KLASIFIKASI TANAH

BAHAN KULIAH DASAR-DASAR ILMU TANAH

Fakultas Pertanian Unibraw

Klasifikasi Tanah:

Usaha membeda-bedakan

mengelompokkan tanah berdasar-

kan sifat-sifatnya 

Tujuan :

mengetahui sifat dan ciri tanah pada

masing2 kelompok tanah (kelas

tanah) sehingga memudahkan

pengguna tanah untuk mengelola

tanah tersebut agar dapat

berproduksi secara optimal. 

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Alami/taksonomi : berdasarkan sifat2 alami tanah tanpa dihub. dgn pengunaannya

- Taksonomi Tanah (USDA)

 

Teknikal : berdasarkan tujuan khusus dgn memilih ciri2 ttt yg pgrhi kemampuan dan penggunaannya-         - Klasifikasi Kemampuan Lahan USDA-       - Klasifikasi Kesesuaian Lahan FAO

Klasifikasi

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General Principles of Natural Classification Systems:• The system should express general or universal

relationships that exist in nature. One should be able to understand, remember, generalize, or predict from the information obtained.

• The scheme should be based on characteristics or attributes of things classified as related to their genesis. It should place similar things together on the basis of their properties.

• It is technically impossible to use all properties of the items being classified. Existing knowledge must be used to determine which properties are most important

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Why Classify Soils?• Organize knowledge to enable

investigation and communication (structure/organization)

• Provide framework for establishing relationships among soils and their environment (scientific)

• Establish groupings for interpretations (utilitarian)– Optimal use

– Hazard/limitation/remediation assessment

– Potential productivity

– Framework for technology transfer/information dissemination

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Tanah bermacam-macam

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Klasifikasi Tanah di Indonesia

• Sejak th 1988 hanya gunakan sistem Taksonomi Tanah.

• Sebelum 1988 ada 3 :

- Pusat Penelitian Tanah (PPT)

- FAO/UNESCO dan – Taksonomi Tanah.

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Taksonomi Tanah (USDA)

•dikembangkan oleh Soil Survey Staff (USDA), tahun 1975

•Terus direvisi 2ed, 1999

•ada 6 kategori yaitu Order, Suborder, Great group, Subgroup, Family dan Series.

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Categories in ST:

• Order – key soil properties resulting from major soil-forming processes (epipedons, subsurface horizons, materials, characteristics)

• Suborder – key soil properties that are major controls on soil-forming processes, e.g., soil climate (most orders); kinds of salts (Aridisols); kinds of soil parent materials (Entisols); degree of decomposition (Histosols); presence or absence of cryoturbation (Gelisols)

• Great Group – key soil properties that are additional controls on soil genesis (diagnostic horizons)

• Subgroup – central concept (Typic), intergrades, extragrades

• Family – properties important to plant growth (texture, mineralogy, soil temperature regime, etc.)

• Series – soil morphology

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Kategori

Nama Kategori Nama

Phylum Pteridophyta Order Alfisol

Kelas Angiospermae

Sub-order Udalf

Sub-kelas

Dicotyledoneae

Greatgroup

Hapludalf

Order Rosales Sub-group Aquic Hapludalf

Family Leguminoseae

Family Aquic Hapludalf, berlempung halus, Campuran, Aktif, Isohipertermik

Genus Trifolium Seri Lape

Species T. repens (Phase) Berbatu

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Differentiating Characteristics in ST:

• Diagnostic epipedons

• Diagnostic subsurface horizons

• Other diagnostic soil characteristics

• Soil moisture and temperature regimes

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1. Epipedon

•horison penciri yg tbtk di permukaan tanah.

•tidak sinonim dg hor A•dpt mencakup sebag. hor B.

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EPIPEDON

• Surface horizons• Influenced strongly by

biochemical and geochemical processes

• Correspond with A, E, and sometimes upper B horizons

• Important in classifying soils

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EPIPEDON

• Histik: BO tinggi (>75%), tebal 20‑40cm.• Mollik: BO >1%, warna gelap dg value dan kroma <3

(lembab) dan value < 5 (kering), tebal >18cm, KB >50%.

