Diversity of edaphic and epigeic invertebrate fauna in cassava intercropped with green manures

Abstract:

The objective of this work was to evaluate the density and diversity of epigeic and edaphic invertebrate fauna in a cultivation of cassava intercropped with green manures. The study was carried out in soil cultivated with cassava (C) intercropped with jack-beans (JB), millet (MI), and pigeon pea (PP), in comparison with the traditional system of cassava cultivation (TS) without cover species. Invertebrates of the epigeic fauna were collected using pitfall traps and those of the edaphic fauna were collected in soil monoliths. Among the epigeic invertebrates, the Collembola, Diptera, and Formicidae groups were dominant in all intercropping, accounting for over 80% of total relative frequency (RF), while in the soil fauna the Isoptera group was dominant in all intercropping, with the highest RF for the C+PP intercropping (90.2%), followed by C+JB (83.1%) and C+MI (65.6%), and the lowest RF occurred for TS (32%). The number of individuals of the epigeic fauna did not vary among the intercropping systems; however, the number of organism groups varied significantly. The C+MI intercropping showed the greatest richness of groups. The total density of organisms of the edaphic soil fauna varied among intercropping systems, and the highest density was observed in C+PP, in comparison to TS. The edaphic and epigeic fauna invertebrates respond to changes, favored by the intercropping green manure with cassava, by increasing group diversity.

Index terms:
Manihot esculenta; bioindicators; soil fauna; Isoptera; sustainability