MK. DASAR ILMU TANAH TEKSTUR TANAH

MK. DASAR ILMU TANAH TEKSTUR TANAH
Diabstraksikan oleh: smno.jursntnh.fpub.febr2013

Definisi Tekstur Tanah
Texture indicates the relative content of particles of various sizes, such as sand, silt and clay in the soil. Texture influences the ease with which soil can be worked, the amount of water and air it holds, and the rate at which water can enter and move through soil. Diunduh dari: ftp://ftp.fao.org/fi/cdrom/fao_training/FAO_Training/General/x6706e/x6706e06.htm ……… 3/3/2013

Kelas Tekstur Tanah menurut USDA
Nama Umum Tanah (Tekstur secara general) Pasir Debu Liat Kelas Tekstur Tanah berpasir (Tekstur Kasar) 86-100 0-14 0-10 Sand 70-86 0-30 0-15 Loamy sand Loamy soils (Moderately coarse texture) 50-70 0-50 0-20 Sandy loam Loamy soils (Medium texture) 23-52 28-50 7-27 Loam 20-50 74-88 0-27 Silty loam 88-100 0-12 Silt Loamy soils (Moderately fine texture) 20-45 15-52 27-40 Clay loam 45-80 0-28 20-35 Sandy clay loam 40-73 Silty clay loam Tanah berliat (Tekstur Halus) 45-65 35-55 Sandy clay 40-60 Silty clay 0-45 0-40 40-100 Clay Diunduh dari: ftp://ftp.fao.org/fi/cdrom/fao_training/FAO_Training/General/x6706e/x6706e06.htm ……… 3/3/2013

Definition Tekstur tanah didefiniskan sebagai proporsi relatif pasir, debu dan liat. Kisaran diameter dari ketiga separat: Pasir ( mm), Debu ( mm), Liat (<0.002 mm).

Diameter Ranges Soil Fraction Soil Separate Diameter (mm) Sand
Very coarse sand 1 to 2 Coarse sand 0.5 to 1 Medium sand 0.25 to 0.5 Fine sand 0.1 to 0.25 Very fine sand 0.05 to 0.1 Silt 0.002 to 0.05 Clay < 0.002

SEPARAT TANAH = SOIL SEPARATES
Tanah mineral dianggap sebagai suatu campuran porus partikel-pertikel anorganik, bahan organik, air dan udara. particle size and particle size distribution of these inorganic particles have an important bearing on the physical properties of soil.

SEPARAT TANAH = SOIL SEPARATES
mineral fraction of soil is divided into are called soil separates. three major size groups. These groups Pasir : diameternya mm Debu : mm to 0.05 mm in diameter Liat : <0.002 mm Kerikil: 2 mm to 2 cm Batu:- >2 cm. Particles of <0.001 mm are designated as colloids - clay, a colloid is unique because of its large surface area.

TEKSTUR TANAH = %Pasir, Debu & Liat dalam tanah.
Tekstur tanah merupakan sifat fisika-tanah yang sangat penting. Knowing the soil texture alone will provide information about: 1) Pergerakan (aliran) air, 2) Daya simpan air, 3) Potensial kesuburan, 4) Kesesuaian tanah untuk berbagai penggunaan

TEKSTUR TANAH Persentase pasir, debu, liat dalam suatu tanah
Tekstur tanah sangat penting untuk memahami perilaku tanah dan pengelolaan tanah Soil texture is not subject to change in the field but can be changed in potting mixes. Good soil and water conservation practices are always recommended for all soils; however, there are a number of risks associated with particular soil textures that good farm managers should consider. There are management practices that can be adopted to reduce these risks. Sumber:

Ukuran Diameter Partikel
Soil particle diameters range over 6 orders of magnitude: Batu besar 2 m Fragmen kasar > 2 mm Pasir < 2 mm mm Debu < 0.05 mm mm Liat < m

Sand is the biggest soil particle.
PARTIKEL PASIR Terasa seperti berpasir (kasar) Tidak-kohesif – tidak melekat bersama dalam suatu mass kecuali dalam kondisi sangat basah. PARTIKEL PASIR Sand is the biggest soil particle. If blown up to an easily visible size, compared to other soil particles, a sand particle would be the size of a basketball. Soils classified as sandy typically contain 80 to 100 percent sand, zero to 10 percent silt and zero to 10 percent clay by volume. Tanah-tanah berpasir, karena ukuran partikelnya besar-besar, ia tidak mampu menyimpan banyak air dan nilai haranya rendah. Segenggam tanah berpasir akan mudah hancur berderai kalau genggaman dilepaskan. Read more: 3 Types of Soil Particles Sized From Biggest to Smallest | eHow.com

PARTIKEL PASIR Pasir mengandung lebih sedikit hara tanaman dibandingkan dengan partikel yg lebih halus Voids between sand particles promote free drainage and entry of air Menahan sedikit air dan mudah mengalami kekeringan

PARTIKEL PASIR < 2 mm hingga > 0.05 mm Tampak tanpa mikroskop
Bentuknya membulat atau bersudut Sand grains usually quartz if sand looks white or many minerals if sand looks brown, Some sands in soil will be brown, yellow, or red because of Fe and/or Al oxide coatings.

