RESPONSE OF BANANA AND GUAVA PLANTS TO SOME BIOLOGICAL AND MINERAL FERTILIZERS

Abstract

Agriculture is mainly dependent on chemical fertilizers particularly in Egypt, wherever its consumption per hectare is more than the average of the whole world. However, because of shortages in some fertilizer supplies and the current cost of energy, which is used for its production, the cost of fertilizers has risen tremendously and will continue to rise. In addition to that the efficiency of fertilizers used in Egypt is low, either as result of high pH of soil and calcium carbonate levels in the case of chemical P-fertilizers, or due to nitrate leaching and NH% volatilization from the nitrogen fertilizers. In view of the economical and environmental problems of using the chemical fertilizers, utilization of biofertilizers would not only result in increasing soil fertility and crop production through its additional nutrient supply, but would also help in solving sanitary and environmental problems, as well as would save foreign currency for Egypt. Recent developments and insights regarding the potential of vesicular-arbuscular mycorrhizal (VAM) symbiosis in horticultural f practice are discussed by many investigators such as Azcon-Aguilar and Barea (1997). Given the effects of VAM inoculation on plant growth and health, as biofertilizers and bioprotectors, it is accepted that an appropriate management of this symbiosis would permit a satisfactory reduction of chemical fertilizer and pesticide inputs, key aspects for sustainable horticultural plant production. Most Egyptian Soils are rich in asymbiotic N:-fixers (Saber and Gomaa, 1993). Beneficial effects of inoculation with Azotobacteron the growth of cereals and other crops were reported by many investigators that this might be due to supplementing the growing