cultivated in the same experimental site depending on the residual of different. Dealing with squash, inoculation increased roots fresh weight. This was more pronounced with application of 50% mineral fertilizer plus 50% commercial compost, 100% artificial compost and 100% commercial compost. Similar trends, but to high extent were noticed with shoot fresh weight as affected by microbial inoculation and different organic composts. The 50%: 50% treatments as well as 100% artificial compost treatment gave high root and shoot dry weights. Inoculation and 50%: 50% fertilization treatments were more effective on N uptake. Higher N uptake was by shoots than roots. Portion and absolute value of N by roots from mineral fertilizer were significantly affected by combined fertilization treatments. Nitrogen from air (Ndfa) was positively affected by addition of organic compost and bacterial inoculation. Reversible trend was noticed with N from soil (Ndfs) which decreased when treated with compost and bacterial inoculation. All measurements were high in shoots than roots. Similar trends were noticed with spinach in spite of its grown on residual of mineral fertilizer and organic compost.