PARTIKEL PASIR Luas-permukaan jenisnya rendah Sand has less nutrients for plants than smaller particles Voids between sand particles promote rapid permeability of water and entry of air Holds little water and prone to drought

PARTIKEL DEBU < 0.05 mm - > 0.002 mm
Tidak tampak tanpa mikroskop Mineral Kuarsa dominan dalam debu karena minral lainnya telah lapuk.

Silt is the next largest soil particle.
PARTIKEL DEBU Tidak terasa kasar Terasa bertepung – halus lumer Silt is the next largest soil particle. If blown up to an easily visible size, compared to other soil particles, a silt particle would be the size of a baseball. Soils classified as loam have the largest amount of silt particles and typically contain 25 to 50 percent sand, 30 to 50 percent silt and 10 to 30 percent clay by volume. High-silt-content soils are often found along riverbanks. Silt soils feel smooth when wet and powdery when dry. Genggamlah segenggam tanah lempung atau tanah berdebu, maka bentuk yang terjadi tidak akan hancur (lembab) kalau genggaman dilepaskan, kalau kering maka bentuk genggaman tanah akan “crumble away”. Read more: 3 Types of Soil Particles Sized From Biggest to Smallest | eHow.com

PARTIKEL DEBU Smaller particles – retains more water for plants and have slower drainage than sand. Mudah terangkut oleh air yang menmgalir – sangat erosif. Menahan dan menyimpan lebih banyak hara dibanding dengan pasir.

www.pedrocreek.org/ fishcommittee.html
PARTIKEL DEBU Debu berperan dalam proses sedimentasi (silting) di atas material kerikil di dasar sungai yang diperlukan oleh ikan untuk “bertelur”. fishcommittee.html

PARTIKEL LIAT < mm Bentuknya pipih atau serpihan-serpihan halus Partikel liat yang berukuran kecil adalah koloid Kalau tersuspensi dal;am air tidak akan mengendap

Clay is the smallest soil particle.
PARTIKEL LIAT Pada kondisi basah, liat sangat lekat dan plastis, atau dapat digelintir dengan mudah membentuk bola, silinder atau bentuk lainnya. Juga mudah dibentuk menjadi pita-pita yang panjang. Clay is the smallest soil particle. If blown up to an easily visible size, compared to other soil particles, a clay particle would be the size of a golf ball. Soils classified as clay typically contain zero to 45 percent sand, zero to 45 percent silt and 50 to 100 percent clay by volume. Because of the small size of clay particles, clay traps water and air, making it difficult for plants to grow. Segenggam tanah liat akan tetap mempertahankan bentuknya kalau genggaman dilepaskan, pada kondisi lembab. Kalau kering, seringkali sangat keras untuk dapat ditembus dengan sekop “a shovel”. Read more: 3 Types of Soil Particles Sized From Biggest to Smallest | eHow.com

PARTIKEL LIAT Dapat mengembang dan mengkerut – sampai batas tertentu sifat ini juga tergantung pada jenis liat. Certain types of clay are capable of absorbing water. Water molecules can actually squeeze into the chemical structures of the clay minerals that make up the soil. When this happens, the clay can actually expand in order to accommodate the water. Expansion can cause significant volume increases in the soil. Swelling can actually cause the ground and anything constructed upon the ground to gradually to be effected. Expansive soils can also shrink when water is removed from the chemical structure within the clay contained within the soils. Diunduh dari: /3/2013

PARTIKEL LIAT Pores spaces are very small and convoluted
Movement of water and air very slow Water holding capacity Tremendous capacity to adsorb water- not all available for plants. Kapasitas jerapan kimiawinya sangat besar

Rongga pori sangat kecil-kecil dan berbelit-belit rumit
PARTIKEL LIAT Rongga pori sangat kecil-kecil dan berbelit-belit rumit Pergerakan air dan udara sangat lambat Kapasitas simpan air Tremendous capacity to adsorb water- not all available for plants. Soil strength- shrink/swell affects buildings, roads and walls. Jerapan kimiawinya sangat besar.

Pipih atau serpihan halus Partikel liat halus adalah koloid
< mm Pipih atau serpihan halus Partikel liat halus adalah koloid If suspended in water will not settle Permukaannya sangat luas spoonful = football field

TEKSTUR TANAH Proporsi relatif dari berbagai ukuran separat dalam suatu tanah ……. tekstur Sangat penting karena : it affects and is related to several soil properties such as soil structure, aeration, water holding capacity, nutrient storage, water movement, and bearing strength.

Sulit mengubah tekstur tanah pada sekala lapangan.
Separat tanah tidak berfungsi secara individual, tetapi sebagai partner atau agregat. Aggregates are the clumps of soil separates. When aggregates are bound together into large masses they are called peds Sulit mengubah tekstur tanah pada sekala lapangan.

