Soils and rhizosphere's microorganisms associated in the "Seaflower" biosphere reserve

The San Andrés Archipelago, Providencia and Santa Catalina was declared a Seaflower Biosphere Reserve by UNESCO in 2000, constituting one of the most extensive reef systems in the Western Hemisphere located in the Colombian Caribbean. Nowadays, this island presents problems of food security, being serious in San Andrés where there is a high native population and tourist that depends on the importation of food. Although in this were grown coconut, cassava, citrus, etc., agricultural activity has decreased mainly due to the presence of pests and lack of soil management. The objective of this study was to describe the physical-chemical and microbiological characteristics of soils of the Reserve, samples were made at different geographical points of the "Seaflower" Reserve. The results obtained show in general high contents of organic matter (max value 12.8%), calcium (between 2.6 and 64 cmol (+) kg-1 ), potassium (between 0.1 and 1.86 cmol (+) kg-1), magnesium (values between 1.6 and 22.2 cmol (+) kg-1) and phosphorus (max. value 416 ppm), whereas in the case of aluminum, sodium and sulfur, low contents were found, on the other hand, copper, zinc, iron and manganese, presented variable contents. On the island soil texture is variable, it was sandy loam, clay loam, and sandy, with alkaline pH at most of the points sampled. As for the microbiological analysis, 128 isolates were obtained, in which the Trichoderma and Fusarium genera prevailed, other genera were Rhizopus, Penicillium, Aspergillus, Colletotrichum and Botrytis. The Reserve has an optimal fertility status for agricultural production, but must be enhanced through the implementation of integrated management.