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ห้องสมุดกรมพัฒนาที่ดิน

92 ร า ย ง า น การส�ารวจดิน

3. ค�าบรรยายหน้าตัดดิน

Horizon Depth (cm) Description
(ชั้นดิน) (ความลึก) (ค�าบรรยาย)

Ap 0-12 Very dark grayish brown (10YR 3/2) loamy sand; single grain; soft,
friable, non sticky, non plastic; common fine, medium and few coarse

roots; moderately acid (field pH 6.0); clear, smooth boundary.

Bw1 12-47 Brown (10YR 4/3) sandy loam; weak fine subangular blocky structure;

slightly hard, friable, slightly sticky, slightly plastic; common fine and
medium roots; very strongly acid (field pH 5.0); clear, smooth

boundary.

Bw2 47-72 Brown (10YR 4/3 to 10YR 5/3) sandy loam; weak fine subangular blocky
structure; slightly hard, friable, slightly sticky, slightly plastic; few fine

and medium roots; very strongly acid (field pH 5.0); clear, smooth
boundary.

Bt1 72-103 Brown (10YR 5/3) sandy loam; common fine to medium distinct

reddish brown (5YR 4/4) mottles; weak fine subangular blocky

structure; slightly hard, friable, slightly sticky, slightly plastic;
patchy thin clay coatings on ped faces; few fine and medium roots;
very strongly acid (field pH 5.0); clear, smooth boundary.

Bt2 103-135 Brown (10YR 5/3) to pale brown (10YR 6/3) sandy loam; few fine
distinct brown (7.5YR 4/4) and common medium distinct yellowish

brown (10YR 5/6) mottles; weak fine and medium subangular blocky
structure; slightly hard, friable, slightly sticky, slightly plastic; patchy

thin clay coatings on ped faces; few fine roots; very strongly acid
(field pH 5.0); clear, smooth boundary.

Bt3 135-150+ Light brownish gray (10YR 6/2) to pale brown (10YR 6/3) sandy loam;

many medium distinct reddish brown (5YR 4/4) and yellowish brown
(10YR 5/6) mottles; weak fine and medium subangular blocky

structure; slightly hard, friable, slightly sticky, slightly plastic;
patchy thin clay coatings on ped faces; few fine roots; ferric and

manganese concretion consisting about 10% by volume with average
diameter of 1 cm; very strongly acid (field pH 5.0).