DR. IR. ERIZAL, MAGR. DEPARTEMEN TEKNIK SIPIL DAN LINGKUNGAN FAKULTAS TEKNOLOGI PERTANIAN IPB

Transkripsi

1 DR. IR. ERIZAL, MAGR. DEPARTEMEN TEKNIK SIPIL DAN LINGKUNGAN FAKULTAS TEKNOLOGI PERTANIAN IPB

2 Why klasifikasi tanah??? Nampak secara nyata bahwa tanah di permukaan bumi kita ini sangat beragam (warna, tekstur, struktur dll). Maka... Untuk membedakan tanah-tanah tersebut diperlukan klasifikasi tanah.

3 Tujuan Klasifikasi Tanah 1. Mengorganisasi atau menata tanah 2. Mengetahui hubungan individu tanah 3. Memudahkan mengingat sifat-sifat tanah 4. Mengelompokkan tanah untuk : - menaksir sifat - penelitian - mengetahui lahan2 yg baik

4 Klasifikasi Tanah ada 2: Klasifikasi Alami Didasarkan atas sifat tanah yg dimiliki tanpa menghubungkan dg tujuan penggunaan tanah tersebut. Klasifikasi Teknis Didasarkan pada sifat-sifat tanah yang mempengaruhi kemampuan tanah untuk penggunaanpenggunaan tertentu.

5 Selanjutnya......dalam pengertian sehari-hari, Klasifikasi Tanah Alami dikenal dengan... KLASIFIKASI TANAH

6 Sistem Klasifikasi Tanah yang ideal mampu mengelompokkan tanah dalam satu kelas yang Isogenus Tanah yg mpy genesis sama 2. Isomorf Tanah yg mpy kenampakan yg sama 3. Isofungsi Tanah yg mpy fungsi sama dlm lingk. 4. Isotropik Tanah yg mpy lokasi yg sama

7 Macam Sistem Klasifikasi Tanah 1. Pusat Penelitian Tanah Bogor 2. FAO/UNESCO (1974) 3. USDA = Soil Taxonomy (USDA, 1975; Soil Survey Satff, 1999; 2003).

8 Sistem Klasifikasi Tanah Pusat Penelitian Tanah Bogor Sistem Klasifikasi Tanah yang digunakan oleh Pusat Penelitian Tanah Bogor adalah sistem yang dikembangkan oleh Dudal- Soepraptohardjo (1957), sistem tersebut sebenarnya mirip dengan sistem yang berkembang di AS oleh Baldwin, Kellogdan Thorp (1938) : Thorn dan Smith (1949) dengan beberapa modifikasi.

9 Perkembangan selanjutnya... Sistem menurut Dudal-Soepraptohardjo (1957), terus disempurnakan sesuai dengan Sistem AS yg baru(soil Taxonomy, 1975) dan dari USDA terutama dalam : Definisi jenis-jenis tanah (great group) Macam tanah (subgroup)

10 Sistem Dudol-Soepraptohardjo ( ) Modifikasi 1978/1982 (PPT) FAO/UENESCO (1974) USDA Soil Taxonomy ( ) 1. Tanah Aluvial Tanah aluvial Fluvisol - Entisol - Inceptisol 2. Andosol Andosol Andosol Andisol 3. Brown Forest Soil Kambisol Cambisol Inceptisol 4. Grumusol Grumusol Vertisol Vertisol 5. Latosol - Kambisol - Latosol - Lateritik - Cambisol - Nitosol - Ferralsol - Inceptisol - Ultisol - Oxisol 6. Litosol Litosol Litosol Entisol (lithic Subgrup) 7. Mediteran Mediteran Luvisol Alfisol/inceptisol 8. Organosol Organosol Histosol Histosol 9. Podsol Podsol Podsol Spodosol 10. PodsolikMerah Kuning Podsolik Acrisol Ultisol 11. Podsolik Coklat Kambisol Cambisol Inceptisol 12. Podsolik Coklat kelabu Podsolik Acrisol Ultisol 13. Regosol Regosol Regosol Entisol/Inceptisol 14. Renzina Renzina Renzina Rendoll