Ada 12 kategori tekstur tanah, tetapi ada tiga kelas besar :
Pasir – Tanah tekstur kasar – tanah-tanah ringan Lempung - intermediate texture - happy soils - most productive Liat - tanah bertekstur halus hingga tanah berat

TEKSTUR TANAH Soil texture can be determined by the “Textural Triangle” - based on feel of soils. Textural grade is not determined or based on the major soil separates but on the separate that exerts the dominant influence. Tekstur Pasir mengandung % fraksi (separat) pasir atau lebih dari total beratnya.

Pentingnya Tekstur Tanah
Soil texture is one of the most important properties of a soil, and it greatly affects land use and management. Tekstur tanah mempengaruhi jumlah air dan hara yang dapat ditahan tanah dan disediakan bagi tanaman. Tekstur tanah juga mempengartuhi struktur tanah, pergerakan udara dan air dalam tanah.

What affects soil texture?
The parent material, as modified by weathering and soil- forming processes, determines a soil horizon’s texture. Residuum (or bedrock) Marine Sediments

Dapatkah tekstur tanah diubah ?
Texture is a relatively permanent physical property under natural conditions, and, for most agricultural or forestry uses, it is not practical to change soil texture. Dalam sistem pertanian intensif, tekstur tanah dapat diubah dnegan menambahkan material kasar atau material halus.

MENGUBAH TEKSTUR TANAH
Tekstur tanah hanya dapat diubah dengan mencampurkan material tanah lain yang teksturnya berbeda, dalam jumlah (sekala) terbatas.

Adding sand to a clay soil creates a cement like substance Adding peat or compost to a mineral soil is not considered changing the texture – since it only adds organic matter not sand, silt or clay. Mengapa menambah kompos atau gambut?

Dalam janghka panjang (1000 tahun) proses pedologis mengubah tekstur horison tanah. As soils get older sand weathers to silt and silt weathers to clay …………therefore old soils have more clay.

Translokasi Liat = Pembentukan horison B
Liat juga diangkut ke arah bawah dari profil tanah, sehingga subsoil lebih banyak mengandung liat dibandingkan topsoil. 2. Thus ‘Argillic’ horizons form and are zones of clay accumulation Argillic =

Profil-Tekstur suatu Tanah
The graph of the % clay from the surface to the parent material will show if a soil has a clay bulge or an increase in clay. “Textural Profiles” sangat membantu dalam mencari keberadaan “akumulasi” liat. Argillic =

Menentukan tekstur tanah di Laboratorium
Soil textures can be determined in laboratory analyses where the amount of sand, silt, and clay are measured quantitatively. We will do this in the laboratory activities.

Menentukan Tekstur Tanah – Metode Perasaan
Membasahi tanah di telapak tangan Membuat pita tanah Panjangnya pita tanah mencerminkan kandungan liatnya Kasar atau kurang-kasar mencerminkan pasir atau debu Halus menyatakan debu.

KLASIFIKASI TEKSTUR TANAH
Texture refers to the amount of sand, silt,and clay in a soil sample. The distribution of particle sizes determines the soil texture, which can be assessed in the field or by a particle-size analysis in the laboratory. A field analysis is carried out in the following way: a small soil sample is taken, water is added to the sample, it is kneaded between the fingers and thumb until the aggregates are broken down. Pedoman untuk menentukan kelas partikel: PASIR : Sand particles are large enough to grate against each other and they can be detected by sight. Sand shows no stickiness or plasticity when wet. DEBU: Grains cannot be detected by feel, but their presence makes the soil feel smooth and soapy and only very slightly sticky. LIAT: A characteristic of clay is the stickiness. If the soil sample can be rolled easily and the sample is sticky and plastic when wet (or hard and cloddy when dry) it indicates a high clay content. Note that a high organic matter content tend to smoothen the soil and can influence the feeling for clay. DIUNDUH dari: /3/2013

KELAS TEKSTUR TANAH Tekstur Tanah Singkatan Loam l Gravelly loam gl
Very coarse sand vcos Coarse sand cos Sand s Fine sand fs Very fine sand vfs Loamy coarse sand lcos Loamy sand ls Loamy fine sand lfs Sandy loam sl Fine sandy loam fsl Very fine sandy loam vfsl Gravelly sandy loam gsl Tekstur Tanah Singkatan Loam l Gravelly loam gl Stony loam stl Silt si Silt loam sil Clay loam cl Silty clay loam sicl Sandy clay loam scl Stony clay loam stcl Silty clay sic Clay c DIUNDUH dari: /3/2013

Dalam sistem U.S.D.A., klasifikasi ukuran partikel adalah (units: mm): LIAT : < mm DEBU: PASIR HALUS: PASIR MEDIUM: PASIR KASAR: PASIR SANGAT KASAR : KERIKIL: BATU : > 762.0 DIUNDUH dari: ……. 3/3/2013

Tekstur tanah di lapangan ditentukan dg menggunakan segitiga tekstur. Misalnya, distribusi ukuran partikel 33 % liat, 33 % debu, dan 33 % pasir …….. akan termasuk ke dalam kelas tekstur tanah “LEMPUNG LIAT” . DIUNDUH dari: ……. 3/3/2013

Hubungan antara Tekstur Tanah dan Ukuran Pori Tekstur Tanah Pasir Debu Liat DIUNDUH dari: /3/2013

