DESKRIPSI TANAH
Soil is a natural body consisting of layers (soil horizons) that
are primarily composed of minerals which differ from their
parent materials in their texture, structure, consistency, color,
chemical, biological and other characteristics.
It is the unconsolidated or loose covering of fine rock
particles that covers the surface of the earth.
Tanah merupakan hasil akhir dari pengaruh iklim
(temperature, precipitation), relief (slope), organisme (flora
dan fauna), bahan induk (mineral-mineral), dan waktu.
DESKRIPSI TANAH
Pedology (from Greek: πέδον,
pedon
, "soil"; and λόγος,
logos
, "study") is
the study of soils in their natural environment.
It is one of two main branches of soil science, the other being
edaphology.
Pedology mengkaji pedogenesis, morfologi tanah, dan klasifikasi tanah;
sedangkan edaphology mengkaji cara-cara bagaimana tanah
mempengaruhi tumbuhan, fungi, dan organisme lainnya.
Soil is not only a support for vegetation, but it is also the zone beneath
our feet (the pedosphere) of numerous interactions between climate
(water, air, temperature), soil life (micro-organisms, plants, animals) and
its residues, the mineral material of the original and added rock, and its
position in the landscape.
Selama proses genesisnya, profil tanah mengalami pendalaman dan
mengembangkan lapisan-lapisan yang khas, yang disebut 'horizon',
DESKRIPSI TANAH
SOIL MORPHOLOGY is the field observable attributes of the soil within
the various soil horizons and the description of the kind and arrangement
of the horizons.
C.F. Marbut championed reliance on soil morphology instead of on
theories of pedogenesis for soil classification because theories of soil
genesis are both ephemeral and dynamic.
The observable attributes ordinarily described in the field include the
composition, form, soil structure and organization of the soil, color of the
base soil and features such as mottling, distribution of roots and pores,
evidence of translocated materials such as carbonates, iron, manganese,
carbon and clay, and the consistence of the soil.
The observations are typically performed on a soil profile. A profile is a
vertical cut, two dimensional, in the soil and bounds one side of a pedon.
The pedon is the smallest three dimensional unit, but not less than 1
meter square on top, that captures the lateral range of variability.
DESKRIPSI TANAH : HORISON
Horison tanah adalah lapisan-lapisan di dalam profil tanah yang posisinya sejajar dnegan permukaan tanah. A soil profile is made up of several horizons and each is distinguished from the horizon above or below by being different in one or more characteristics. These differences
WARNA
TEKSTUR
STRUKTUR
Density / PorositAS
PERGERAKAN AIR
Reactivity of mineral and organic colloids
KEMASAMAN TANAH & pH
Berdasarkan pada sifat fisika dan kimiawi :
Color
Dark/grayish-black color
Orange vs. Gray colors
Texture
Sandy vs. Clayey
Structure
Good vs. Poor Structure
Density
Porosity, organic matter, compaction
Water
Pore sizes, porosity, water movement, saturation
Reactivity Cation exchange capacity
Factors Affecting Soil Formation
Climate
Organisms/Vegetation
Parent material
Topography
Time
Horison Utama - Master Horizons
1.
O Organik
2.
A Topsoil, Bahan organik,
daur-ulang
3.
E Elluviasi
4.
B Berkembang /akumulasi
5.C Bahan induk tanah
6.
R Batuan dasar
A horizon
B horizon
Horison C
O Horizon
PENAMAAN / PENGENALAN HORISON TANAH
E horizon
Organic matter
Sandy
Clays/iron
E horizon
A horizon
B horizon
(Illuvial)
(Elluvial)
C horizon
R horizon
O horizon
Master Horizons; Horison Utama
B horizon
b – buried horizon – Horison terkubur
c – concretions
d – root restrictive
g – gleying
h – illuvial organic matter
k – carbonates
m – cementation
o - oxic
p – plowing/disturbance
q – secondary silica
r – soft bedrock (saprolite)
s – illuvial sesquioxides and O.M.
t – clay accumulation
v – plinthite
w – development of color/structure
x - fragipan
Subordinate Distinctions
g – gleying
h – illuvial organic matter
p – plowing/disturbance
t – clay accumulation
w – development of color/structure
o – oxic - Oksik
h = Akumulasi bahan organik
1. Akumulasi bahan illuvial kompleks logam-bahan organik
2. Selimut pada pasir dan partikel diskrit
3. h = “humik”
4. Value dan chroma sekitar 3 atau kurang
5. Digunakan dnegan horison utama B (mos. Horison Bh)
Horison Bh
“Horison Spodik”
p = dibajak/diolah, plowed
Horison permukaan yang terganggu (Kultivation, pasture, Kehutanan)
Digunakan dengan horison utama A (mis. Horison Ap)
Ap horizon
t = akumulasi liat
1. Translokasi liat atau terbentuk di tempat
2. Selimut atau diskrit
3. Digunakan dnegan horison utama B (mis. Bt)
4. Kalau reduksi, dapat digunakan dengan sub-horison g (Btg)
w = warna atau struktur
Perkembangan warna atau
struktur secara Non-illuvial
“w” = “weak”
Biasanya digunakan dnegan
horison utama B (mis. Bw)
Bw
o = oxic horizon
1. Aktivitas liat rendah
2. Sedikit bahan dapat lapuk
3. Struktur batuan sedikit
4. Oksida Fe dan Al
Horison oksik mempunyai:
1. a CEC 7 < 16cmol(+)/kg of clay and an ECEC < 12 cmol(+)/kg of clay which is due to the low activity clay minerals (1:1 clays, Fe and Al oxides, etc)
2. < 10% weatherable minerals in the sand fraction 3. Struktur batuan < 5%
Subordinate Distinctions
g – gleying
h – illuvial organic matter p – plowing/disturbance t – clay accumulation
w – development of color/structure o – oxic
DIUNDUH DARI: soillab.ifas.ufl.edu/.../... ……. 13/2/2013
KEJELASAN - DISTINCTNESS
Distinctness describes the ease with which features can be identified. It is often used for mottle colour and surface
coatings.
Faint:
Features can only be identified using 10x lens and cannot be positively identified in all places. They are generally thin and their contrast with the adjacent matrix is small.
Distinct:
Features have sufficient colour or texture contrast to be seen without magnification, but may need a lens for
positive identification.
