Page 93 - E-BOOK English

Soil classification

WRB: Fibric Histosols
Soil taxonomy: Dysic, isohyperthermic Typic Haplofibrists

Soil series: Narathiwat series (Nw)

Profile description

 0-4 cm (Oig1) (7.5YR 2/0) unrubbed and rubbed,
fibric materials (burnt) about 70% fiber; most remain
consisting of roots; many charcoal fragments (irreversible
drying); fine subangular blocky structure; hard,
nonsticky and nonplastic; not react with a-dipyridyl
and bentizine; sodium pyrophosphate test paper is
pinkish gray to pink (7.5YR 7/2-4); extremely acid
(field pH 4.0).

 4-15 cm (Oeg) Dark reddish brown (5YR 3/2)
unrubbed and rubbed, fibric materials about 50%
fiber; most remain consisting of roots and woody
fragments; massive; nonsticky and nonplastic;
not react with a-dipyridyl and bentizine; sodium
pyrophosphate test paper is light brown (7.5YR 6/4);
very strongly acid (field pH 4.5).

 15-30 cm (Oig2) Black (5YR 2.5/1) unrubbed and
rubbed, fibric materials about 70% fiber; most
remain consisting of roots; massive; nonsticky and
nonplastic; not react with a-dipyridyl and bentizine;
sodium pyrophosphate test paper is pink (7.5YR 7/4);
very strongly acid (field pH 4.5).

 30-90 cm (Oig3) Dark reddish brown (5YR 2.5/2)
unrubbed and rubbed, fibric materials about 50%
fiber; most remain consisting of fine roots and easy
to be rubbed; massive; nonsticky and nonplastic; not react with a-dipyridyl and bentizine; sodium
pyrophosphate test paper is pink (7.5YR 8/4); very strongly acid (field pH 4.5).

 90-140 cm (Oig4) Dark reddish brown (5YR 3/2) unrubbed and rubbed, fibric materials about 52%
fiber; most remain consisting of fine roots, some as coarse as 2 cm partially decayed and easy to
be rubbed; massive; nonsticky and nonplastic; not react with a-dipyridyl and bentizine; sodium
pyrophosphate test paper is pinkish white (7.5YR 8/2); very strongly acid (field pH 4.5).
 140-200 cm (Oig5) Dark reddish brown (5YR 2.5/2) unrubbed and rubbed, fibric materials about 68%
fiber; most remain consisting of roots and wood fragments about 2-4 cm; massive; nonsticky and
nonplastic; not react with a-dipyridyl and bentizine; sodium pyrophosphate test paper is pinkish white
(7.5YR 8/2); very strongly acid (field pH 4.5).

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