MENDUGA TEKSTUR TANAH SECARA CEPAT
Soil texture is the "feel" of the soil when a moist quantity is manipulated. Some soils are sticky, others will not stick together at all, and others feel "doughy" or "spongey". Some soils can be played with like plasticine. These differences in properties gave rise, in agriculture, to soils being called clays, loams or sands. Clays stick to your boots, loams are easily moulded but non-sticky, sands are not cohesive at all and cannot be moulded when moist. When moist soil is manipulated in the hand, sands, loams and clays feel very different. You can use one of the two methods outline below to match up how the soil feels in your hand with the texture of the soil. For more information on what texture means for your soils, refer to ‘Practical Note – Soil Texture’. Anda memerlukan: Soil (with any coarse organic matter and stoney material removed) Rain water or distilled water DIUNDUH dari: ……. 3/3/2013

PENYIAPAN CONTOH TANAH Take a sample of soil sufficient to fit comfortably into the palm of the hand. Moisten the soil with water, a little at a time, and work the water into the soil. Water is added until the soil reaches a consistency where further water added would cause the soil to stick to the hands. Knead and moisten the soil until there is no further change in the soil ball - very dry clayey samples may need considerable working to break down fine aggregates. A working time of one to ten minutes may be needed depending on the material. Usually minutes is sufficient. The behaviour of the bolus during manipulation indicates soil texture; you can either use the ribboning method (particularly useful for assessing clay samples/soils) or the flowchart over the page. DIUNDUH dari: ……. 3/3/2013

METODE PITA-TANAH Attempt to make a ribbon by using your thumb to squeeze the bolus of soil over the side of your first finger - this is best learnt by demonstration. The tendency of a soil to form a thin, strong ribbon is what is known as "resistance to shearing". Using Table 1, identify which field texture best suits the behaviour of the moist bolus of soil you are manipulating. This technique can take some practice. DIUNDUH dari: ……. 3/3/2013

PERILAKU BOLA TANAH LEMBAB KALAU DIMANIPULASI DENGAN TANGAN
Tekstur Perilaku bola tanah lembab % liat PASIR Coherence nil to very slight; cannot be moulded; single sand grains adhere to fingers. Kurang dari 5% PASIR BERLEMPUNG Slight coherence; can be sheared between thumb and forefinger to give minimal ribbon of about 5 mm. Sekitar 5% PASIR BERLIAT SAND Slight coherence; sticky when wet; many sand grains stick to fingers; will form minimal ribbon of mm. Discolours fingers with clay stain. 5-10% LEMPUNG BERPASIR Bolus just coherent but very sandy to touch; will form ribbon mm; dominant sand grains are medium size and readily visible. 10-20% FINE SANDY LOAM Bolus coherent; fine sand can be felt and heard when manipulated; will form ribbon of mm; sand grains are clearly evident under hand lens. LIGHT SANDY CLAY LOAM Bolus strongly coherent but sandy to touch; sand grains dominantly medium size and easily visible; will form ribbon of mm. 15-20% LEMPUNG Bolus coherent and rather spongy; smooth feel when manipulated but with no obvious sandiness or 'silkiness'; may be somewhat greasy to the touch if much organic matter present; will form ribbon about 25 mm. sekitar 25% DIUNDUH dari: ……. 3/3/2013

TEKSTUR Perilaku Bola Tanah Lembab % Liat LOAM, FINE SANDY Bolus coherent and slightly spongy; fine sand can be felt and hard when manipulated; will form ribbon about 25 mm. sekitar 25% LEMPUNG BERDEBU Coherent bolus, very smooth and silky; will form ribbon about 25 mm. Sekitar 25% & debu >25% SANDY CLAY LOAM Strongly coherent bolus sandy to touch; medium size sand grains visible in a finer matrix; will form ribbon of mm. 20-30% LEMPUNG LIAT Coherent plastic bolus; will form ribbon of mm. 30-35% CLAY LOAM, SANDY Coherent plastic bolus; medium size sand grains visible in finer matrix; will form ribbon of mm. SILTY CLAY LOAM Coherent bolus; fine sand can be felt and heard when manipulated; will form ribbon of mm. 30-35% & sebu >25% FINE SANDY CLAY LOAM LIAT BERPASIR Plastic bolus; fine to medium sand can be seen, felt or heard in clayey matrix; will form ribbon of mm. 35-40% LIAT BERDEBU Plastic bolus; smooth and silky to manipulate; ribbon mm. 35-40% & debu >25% DIUNDUH dari: ……. 3/3/2013

Tekstur Perilaku bola tanah lembab % Liat LIAT RINGAN Plastic bolus; smooth to touch; slight resistance to ribbon shearing between thumb and forefinger; will form ribbon of mm. 35-40% LIGHT MEDIUM CLAY Plastic bolus; smooth to touch; slight to moderate resistance to ribboning shear (greater than for light clay); will form ribbon of about 75 mm. 40-45% LIAT MEDIUM Smooth plastic bolus; handles like plasticine; can be moulded into rods without fracture; has moderate resistance to ribboning shear; will form ribbon of 75 mm or more. 45-55% MEDIUM HEAVY CLAY Smooth plastic bolus; handles like plasticine; can be moulded into rods without fracture; has moderate to firm resistance to ribboning shear; will form ribbon of 75 mm or more. >50% LIAT BERAT Smooth plastic bolus; handles like stiff plasticine; can be moulded into rods without fracture; has firm resistance to ribboning shear; will form ribbon of 75 mm or more. DIUNDUH dari: ……. 3/3/2013