Prominent:
Features are conspicuous without magnification and can be readily distinguished from the matrix by sharp colour or texture contract or by their thickness. Some thin features,
eg mangans can be prominent. Sumber:
a, e, i
Menyatakan derajat dekomposisi bahan organik
dalam Horison O
Oa – Dekomposisi lanjut (Saprik)
Oe – Dekomposisi moderat (Hemik)
Oi – Dekomposisi ringan (Fibrik)
Saprik – Dekomposisi lanjut, serat tumbuhan sedikit, kandungan air rendah
Hemik – Dekomposisi sedang / intermediate
Fibrik – dekomposisi ringan, serat-serat masih dapat dikenali
Subordinate Distinction
Ikhtisar
Horison Utama: O, A, E, B, C, R
Simbol Subordinate : g, h, p, t, w and a,e,i
Contoh:
Oa, Oe, Oi
Bt
Bg
Btg
Bw
Ap
Vertical Subdivisions
Dicirikan oleh sifat-penciri utama dan/atau subordinat
yang serupa, dipisahkan oleh “degree”.
Bt1
Bt2
Bt3
Horison Transisi
Lapisan transisi di antara horison utama.
A
E
E
B
B
E
Order
Suborder
Great group
Sub group
Family
Series
12
19,000
Hierarkhi Taksonomi Tanah
63
250
1400
8000
Kingdom
Phylum
Class
Order
Family
Genus
Species
Unit-unit untuk klasifikasi tanah
Pedon –
smallest three-dimensional unit that displays
the full range of properties characteristic of
a given soil. (1-10 m
2of area)
- Unit mendasar dari klasifikasi tanah
Polypedon
– Sekelompok pedon yang berhubungan erat di
lapangan
Soil Series –
class of soils world-wide which share a common
suite of soil profile properties
Horison Diagnostik (Horison Penciri)
untuk Klasifikasi Tanah
Permukaan
Diagnostic Surface Horizons
Epipedon
Mollik
Umbrik
Ochrik
Histik
Melanik
Plaggen
Anthropik
Mollic
Histik
Umbrik
Okhrik
Melanik
Plaggen
Anthropik
X
X
X
X = Florida
Horison-permukaan Diagnostik =
Diagnostic Surface Horizons
Mollic Epipedon
Tebal
> 18-25 cm
Warna
Value < 3.5 lembab
Chroma < 3.5 lembab
C-organik
> 0.6 %
Kejenuhan basa
> 50 %
Struktur tanah
Berkembang sangat
baik
EPIPEDON UMBRIK
Memenuhi semua kriteria Epipedon Molik,
Kecuali kejenuhan basanya < 50%
EPIPEDON OKRIK = Ochric Epipedon
Terlalu : Tipis
Ringan, warna terang
Muskin bahan organik
Mollic
Umbric
Ochric = Pucat
Epipedon Histik
1. Horison organik yg
terbentuk di daerah
basah
2. Warna hitam hingga
coklat gelap
3. Bobot Isi rendah
4. Tebalnya 20-30 cm
Organik = > 20% - 35% bahan organik.
(Jenuh air
, kadar liat )Epipedon Melanik
1. Sifatnya serupa dnegan Molik
2. Terbentuk dalam abu vulkanik
3. Ringan, Fluffy
Melanic Epipedon:
The melanic epipedon is a thick black horizon which contains high concentrations of organic matter, usually
associated with short-range-order minerals or aluminium-humus complexes. The intense black color is attributed to the accumulation of organic matter from
which "Type A" humic acids are extracted. This organic matter is thought to result from large
amounts of gramineous vegetation, and can be distinguished from organic matter formed under forest
vegetation by the melanic index.
HORISON ANTHROPIK
• Serupa dengan Molik (warna, bahan organik) • Digunakan manusia
• Tulang dan kerangka • Air dari aktivitas manusia
Anthropic Epipedon:
The requirements for the anthropic
epipedon are the same for the mollic,
except that P
2O
5soluble in 1% citric acid is
> 250 ppm.
(http://www.soils.wisc.edu/courses/SS325/organic.ht m)
Epipedon Plaggen
Dihasilkan oleh penggunaan rabuk jangka
panjang (100s tahun)
Horison permukaan buatan manusia, tua
Tebal > 50 cm
Plaggen Epipedon:
The plaggen epipedon is a cultural surface
horizon produced by long continued
manuring. Its color depends on the nature
of the manure. Commonly it contains
artifacts, such as bits of bricks and pottery
through out its depth.
Diagnostic Surface Horizons
Epipedon:
Mollic
Umbric
Ochric
Histic
Melanic
Plaggen
Anthropic
Very common
Human-derived
“specialized”
Vegetasi
Akumulasi bahan organik
waktu
Akumulasi Bahan ORganik
Histic
Mollic, Umbric ochric
Bahan induk
Diagnostic Subsurface
Horizons
Clays Organic Matter Oxides
Pembentukan
Translokasi
Transformasi
Horison-penciri yang lokasinya di bawah-permukaan
Endopedon (B)
Agric
: Akumulasi liat dan humus, akibat pengolahan tanah
Argillic
: Akumulasi liat
Cambic
: "color" atau perkembangannya lemah
Kandic
: Argillik dengan liat seperti-kaolinit
Natric
: Argillic, nilai ESP tinggi
Oxic
: Pelapukan lanjut
Sombric
: Masam, akumulasi humus, tropis
Bahan organik Liat
Oksida
Smectit
Subsurface Horizons
Kaolinit
Juga: garam, karbonat, sulfida
Warna gelap
Logam (Fe, Al)
Iron
Aluminum
Formation
Translocation
Transformation
Diagnostic Subsurface Horizons
Albic
Argillic
Spodic
Oxic
Kandic
Cambic
Sombric
sulfuric
Natric
Agric
Calcic
Gypsic
Salic
Duripan
Fragipan
Placic
Sub-Horizon Designations
Horison-penciri yang lokasinya di bawah-permukaan
Diagnostic Subsurface Horizons
Horison Albik (putih)
Light-colored (Value > 6 moist )
Elluvial (E master horizon*)
Low in clay, Fe and Al oxides
Generally sandy textured
Low chemical reactivity (low CEC)
Typically overlies Bh or Bt horizons
albic
*tidak semua horion E adalah horison albik
Horison Argilik
Akumulasi liat silikat hasil iluviasi
Illuvial based on overlying horizon
Jembatan liat
Selimut liat
Diagnostic Subsurface Horizons
Accumulation based on absolute increases compared to relevant horizon above or below. Argillic horizon. An argillic horizon is an illuvial horizon in which layer-silicate clays have accumulated to a significant extent by
illuviation. They have formed below the surface of a mineral soil but may be exposed at the surface by erosion. In general, this is a B horizon which has an increase in clay content of at least 1.2 times that of the eluvial horizon above and is, in general, parallel to the surface of the polypedon. This increase of 20% in clay
content occurs most in soils within a vertical distance of less than 30 cm. In case of clayey soils, this requirement would be unreasonable. If the surface horizon is greater than 40% clay, the increase of clay needed is only 8%. For sandy soils with less than 15% clay, an increase of 3% is required for meeting the criteria of an argillic horizon. In other words, if the clay content of the eluvial horizon is between 15 and
Diagnostic Subsurface Horizons
Horison Argilik
Horison Kandik
Aktivitas liat
TINGGI
RENDAH
Iluviasi Liat
Pasti
Belum tentu
Diagnostic Subsurface Horizons
Spodic Horizon
Spodik
1. Akumulasi bahan organik dan
aluminum (+/- besi) hasil Iluviasi
2. Berwarna gelap (value, chroma < 3)
3. Kejenuhan basa rendah (masam)
Eluviasi (Horison E dan Horison A)
Bahan organik
Liat
Spodic horizon
Bh horizon
Bt horizon
Argillic horizon
Eluviasi dan Iluviasi
A
E
Bh
A
Bt
E
Diagnostic Subsurface Horizons
Oxic horizon
• Highly weathered (high temperatures, high rainfall)
- High in Fe, Al oxides
- High in low-activity clays (kaolinite < smectite < vermiculite)
DESKRIPSI TANAH
KARAKTERISTIK PERMUKAAN TANAH
Beberapa karakteristik permukaan tanah yang penting:
1. Singkapan batuan
2. Fragmen kasar batuan
3. Erosi tanah
4. Kerak permukaan
5. Retak permukaan
6. Adanya garam
7. Pasir putih
8. Seresah tumbuhan
9. Kotoran cacing
10.Bongkahan/gumpalan
11.Pelumpuran.
