dasar ilmu tanah – genesis pembentukan tanah

MK. DASAR ILMU TANAH. Smno.jursntnh.fpub.febr2013

GENESISTANAH

Foto: smno.kampus.ub.janu2013

Soil: Definisi

• Material padatan di permukaan bumi yang telah mengalami perubahan oleh proses-proses fisika, kimia dan biologi, sehingga ia mampu menunjang kehidupan tumbuhan berakar.

• Definisi ke-teknik-an: Anything that can be removed without blasting

DIUNDUH DARI: gis.ess.washington.edu/grg/courses/ess230/lectures/Soils_2012.ppt ….. 11/2/2013

Pembentukan tanah


Pembentukan Tanah: Input


Konversi batuan menjadi tanah

Pembentukan Tanah: Output

Gerakan tanah menuruni lereng


Ketebalan Tanah: Storage• input ± output = Ketebalan tanah• atau: Konversi batuan ± transpor tanah = ketebalan

• that is, soil thickness reflects the balance between rates of soil production and rates of downslope soil movement.

1. Kemiringan2. Laju

pelapukan


DIUNDUH DARI: www.indiana.edu/~g225/G225-Soils.ppt ....... 10/2/2013

Pembentukan Tanah - Pelapukan

Batuan induk

Silika

Debu

Pasir/Kuarsa

Liat 2

lapis

Liat 3

lapis

Ion-ion hara mineral dalam

larutanOksida Fe dan Al

Bahan induk halus

http://www.indiana.edu/~g225/G225-Soils.ppt

Beberapa tipe tanah:

1. Loess : tanah-tanah subur yang berkembang dari bahan induk debu glasial yang diangkut angin pada jaman es.

2. Laterites: tanah-tanah merah kaya oksida besi, di daerah tripika basah-panas, berkembang dari pelapukan intensif bahan induk

3. Pedalfers: rich soils with brown color, high in aluminum and iron; typical of cooler, wet temperate climates world-wide.

4. Pedocals: soils typical of warm, arid regions; high in calcium and commonly contain caliche (white deposits of calcium carbonate)

5. Tanah-tanah Tundra : tanah yang terbentuk pada kondisi iklim salju permanen menutup permukaan (permafrost).



Apakah “Tanah “ itu?

“Tanah” merupakan lapisan di permukaan bumi terdiri atas batuan lapuk, mineral dan bahan organik yang mampu mendukung kehidupan

tumbuhan.

Komposisi spesifik suatu tanah.

Soil is composed of mineral matter from

weathered rock; water, gases, and

organic matter (the remains of plant and animal material and

bacteria).


Persentase komposisi tanah



Sumur pompa dapat

menurunkan permukaan

groundwater


Penggunaan tanah untuk

mendukung kemanusiaan.


Simpanan air

Filtrasi air Buangan

limbah

Produksi seratProduksi

panganProduksi

kayu

Siklus karbon

Siklus Hara

Sumber bahan

bangunan

Landasan bagi

konstruksi


Model profil tanahDIUNDUH DARI: www.indiana.edu/~g225/G225-Soils.ppt ....... 10/2/2013

Struktur TanahHorison O, seresah dedaunan, bahan organik

Horison B, Zone akumulasi

Horison R, bahan induk yang belum terlapuk


PROFIL TANAH

• Horizon A– Zone eluviaSI

• Horizon B– Zone iluviaSI

• Horizon C– Bahan lapuk

• Horizon D– Batuan belum

lapuk

DIUNDUH DARI: www.csbs.edu.hk/.../ppt/Soil%20and%20Soil%20Forming%20Proces........5/2/2013

SoilsTANAH: Salah satu fenometa

penting di permukaan bumi untuk produksi, penghancuran

partikel sedimen, dan komponen-komponen

terlarut.

DIUNDUH DARI: smu.edu/earthsciences/academics/courses/geol3472/Lecture%202.ppt ……. 10/2/2013

“Pedogenesis” = Pembentukan tanah

ANATOMI TANAH

Terorganisir menjadi lima lapisan yang

berbeda,

disebut

Horison Tanah


Profil tanah yang ideal

Horison - O1. Characterized by in-situ

accumulation of plant material

2. Occurs only as a surface horizon, unless buried by sediment

3. Tidak semua tanah mempunyai Horison O

4. Typical of Everwet LowlandsKalau horison O terkubur, ia akan menjadi sumberdaya ekonomi berupa gambut

dan batubara


A-Horizons1. Zone pencucian ion-ion larut,

proses “eluviasi”.2. Akumulasi akar tumbuhan dan

bahan organik3. Organic acids and chelates to

promote weathering of minerals for plant nutrients

4. Unless an O-horizon is present, A horizons will occur at the surface of the soil

5. Semua tanah mempunyai Horison A

6. Dicirikan oleh warna gelap dari bahan organik


Horison B1. Zone of accumulation of new and residual

minerals from chemical weathering and physical transport (“illuviation”)