The Flowchart Method: Follow the flowchart by manipulating the soil and answering each question ‘yes’ or ‘no’. Apa yg terjadi kalau bola tanah ditekan di antara ibujari dan telunjuk ? Apakah tanah membentuk bola koheren? Ya, mudah Tidak PASIR Ya, tetapi dg cara hati-hati sekali PASIR BERLEMPUNG Bola tanah memipih Bola hancur LEMPUNG BERPASIR Tidak Dapatkah bola digelintir menjadi silinder yg tebal? Ya Dapatkah bola digelintir menjadi benang yg tebal? Ya Tidak Dapatkah benang dibentuk menjadi tapal-kuda-U tanpa retakan ? Ya Dapatkah benang dibentuk melingkar menjadi “sawan lengkung”? Tidak Ya Apakah “rasa” tanah secara umum? Dapatkah dibentuk cincin diameter 2.5 cm dengan menggabungkan ujung-ujung benang tanpa retakan? Kasar dan gritty LEMPUNG Seperti sutera – LEMPUNG DEBU atau DEBU Tidak Digelintir ekmbali menjadi bola dan dielus-elus dg jari supaya permukaannya mengkilap halus – apakah “rasa” tanah secara umum ? Ya Apakah “rasa” tanah secara umum? Sangat kasar LEMPUNG BERPASIR Lumer LEMPUNG LIAT BERDEBU Permukaan sangat halus-mengkilap LIAT atau LIAT BERDEBU (Pembedaannya secara subyektif berdasar kelekatan) Permukaan halus, dengan bentuk tidak teratur LEMPUNG LIAT Permukaan sangat halus-mengkilap, tetapi ada beberapa partikel kasar yang menonjol LIAT BERPASIR Agak kasar LEMPUNG LIAT DIUNDUH dari: ……. 3/3/2013

Improving Soil Texture The good news is, adding organic matter will help all types of soil. It makes clay soils looser, helps sandy soils retain water and nutrients, and generally improves the texture and drainage of all soil types. Organic matter such as compost, leaf mold, and humus add both soil particles and organic nutrients that balance out soil types. After amending your soil, conduct another jar test to see how your soil measures up, then add more or less organic matter next time to even out the ratios. DIUNDUH dari: ……. 3/3/2013

KELAS TEKSTUR TANAH Soil textural classes are based on the relative proportions of the various soil separates (sand, silt, and clay). Ada 12 kelas tekstur tanah. Kelas tekstur tanah dapat ditentukan dnegan menggunakan segitiga tekstur.

SEGITIGA TEKSTUR The percentage units (0-100%) of sand, silt, and clay are listed along the sides of the triangle. Perhatikan bahwa proporsi relatif pasir, debu dan liat, jumlhanya selalu 100%.

SEGITIGA TEKSTUR Tell me what the textural class is if we have: 42% sand, 35% silt, and 23% clay. Kita dapatkan Tekstur LEMPUNG

TANAH-TANAH BERPASIR Tekstur kasar: Pasir Pasir berlempung

TANAH-TANAH PASIR (Sands) SAND OR LOAMY SAND - PASIR BERLEMPUNG
TEKSTUR TANAH TANAH-TANAH PASIR (Sands) The sand group includes all soils in which the sand separates make up at least 70% and the clay separate 15% or less of the material by weight. The properties of such soils are therefore characteristically those of sand in contrast to the stickier nature of clays. Dua kelas tekstur yang termasuk ke dalam tanah pasir adalah Tanah Berpasir (sandy) dan Pasir berlempung (loamy sand). SAND OR LOAMY SAND - PASIR BERLEMPUNG Dry: Loose, single grained; gritty; no or very weak clods. Moist: Gritty; forms easily crumbled ball; does not ribbon. Wet: Lacks stickiness, but may show faint clay staining (loamy sand especially). Individual grains can be both seen and felt under all moisture conditions. DIUNDUH dari: 3/3/2013

TANAH-TANAH BERLEMPUNG
Tekstur agak-kasar: Sandy loam (Lempung Berpasir) 2. Fine sandy loam (Lempung Berpasir-halus)

SANDY CLAY LOAM – LEMPUNG LIAT BERPASIR
TEKSTUR TANAH SANDY CLAY LOAM – LEMPUNG LIAT BERPASIR KERING: Gumpalan tanah agtak sulit hancur. LEMBAB: Forms firm ball that dries moderately hard; forms ½" ribbons that hardly sustain own weight; may show poor to good fingerprint. BASAH: Grittiness of sand and stickiness of clay about equal, masking smoothness of silt; stains fingers. DIUNDUH dari: ……. 3/3/2013

