Soils dominated by smectitic clay minerals that are found in a strongly seasonal climate, usually exhibit ‘vertic properties’. These are a combination of 1) deep cracks when dry (Fig. 10.1), 2) intersecting slickensides in the subsoil (polished and grooved shiny surfaces, produced by one mass of soil sliding past another) 3) wedge-shaped structural aggregates in the subsurface soil (25 to 100 cm deep), and 4) a strong, nutty structure at the soil surface. Often, these soils show a so-called gilgai microrelief: rounded mounds and depressions or series of ridges and inter-ridge depressions, with distances between highs and lows of 2 to 8 m and vertical differences of 15 to 50 cm. The combination of these properties characterizes vertisols. Two sets of processes related to the genesis of vertisols will be discussed: the formation of smectitic clays, and the development of the typical physical characteristics.
KeywordsFailure Plane Optimum Depth Smectitic Clay Aluminium Silicate Surface Mulch
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- Ahmad, N., 1983. Vertisols. In: L.P. Wilding, N.E. Smeck and G.F. Hall (eds). Pedogenesis and Soil Taxonomy. II. The Soil Orders, pp. 91–123. Developments in Soil Science 11B. Elsevier, Amsterdam.Google Scholar
- Bocquier, G. 1973. Genèse et évolution de deux toposèquences de sols tropicaux du Chad. Mém. ORSTOM no 62, 350 p., ORSTOM, Paris. 222Google Scholar
- Dudal, R. and H. Eswaran, 1988 Distribution, properties and classification of vertisols. p. 1–22 in: L.P. Wilding and R. Puentes (eds) vertisols: their distribution, properties, classification and management. Technical Monograph no 18 Texas A&M University Printing Center, College Station TX USAGoogle Scholar
- Jaillard, B. et Y.-M. Cabidoche, 1984. Etude de la dynamique de l’eau dans un sol argileux gonflant: dynamique hydrique. Science du Sol 1984: 239–251.Google Scholar
- Wilding, L.P., and R. Puentes (eds), 1988. Vertisols: their distribution, properties, clas sification and management. Technical Monograph no 18, Texas A&M University Printing Center, College Station TX USA.Google Scholar
- Wilding, L.P. and D. Tessier, 1988. Genesis of vertisols: shrink-swell phenomena, p.55–81 in: L.P. Wilding and R. Puentes (eds) Vertisols: their distribution, properties, classification and management. Technical Monograph no 18, Texas A&M University Printing Center, College Station TX USA.Google Scholar