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Soil texture and structure

Soil texture and structure. SUMBER: jpkc.njau.edu.cn/land/ ppt /4. Soil %20texture%20and%20structure. ppt ‎. Soil density and bulk density Bobot Jenis (BJ) dan Bobot Isi (BI). Soil density ( or Particle density)

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Soil texture and structure

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  1. Soil texture and structure SUMBER: jpkc.njau.edu.cn/land/ppt/4.Soil%20texture%20and%20structure.ppt‎

  2. Soil density and bulk density BobotJenis (BJ) danBobotIsi (BI) Soil density ( or Particle density) Soil density is the density of the solid soil particles only; the measurement does not include water weight or pore (air) space. The dominant soil minerals- quartz, feldspars, micas, and clay minerals-average approximately 2.65 g/cm3, the “standard” value used in calculations if particle density is not measured. Individual minerals have densities from 2.0 g/cm3 for bauxite (aluminum ore) to 5.3 for hematite (iron ore) or 7.6 for galena (lead ore). SUMBER: jpkc.njau.edu.cn/land/ppt/4.Soil%20texture%20and%20structure.ppt‎

  3. BobotIsi Tanah (Soil bulk density) 1. Bulk density, the density for a volume of soil as it exists naturally, includes any air space and organic materials in the soil volume. ρb= (mass of dry soil)/(total volume of soil) = Ms/Vt = Ms/(Vs + Vw +Va) A recently cultivated topsoil is likely to have a bulk density in the range from 0.9 to 1.2 g/cm3, while a compact subsoil may have a bulk density of 1.6 g/cm3 or even more. SUMBER: jpkc.njau.edu.cn/land/ppt/4.Soil%20texture%20and%20structure.ppt‎

  4. Penggunaan BI tanah： ① untukmenghitungPorositas Tanah (p0): P0 = 1- (Bulk density/soil density) ② To calculate soil weight ③ To calculate storage of soilcompositions ④ To calculate total water storage capacity and irrigation (or drainage) quota. 2. Bulk density in water = (soil mass over-dry)/(precipitation volume) 3. Affect the factors of soil bulk density: Texture, structure, content of organic matter, and various nature factors and anthropogenic factors. SUMBER: jpkc.njau.edu.cn/land/ppt/4.Soil%20texture%20and%20structure.ppt‎

  5. 1、 Index three phases constitution Solid phase (%) =（solid volume /soil body volume) ×100 Liquid phase (%) =（liquid volume /soil body volume) ×100 Gas phase (%) =（air volume /soil body volume) ×100 2、Porositas Tanah: Soil porosity is the percentage of the volume of pores to the total volume of soil. Soil porosity ＝1－ Solid phase (%) = Liquid phase (%) + Gas phase (%) SUMBER: jpkc.njau.edu.cn/land/ppt/4.Soil%20texture%20and%20structure.ppt‎

  6. 3、RasioRuang - Void ratio The void ratio is the ratio of the volume of pores to the volume of solids. Void ratio = (volume of pores)/(volume of solids) • Calculation of three phases constitution and porosity • Solid ratio • Solid ratio =（bulk density /density）= ρb/ ρp • 2. Liquid ratio (volumetric water content) • θm = (mass of water /mass of dry soil) = MW/MS • θv = (volume of water/ total volume of soil) = Vw/Vt • = Vw/(Vs+Vw+Va) = θm× ρb SUMBER: jpkc.njau.edu.cn/land/ppt/4.Soil%20texture%20and%20structure.ppt‎

  7. 3. RasioFase Gas Porosity(P0) =1- solid phaseratio =1- bulk density /density） = ρb/ ρp Gas phase ratio = porosity- volumetric water content = P0- θv 4. Actual volume ratio Solid phase ratio ＝ actual volume ratio－ volumetric water content Gas phase ratio = 1－ actual volume ratio Soil three phases ratio ＝ solid phase ratio : volumetric water content : gas phase ratio Rasiotigafasetanah yang ideal： Solid phase ratio is about 50%， volumetric water content is 25% to 30%， Gas phase ratio is 15% to 25%. SUMBER: jpkc.njau.edu.cn/land/ppt/4.Soil%20texture%20and%20structure.ppt‎