2. Kebanyakan tanah mempunyai horison B, tetapi tidak semua tanah

3. Dicirikan oleh perkembangan struktur tanah


Struktur Granuler

Struktur Pipih

Struktur Prismatik

Struktur Kolumner

Struktur Blocky

Butir-tunggal lepas

Horison C

1. Terdiri atas bahan induk tanah yang baru sedikit terlapuk

2. PARENT MATERIAL is rock (igneous, metamorphic or sedimentary) or sediment upon which the soil forms

3. Tidak mempunyai struktur tanah, dan sifat batuan aslinya masih tampak

4. Hampir semua tanah mempunyai Horison C


Horison R

1. Bahan induk yang kondisinya sementasi dan belum lapuk, tidak terpengaruhi oleh proses pembentukan tanah.

2. With time, this cemented material will be disaggregated and dissolved to form new sedimentary particles.

} Tanah - Soil

Horison R


PROSES GENESIS TANAH


DIUNDUH DARI: ……. 17/2/2013

A large number of processes are responsible for the formation of soils. This fact is evident by the large number of different types of soils that have been

classified by soil scientists. However, at the macro-scale we can suggest that there are five main principal pedogenic processes acting on

soils.

Proses-proses pembentukan tanah :1. Laterisasi, 2. Podsolisasi, 3. Klasifikasi, 4. Salinisasi5. Gleisasi.



LATERISASILaterisasi merupakan proses pedogenesis yang banyak terjadi

pada tanah-tanah di lingkungan tropis dan subtropis.

High temperatures and heavy precipitation result in the rapid weathering of rocks and minerals. Movements of large amounts

of water through the soil cause eluviation and leaching to occur. Almost all of the by products of weathering, very simple

small compounds or nutrient ions, are translocated out of the soil profile by leaching if not taken up by plants for nutrition.

Dua perkecualian bagi proses ini adalah senyawa Fe dan Al. Oksida-oksida Fe memberikan warna kemerahan pada tanah-

tanah tropis.

Pencucian yg intensif juga menyebabkan tanah-tanah ini mempunyai pH masam karena kehilangan kation basa.

http://www.physicalgeography.net/physgeoglos/w.html

FERRALIZATIONPencucian hampir semua kartion basa dan silika, destruksi aluminosilicates dan phyllosilicates

Pengkayaan oksi-hidroksida Fe dan Al, seperti Hematite, Goethite, dan GibbsiteHanya terjadi pada daerah iklim basah-panas.




PODSOLISASIPodzolization is associated with humid cold mid-latitude climates and coniferous vegetation.

Decomposition of coniferous litter and heavy summer precipitation create a soil solution that is strongly

acidic. Larutan tanah yang bersifat masam ini memacu proses-proses

eluviasi dan pencucian yg menyebabkan pengusiran kation basa larut dan senyawa-senyawa Al dan Fe dari Horison A.

Proses ini mneghasilkan sub-lapisan dalam Horison A yang berwarna putih hingga kelabu dan terdiri atas pasir silika.

http://www.physicalgeography.net/physgeoglos/c.html



PodsolisasiDescribes the process by which

fairly acid conditions (hydrolysis) and organo-metallic bonding (chelation) translocate Fe and Al from the topsoil to the

subsurface B-horizons.

Proses ini menghasilkan permukaan tanah yang diperkaya dengan silica

(khususnya kuarsa) dengan warna pucat..




KALSIFIKASI

Calcification occurs when evapotranspiration exceeds precipitation causing the upward movement of dissolved alkaline salts from the groundwater. At the same time, the movement of

rain water causes a downward movement of the salts.

Hasil dari proses ini adalah deposisi kation-kation terangkut dalam Horison B. Dalam beberapa kasus, deposit ini dapat membentuk suatu lapisan keras yang disebut “caliche”.

Substansi yang paling banyak terlibat dalam proses ini adalah kalsium karbonat.. Kalsifikasi banyak terjadi pada lingkungan

padnag-rumput prairie.

Kalsifikasi

1. Proses ini dicirikan oleh akumulasi kalsit dalam horison bawah-permukaan.

2. Ca2+ leached from upper horizons downward to depth of wetting in the soil

3. Upon drying, Ca2+ combines with CO3

2- to form calcite, CaCO3

4. Proses ini memerlukan evaporasi, terjadi di daerah iklim semi-arid dan arid .

Modern CaliforniaDIUNDUH DARI: smu.edu/earthsciences/academics/courses/geol3472/Lecture%202.ppt ……. 10/2/2013



SALINISASI

Salinization is a process that functions in the similar way to calcification. It differs

from calcification in that the salt deposits occur at or very near the soil surface.

