It was long accepted that the microgranular structure which is characteristic of many Ferralsols was mainly related to physico-chemical processes and to their mineralogical composition. It now appears, however, that this microgranular structure originates from the burrowing activity of termites and ants. Given its importance for the physical properties of Ferralsols, it will be necessary to study the different termite and ant species responsible for this microgranular structure and the characteristics of the burrowing activity associated with species. This is a major point to better understand the possible long-term consequences of agriculture on Ferralsol properties because it strongly affects soil faunal biodiversity Most yellow or red soils found in the South American, African and Asian tropics are classified as Ferralsols in the World Reference Base (IUSS Working Group WRB, 2015). They correspond to Latosols in the Brazilian taxonomy (Embrapa, 2006), mainly to Ferrallisols in the Genetic Soil Classification of China and to Ferrosols in the Chinese Soil Taxonomy (Shi et al., 2004 and 2006), and to Oxisols or Ultisols in the Soil Taxonomy (Soil Survey Staff, 2006). They represent a large land surface area with 750 million hectares worldwide (IUSS Working Group WRB, 2015), which corresponds in the tropics to about 14 % of the land surface area. They result from a long sequence of deep weathering under conditions that in most cases have prevailed for at least several tens of thousands of years (van Wambeke, 1992; Scholten et al., 1997; Schaefer, 2001). In such soils, easily weatherable primary minerals such as feldspar and micas have disappeared, resulting in a fine material essentially made up of kaolinite and of iron and aluminium sesquioxides (Pédro, 1968; Melfi and Pédro, 1977, 1978). As a result, Ferralsols are characterized by extremely low native chemical fertility, resulting from very low nutrient reserves, low pH, high phosphorus retention by oxide minerals, and low cation exchange capacity (Yu, 1997; Kögel-Knabner and Amelung, 2014). On the other hand, most Ferralsols are characterized by a well-developed microgranular structure and consequently exhibit high physical fertility resulting from high porosity, low resistance to root penetration, high infiltration rate and high available water retention (Stoops