TANAH-TANAH BERLEMPUNG – kasar
Tekstur Medium: Very fine sandy loam (Lempung Berpasir-sangat halus) Loam (Lempung) Silt loam (Lempung debu) Silt (debu)

TEKSTUR MEDIUM Loams: DEBU - SILT
The silt group includes soils with at least 80% silt and 12% or less clay. Naturally the properties of this group are dominated by those of silt. Only one textural class - Silt is included in this group. Loams: The loam group, which contains many subdivisions, is a more complicated soil textural class. An ideal loam may be defined as a mixture of sand, silt and day particles that exhibits the properties of those separates in about equal proportions. Loam soils do not exhibit dominant physical properties of sand, silt or clay. Loam does not contain equal percentage of sand, silt and clay. However, exhibit approximately equal properties of sand, silt and clay. LOAM This is the most difficult texture to place since characteristics of sand, silt, and clay are all present but none predominates. Suggests other textures. Dry: Clods slightly difficult to break; somewhat gritty. Moist: Forms firm ball; ribbons poorly; may show poor fingerprint. Wet: Gritty; smooth, and sticky all at same time. Stains fingers. SANDY LOAM Individual grains can be seen and felt under nearly all conditions. Dry: Clods break easily. Moist: Moderately gritty to gritty; forms ball that stands careful handling; ribbons very poorly. Wet: Definitely stains fingers; may have faint smoothness or stickiness, but grittiness dominates. DIUNDUH dari: 3/3/2013

TEKSTUR TANAH SILT atau SILT LOAM
Grittiness of sand is well masked by other separates. (Texture most likely SILT LOAM, there are a few SILT soils.) KERING: Clods moderately difficult to break and rupture suddenly to a floury powder that clings to fingers; shows fingerprint. LEMBAB: Has smooth, slick, velvety, or buttery feel; forms firm ball; may ribbon slightly before breaking; shows good fingerprint. BASAH: Smooth with some stickiness from clay; stains fingers. DIUNDUH dari: 3/3/2013

TANAH-TANAH BERLEMPUNG - HALUS
Moderately fine texture Sandy clay loam (Lempung liat berpasir) Clay loam (Lempung liat) Silty clay loam (Lempung liat berdebu)

TEKSTUR TANAH SILTY CLAY LOAM – LEMPUNG LIAT BERDEBU
Dry: Clods break with difficulty. Moist: Forms firm ball that dries moderately hard; ribbons fairly well, but ribbons barely support own weight; shows fair to good fingerprint. Wet: Moderately sticky with stickiness dominating over grittiness and smoothness; stains fingers. SILTY CLAY LOAM – LEMPUNG LIAT BERDEBU Resembles SILT LOAM but with more stickiness of clay. Dry: Clods break with difficulty. Moist: Shows a good fingerprint; forms a firm ball; drying moderately hard; ribbons ½"-1" that can be fairly thin. Wet: Stains fingers; has sticky-smooth feel with little grittiness of sand. DIUNDUH dari: 3/3/2013

TANAH-TANAH BERLIAT Tekstur Halus Silty clay (Liat berdebu)
Sandy clay (liat berpasir)

Clays – TANAH-TANAH LIAT
TEKSTUR TANAH Clays – TANAH-TANAH LIAT To be designated clay a soi1 must contain at least 35% of the clay separate and in most cases not less than 40%. In such soils the characteristics of the clay separates are distinctly dominant, and the class names are clay, sandy clay and silty clay. Sandy clays may contain more sand than clay. Likewise, the silt content of silty clays usually exceeds clay fraction. CLAY – TANAH LIAT Dry: Cloddy, clods often cannot be broken even with extreme pressure. Moist: Forms firm, easily molded ball; drying very hard; squeezes out to a very thin ribbon 2-3" long. Wet: Stains fingers, clouds water; usually very sticky with stickiness masking both smoothness and grittiness; wets slowly. DIUNDUH dari: 3/3/2013

TEKSTUR TANAH SANDY CLAY – LIAT BERPASIR SILTY CLAY – LIAT BERDEBU
Dry: Often cloddy, clods broken only with extreme pressure. Moist: Forms very firm ball, drying quite hard; shows fingerprint; squeezes to thin, long, somewhat gritty ribbon. Wet: Stains fingers; clouds water; usually quite sticky and plastic, but has some grittiness present. SILTY CLAY – LIAT BERDEBU Dry: Same as SANDY CLAY. Moist: Forms very firm ball; becoming quite hard on drying; shows fingerprint; squeezes out to a thin, long, smooth ribbon. Wet: Stains fingers, clouds water, stickiness dominates over smoothness, grittiness is virtually absent. DIUNDUH dari: 3/3/2013

Organik dalam Tekstur Tanah
Sand, silt, and clay are the only particles used to determine soil texture. Soil texture refers only to the mineral fraction of the soil. Bahan organik tidak diperhitungkan dalam menentukan kelas tekstur tanah. Analisis tekstur tanah secara akurat mensyaratkan bahan organik harus disingkirkan lebih dulu.