DESKRIPSI TANAH
Singkapan Batuan
Batuan-dasar yang
tersingkap di permukaan
dapat mengganggu
aktivitas pertanian.
Singkapan batuan ini
dideskripsikan dalam
bentuk persentase tutupan
permukaan, dan informasi
lainnya seperti ukurannya,
tata-letaknya, dan
kekerasan batuan yang
tersingkap.
DESKRIPSI TANAH
Fragmen kasar di
permukaan
Fragmen kasar ini
termasuk fragmen
yang tersingkap
sebagian,
dideskripsikan
dalam bentuk
persentase tutupan
permukaan, dan
ukuran fragmen.
Klasifikasi fragmen kasar di
permukaan
DESKRIPSI TANAH
Erosi Tanah
Deskripsi erosi tanah harus difokuskan pada erosi tanah
akibat aktivitas manusia. Biasanya sulit membedakan antara
erosi alamiah dan erosi yang dipercepat akibat manusia.
Erosi yang dipercepat merupakan akibat dari pengelolaan
tanah yang “tidak tepat” , seperti budidaya pertanian yang
tidak tepat, overgrazing dan panen vegetasi alamiah yang
DESKRIPSI TANAH
Kategori Erosi
Erosi dapat
dikelompokkan
menjadi erosi oleh air
dan erosi oleh angin,
dan mencakup efek
eksternal (off-site)
seperti sedimentasi
atau deposisi; kategori
lainnya adalah
gerakan massa tanah
(longsor dan
fenomena yang
terkait).
DESKRIPSI TANAH
Luas area yang
terpengaruh erosi
Total aera yang
terpengaruh oleh erosi
dan
sedimentasi/deposisi
diestimasi dengan
kelas-kelas yang didefinisikan
oleh SOTER
(FAO, 1995)
Klasifikasi luas area yang ada
erosinya
DESKRIPSI TANAH
Derajat Erosi
It is difficult to define classes of the degree of erosion that would be equally appropriate for all soils and environments and that would also fit
the various types of water and wind erosion.
Ada empat kelas derajat erosi yang direkomendasikan, dan ini harus dideskripsikan lebih lanjut, yaitu S (ringan), M (moderat), V (parah), E
(sangat parah).
For example, in the case of gully and rill erosion, the depth and spacing may need to be recorded; for sheet
erosion, the loss of topsoil; for dunes, the height; and for deposition,
the thickness of the layer .
DESKRIPSI TANAH
Klasifikasi aktivitas erosi
Aktivitas erosi
Periode aktivitas
erosi dan deposisi
yang dipercepat
dideskripsikan
menurut klasifikasi
DESKRIPSI TANAH
Kerak permukaan = Surface sealing
Kerak permukaan digunakan untuk mendeskripsikan adanya
kerak yang berkembang di permukaan ntanah setelah topsoil
mengering.
Kerak-kerak permukaan ini dapat menghambat
perkecambahan benih , menghambat infiltrasi air, dan
meningkatkan runoff. Atribut kerak permukaan adalah
konsistensi (kering), dan tebalnya kerak.
Kerak permukaan yang tuidak menggulung seluruhnya pada
saat mengering → Horison takyric.
DESKRIPSI TANAH
DESKRIPSI TANAH
RETAKAN DI PERMUKAAN
Retak-permukaan (Surface crack) berkembang pada tanah-tanah yang
kaya tipe liat mengembang-kerut setelah mengering. Lebarnya retakan
( lebar rata-rata atau rata-rata lebar dan lebar maksimum) di permukaan
diukur dengan satuan sentimeter.
Rata-rata jarak di antara retakan juga diukur dengan satuan sentimeter.
1. Retakan yang membuka dan menutup secara periodik → Vertisols.
2. Retakan yang membuka dan menutup periodik , lebarnya ≥ 1 cm → Ciri vertik. 3. Retakan poligon yang dalamnya ≥ 2 cm kalau tanah mengering → Horison
DESKRIPSI TANAH
DESKRIPSI TANAH
Klasifikasi Garam di permukaan
Garam - Salt
The occurrence of salt at the
surface may be described in
terms of cover, appearance
and type of salt.
Klasifikasi berdasarkan
persentase tutupan
permukaan dan ketebalan.
Catatan untuk klasifikasi
tanah:
Kerak terdorong oleh kristal
garam → Puffic qualifier.
DESKRIPSI TANAH
Klasifikasi karakteristik Pasir
Pasir = Bleached sand
The presence of bleached, loose
sand grains on the surface is
typical for certain soils and
influences the reflection
characteristics of the area and,
hence, the image obtained
through remote sensing.
Klasifikasi berdasarkan pada
persentase tutupan permukaan.
Batas-batas horison - HORIZON BOUNDARY
Batas-batas horison memberikan informasi tentang proses apa ayang dominan dalam genesis tanah. Dalam kasus-kasus tertentu, dampak antropogenik masa lalu terhadap
bentang-lahan. Batas-batas horison dideskripsikan dnegan indikator “kedalaman”, “kejelasan” dan “topografi”.
Kedalaman
Most soil boundaries are zones of transition rather than sharp lines of division.
