The macrofauna of the soil in systems of agricultural production: Answers to the perturbations and handling perspectives. A case of study in the Oriental Plains of Colombia

During the last 20 years, numerous investigations were dedicated to the understanding of the relationships between soil macro-invertebrates and the abiotic factors that determine soil function. Important effects of macro-fauna activities were observed in soil organic matter dynamics, cycles of assimilable nutrients, soil structure and plant growth. Actual investigation in the Eastern Plains of Colombia (Investigation Centre of Carimagua and Matazul Farm) aims to identify sustainable and macrofauna-protecting systems of production; managing savanna results in important changes in soil faunal communities. Sowing improved pastures increases the activity of local macro-invertebrates populations (especially earthworms) and conserves the initial biodiversity of the savanna. On the other hand, monocrops have a dramatic effect on the whole soil macrofauna. An appropriate management of soil tillage and plant residues may minimize the negative effects of such monocrops. Other alternative is the use of rotations and/or juxtapositions of suitable and unfavorable situations, which may facilitates macrofaunal migrations from one system to another