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Abstract
Tomato (Lycopersicon esculentum, Mill.) is one of the most important vegetable crops grown in Egypt. Its importance is due to the wide consumption in human daily diet .Moreover, it is considered an important source of vitamins such as vitamin C, niacin and riboflavin, and a source of important minerals such as calcium, phosphorus, potassium and iron that are not found in the other Solanaceae crops.
Tomato is also a source of carbohydrates and proteins. In Egypt, tomato is one of the major cash crops with a total planting area of 459,283 feddan which yielded about 7,140,198 ton of fruits (Ministry of Agriculture and land Reclamation, Department of Agriculture Economic Statistical, March 2005).This area is about 31.5% of the total vegetable cultivated area in Egypt. Globally, Egypt ranked in the fifth position in growing tomato crop.
Most Egyptian soils are classified as a second or third degree regarding fertility. The soils contain low content of total and available nutrients as well as organic matter. Under such conditions, the productivity tendences of different crops decrease markedly .The newly reclaimed lands in west Nubaria are mainly calcareous and sandy soils. Calcareous soils occupy wide areas in the North African Countries such as Egypt. The soils have high percentage of calcium carbonate and they are normally basic in reaction. The availability of macro and micronutrients is not enough in these soils. In order to increase the productivity of these soils, addition of nitrogen, phosphate, potassium as mineral nutrients and other amendments are recommended (Hilal et al., 1990 and Awad et al., 1996).
Low soil fertility and nutrients deficiency in these soils are very common and could be the main constraints for agriculture production. Phosphorus and micronutrients deficiency is an obvious pose problem in highly calcareous soils with alkaline soils pH.
Therefore, it is more useful to use biofertilizers with reduced levels of mineral fertilizers in these new lands. Biofertilizers become an important factor to increase the availability of phosphorus and micronutrients to correct their deficiency and increase crop production in calcareous soils.
The most import biological fertilizers are arbuscular -mycorrhizal fungi (AMF) and biological potassium fertilizer (BPF) bacteria, which enhance nutrients uptake, growth and crop yield, particularly on phosphate and potassium deficient calcareous soils (El-Awamy, 2004).
The purpose of this investigation was to study. (1) The positive effects of some biofertilizers with different levels of mineral phosphate and potassium fertilizers on growth, yield and chemical content of tomato plants under calcareous soil condition. (2) The suitable quantity of PK mineral fertilizers for the host in the present of arbuscular mycorrhizal fungi (AMF) and biological potassium fertilizer (BPF). (3) The application effect of urea derivatives (thidiazuron) on the early colonization of AMF fungi and the reflection of the beneficial symbiosis on inoculated tomato plants.