The depth of the upper and lower boundaries of each horizon is given in centimetres, measured from the surface (including organic and mineral covers) of the soil downwards.
Precise notations in centimetres are used where boundaries are abrupt or clear. Rounded-off figures (to the nearest 5 cm) are entered where the boundaries are gradual or diffuse, avoiding the suggestion of spurious levels of accuracy. However, if boundary depths are near diagnostic limits, roundedoff figures should not be used. In this case, the depth is indicated as a medium value for the transitional zone (if it starts at 16 cm and terminates at 23 cm, the depth should be 19.5 cm). Most horizons do not have a constant depth. The variation or irregularity of the surface of the boundary is described by the topography in terms of smooth, wavy, irregular and broken. If required, ranges in depth should be given in addition to the average depth, for example 28 (25–31) cm to 45 (39–51) cm.
Catatan untuk klasifikasi tanah:
Banyak horison penciri dan sifat-penciri ditemukan pada kedalaman tertentu. Batas kedalaman yang penting adalah 10, 20, 25, 40, 50, 100 dan 120 cm.
DESKRIPSI TANAH
Kejelasan dan Topografi
Kejelasan batas-horison menyatakan ketebalan zone dimana batas horison belokasi tanpa menjadi bagian dari salah
satu horison terdekat.
Topografi batas-horison menyatakan “smoothness” variasi kedalaman dari
batas-horison.
Catatan untuk klasifikasi tanah 1. Cryoturbation → cryic horizon,
Cryosols and Turbic qualifier. 2. Tonguing of a mollic or umbric
horizon into an underlying layer → Glossic qualifier.
3. Tonguing of an eluvial albic horizon into an argic horizon → albeluvic tonguing and Glossalbic qualifier.
4. Diffuse horizon boundaries → Nitisols.
Klasifikasi batas horison, menurut kejelasan dan topografinya
DESKRIPSI TEKSTUR TANAH
Tekstur tanah menyatakan proporsi berbagai kelas ukuran partikel primer (atau separat tanah, atau fraksi tanah) dalam suatu volume tanah dan dideskripsikan
sebagai Kelas Tekstur Tanah.
The names for the particle-size classes correspond closely with commonly used standard terminology, including that of the system used by the United States Department of Agriculture (USDA). However, many national systems describing particle-size and textural classes use more or less the same names but different
grain fractions of sand, silt and clay, and textural classes.
KELAS TEKSTUR TANAH
Nama kelas tekstur (yang mendeskripsikan kombinasi kelas ukuran partikel primer) dari suatu tanah dinyatakan dnegan kode-kode.
In addition to the textural class, a field estimate of the percentage of clay is given. This estimate is useful for indicating increases or decreases in clay content within
textural classes, and for comparing field estimates with analytical results. The relationship between the basic textural classes and the percentages of clay, silt
DESKRIPSI TANAH
Pembagian Fraksi Pasir
Sands, loamy sands and sandy loams are subdivided according to the proportions of very coarse to coarse, medium, fine and very fine sands in the sand fraction. The proportions are calculated from the particle-size distribution, taking the total of the sand fraction as being 100 percent.
Estimasi Kelas Tekstur Tanah di Lapangan
The textural class can be estimated in the field by simple field tests and feeling the constituents of the soil. For this, the soil sample must be in a moist to weak wet state. Gravel and other constituents > 2 mm must be removed.
Komponen yang mempunyai “rasa” berikut:
1. Clay: “soils finger”, kohesif (melekat), dapat dibentuk, plastisitas tinggi dan mempunyai permukaan mengkilap setelah diremas (dipirit-pirit) di antara jari-jari tangan.
2. Silt: “soils finger”, tidak melekat, agak sulit dibentuk, mempunyai permukaan kasar setelah diremas di antara jari-jari tangan dan rasanya sangat bertepung (seperti bedak).
3. Sand: tidak dapat dibentuk, bukan “soil finger” dan rasanya sangat berbutir grainy.
TEKSTUR TANAH
Catatan untuk klasifikais tanah :Karakteristik diagnostik penting yang berasal dari kelas tekstur:
1. Tekstur pasir berlempung atau lebih kasar hingga kedalaman ≥ 100 cm → Arenosol.
2. Tekstur pasir halus berlempung atau lebih kasar dalam lapisan yg tebalnya ≥ 30 cm di dalam 100 cm permukaan tanah → Arenic qualifier.
3. Tekstur debu, lempung debu, lempung liat berdebu atau liat berdebu dalam lapisan yang tebalnya ≥ 30 cm, di dalam 100 cm tanah permukaan → Siltic qualifier.
4. A texture of clay in a layer ≥ 30 cm thick within 100 cm of the soil surface → Clayic qualifier. 5. ≥ 30 percent clay throughout a thickness of 25 cm → vertic horizon.
6. ≥ 30 percent clay throughout a thickness of 15 cm → vertic properties. 7. ≥ 30 percent clay between the soil surface and a vertic horizon → Vertisol.
8. ≥ 30 percent clay, < 20 percent change (relative) in clay content over 12 cm to layers immediately above and below, a silt/clay ratio of < 0.4 → nitic horizon.
9. Sandy loam or finer particle size → ferralic horizon.
10. A texture in the fine earth fraction of very fine sand, loamy very fine sand, or finer → cambic horizon. 11. A texture in the fine earth fraction coarser than very fine sand or loamy very fine sand → Brunic
qualifier.
12. A texture of loamy sand or finer and ≥ 8 percent clay → argic and natric horizons.
13. A texture of sand, loamy sand, sandy loam or silt loam or a combination of them → plaggic horizon. 14. A higher clay content than the underlying soil and relative differences among medium, fine and very
fine sand and clay < 20 percent → irragric horizon.
15. A texture of sandy clay loam, clay loam, silty clay loam or finer → takyric horizon.
16. ≥ 8 percent clay in the underlying layer and within 7.5 cm either doubling of the clay content if the overlying layer has less then 20 percent or 20 percent (absolute) more clay → abrupt textural change.
TEKSTUR TANAH
Catatan untuk klasifikais tanah :
Karakteristik diagnostik penting yang berasal dari kelas tekstur:
1. An abrupt change in particle-size distribution that is not solely associated with a change in clay content resulting from pedogenesis or a relative change of ≥ 20 percent in the ratios between coarse sand, medium sand, and fine sand → lithological discontinuity.
2. The required amount of organic carbon depends on the clay content, if the layer is saturated with water for ≥ 30 consecutive days in most years → organic and mineral materials.
3. The required amount of organic carbon depends on the texture → aridic properties.
4. The depth where an argic horizon starts depends on the texture → Alisols, Acrisols, Luvisols and Lixisols, and Alic, Acric, Luvic and Lixic qualifiers.
