Soils are classified in the Ultisol order and Udult
suborder according to the USDA soil classification system .
Soils at Misiones are typified as Rhodudults and the one from Corrientes as an Udult
This soil is a sandstone-derived sandy haplic acrisol (or udult
ultisol, see Davies and Becker 1996), with a high sand content, and is generally nutrient poor (Baillie et al.
The low-mountain forestland (LF) is now covered with secondary shallow-rooted coniferous forests (altitude <800m a.s.1.), such as Cunninghamia lanceolata, Pinns massoniana, Cupressus funebris, and Pinns armandii (Xie and Chen 1998), and the local soils are classified as Udults
(Soil Survey Staff 1992).
The soil used in these experiments was an ultisols sub-order udults
1) and its Ultisol Udults
soils possess a low base saturation, which requires farmers to abandon fields after a few years of production (Soil Survey Staff, 1999).
The dominant suborders of Ultisols are Aquults, Humults, Udults
, Ustults, and Xerults (Table 3-5).
Characters of three udults
and their relevance to the composition and structure of virgin rain forest of Amazonian Ecuador.
Soils are primarily well drained, clayey Udults
formed in residuum of granite, gneiss, schist, or Carolina Slate.