Thanks from ttcf and others for answering:
P 71 kes to soil taxonomy 2014 :
2. A mesic or thermic soil temperature regime and a
moisture control section that in normal years is dry in some
part for six-tenths or more of the cumulative days per year
when the soil temperature at a depth of 50 cm below the soil
surface is higher than 5 oC; or
b. Is dry in some part for six-tenths or more of the
cumulative days per year when the soil temperature at a
depth of 50 cm below the soil surface is high
Aridic Haplustalfs
p 248
A horizon within 100 cm of the mineral soil surface that
is 15 cm or more thick and either has 20 percent or more (by
volume) durinodes or is brittle and has at least a firm rupture resistance
class when moist; and
2. An aridic soil moisture regime.
Argiduridic Argixerolls
P 312
Other Calciusterts that, if not irrigated during the
year, have cracks in normal years that are 5 mm or more wide,
through a thickness of 25 cm or more within 50 cm of the
mineral soil surface, for 210 or more cumulative days per year.
Aridic Calciusterts
If the mean annual soil temperature is lower than 22 oC and
if the mean summer and winter soil temperatures differ by
6 oC or more at a depth of 50 cm below the soil surface, the
soil moisture control section in areas of the ustic soil moisture
regime is dry in some or all parts for 90 or more cumulative
days in normal years, but it is not dry in all parts for more than
half of the cumulative days when the soil temperature at a depth
of 50 cm is higher than 5 oC.
P 30
Ustic soil moisture regime
If the mean annual soil temperature is lower than 22 oC and
if the mean summer and winter soil temperatures differ by
6 oC or more at a depth of 50 cm below the soil surface, the
soil moisture control section in areas of the ustic soil moisture
regime is dry in some or all parts for 90 or more cumulative
days in normal years, but it is not dry in all parts for more than
half of the cumulative days when the soil temperature at a depth
of 50 cm is higher than 5 oC
question : we see a discrepancy about definition of aridic in subgroup and ustic in above .please explain
that in ustic we have less than 180 cumulative days and if we have 6/10 per year or 210 per year dry then haplustalf would be aridisol not alfisol . what is the reason for this .
As a whole in what time we use aridic in subgroup and what is the meaning for 6/10 per year is dry ?
