ARBUSCULAR MYCORRHIZAL FUNGI AND ENZYMATIC ACTIVITY IN SOIL CULTIVATED OF THE CHAPADA OF APODI - CE

This paper has evaluated the alterations in the number of spores of arbuscular mycorrhizal fungi (AMF) and enzymatic activity in soil under cultivation of banana trees in Chapada of Apodi. The hypothesis was tested that the agricultural use causes environmental alterations that they reduce the presence of population of AMF and the microbial activity. An area was selected under cultivation of banana trees (Farm Frutacor) and its control (natural vegetation). Four soil samples were collected in three depths in which analyses were accomplished, the number of spores of AMF by Gerdemann and Nicholson (1964) and enzymatic activity: acid phosphatase, arylsulphatase and b-glucosidase by Tabatabai, (1994). The number of spores of AMF show values decreasing with the rise in depth in area cultivated. The activity of the arylsulphatase and acid phosphatase were stimulated by the competition of the anions H2PO4- and SO4- for the same ranches of adsorption in the colloids of the soil. For b-glucosidase, there was a larger activity in the cultivated area, influenced by the amount and quality of the vegetable residue. The enzymatic activity evidences a difficulty of establishing correlations between the biochemistry and chemistry of the soil in area where the entrance of nutrients is high.