5. An argic horizon in which the clay content does not decrease by 20 percent of more (relative) from its maximum within 150 cm → Profondic qualifier.
6. Peningkatan absolut liat ≥ 3 % → Hypoluvic qualifier. 7. Rasio Debu/Liat < 0.6 → Hyperalic qualifier.
Kunci Kelas Tekrtur Tanah
1. Tidak mungkin membuat gulungan (seperti kawat) diameter 7 mm (sekitar diameter pensil)
1.1. not dirty, not floury, no fine material in the finger rills:
• if grain sizes are mixed: unsorted sand US < 5 • if most grains are very coarse (> 0.6 mm):
• if most grains are of medium size (0.2–0.6 mm): • if most grains are of fine size (< 0.2 mm) but still grainy:
• if most grains are of very fine size (< 0.12 mm), tending to be floury:
Sand
Very coarse & coarse sand Medium sand
Fine sand
Very fine sand
S CS MS FS VFS % liat <5 <5 <5 <5 <5
1.2. not floury, grainy, scarcely fine material in the finger rills, weakly shapeable, adheres slightly to the fingers:
Loamy sand LS <12
1.3. similar to 1.2 but moderately floury: sandy loam SL (clay-poor)
Kunci Kelas Tekrtur Tanah
2. Possible to roll a wire of about 3–7 mm in diameter
(about half the diameter of a pencil) but breaks when trying to form the wire to a ring of about 2–3 cm in diameter,
moderately cohesive, adheres to the fingers
2.1 very floury and not cohesive • some grains to feel:
• no grains to feel:
2.2 moderately cohesive, adheres to the fingers, has a rough and ripped surface after squeezing between fingers and
• very grainy and not sticky: • moderate sand grains:
• not grainy but distinctly floury and somewhat sticky:
Silt loam Silt Sandy loam Loam Silt loam SiL Si SL L SiL <10 <12 10-25 8-27 10-27
2.3 rough and moderate shiny surface after squeezing between fingers and is sticky and grainy to very grainy:
Kunci Kelas Tekrtur Tanah
3. Possible to roll a wire of about 3 mm in diameter (less than half the diameter of a pencil) and to form the wire to a ring of about 2–3 cm in diameter, cohesive, sticky, gnashes between teeth, has a moderately shiny to shiny surface after squeezing between fingers
3.1. very grainy:
3.2. some grains to see and to feel, gnashes between teeth
• moderate plasticity, moderately shiny surfaces:
• high plasticity, shiny surfaces:
Sandy clay (Liat berpasir) Clay loam (Lempung liat) Clay (Liat) SC CL C 35-55 25-40 40-60 3.3. no grains to see and to feel, does not gnash
between teeth • low plasticity:
• high plasticity, moderately shiny surfaces: • high plasticity, shiny surfaces:
Silty clay loam
Silty clay (Liat berdebu) Heavy clay Iliat berat)
SiCL SiC HC 25-40 40-60 >60
Kunci Kelas Tekrtur Tanah
Catatan:
Penentuan tekstur tanah di lapangan tergfantung pada komposisi mineralogis liat. Kunci-kunci yang disajikan di atas, terutama untuk tanah-tanah yang mengandung illite, chlorite dan / atau vermiculite. Liat Smectite lebih plastis, dan liat kaolinitik lebih lengket. Sehingga adanya liat Smektit dapat mengakibatkan overestimasi, dan adanya liat kaolinitik dapat mengakibatkan under-estimasi.
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Fragmen Batuan dan Artefacts
Keberadaan fragmen batuan dapat mempengaruhi status ketersediaan hara, pergerakan air, penggunaan dan pengelolaan tanah. Hal ini juga mencerminkan asal-usul dan tingkat perkembangan tanah.
Artefacts (sections on artefacts and description of artefacts [below]) are useful for identifying colluviation, human occupation, and industrial processes.
Large rock and mineral fragments (> 2 mm) and artefacts are described according to abundance, size, shape, state of weathering, and nature of the fragments. The abundance class limits correspond with the ones for surface coarse fragments and mineral nodules, and the 40 percent boundary coincides with the requirement for the skeletic phase.
Kalau fragmen batuan tidak terdistribusi secara teratur di dalam suatu horison, tetapi membentuk semacam “stone line”, maka harus dinyatakan dnegan jelas.
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Ukuran fragmen batuan dan artefacts
Klasifikasinya disjaikan dalam tabel berikut. Catatan untuk klasifikais tanah:
Karakteristik penciri penting yang berasal dari jumlah fragmen batuan:
1. < 20 percent (by volume) fine earth averaged over a depth of 75 cm or to continuous rock → Leptosols and Hyperskeletic qualifier.
2. ≥ 40 percent (by volume) gravel or other coarse fragments averaged over:
• a depth of 100 cm or to continuous rock → Skeletic qualifier; • a depth of 50–100 cm → Endoskeletic qualifier;
• a depth of 20– 50 cm → Episkeletic qualifier.
3. ≥ 20 (volume) artefact dalam lapisan atas upper 100 cm → Technosols.
4. < 40 persen volume berupa kerikil atau fragmen kasar lain dalam semua lapisan hingga 100 cm atau horison petroplinthic, plinthic atau salic → Arenosols.
5. Material Fragmental, rongga-rongga di antara fragmen diisi oleh bahan organik → Histosols.
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Klasifikasi fragmen batuan dan artefact
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Klasifikasi bentuk fragmen batuan
Bentuk fragmen Batuan
Bentuk umum atau kebulatan
fragmen batuan dapat
dideskripsikan sebagai: Pipih,
Bersudut, Membulat, Bulat
(Rounded)
Catatan unt klasifikasi:
Layers with rock fragments
of angular shape overlying or
underlying layers with rock
fragments of rounded shape
or marked differences in size
and shape of resistant minerals
between superimposed layers →
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Kondisi pelapukan fragmen batuan dan artefact Kondisi pelapukan fragmen kasar dideskripsikan sebagai
F (Lapuk ringan), W (lapuk) dan S (lapuk lanjut).
Catatan untuk klasifikasi tanah
A layer with rock fragments without weathering rinds overlying a layer with rock fragments with weathering
rinds → lithological discontinuity.
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Sifat fragmen batuan
Sifat fragmen batuan dideskripsikan dengan menggunakan terminologi yang
sama dnegan deskripsi tipe-batuan. Untuk fragmen mineral primer, dapat dipakai kode-kode lainnya.
Fragments of individual weatherable minerals (e.g. feldspars and micas) may be smaller than 2 mm in diameter. Nevertheless, where present in appreciable quantities, such fragments should be mentioned separately in the description. For artefacts, see section on artefacts.
