Many soils in California have horizons (layers) with exceptionally low K[sub.sat] values that severely limit downward percolation, such as cemented layers (duripan, petrocalcic), claypans
(abrupt increases in clay content) and strongly contrasting particle size distributions.
Based on definitions offered of deserts and desert environments, the most important factors influencing biological growth and ecological conditions are soil salinity, soil depth, alkaline soils, soil texture, organic matter, evolution, claypans
, soil crusting, groundwater level, and gypsum.
In NSW, it is described as mostly found on flat areas, such as dune swales and claypans
subject to seasonal inundation, in areas of open grassy woodland.
Soils in the sand plains are alkaline red Tenosols, red Kandosols, and Calcarosols with saline, alkaline, grey Vertosols and Sodosols common in the depressions and claypans
, hundreds of which are scattered across the sandplain.
It should be noted that the assemblages at these sites are similar to that described by Veth (1987:105) for claypan
sites in the Great Sandy Desert, although gilgais differ from claypans
in responding much more quickly to rain.
d) La sobrepreparacion del suelo mediante el empleo del arado convencional que contribuye fuertemente a la rapida perdida de materia organica, compactacion y formacion de capas duras (claypans
) y costras, caracteristica tipica del manejo de suelos en la zona con riego.
'However,' he writes, 'pick the right date and view the landscape from above and a surprising amount of water may be evident on claypans
between the dunes or in wide shallow lakes that cover many square kilometres.' (12) And in this incredible environment, more is being lost than species biodiversity.
Estimating depth to claypans
using electromagnetic induction methods.
occur where extreme illuviation has caused a very high clay content in a subsoil layer.
Rocky uplands or river valleys may also house true forests, or even vine thickets, while claypans
, wetlands and other landscape features add to the diversity of the regions that are dominated by woodland communities.
These results indicate that the soil depressions on our site are not persistent bison disturbances or relict wallows, but pedogenic features described by rangeland and soil scientists as claypans
or slick or sodic spots (Hazeli, 1965; Culver and Gray, 1968; Bakhtar and Gray, 1971; White and Gartner, 1981; White et al., 1981).
"Its roots grow well in soils with pH in the range of 4.2 to 5.0, which is common for claypans
and other restrictive layers and is toxic to roots of most crops," says Foy.