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Diversity indices using arbuscular mycorrhizal fungi to evaluate the soil state in banana crops in Colombia

Mahecha-Vásquez, Germán, Sierra, Sair, Posada, Raúl
Applied soil ecology 2017 v.109 pp. 32-39
bananas, correlation, cost effectiveness, crops, edaphic factors, mycorrhizae, mycorrhizal fungi, pH, phosphorus, plantations, soil, species diversity, tropics, Colombia
The banana is widely and intensively cultivated in the tropics. Traditional production employs a high input of industrial supplements, the excess of which contaminates the environment, altering existing edaphic populations and their functions. Some producers have incorporated other plant species in polycultures to reduce costs and achieve an alternative production without the high consumption of chemical supplements. With the aim of evaluating the effect of management system (monoculture vs. polyculture) and determining the edaphic factors that influence the richness and diversity of arbuscular mycorrhizal fungi (AMF), an edaphic component of great importance, 17 banana plantations in Colombia with high contents of edaphic phosphorous were sampled in two high production zones managed under a monoculture system and a zone of low production managed under a polyculture system. Between 11 and 18 species of AMF were found on average per plantation, both in intensive agricultural systems and in polyculture, where the diversity índices Simpson, Shannon and Margalef as well as the abundance and richness of AMF did not appear to be influenced by the cultivation system but instead by the dominant species in the communities; pH was the only factor that correlated positively with richness and the Margalef index; the monocultures were the least acidic and for this reason presented higher species richness. It is concluded that, in soils with high Phosphorus content, pH shows a direct relationship with species richness and the Margalef index, the composition of AMF species in the community exists in heterogeneous patches that are little influenced by cultivation management practice (mono or polyculture). Generalization in the development of specific bioinoculants based on mycorrhizae without considering local adaptations of the species is questioned.