Agriculture Reference
In-Depth Information
Table 1.6
The main wetland soils in riverine and coastal landforms
Histosols
Entisols
Inceptisols
Alfisols
Ultisols
Aquents
Fluvents
Aquepts
Tropepts/
Ochrepts
Aqualfs
Ustalfs/
Udalfs
Aquults
Ustults/
Udults
++
++
++
+
+
−
−
−
Coastal plains
na
+
++
++
++
+
+
+
+
+
Inland valleys
Alluvial fans
−
+
++
++
++
++
+
+
+
Floodplains
−
+
++
++
++
++
++
+
+
Alluvial terraces
−
+
+
+
++
++
++
++
++
USDA (1999) soil classification. na
,
not applicable;
−
,
absent or rare;
+
,
common;
++
,
abundant.
Explanation of soil categories (FAO (1999) equivalents in parentheses):
Histosols
(
Histosols
) have high organic matter throughout the profile.
Entisols
show no evidence of soil-forming processes leading to profile development:
Aquents
(
Gleysols
,pt;
Fluvisols
, pt) are formed in continuously or near-continuously wet
environments;
Fluvents
(
Fluvisols
, pt) in recent alluvium in areas that are frequently flooded by rivers depositing new sediment.
Inceptisols
show weak profile development:
Aquepts
(
Gleysols
,pt;
Thionic Luvisols
, pt) are water-saturated for at least part of the year and show gray or rusty mottling;
Tropepts
(
Cambisols
, pt) are well-drained and occur in warm regions with only slight annual temperature changes;
Ochrepts
(
Cambisols
, pt) occur in regions with greater annual
temperature changes.
Alfisols
show marked clay translocation down the profile without excessive depletion of bases:
Aqualfs
(
Gleyic Luvisols
) are water-saturated for part of the year;
Ustalfs
(
Luvisols
,
except
Gleyic
,pt;
Eutric Nitosols
, pt) are seasonally dry;
Udalfs
(
Luvisols
, except
Gleyic
,pt;
Eutric Nitosols
, pt) are continuously moist.
Ultisols
show marked clay translocation with intensive leaching and depletion of bases:
Aquults
(
Gleyic Acrisols
;
Plinthic Acrisols
,pt;
Dystric Plansols
,pt),
Ustults
(
Acrisols
,pt;
Dystric Nitosols
)and
Udults
(
Acrisols
,pt;
Dystric Nitosols
) as for Alfisols.
Source
: after Driessen and Moorman (1985). Reproduced by permission of IRRI.