Salinisasi juga dapat berlangsung pada kondisi iklim yang lebih kering.

SALINISASI

Ions in solution are concentrated by evaporating

water. Cations and anions force to combine and form

salts in the soil:

Na++Cl-<=>NaCl Ca2++SO4=<=>CaSO4

Proses ini penting pada lahan-lahan di daerah iklim Arid.

Ask me about the Mesopotamian Empire!DIUNDUH DARI: smu.edu/earthsciences/academics/courses/geol3472/Lecture%202.ppt ……. 10/2/2013



GLEISASI

Gleisasi merupakan proses pedogenesis yang berhubungan dnegan kondisi drainage ayang

buruk.

This process involves the accumulations of organic matter in the upper layers of the soil. In lower horizons, mineral layers are stained blue-gray because of the chemical reduction of iron.

http://www.physicalgeography.net/physgeoglos/r.html

Gleization1. Proses ini mencerminkan reaksi

oksidasi-reduksi dalam tanah2. Chemical reduction of elements

(mostly Fe, but also Mn) Poorly drained, anoxic soils:Fe3+ + e- <=> Fe2+

3. Fe2+ is a mobile valence state for iron, and it may be transported as a dissolved species away from the soil

4. Proses ini menghasilkan profil tanah yang warnanya hijua, kelabu, dan umumnya warna-warna “drab”

5. Proses ini bukan merupakan “bentuk yang cepat” dari pelapukan kimiawi


PROSES – PROSES GENESIS TANAH


Adsorption – Adsorpsi - Penjerapan:

Proses ini terjadi kalau gaya-gaya tarik antara permukaan padatan-tanah

(adsorbent) dan komponen larutan-tanah (adsorbat ) lebih besar dibandingkan gaya-gaya tarik antara komponen terlarut dan larutan tanah (solvent), serta gaya tolak

antara permukaan tanah dan spesies yang dijerap.



Aggregation - Agregasi:

Partikel-partikel diikat (dipegang) bersama menjadi unit-unit yang ukurannya beragam, bentuknya bebreda-beda, dengan bvantuan proses-proses fisika, kimiawi dan biologis.

Suatu Agregat dipisahkan dari agregat lainnya melalui bidang permukaan yang lemah.



Alkalization - Alkalisasi: Akumulasi kation Na; pembentukan Horison

natrik..

Audification - Pengasaman: Akumulasi ion-ion H+.

Carbonation – Karbonasi (calcification): Akumulasi kalsium karbonat; pembentukan

Horison Kalsik atau Horison Petrokalsik.

Chelation- Khelasi – Peng-khelat-an: Pembentukan senyawa kompleks logam

dengan agen organik. Logal dijebak dalam struktur cincin, sehingga menjadi sangat

stabil.



Compaction – Kompaksi - Pemadatan: Reduksi fisik kandungan uadar tanah yang mengakibatkan meningkatnya Bobot Isi.

Cryoturbation: Pencampiran tanah akibat dari suhu rendah, mis.

Untuk merusak horison, memasukkan bahan organik ke dalam horison bawah, dan untuk menata batu-

batu.

Dealkalization (solodization): Pergerakan ion Na ke luar dari bagian tertentu profil

tanah.

Decarbonation (decalcification): Pergerakan kalsium karbonat ke luar dari bagian

tertentu profil tanah.



Decomposition - Dekomposisi: Penghancuran bahan mineral dan bahan organik

secara biokimiawi.

Dehydration - Dehidrasi: Kehilangan air yang mengakibatkan suatu senyawa kembali ke keadaan orisinalnya.

Deposition merupakan sedimentasi bahan yang terangkut:1. Akumulasi partikel tanah / colluvium2. Akumulasi unsur hara / Peningkatan KTK3. Pengkayaan partikel berukuran medium.



Desalinization - Desalinisasi: Pergerakan garam-garam larut ke luar dari bagian tertentu profil

tanah.

Desilication - Desilikasi: Pergerakan silika ke luar dari bagian tertentu profil tanah.

Diffusion (into and out of the soil): Pertukaran udara antara atmosfir dan tanah karena pengaruh

tekanan partial gerakan massa.

Disaggregation - Disagregasi: Hancurnya agregat atanah.

Dispersion - Dispersi: Proses hancurnya struktur tanah dalam air dan memisah menjadi

separat komponen-komponennya.



Eluviation - Eluviasi: Movement of material out of a section of the soil

profile (literally washing away of material); depletion of the material washed away (e.g.

sequioxides, clay minerals, organic material)

Energy influx / outflux: Radiation absorption / reflection:1. Suhu Tanah2. Aktivitas mikroba tanah -> humifikasi,

decomposition, mineralisasi3. Evaporasi4. Lengas tanah



Erosi merupakan proses pengangkutan partikel tanah (dan bahan organik) oleh air atau angin.