Catatan untuk klasifikasi tanah:
Fragmen batuan yang tidak mempunyai sifat litologis sama dnegan batuan dibawahnya → lithological discontinuity.
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Derajat dekomposisi dan humifikasi gambut – peat
In most organic layers, the determination of the texture class is not possible. More valuable is an estimate of the degree of decomposition and humification of the organic material.
Warna dan persentase jaringan tumbuhan aslinya pada bahan organik kering atau basah, dapat digunakan untuk estimasi derajat dekomposisinya.
Catatan unbtuk klasifikasi tanah:
1. Histosol mempunyai lebih dari dua-pertiga (volume) jaringan tumbuhan yang masih dapat dikenali → Fibric qualifier.
2. Histosols have between two-thirds and one-sixth (by volume) recognizable plant tissues → Hemic qualifier.
3. Histosol mempunyai kurang dari seper-enam (1/6) (volume) ) jaringan tumbuhan yang masih dapat dikenali → Sapric qualifier.
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WARNA TANAH (MATRIX)
Warna tanah mencerminkan komposisi dan kondisi oksidasi-reduksi saat ini dan masa lalu yang dialami oleh tanah. Warna biasanya ditentukan oleh penyelimutan
partikel sangat halus bahan organik humik (warna gelap), oksida besi (kuning, coklat, orange dan merah), Oksida manganese (hitam) dan lainnya; atau
ditentukan oleh warna bahan induk tanah.
The colour of the soil matrix l of each horizon should be recorded in the moist condition (or both dry and moist conditions where possible) using the notations for
hue, value and chroma as given in the Munsell Soil Color Charts (Munsell, 1975). Hue is the dominant spectral colour (red, yellow, green, blue or violet), value is the lightness or darkness of colour ranging from 1 (dark) to 8 (light), and chroma is the purity or strength of colour ranging from 1 (pale) to 8 (bright). Where there is no dominant soil matrix colour, the horizon is described as mottled and two or
more colours are given.
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WARNA TANAH
For routine descriptions, soil colours should be determined out of direct sunlight and by matching a broken ped with the colour chip of the Munsell Soil
Color Charts.
For special purposes, such as for soil classification, additional
colours from crushed or rubbed material may be required. The occurrence of contrasting colours related to the structural organization of the soil, such as ped
surfaces, may be noted.
Where possible, soil colour should be determined under uniform conditions. Early morning and late evening readings are not accurate. Moreover, the determination of colour by the same or different individuals has often proved to be inconsistent. Because soil colour is significant with respect to various soil properties, including organic matter contents, coatings and state of oxidation or reduction, and for soil classification, cross-checks are recommended and should
DESKRIPSI WARNA TANAH
Catatan untuk kalsifikasi tanah:
Intermediate colours should be recorded where desirable for the distinction between two soil horizons and for purposes of classification and interpretation of the soil profile. Intermediate hues (important for qualifiers, such as Chromic or Rhodic, and for diagnostic horizons, such as cambic) that may be used are: 3.5, 4, 6, 6.5, 8.5 and 9 YR.
Misalnya: 3.5 YR, berarti bahwa nilai intermediate-hue lebih dekat dengan nilai 2.5 YR daripada 5 YR; 4 YR berarti lebih dekat ke 5 YR, dst.
Kalau “value” dan “chroma” mendekati batas-batas diagnostik, tidak boleh dilakukan pembulatan nilai, tetapi pencatatan akurat harus dilakukan dnegan menggunakan nilai-nilai intermediate, atau dnegan jalan menambah tanda + atau tanda - .
Pentingnya diagnostik hue, value dan chroma:
1. Abrupt changes in colour not resulting from pedogenesis → lithological discontinuity.
2. Redder hue, higher value or higher chroma than the underlying or an overlying layer → cambic horizon. 3. Hue redder than 10 YR or chroma ≥ 5 (moist) → ferralic properties, Hypoferralic and Rubic qualifier. 4. Hue 7.5 YR or yellower and value ≥ 4 (moist) and chroma ≥ 5 (moist) → Xanthic qualifier.
5. Hue redder than 7.5 YR or both hue 7.5 YR and chroma > 4 (moist) → Chromic qualifier. 6. Hue redder than 5 YR, value < 3.5 (moist) → Rhodic qualifier.
7. Hue 5 YR or redder, or hue 7.5 YR and value ≤ 5 and chroma ≤ 5, or hue 7.5 YR and value ≤ 5 and chroma 5 or 6, or hue 10 YR or neutral and value and chroma ≤ 2, or 10 YR 3/1 (all moist) → spodic horizon.
8. Hue 7.5 YR or yellower or GY, B or BG; value ≤ 4 (moist); chroma ≤ 2 (moist) → puddled layer (anthraquic ). 9. Hue N1 to N8 or 2.5 Y, 5 Y, 5 G or 5 B → reductimorphic colours of the gleyic colour pattern.
10. Hue 5 Y, GY or G → gyttja (limnic material).
11. Chroma < 2.0 (moist) and value < 2.0 (moist) and < 3.0 (dry) → voronic horizon. 12. Chroma ≤ 2 (moist) → Chernozem.
13. Chroma ≤3 (moist) and value ≤ 3 (moist) and ≤ 5 (dry) → mollic and umbric horizon. 14. Value and chroma ≤ 3 (moist) → hortic horizon.
15. Value ≤ 4 (moist) and ≤ 5 (dry) and chroma ≤ 2 (moist) → plaggic horizon. 16. Value > 2 (moist) or chroma > 2 (moist) → fulvic horizon.
17. Value ≤ 2 (moist) and chroma ≤ 2 (moist) → melanic horizon.
18. Values 4 to 8 and chroma 4 or less (moist) and values 5–8 and chromas 2–3 (dry) → albic horizon. 19. Lower value or chroma than the overlying horizon → sombric horizon.
20. Value ≥ 3 (moist) and ≥ 4.5 (dry) and chroma ≥ 2 (moist) → aridic properties. 21. Value ≤ 4 (moist) → coprogenous earth or sedimentary peat (limnic material). 22. Value 3, 4 or 5 (moist) → diatomaceous earth (limnic material).
23. Value ≥ 5 (moist) → marl (limnic material).
24. Value ≤ 3.5 (moist) dan chroma ≤ 1.5 (moist) → Pellic qualifier.
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MOTTLING : BECAK-BECAK
Mottles are spots or blotches of different colours or shades of colour interspersed with the dominant colour of the soil. They indicate that the soil has been subject to alternate wetting (reducing) and dry (oxidizing) conditions.
Becak dideskripsikan dengan indikator “kelimpahan”, ukuran, kontras, batas, dan warna. Selain itu, “bentuk”, posisi, dan ciri-ciri lainnya juga dapat dicatat.