Sifat tanah yang berhubungan dengan tekstur
POROSITAS: indeks volume pori relatif dalam suatu tanah INFILTRASI: pergerakan masuknya air menembus permukaan tanah ERODIBILITAS: Umumnya, partikel-partikel besar kurang erodible, kecuali liat DAYA SIMPAN AIR (WHC): Tekstur Lempung-debu paling tinggi WHC nya

Sifat tanah : Tekstur Tekstur tanah: Proporsi relatif partikel pasir, debu dan liat dalam massa tanah (material yg ukurannya < 2 mm)

Sifat tanah : Tekstur Fragmen kasar ukurannya > 2 mm (kerikil, kerakal, batu, batu besar) PENTINGNYA: Pembentukan tanah, mekanika tanah, pergerakan air, erosi, KTK, mengembang-mengkerut, dll. Liat: permukaannya sangat luas, bermuatan negatif, banyak pori mikro, mengembang

BAGAIMANA MENENTUKAN TEKSTUR TANAH? ANALISIS UKURAN PARTIKEL
Metode Pipette – menggunakan Hukum Stoke untuk mengukur laju penghendapan. Metode ini sangat akurat, tetapi mahal dan memerlukan waktu yang lama Hidrometer – Berat Jenis: Metode ini murah dan cepat; tidak terlalu akurat METODE PIPET seringkali dipakai sebagai standar pembanding bagi metode lain. It depends upon the fact that sedimentation eliminates from the depth, h, in a time, t, all particles having settling velocities greater than h/t, while retaining at that depth the original concentration of particles having settling velocities less than h/t. The taking of a small volume element by a pipet at a depth h at time t furnishes a sample from which all particles coarser than c (particle diameter as determined by Stokes' equation) have been eliminated, and in which all particles finer than that size are present in the same amount as initially. The volume element at depth h has, in effect, been "screened" by sedimentation, so that the ratio of the weight, w, of particles present in that volume at time t, divided by the weight of particles present in it initially, w0, is equal to P/100, where P is the percentage of particles, by weight, smaller than c. Now, the ratio, w/w0, can also be written as the concentration ratio, c/c0, giving c/c0 = P/100. This equation connects the concentration, c, of the pipet sample, in grams per liter, to the parameter P of the particle-size distribution, c0 being the weight of solids in the entire sample divided by the volume of the suspension. (Sheldrick & Wang 1993; Gee & Bauder 1986).

BAGAIMANA MENENTUKAN TEKSTUR TANAH?
Metode Hidrometer The velocity of settling (V) is proportional to the square of particle diameters (d) Partikel yg lebih besar mengendap lebih cepat Kerapatan air (karena debu dan liat yang tersuspensi) menahan hidrometer Metode hidrometer Bouyoucos agak kurang akurat dibanding dnegan Metiode Pipet, tetapi lebih mudah melakukannya. The theory of the hydrometer method is similar to that of the pipet method except for the manner of determining the concentration of solids in suspension. Letting r represent the suspension density, rl the density of liquid, and rs the particle density, all in grams per liter, we have the equation, r = rl + (c/1000)(1 - rl/rs). Although the buoyant force on a hydrometer is determined directly by the suspension density, r, hydrometer scales can be calibrated in terms of c for particular values of rl and rs. The large size of hydrometer bulb necessary to give adequate sensitivity reduces the depth discrimination of the instrument, but this limitation can be overcome by a simple correction (Day 1965). Hukum Stokes: V = kd2

BAGAIMANA MENENTUKAN TEKSTUR TANAH?
Metode Hidrometer Mengaduk tanah dengan hati-hati dan kemudian mengangkat pengaduk pelan-pelan. Hydrometer dipakai untuk mengukur jumlah debu dan liat dal;am suspensi setelah 40 detik Or reading No. 1 = silt and clay in suspension and if we subtract it from total soil this equals amount of sand. Or % sand = total soil –reading one÷total soil x100

BAGAIMANA MENENTUKAN TEKSTUR TANAH? Slowly inserting hydrometer
Metode Hidrometer Pengukuran 2 jam menentukan liat yang tersuspensi atau apa yang tertinggal setelah debu mengendap. %clay = reading two÷total soil x 100 % silt determined by subtraction (reading #1) – (reading #2)=silt %Silt= 100 – [(% sand) + (% clay)] Slowly inserting hydrometer

Sifat tanah yang berhubungan dengan tekstur
Mengembang-mengkerut : tingginya aktivitas liat, terutama liat tipe mengembang 2:1 Pembentukan tanah: Rasio Liat kasar : Liat halus Permeabilitas: Kualitas tanah yg memungkinkan air bergerak ke arah bawah dalam profil tanah.