• Melanik: mirip Mollik, tetapi miliki sifat tanah andik• Umbrik: sep molik tetapi KB <50%.• Anthropik: sep molik, tetapi mengandung >1500 ppm

P2O5 larut dlm 1% as sitrat. • Ochrik: warna terang (value dan kroma lembab >3), BO

<1% atau keras‑sangat keras dan masif.• Plaggen: hor buatan, akibat penggunaan pupuk kandang

yg terus menerus, tebal >50cm, berwarna hitam.• Folistik: t.a. BO, jenuh < 30 hari

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Horison Penciri Bawah• Agrik: hor iluviasi yg tbtk krn pgrh pengolahan

tanah shg terjadi akumulasi sejumlah debu, liat, dan humus.

• Albik: hor berwarna pucat (E) dg value lembab >5.

• Argillik: hor penimbunan liat; minimal mengandung liat >1.2 kali lebih banyak d/p kand. liat di

atasnya. Tdpt selaput liat.• Kalsik: hor yg mengandung karbonat sekunder

(CaCO3 atau MgCO3) tinggi, tebal >15cm.• Petrokalsik:hor kalsik yang mengeras.• Kambik: indikasi lemah adanya argillik atau spodik,

tapi tidak memenuhi syarat kedua hor tsb.

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Horison Penciri Bawah (lanjutan)• Gipsik : banyak mengandung gipsum (CaSO4) sekunder.• Petrogipsik: hor gipsik yg mengeras.• Natrik : hor argillik yg banyak mengandung Na• Oksik : hor bertekstur agak kasar, KTK <16 me/100g liat,

tebal >30cm.• Salik: banyak mengandung garam sekunder mudah larut,

tebal >15cm.• Sombrik : sep umbrik, gelap, terjadi iluviasi humus tanpa Al,

tidak terletak di bawah hor albik.• Spodik : hor iluviasi seskuioksida bebas dan BO.• Sulfurik : hor yg mengandung sulfat, pH ,3.5, tdpt karatan

jarosit. • Plasik: padas tipis tersementasi seny. Fe, Mn dan BO

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Kategori

Nama Kategori Nama

Phylum Pteridophyta Order Alfisol

Kelas Angiospermae

Sub-order Udalf

Sub-kelas

Dicotyledoneae

Greatgroup

Hapludalf

Order Rosales Sub-group Aquic Hapludalf

Family Leguminoseae

Family Aquic Hapludalf, berlempung halus, Campuran, Aktif, Isohipertermik

Genus Trifolium Seri Lape

Species T. repens (Phase) Berbatu

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TAKSONOMI TUMBUHAN vs TAKSONOMI TANAH

“Soil Taxonomy"

Degree of Weathering and B Horizon Development

Little Slight Moderate Large Extreme

Entisols Aridisols

Inceptisols Alfisols

Spodosols Ultisols

Mollisols Oxisols

Soils Defined by Special Constituent Materials

Andisols Volcanic Ash

Histosols Peat, Organic Matter

Vertisols “Self-Mixing” Clay Soils

Gelisols Soils on Permafrost

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ALFISOL

• The central concept of Alfisols is that of soils that have an argillic, a kandic, or a natric horizon and a base saturation of 35% or greater.

• They typically have an ochric epipedon, but may have an umbric epipedon. They may also have a petrocalcic horizon, a fragipan or a duripan.

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ANDISOLS• The central concept of Andisols

is that of soils dominated by short-range-order minerals.

• They include weakly weathered soils with much volcanic glass

as well as more strongly weathered soils.