1. Pukulan tetes-tetes air hujan menyebabkan hancurnya agregat tanah

2. Soil movement / removal of the A horizon3. Smoothing or levelling of the soil surface4. Loss of nutrients / decrease of CEC 5. Selective particle transport results in the

relative enrichment of coarse and fine particles and depletion of medium-sized particles

6. Mereduksi infiltrasi / meningkatkan runoff / mereduksi kandungan lengas tanah

7. Membentuk kerak di permukaan tanah.



Ferrugination: Perkembangan warna tanah coklat, coklat kemerahan, dan

kemerahan.

Flocculation: It is a process where the individual particles of clay are

coagulated to form floccular aggregates.

Gleization: It involves the reduction of iron and its segregation into

redoximorphic features, or its removal by leaching form the gleyed horizon; process occuring in poorly drained soil.

Humification - Humifikasi: Pembentukan HUMUS dari bahan organik segar.

Hidration: Penyerapan air oleh suatu senyawa dan membentuk senyawa baru yang hanya sedikit berbeda dengan keadaan orisinalnya.

1. Mendeskripsikan penambahan bahan organik, dan dekomposisi kimiawinya menjadi dalam humus dan asam organik

2. HUMUS merupakan material berwarna gelap, yang membuat tanah berwarna hitam atau coklat

3. Breakdown of the humus and organic acids also produces high CO2 concentrations in the soil, leading to carbonic acid and another form of chemical weathering.

Humification




Hydrolysis: Penggantian kation-kation dalam struktur mineral oleh

kation hidrogen dari larutan tanah.

Illuviation: Movement of material into a section of the soil profile

(literally washing into or towards); accumulation of material washed into (e.g. sequioxides, clay minerals, organic

material)

Induration: Pengerasan sebagian profil tanah akibat asosiasi dengan cadas besi dan plinthite, dan dengan agen-agen semen

lainnya (Si atau Ca).

Infiltration: The entry of water into the soil surface

Rainwater infiltrates in the soil with soluble and suspended matter.

PROSES – PROSES GENESIS TANAHInterflow (Subsurface flow, through flow, seepage): Lateral subsurface flow.

Lessivage: Pergerakan mineral liat secara fisik ke arah bawah.

Leucinization (decoloration): Pencerahan warna pada sebagian profil tanah – pembentukan horison albik.

Melanization: Darkening the color of light-colored mineral initial unconsolidated material

by mixture and accumulation of organic matter; formation of a mollic horizon due to incorporation of organic matter.

Mineralization: Pelepasan berbagai bentuk mineral selama dekomposisi bahan organik.

Neutralisasi: Menetralkan ion-ion H+.

Outflow: Loss of water from the pedosphere to the groundwater. Loss of water and

soluble and suspended matter from the system, i.e. loss from the soil zone (unsaturated and saturated zone) into the groundwater.

Lessivage1. Transport fisik material berukuran liat dari

horison permukaan ke lapisan bawah (Translokasi)

2. Leads to reddish coloration and clay-rich subsurface horizons

3. Iklim basah musiman

Modern California Argentina, 225 Million Year old rocks




Oksidasi: Pembentukan oksida atau pelepasan elektron.

Pedoturbation: The churning and disruption of horizon formation by biological, physical and to some extent chemical activity, such as

wetting and drying, swelling and contraction, freezing and thawing, root pressures, animal burrowing, acitivty of man.

Podzolization: Process by which sequioxides are translocated in a soil profile. The soluble ferrous iron forms ate the sites of

eluviation, and the insoluble ferric iron forms at the point of illuviation. Podzolization is a soil forming process resulting in the

genesis of Podzols.

Precipitation (Pengendapan): Pemisahan dan deposisi substansi padatan dari larutan.

Reduksi: Kehilangan oksigen atau penerimaan elektron.

Salinization: Accumulation of soluble salts such as chlorides and sulphates of

Ca, Mg, Na, or K.


Silication: Accumulation of silica.Solifluction: Slow flow of saturated soil on a permanent frozen soil

(permafrost table).

Solution: Dissolving of minerals into solution (e.g. calcium carbonate into bicarbonate).

Surface crusting (soil sealing): A process which results in the formation of soil crusts on the soil surface, ranging in thickness from a few mm to perhaps as much as 3 cm, that is much mor compact, hard and brittle, when dry, than

the material immediately beneath.Surface runoff (overland flow): Discharge of rainwater over the surface of the land. Surface runoff is composed of unconcentrated and concentrated flow.

Suspension: The floating of dispersed particles in a medium like water. It is one of the states of particle transport of eroded sediments, especially for the

smaller and lighter particles such as clay.Synthesis: Pembentukan senyawa baru secara biokimiawi dengan jalan

kombinasi unsur atau kompkinen-komponen tanah.