Pentingnya TEKSTUR TANAH
TANAH-TANAH BERPASIR Texture has good effect on management and productivity of soil. Sandy soils are of open character usually loose and friable. Such type of the texture is easy to handle in tillage operations. Sand facilitates drainage and aeration. It allows rapid evaporation and percolation. Sandy soils have very little water holding capacity. Such soils can not stand drought and unsuitable for dry farming. Kemampuan tanah ini menyimpan hara-tersedia sangat jelek (rendah) Tanah ini biasanya miskin bahan organik Pencucian unsur hara pupuk sangat intensif. Dalam tanah berpasir, beberapa jenis tanaman dapat diusahakan seperti kentang, kacangtanah dan cucumbers. DIUNDUH dari: 3/3/2013

TANAH-TANAH BERLIAT Partikel liat sangat penting peranannya dalam menentukan kesuburan tanah. Tanah-tanah berliat sulit diolah dan memerlukan banyak ketrampilan dalam pengelolaannya. Kalau lembab tanah-tanah ini sangat lekat dan kalau kering menjadi sangat keras sehingga sulit dihancurkan. They have fine pores, and are poor in drainage and aeration. They have a high water holding capacity and poor percolation, which usually results in water logging. They are generally very fertile soils, in respect of plant nutrient content. Rice, jute, sugarcane can be grown very successfully in these soils. DIUNDUH dari: 3/3/2013

TANAH-TANAH LEMPUNG Tanah-tanah Lemung dan Lempung-debu sangat cocok untuk budidaya tanaman Generally, the best agriculture soils are those contain 10 – 20 per cent clay, 5 – 10 per cent organic matter and the rest equally shared by silt and sand . DIUNDUH dari: 3/3/2013

Best Management Practices for different soil textures
TANAH-TANAH BERPASIR Tanah-tanah berpasir mempunyai ruang pori yang besar-besar ukurannya (makro), sehingga memudahkan pergerakan udara dan air dalam tanah. Substances, dissolved in leaching waters, are readily transported deep into the soil and potentially to groundwater. Agricultural activities such as pesticide mixing and tank rinsing, and storage of manure, fertilizer and fuels may pose particular risks on sandy soils. Where the farm water supply is obtained from a well, the effects of contaminating an underground aquifer can be immediate and serious. One litre of oil can make two million litres of water unfit for drinking by humans. DIUNDUH dari: 4/3/2013

TANAH-TANAH BERPASIR Kontaminasi groundwater juga dapat berdampak luas terhadap berbagai penggunaan lain yg memanfaatkan aquifer. A high degree of caution should be exercised when storing and handling potential contaminants in areas of sandy soils. Wells should be properly sited and maintained because they can provide a 'short cut' for contaminants to reach ground water. A permanent, ten foot, grassed buffer should be maintained around the well. Sources of contamination, such as livestock and household waste water should be kept at a sufficient distance. Over-fertilization of sandy crop land with nitrogen may lead to contamination of groundwater by leaching nitrogen. High concentrations of nitrates in drinking water are known to pose a health risk to infants and immune-suppressed individuals. Nutrient management plans should be developed and implemented to prevent over-application of fertilizers and manure. DIUNDUH dari: 4/3/2013

TANAH-TANAH BERPASIR Tanah-tanah berpasir biasanya strukturnya jelek, sehingga sangat peka terhadap erosi oleh angin. This can be an important pathway for the loading of surface waters with sediment and nutrients that are attached to eroding particles. Coarse-textured soils dry out quickly, which tends to increase wind erodability. Teknologi untuk mengurangi erosi oleh angin adalah pergiliran tanaman, cover cropping, reduced tillage, shelterbelts dan barrier tahunan. DIUNDUH dari: 4/3/2013

TANAH-TANAH BERDEBU Tanah-tanah yang teksturnya Debu, Lempung debu, dan Lempung biasanya sangat peka erosi. Water erosion is greatly increased on long or steep slopes where runoff can reach high velocities. Surface runoff of both dissolved and attached compounds occurs during a water erosion event. Teknologi untuk mengurangi erosi tanah oleh air adalah crop rotations, cover cropping, conservation tillage, contour cropping, vegetated buffer strips dan saluran berumput. DIUNDUH dari: 4/3/2013

TANAH-TANAH BERLIAT Despite their value for dryland agriculture, soils with high clay contents have several properties which may lead to movement of contaminants from farm land. Surface structure can become degraded in clay soils, forming a crust. Crusting limits infiltration and increases runoff. When wet, clay soils are easily compacted, which also increases runoff. The runoff may contain contaminants and could affect the quality of surface and ground water. Clay-sized sediment, because of its very small size, is very slow to settle out of dugouts, streams and lakes. This can greatly increase water treatment costs. Teknologi untuk mengurangi erosi tanah oleh air adalah rotasi tanaman, cover cropping, pengolahan tanah konservasi, pertanaman kontur, strip vegetatif sebagai penyangga dan saluran air berumput. DIUNDUH dari: 4/3/2013

TANAH-TANAH BERLIAT Clay soils may also be highly susceptible to wind erosion. Normally, clay helps form stable clods. However, under dry conditions, the surface of heavy clays may become pulverized to a condition where clods are the size of large sand grains. Particles of this size are highly wind erodible. Minimizing tillage of clay soils and maintaining surface residues will help to protect surface structure. Teknologi untuk mengendalikan erosi angin adalah pergiliran tanaman, tanaman penutup tanah, pengolahan konservasi, shelterbelts dan barier tahunan. DIUNDUH dari: 4/3/2013

Bagaimana pentingnya tekstur tanah ?
Foto: smno.hutanpinus.batu.jan2013

MK. DASAR ILMU TANAH TEKSTUR TANAH

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