A highly weathered leached red or reddish-yellow acid soil with a clay-rich B horizon (subsoil), occurring in warm, humid climates.‘Upland soils are highly weathered alfisols and ultisols, with large clay fractions and chert intermixed throughout the profile.’
- ‘Very thick root mats inside forest litter have been described in undisturbed tropical forests growing on atypical soils such as giant podzols, but less dramatic root mats can be found beneath forests on more typical oxisols and ultisols.’
- ‘The species is extremely rare throughout its range, being known from wet savannas on calcium-influenced ultisol soils in southeastern North Carolina, Florida and Georgia.’
- ‘Plants inoculated with both organisms had the lowest shoot weight, pod weight and height in all the test ultisols.’
- ‘These soils used to be called latisols, but are called oxisols and ultisols by the USDA and ferralsols or acrisols by the UN these days.’
- ‘Alfisols are relatively more fertile than oxisols and ultisols.’
1960s from ultimate + Latin solum ‘soil’.
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