Upward movement: Pergerakan kapilaritas substansi terlarut dan tersuspensi.

Pelapukan: Semua perubahan fisika dan kimiawi yang terjadi pada batuan, di permukaan

bumu, oleh agen-agen atmosferik.


PROSES PEDOGENESIS TANAH


PEDOGENESIS TANAH(SUMBER: (http://www.physicalgeography.net/fundamentals/10u.html)

Pedogenesis dapat didefinisikan sebagai “proses perkembangan tanah”

Jenny believed that the kinds of soils that develop in a particular area are largely determined by five

interrelated factors: 1.Iklim; 2.Organisme; 3.Bahan induk; 4.Topografi; 5. Waktu .

Faktor-faktor yang mempengaruhi Pembentukan Tanah

• Faktor-faktor Pasif– Bahan induk– Topografi / Landform– Waktu

• Faktor-faktor aktif– Iklim– Faktor Biotik




Perkembangan tanah

dipengaruhi oleh lima

faktor yang saling

berkaitan:

1.organisms,

2.topography,

3.time, 4.parent

material, and

5.climate.



IklimClimate plays a very important role in the genesis of a soil. On the global scale, there is an

obvious correlation between major soil types and the Köppen climatic classification systems major climatic types. At regional and local scales, climate becomes less important in soil

formation. Instead, pedogenesis is more influenced by factors like parent material, topography, vegetation, and time. The two most important climatic variables influencing soil

formation are temperature and moisture. Temperature has a direct influence on the weathering of bedrock to produce mineral particles. Rates of bedrock weathering generally increase with higher temperatures. Temperature also influences the activity of soil microorganisms, the frequency and

magnitude of soil chemical reactions, and the rate of plant growth. Moisture levels in most soils are primarily controlled by the addition of water via

precipitation minus the losses due to evapotranspiration. If additions of water from precipitation surpass losses from evapotranspiration, moisture levels in a soil tend to be high. If the water loss due to evapotranspiration exceeds inputs from precipitation, moisture levels

in a soil tend to be low. High moisture availability in a soil promotes the weathering of bedrock and sediments, chemical reactions, and plant growth.

Ketersediaan air juga mempengaruhi pH tanah dan dekomposisi bahan organik.

Faktor-faktor Pembentukan TanahFAKTOR IKLIM

• Temperatur dan presipitasi (hujan)

• Kontrol tidak langsung (mis. Tipe tumbuhan)

• Laju pelapukan

– The greater the rainfall amount, the more rapid the rate of both weathering and erosion.


IKLIM

Pelapukan secara fisika – diakibatkan oleh agen-agen mekanik, seperti pemanasan dan pendinginan, pembekuan dan pencairan, abrasi.

– Materials are still the same at the molecular level.

– Materials are classified by the way they have been moved or scattered

DIUNDUH DARI: freshman.lpsb.org/.../Soil%20Science/....... 10/2/2013

IklimPelapukan kimiawi – dihasilkan dari aksi-aksi air,

oksigen, dan CO2 pada batuan induk.

– CO2 yang larut dalam air hujan membentuk asam lemah, mempercepat proses pelapukan bahan induk.

– Materials that have been chemically weathered are no longer the same at the molecular level.

• Example – Clay has been synthesized into something physically and chemically different from the parent rock.


Faktor pembentuk tanah yang aktif - Iklim

• Air - Moisture– Aktivitas kimiawi dan biologis– Hujan berlebihan– eluviasi dan illuviasi– Penguapan berlebih – aksi kapilaritas air dalam

tanah


• Temperatur–Reaksi-reaksi kimiawi–Aktivitas Bacteri– Laju dekomposisi bahan organik



• Angin - Wind: Faktor Minor– Meningkatkan penguapan air (evaporasi)– Realokasi tanah (pengangkutan dan akumulasi)





ORGANISMELiving Organisms have a role in a number of processes

involved in pedogenesis including organic matter accumulation, profile mixing, and biogeochemical nutrient cycling. Under

equilibrium conditions, vegetation and soil are closely linked with each other through nutrient cycling.

The cycling of nitrogen and carbon in soils is almost completely controlled by the presence of animals and plants. Through

litterfall and the process of decomposition, organisms add humus and nutrients to the soil which influences soil structure

and fertility. Vegetasi permukaan juga melindungi lapisan atas

suatu tanah dari efek erosi dengan jalan mengikat permukaan tanah dan mereduksi kecepatan angin dan

kecepatan air yang mengalir di permukaan tganah.

