Studies on the activities of Microorganisms in desert soils and their relation to soil fertility

Egypt is one of the over-populated countries owing to the very limited suitable areas for cultivation. Therefore, after 1952 Revolution, a great attention to soil reclamation was given for facing the continuous increase in population. In the meantime , the cultivation of new sandy and calcareous soils which represent a large part of Eglptian desert area is considered as an important aspect for extensive cultivation. Sandy soils usually suffer from low water holding capacity, cation exchange capacity, poor structure and low fertility status. On the other hand calcareous soils are Lacking the favourable structure sndother related physical properties. The fertility level is extremely low and most of the major nutrients are either absent or present in low concentrations . Improving the productivity of both soils is a complicated problem particularly in arid regions. To cultivate such soils successfully, one should over come the poor physical, chemical, and nutritional properties of these soils, these problems can be solved through the addition of organic materials. The present work is intended to test the use of different organic residurs and one of the synthetic soil conditioners in reclamation of sandy and calcareous soils under green house conditions.