Catatan untuk klasifikais tanah:
1. Mottles of oxides in the form of coatings or in platy, polygonal or reticulate patterns are
diagnostic for the anthraquic (plough pan), hydragric, ferric, plinthic and petroplinthic horizons and for the gleyic colour pattern.
2. Mottles of oxides in the form of concretions or nodules are diagnostic for the hydragric, ferric, plinthic, petroplinthic and, pisoplinthic horizons and for the stagnic colour pattern.
3. Redox depleted zones in macropores with a value ≥ 4 and a chroma ≤ 2 are diagnostic for the hydragric horizon.
4. Becak atau selimut yang berupa jarosite atau schwertmannite merupakan penciri untuk horison thionic dan Aceric qualifier.
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Warna Becak
Biasanya warna becak dideskripsikan secara umum sesuai dengan Munsell
Soil Color Charts.
Kelimpahan Becak
Kelimpahan becak dideskripsikan dalam “Kelas-kelas” yang
menyatakan persentase permukaan yang ditempati becak.
Batas-batas kelas sesuai dnegan nodul mineral.
When the abundance of mottles does not allow the distinction of a single predominant matrix or groundmass
colour, the predominant colours should be determined and entered as
soil matrix colours.
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Ukuran Bercak
Kelas-kelas yang digunakan
untuk menyatakan diameter
individual bercak.
Kelas-kelas ini sesuai dengan
kelas-kelas ukuran nodul
mineral.
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Kontras Becak
Kontras warna antara becak dan matriks tanah dapat dideskripsikan sebagai Haint,
Distinch, dan Prominent.
Batas Becak
Batas antara becak dan matriks dideskripsikan sebagai “tebal” zone transisi
warna.
Klasifikasi ke-Kontras-an becak
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SOIL REDOX POTENTIAL AND REDUCING CONDITIONS Determination of redox potential by field method
Soil redox potential is an important physico-chemical parameter used to characterize soil aeration status and availability of some nutrients. The redox potential is also used in the WRB classification to classify redoximorphic soils.
To measure redox potential (DIN/ISO Draft, DVWK, 1995), drive a hole into the soil using a rigid rod (stainless steel, 20–100 cm long, with a diameter that is 2 mm greater than the redox electrodes) to a depth about 1–2 cm less than the desired depth to be measured. Immediately clean the platinum surface of the redox electrode with sandpaper and insert the electrode about 1 cm deeper than the prepared hole. At least two electrodes should be installed for each depth being measured. After at least 30 minutes, measure the redox potential with a millivoltmeter against a reference electrode (e.g. Ag/AgCl in KCl of the glass electrode of pH measurements, installed in a small hole on the topsoil that has been filled with 1-M KCl solution). For dry topsoil, a salt bridge (plastic tube 2 cm in diameter and with open ends, filled with 0.5 percent (M/M) agar in KCl solution) should be installed in a hole beside and at the depth of the platinum electrodes. In this tube, the reference electrode should be installed.
The measured voltage (Em) is related to the voltage of the standard hydrogen electrode by adding the potential of the reference electrode (e.g. +244 millivolt at 10 °C of Ag/AgCl in 1 M KCl, +287 of Calomel electrode).
For interpretation, the results should be transformed to rH values using the formula: rH = 2pH + 2Eh/59 (Eh in mV at 25 °C).
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Karakteristik Redoximorphic tanah dan hubungannya dnegan nilai rH dan proses-proses tanah
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Kondisi Reduksi
Reductimorphic properties of the soil matrix reflect permanently wet or at least reduced conditions. They are expressed by neutral (white to black:
Munsell N1 to N) or bluish to greenish colours (Munsell 2.5 Y, 5 Y, 5 G, 5 B). The colour pattern will often change by aeration in minutes to days owing to oxidation processes.
The presence of FeII ions can be tested by spraying the freshly exposed soil surface with a 0.2-percent (M/V) α,α dipyridyl solution in 10-percent (V/V) acetic acid solution. The test yields a striking reddish-orange colour in the presence of Fe2+ ions but may not give the strong red colour in soil materials with a neutral or alkaline soil reaction. Care is necessary as the chemical is slightly toxic.
Catatan untuk klasifikasi tanah:
An rH value of < 20 is diagnostic for reducing conditions in Gleysols, Planosols and Stagnosols, and stagnic and gleyic lower level units of other RSGs. Gaseous emissions (methane, carbon dioxide, etc.) are diagnostic for the Reductic qualifier.
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CARBONATES : KandunganKarbonat dalam tanah dapat berupa residu bahan induk atau hasil bentukan baru (carbonate sekunder). Karbonat sekunde rterutama berbentu bubuk halus kapur, selimut pada agregat, konkresi, kerak permukaan
atau bawah permukaan, atau “hard banks”.
The presence of calcium carbonate (CaCO3) is established by adding some drops of 10-percent HCl to the soil. The degree of effervescence of carbon dioxide
gas is indicative for the amount of calcium carbonate present. In many soils, it is difficult to distinguish in the
field between primary and secondary carbonates. Classes for the reaction of carbonates in the soil matrix
are defined as per Table xx.
The reaction to acid depends upon soil texture and is usually more vigorous in sandy material than in
fine-textured material with the same carbonate content. Other materials, such as roots, may also give an audible
reaction.
Dolomite biasanya bereaksi lebih lambat dan kurang kuat dibanding kalsit. Karbonat sekunder harus diuji
secara terpisah; biasanya mereka ini bereaksi lebih intensif dengan HCl.
Classification of carbonate reaction in the soil matrix
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Klasifikasi bentuk karbonat sekunder
Bentuk Karbonat
The forms of secondary carbonates in soils are diverse and are considered to be informative for diagnostics of soil genesis. Soft carbonate concentrations are considered to be
illuvial, and hard concretions are generally believed to be of hydrogenic nature.
Untuk Klasifikasi tanah:
Pentingnya kandungan karbonat:
1. ≥ 2 percent calcium carbonate equivalent → calcaric material.
2. ≥ 15 percent calcium carbonate equivalent in the fine earth, at least partly secondary → calcic horizon. 3. Indurated layer with calcium carbonate, at least partly
secondary → petrocalcic horizon.
4. 15–25 percent calcium carbonate equivalent in the fine earth, at least partly secondary → Hypocalcic qualifier. 5. ≥ 50 percent calcium carbonate equivalent in the fine
earth, at least partly secondary → Hypercalcic qualifier. 6. Where a soil has a calcic horizon starting 50–10 cm
from the soil surface, it is only a Calcisol if the soil matrix between 50 cm from the soil surface and the calcic horizon is calcareous throughout.