Faktor Pembentukan TanahOrganisme

1. Tipe-tipe vegetasi alamiah2. Pelapukan tergantung pada pertumbuhan

tetumbuhan

3. Plant and animal activity produces humic acids that are powerful weathering agents. [acids derived from chemical breakdown of organic matter]

4. Plants can physically as well as chemically break down rocks.

5. Tumbuhan menstabilkan profil tanah, Hewan (termasuk manusia) cenderung meningkatkan erosi.


BiotaBiota terdiri atas organisme hidup seperti

tumbuhan, hewan, serangga, bakteri dan fungi.

– Plants have the most important affect because they determine the type & amount of organic matter.

– Animals & insects mix and aerate the soil as well as add organic matter.


Faktor pembentuk tanah yang aktif: Biotik

Vegetasi:1. Menyediakan hyumus, mengikat tanah dan

mengimbangi perkolasi melalui transpirasi2. Maintain fertility3. Different types of vegetation require different

proportions of bases.4. Pepohonan: Sedikti Ca dan Mg5. Rerumputan: Kaya Ca dan Mg


• Mulai dari Bakteri hingga hewan-hewan besar

• Mekanis– mis. Burrowing by earthworms– mis. Excavation by man

• Kimiawi– Mis. Asam-asam organik


Faktor pembentuk tanah yang aktif: Biotik



BAHAN INDUK

Parent Material refers to the rock and mineral materials from which the soils develop. These

materials can be derived from residual sediment due to the weathering of bedrock or from sediment

transported into an area by way of the erosive forces of wind, water, or ice.

Pedogenesis is often faster on transported sediments because the weathering of parent material usually takes a long period of time. The influence of parent material on pedogenesis is usually related to soil

texture, soil chemistry, and nutrient cycling.

http://www.physicalgeography.net/physgeoglos/r.html

http://www.physicalgeography.net/physgeoglos/m.html

BAHAN INDUK TANAH1. Alluvium – Hancuran Batuan yang halus,

diendapkan oleh aliran air, kebanyhakan partikel debu dan liat, sebagian kecil pasir.

2. Marine Deposits – finely pulverized rock laid down under sea. This material has been thrust up by shifts in the earth’s crust.

3. Loess – material berdebu , seperti bubukan- diendapkan oleh angin. Sebagian besar debu dan liat, hanya sedikit sekali pasir.


Factors of Soil Formation

• Parent Material• Chemistry• Mineralogy • Grain size




TOPOGRAFI – RELIEFTopografi umumnya memodifikasi perkembangan tanah

pada sekala lokal atau regional. Pedogenesis sangat dipenngaruhi oleh efek topografi terhadap iklim mikro dan

drainage.

Soils developing on moderate to gentle slopes are often better drained than soils found at the bottom of valleys. Good drainage enhances an number of pedogenic processes of illuviation and

eluviation that are responsible for the development of soil horizons. Under conditions of poor drainage, soils tend to be

immature. Steep topographic gradients inhibit the development of soils because of erosion. Erosion can retard the development

through the continued removal of surface sediments. Soil microclimate is also influenced by topography.

In the Northern Hemisphere, south facing slopes tend to be warmer and drier than north facing slopes. This difference

results in the soils of the two areas being different in terms of depth, texture, biological activity, and soil profile development.

http://www.physicalgeography.net/physgeoglos/i.html

http://www.physicalgeography.net/physgeoglos/e.html

http://www.physicalgeography.net/physgeoglos/s.html

Topography

• Topografi mencerminkan “lay of the land” atau sudut dan panjang lereng.

• Topografi mempengaruhi proses pembentukan tanah karena ia mempengaruhi runoff, drainage, dan erosi tanah.

• It also may affect the type & amount of plant growth (biggest factor in determining type & amount of organic matter)


Topografi

Lereng Curam– Laju runoff sangat tinggi– Infiltrasi air hujan kurang– Lebih sedikit vegetasinya– Less organic matter– Increased erosion– Thinner surface soil– Slower formation/development


Kemiringan yang lebih landai– Runoff lebih sedikit– Infiltrasi air hujan lebih banyak– Pertumbuhan vegetasi lebih cepat dengan

menghasilkan banyak bahan organik– Less erosion– Deeper surface soil– Faster formation/development• Excessive water can slow development


Topografi

Faktor-faktor Pembentukan Tanah

Topografi:• Kemiringan muka lahan• Elevasi (Ketinggian tempat)• Aspek lereng (lereng menghadap ke

urata atau ke selatan)


• Transport material tanah menuruni lereng merupakan fungsi kemiringan:

– Erosion rate = f(S)

• Lereng lebih curam, erosi lebih cepat.

• The steeper the surface slope, the more likely any eroded material is to be transported out of the system.



1. Tanah-tanah pada lereng-bukit biasanya mencapai ketebalan setimbang , sekitar 1m.

2. Soils on flat surfaces, such as floodplains or plateaus, tend to thicken through time due to weathering rates being greater than sediment transport rates.