• Hence the content of volcanic glass is one of the

characteristics used in defining andic soil properties

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ARIDISOLAridisols is that of soils that are too dry for mesophytic plants to grow. They have either: (1) an aridic moisture regime and an ochric or anthropic epipedon and one or more of the following with an upper boundry within 100 cm of the soil surface: a calcic, cambic, gypsic, natric, petrocalcic petrogypsic, or a salic horizon or a duripan or an argillic horizon, or (2)A salic horizon and saturation with water within 100 cm of the soil surface for one month or more in normal years.

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ENTISOLS• The central concept of

Entisols is that of soils that have little or no evidence of development of pedogenic horizons.

• Many Entisols have an ochric epipedon and a few have an anthropic epipedon. Many are sandy or very shallow.

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GELISOLS• The central concept of Gelisols is

that of soils that have permafrost within 100 cm of the soil surface and/or have gelic materials within 100 cm of the soil surface and have permafrost within 200 cm.

• Gelic materials are mineral or organic soil materials that have evidence of cryoturbation (frost churning) and/or ice segeration in the active layer (seasonal thaw layer) and/or the upper part of the permafrost.

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HISTOSOLS

• The central concept of Histosols is that of soils that are dominantly organic. They are mostly soils that are commonly called bogs, moors, or peats and mucks.

• A soil is classified as Histosols if it does not have permafrost and is dominated by organic soil materials.

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INCEPTISOLS • The central concept of Inceptisols is

that of soils of humid and subhumid regions that have altered horizons that have lost bases or iron and aluminum but retain some weatherable minerals. They do not have an illuvial horizon enriched with either silicate clay or with an amorphous mixture of aluminum and organic carbon.

• The Inceptisols may have many kinds of diagnostic horizons, but argillic, natric kandic, spodic and oxic horizons are excluded.

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MOLLISOLS• The central concept of Mollisols

is that of soils that have a dark colored surface horizon and are base rich. Nearly all have a mollic epipedon.

• Many also have an argillic or natric horizon or a calcic horizon. A few have an albic horizon. Some also have a duripan or a petrocalic horizon.

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OXISOLS • The central concept of Oxisols is

that of soils of the tropical and subtropical regions. They have gentle slopes on surfaces of great age. They are mixtures of quartz, kaolin, free oxides, and organic matter.

• For the most part they are nearly featureless soils without clearly marked horizons. Differences in properties with depth are so gradual that horizon boundaries are generally arbitrary.

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SPODOSOLS • The central concept of Spodosols is

that of soils in which amorphous mixtures of organic matter and aluminum, with or without iron, have accumulated. In undisrurbed soils there is normally an overlying eluvial horizon, generally gray to light gray in color, that has the color of more or less uncoated quartz.

• Most Spodosols have little silicate clay. The particle-size class is mostly sandy, sandy-skeletal, coarse-loamy, loamy, loamy- skeletal, or coarse-silty.

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ULTISOLS

• The central concept of Ultisols is that of soils that have a horizon that contains an appreciable amount of translocated silicate clay (an argillic or kandic horizon) and few bases (base saturation less than 35 percent).

• Base saturation in most Ultisols decreases with depth.

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VERTISOLS • The central concept of

Vertisols is that of soils that have a high content of expending clay and that have at some time of the year deep wide cracks.

• They shrink when drying and swell when they become wetter.

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MU Map Unit Name

1 Arnot loam, 25 to 35 percent slopes.

2 Arnot loam, 35 to 50 percent slopes.

3 Branford fine sandy loam, 3 to 8 percent slopes.

4 Branford fine sandy loam, 8 to 15 percent slopes.

5 Canarsie sandy loam, 0 to 3 percent slopes, compacted surface.

6 Canarsie sandy loam, 3 to 8 percent slopes, compacted surface.

7 Centralpark coarse sandy loam, 0 to 3 percent slopes, compacted substratum.

8 Centralpark coarse sandy loam, 3 to 8 percent slopes.

9 Cheshire loam, 8 to 15 percent slopes.

10 Cheshire loam, 15 to 25 percent slopes.

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SEKIANSampai ketemu di materi kuliah lain

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