11 Sistem Klasifikasi Tanah USDA (1975, 1999, 2003) ORDO (ORDER) SUBORDO (SUB-ORDER) GRUP (GREAT GROUP) SUB-GRUP (SUBGROUP) FAMILY SERI

12 Nama Ordo Akhiran Untuk Kategori Lain Arti Asal Kata Alfisol ALF Dari Al-Fe Andisol AND Ando, tanah hitam Aridisol ID Aridus, sangat kering Entisol ENT Dari Recent Gelisol EL Gelare, membeku Histosol IST Histos, jaringan Inceptisol EPT Inceptum, permulaan Mollisol OLL Mollis, lunak Oxisol OX Oxide, oksida Spodosol OD Spodos, abu Ultisol ULT Ultimus, akhir Vertisol ERT Verto, berubah

13 ORDO Ordo tanah dibedakan berdasarkan ada tidaknya horison penciri serta jenis (sifat) dari horison penciri tersebut. Contoh : Horison penciri : argilik,kb >35 % = ordo Alfisol Horison penciri : argilik,kb <35% = ordo Ultisol

14 SUBORDO Subordo tanah dibedakan perbedaan genetik tanah, misal : ada tidaknya sifat2 tanah yg berhub.dg : air, kelembaban, bi, vegetasi. Khusus Histosol, sub ordo dibedakan tk.pelapukan b.o. nya (febris, hemis, safris)

15 Contoh : Subordo : Udult berasal dari Udus/udic = tanah yg pernah lembab, singkatannya Ud. Ud ditambah dg ordo Ultisol (disingkat Ult), sehingga sub ordo = Udult

16 GRUP (GREAT GROUP) Dibedakan berdasarkan perbedaan (1)jenis, (2) tk.perkembg, (3) susunan horiz, (4) KB, (5) kelembaban, (6) ada tidaknya lapisan2 penciri lain : plinthite, fragipan, duripan Contoh : Grup Fragiudult Lapisan tsbt memiliki lapisan padas Fragipan mk disingkat fragi. Shg kata fragi ditambah pd Sub ordo Udult, jadi... Fragiudult.

17 SUBGRUP Dibedakan berdsr : (1) sifat inti grup & diberi nama Typic, (2) sifat2 tanah peralihan ke grup lain, sub ordo lain atau ordo lain. Contoh : Subgrup : Aquic Fragiudult tanah tsbt memiliki sifa peralihan ke sub ordo Aquult, krn kadang2 adanya pgrh air, shg tmsk sub grup Aquic

18 Family Dibedakan berdsr sifat2 yg penting u/ pertanian atau teknik, (1) sebaran butir, (2) mineral liat, (3) regim temperatur pd kedlmn 50 cm. Contoh : Aquic Fragiudult, berliat halus, kaolonit, isohipertermik. Penciri famili, susunan butir berliat halus & jenis liat adl kaolinit, regim temperatur isohipertemik (> 22 C dg perbedaan suhu tnh musim panas & dingin <5 C)

19 Seri Tanah Seri tanah menunjukkan nama lokasi tanah tersebut pertama kali ditemukan. Contoh : Aquic Fragiudult, berliat halus, kaolonit, isohipertermik,sitiung Sitiung : lokasi pertama kali ditemukan tanah pada kategori seri tersebut.

20 HORIZON PENCIRI 1. Epipedon Horizon bagian permukaan ( horizon A), mungkin lebih lebih tipis dari horizon A, tetapi mungkin juga meliputi horizon B. 2. Endopedon Horizon dibawah permukaan

21 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.

22 ANDISOLS The central concept of Andisols is that of soils dominated by short-rangeorder 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

23 ARIDISOL Aridisols 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.

24 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.

25 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.

26 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.

27 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.

28 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.

29 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.

30 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, loamyskeletal, or coarse-silty.

31 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.

32 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.