WAKTUTime influences the temporal consequences of all of the factors described above. Many soil

processes become steady state overtime when a soil reaches maturity.

Proses pedogenesis pada tanah-tanah muda biasanya mengalami modifikasi aktif melalui mekanisme umpan-balik positif dan negatif

dalam rangka mencapai kesetimbangan.

http://www.physicalgeography.net/physgeoglos/s.html

Waktu

As soon as material has become loose enough to hold enough water, air, and nutrients for plant

growth, it is considered a soil.

– Pembentukan / perkembangan tanah dapat berlangsung selama beberapa abad atau hanya beberapa hari saja.


Tanah-tanah Muda– Asalnya dari bahan vulkanik atau aluvial– Mempunyai kesuburan lebih baik– Profil tanah belum berkembang lanjut– Usually they are highly productive.– Where are the youngest soils in Louisiana located?


Waktu

• Tanah-tanah Tua1. Profil tanah berkembang dnegan baik2. Kandungan liatnya meningkat semakin tinggi3. pH tanah lebih masam4. Nutrients are leached5. Lower fertility & productivity than younger soils.


Waktu

Faktor-faktor Pembentukan Tanah1. Waktu untuk perkembangan dan destruksi

profil tanah

2. Typical chemical reaction rates are slow the longer a rock unit has been exposed, the more likely it is to be weathered

3. Semakin lama material-tanah menunggu sebelum diangkut, maka ia akan mnejadi semakin tebal ……..…


PROSES-PROSES PEDOGENIK

Banyak proses yang terlibat dalam transformasi bahan induk tanah menjadi horison-horison

tanah.The exact combinations of these processes and

reactions are however not known.

If the combination is dominated by a particular process, it is usually assigned a name. e.g.,

laterization, podzolization were commonly used as simplifications.

DIUNDUH DARI: myspace.aamu.edu/users/monday.../soils/Pedogenic%20Processes.ppt ….. 11/2/2013

Proses-proses Pedogenik yang utamaProses-proses Pedogenik dapat dikelompokkan menjadi empat, yaitu:

– Penambahan atau Pengkayaan– Kehilangan atau Pengambilan– Translokasi atau Transfer– Transformasi

Each major pedogenic process is made up of a number of processes acting singly or in combination


Penambahan atau Pengkayaan• Enrichment - Pengkayaan– General term for addition of material to a soil body. e.g.,

adjoining pedons as in depressions.• Cummulization– Aeolian and hydrologic additions of mineral particles to the

surface of a soil. The effects are more pronounced in depressions.

• Littering– The accumulation of vegetable and associated faunal debris

(litter) including humus on the mineral soil surface to a depth of less than 30cm

• Melanization - Melanisasi– The darkening of light-colored mineral materials which are

initially unconsolidated by admixture of organic matter. Melanization involves some translocation.


Penambahan ke tanah• Input dari luar ekosistem– Input dari atmosfir• Precipitation, dust, deposition

– Input Horisontal• Floods, tidal exchange, erosion, land-

water movement

• Input dari dalam ekosistem– Seresah dedaunan dan akar-akar yang

mati turnover


Kehilangan atau Pengambilan

• Erosi tanah– surficial removal of material from the surface layer

of a soil This is effected by raindrop splash, runoff waters, wind, creep, and other mass wasting processes.

• Pencucian– Pencucian atau eluviasi material terlarut dari

solum tanah.


Translokasi atau Transfer1. Eluviasi: Pergerakan material ke luar dari “bagian

tertentu” profil tanah, seperti pada Horison Albik.2. Iluviasi: Pergerakan material memasuki “bagian tertentu”

profil tanah, seperti pada Horison Argilik dan Spodik

3. Lessivage: Washing in suspension of fine clay and lesser amounts of coarse clay and fine silt down cracks and other voids in a soil body; leading to the depletion of clay in the A horizon and enrichment of clay in the B horizon.

4. Pedoturbation: Biologic, physical (freeze-thaw and wet-dry cycles) churning and cycling of soil materials thereby homogenizing the solum in varying degrees


• Kalsifikasi– Processes including the accumulation of calcium carbonate in a

Ck and possibly other horizons of a soil. • Dekalsifikasi– Reactions that remove calcium carbonate from one or more soil

horizons. • Salinization– The accumulation of soluble salts such as sulfates and chlorides

of calcium, magnesium, sodium and potassium in salty (salic) 'horizons.

• Desalinization– The removal of soluble salts from salic horizons.

• Alkalization (solonization)– The accumulation of sodium ions on the exchange sites in a soil.

• Dealkalization (solodization)– The leaching of sodium ions and salts from sodium-rich (natric)

horizons.


• Leucinization – The paling of soil horizons by disappearance of dark organic materials either

through transformation to light- colored ones or through removal from the horizons.