7. Calcisols and Gypsisols can only have an argic horizon where the argic horizon is permeated with calcium carbonate (Calcisols) or calcium carbonate or gypsum
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pH tanah di lapang
Soil pH expresses the activity of the hydrogen ions in the soil solution. It affects the availability of mineral
nutrients to plants as well as many soil processes. When the pH is measured in the field, the method used should be indicated on the field data sheet. The field soil pH should not be a substitute for a laboratory
determination. Field soil pH measurements should be correlated with laboratory determinations where
possible.
In the field, pH is either estimated using indicator papers, indicator liquids (e.g. Hellige), or measured with a portable pH meter in a soil suspension (1 part
soil and 2.5 parts 1 M KCl or 0.1 M CaCl2 solution). After shaking the solution and waiting for 15 minutes, the pH value can be read. For the measurement, use a
transparent 50-ml plastic cup with marks for 8 cm3 soil (~ 10 g) and 25 ml solution.
Catatan untuk Klasifikasi Tanah
Pada kebanyakan tganah, nilai pH berkorelasi dnegan kejenuhan basa, hal ini penting dalam klasifikasi tanah di lapangan. Akan tetapi hal ini memerlukan
pembuktian di laboratorium.
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Kandungan Bahan organik tanah
“Bahan organik” refers to all decomposed, partly decomposed and undecomposed organic materials of plant and animal origin. It is generally synonymous with humus although the latter is more commonly used when referring to the well decomposed organic matter called “substansi humik”.
The content of organic matter of mineral horizons can be estimated from the Munsell colour of a dry and/or moist soil, taking the textural class into account. This estimation is based on the assumption that the soil colour (value) is due to a mixture of dark coloured organic substances and light coloured minerals.
This estimate does not work very well in strongly coloured subsoils. It tends to overestimate organic matter content in soils of dry regions, and to underestimate the organic matter content in some tropical soils. Therefore, the organic matter values should always be locally checked as they only provide a rough estimate.
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Kandungan BOT untuk klasifikasi tanah
1. If saturated with water for ≥ 30 consecutive days in most years (unless drained):
• ≥ [12 + (clay percentage of the mineral fraction × 0.1)]% organic carbon or • ≥ 18 percent organic carbon, else ≥ 20 percent organic carbon → organic
material.
2. Organic material saturated with water for ≥ 30 consecutive days in most years (unless drained) → histic horizon.
3. Organic material saturated with water for < 30 consecutive days in most years → folic horizon.
4. Weighted average of ≥ 6 percent organic carbon, and ≥ 4 percent organic carbon in all parts → fulvic and melanic horizon.
5. Organic carbon content of ≥ 0.6 percent → mollic and umbric horizon. 6. Organic carbon content of ≥ 1.5 percent → voronic horizon.
(Note: the ratio of organic carbon to organic matter is about 1:1.7–2.) Write the range or average value in the description sheet.
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STRUKTUR TANAH
Soil structure refers to the natural organization of soil particles into discrete
soil units (aggregates or peds) that result from pedogenic processes. The
aggregates are separated from each other by pores or voids. It is preferred
to describe the structure when the soil is dry or slightly moist. In moist or
wet conditions, it is advisable to leave the description of structure to a later
time when the soil has dried out. For the description of soil structure, a
large lump of the soil should be taken from the profile, from various parts of
the horizon if necessary, rather than observing the soil structure
in situ.
Sruktur tanah dideskripsikan dengan indikator “grade”, “ukuran” dan “tipe”
agregat.
Kalau suatu horison tanah mengandung agregat dnegan bermacam
“grade”, ukuran atau tipe, semuanya harus dideskripsikan dan hubungan
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Grade Struktur
In describing the grade or development of the structure, the first division is into apedal soils (lacking soil structure) and
pedal soils (showing soil structure). In apedal or structureless soil, no aggregates are observable in place and there is no definite arrangement of natural
surfaces of weakness. Structureless soils are subdivided into single grain and
massive.
Single-grain soil material has a loose, soft or very friable consistence and consists
on rupture of more than 50 percent discrete mineral particles. Massive soil material normally has a
stronger consistence and is more coherent on rupture. Massive soil material
may be further defined by consistence (below) and porosity (below).
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Klasifikasi Tipe Struktur
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Tipe Struktur
Tipe-tipe alamiah dari
struktur tanah adalah
gumpal, pipih, granuler, dan
lainnya.
Where required, special
cases or combinations of
structures may be
distinguished, which are
subdivisions of the basic
structures.
Kode-kode yang
direkomendaiskan adalah
seperti pada tabek berikut.
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Ukuran Struktur
Size classes vary with the structure type. For prismatic, columnar and
platy structures, the size classes refer to the measurements of the smallest dimension of the aggregate.
Combined classes may be Constructed.
Where a second structure is present, its relation to the first structure is
described. The first and second structures may both be present (e.g. columnar and prismatic structures). The primary structure
may break down into a secondary structure (e.g. prismatic breaking into angular blocky). The first structure may merge into the second structure (e.g. platy
merging into prismatic).
Kelas ukuran kombinasi
DESKRIPSI TANAH
DESKRIPSI STRUKTUR TANAH
Catatan untuk klasifikasi tanah:1. Soil structure, or absence of rock structure (the term “rock structure” also applies to unconsolidated sediments in which stratification is still visible) in half of the volume or more of the fine earth → cambic horizon.
2. Soil structure sufficiently strong that the horizon is not both massive and hard or very hard when dry (prisms larger than 30 cm in diameter are included in the meaning of massive if there is no secondary structure within the prisms) → mollic, umbric and anthric horizons.
3. Granular or fine subangular blocky soil structure (and worm casts) → voronic horizon.
4. Columnar or prismatic structure in some part of the horizon or a blocky structure with tongues of an eluvial horizon → natric horizon.
5. Moderate to strong, angular blocky structure breaking to flat-edged or nutshaped elements with shiny ped faces → nitic horizon.
6. Wedge-shaped structural aggregates with a longitudinal axis tilted 10–60 ° from the horizontal → vertic horizon.
7. Wedge-shaped aggregates → vertic properties. 8. Platy structure → puddled layer (anthraquic horizon). 9. Uniformly structured → irragric horizon.
10. Separations between structural soil units that allow roots to enter have an average horizontal spacing of ≥ 10 cm → fragic horizon.
11. Platy or massive structure → takyric horizon. 12. Platy layer → yermic horizon.
13. Strong structure finer than very coarse granular → Grumic qualifier.
14. Massive and hard to very hard in the upper 20 cm of the soil → Mazic qualifier. 15. A platy structure and a surface crust → Hyperochric qualifier.