• Braunification, Rubification and Ferrugination-– Release of iron from primary minerals and the dispersion of particles of iron

oxide in increasing amounts; the progressive oxidation or hydration, giving the soil mass brownish, reddish-brown and red colors, respectively. (Also transformation).

• Gleization– The reduction of iron under anaerobic water-logged soil conditions, with the

production of bluish to greenish-gray matrix colors, with or without yellowish-brown, brown and black mottles and ferric and manganiferous concretions.

• Podzolization (silication)– The chemical migration of aluminum and iron and/or organic matter, resulting

in the concentration of silica (i.e. silication) in the layer eluviated. (Also transformation)

• Laterization (desilication, ferrugination, ferritization, allitization)– The chemical migration of silica out of the soil solum and thus the

concentration of sesquioxides in the solum (goethite, gibbsite, etc.)


Transformations• Decomposition– The breakdown of mineral and organic materials

• Mineralization– The release of oxide solids during decomposition of organic. It

concerns the biochemical breakdown of dead plant tissues by soil micro-organisms to produce simple-structured soluble organic substances, purely mineral compounds like nitrates, and metal cations and gases (mostly carbon dioxide)

• Humification– Transformation of raw organic material into humus. In this the

simple structured soluble organic substances are grouped into lager molecules by polymerization They then become poorly soluble and are stabilized to form a major component of humus

• Synthesis– The formation of new particles of mineral and organic species.


• Paludization:– Akumulasi bahan organik dalam lapisan tebal

(> 30 cm) sebagai mucks dan peats.

• Ripening– Perubahan tanah organik secara kimiawi,

biologis dan fisik setelah udara menembus deposit organik, sehingga memungkinkan aktivitas mikroba berlangsung intensif.


Transformasi• Decomposition of organic matter

– Breakdown to form soluble compounds that can be absorbed leached away

– Depends on input quantity, location (roots, leaves), environment (temp & precip)

• Humifikasi membentuk bahan organik kompleks

• Pelapukan batuan– Pelapukan Fisika / fragmentasi batuan

– Freeze-thaw; drying-wetting; fire– Pelapukan kimiawi

• Mineral primer Mineral sekunderDIUNDUH DARI: gis.ess.washington.edu/grg/courses/ess230/lectures/Soils_2012.ppt …..

11/2/2013

Proses-proses Pedogenesis• Setiap proses pedogenesis dapat mempengaruhi banyak

senyawa dan komponen penyusun tanah. • Misalnya, proses-proses penambahan, kehilangan, transfer, dan

transformasi bahan organik, garam larut, karbonat dan sesquioksida.

• Organic matter may be added to the soil by littering; it may be transformed by decomposition; it may be translocated by podzolization and it may be lost by erosion.

• These processes can all be going on singly or in combination with other processes to give rise to the soil profile.

• However, not all of the processes will necessarily promote horizon differentiation.

• Some of the processes may actually retard or offset differentiation e.g. pedoturbation.


Proses-proses pembentukan tanahEfek kombinasi dari:

• Penambahan ke permukaan

• Transformasi kimiawi

• Transfer vertikal• Pengusiran dari

tanah

Peranan relatifnya beragam


Perkembangan Horison Tanah

• Perkembangan Horison A– Akumulasi bahan organik– Penggerombolan individual partikel tanah– Berbeda dari bahan induk dan lapisan lainnya.

• Perkembangan Horison B dan C– Carbonic and organic acids are carried by water into soil where dissolve

various minerals (transformations)– Soluble materials (ions –Ca2+, CO32-, SO42-, etc) are carried by water and

precipitate in the soil from upper to lower horizons (translocation)– Weathering of primary minerals into secondary minerals– Wetting and drying cracks soils and makes structures.


Perkembangan Horison Tanah


Bahan induk (bedrock) mengalami pelapukan menjadi “regolith” (tanah + saprolite).


Tanah (Soil) merupakan campuran bahan mineral dan bahan organik , struktur batuan induknya

kurang nampak.

Soil


“Saprolite “ adalah batuan terlapuk yang masih menampakkan struktur batuan asalnya.

Saprolite


Horizon dan Profil TanahHorison Tanah

– over time, soil layers differentiate into distinct ‘horizons’

– not deposited, but zones of chemical action• Reaksi kimia dan pembentukan mineral sekunder (liat) • Pencucian oleh air infiltrasi (elluviasi)• Deposisi dan akumulasi material yang tercuci dari

bagian di sebelah atas, dalam suatu tanah (illuviasi)

Profil Tanah– Suite of horizons at a given locality


DeskripsiPROFIL TANAH

………. Selanjutnya ….…

Bundaran Kantor Pusat Kampus UB

Foto: smno.kampus.ub.agst2012

Documents

dasar ilmu tanah – genesis pembentukan tanah