  8. Partikel Tanah & FraksiPartikel(Separat Tanah) • (1) TipePartikel Tanah： • Mineral soil particle and organic soil particle • Single particle and compound particle • Primary particle and second particle • (2). Fraksipartikeltanah (separattanah) • Natural soils are comprised of soil particles of varying sizes. The soil particle-size groups, called soil particle fraction (soil separates), are sands (the coarsest), silts, and clays (the smallest). SUMBER: jpkc.njau.edu.cn/land/ppt/4.Soil%20texture%20and%20structure.ppt‎

  9. Ukuran Diameter Partikel • Soil particle diameters range over 4 orders of magnitude • Boulders • Sand • Silt • Clay SUMBER: jpkc.njau.edu.cn/land/ppt/4.Soil%20texture%20and%20structure.ppt‎

  10. Kachinsky classification system of soil separates Physical sandy particle: 1 mm to 0.01 mm. Physical clay particle: <0.01 mm SUMBER: jpkc.njau.edu.cn/land/ppt/4.Soil%20texture%20and%20structure.ppt‎

  11. Soil particle Classification system of soil separates：(mm) Diameter International USDA Kachinsky Chinese Boulders >2 >2 > 1 >1 Sand 2-0.02 2-0.05 1-0.05 1-0.05 Silt 0.02-0.002 0.05-0.002 0.05-0.001 0.05-0.002 Clay 〈0.002 〈0.002 〈0.001 〈0.002 SUMBER: jpkc.njau.edu.cn/land/ppt/4.Soil%20texture%20and%20structure.ppt‎

  12. KomposisimekaniktanahdanTeksturtanah (1).KomposisiMeknaik Tanah （2). Tekstur Tanah 1.Concept: Soil texture-The relative proportions of the various soil separates in a soil. 2. Classification of soil texture. SUMBER: jpkc.njau.edu.cn/land/ppt/4.Soil%20texture%20and%20structure.ppt‎

  13. International classification： The textural triangle is used to determine the soil textural name after the percentages of sand (2-0.02mm), silt (0.02-0.002 mm), and clay (<0.002 mm) are determined from a laboratory analysis. The main criterion of classification： Clay <15% is sand and loamy groups; 15％－25％ is clay loam group; >25% is clay group. When soil contains silt >45%， soil will be called “silty”； When soil contains sand in 55%-85%，called “sandy”， When soil contains sand >85%，called “loamysand”or “sand”. SUMBER: jpkc.njau.edu.cn/land/ppt/4.Soil%20texture%20and%20structure.ppt‎

  14. The fertility characteristics, utilize and improves of different soil textures 1. Sand The fertility characteristics of different soil textures • < 2 mm to > 0.02 mm • Visible without microscope • Rounded or angular in shape • 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. SUMBER: jpkc.njau.edu.cn/land/ppt/4.Soil%20texture%20and%20structure.ppt‎

  15. PASIR - Sand • Feels gritty • Considered non-cohesive – does not stick together in a mass unless it is very wet. SUMBER: jpkc.njau.edu.cn/land/ppt/4.Soil%20texture%20and%20structure.ppt‎

  16. PASIR - Sand • Low specific surface area • Sand has less nutrients for plants than smaller particles • Voids between sand particles promote free drainage and entry of air • Holds little water and prone to drought SUMBER: jpkc.njau.edu.cn/land/ppt/4.Soil%20texture%20and%20structure.ppt‎

  17. LIAT • < 0.002 mm • Flat palettes or tiny flakes • Small clay particles are colloids • If suspended in water will not settle • Large surface area • spoonful = football field SUMBER: jpkc.njau.edu.cn/land/ppt/4.Soil%20texture%20and%20structure.ppt‎

  18. LIAT - Clay • Wet clay is very sticky and is plastic or it can be molded readily into a shape or rod. • Easily formed into long ribbons • Shrink and swell SUMBER: jpkc.njau.edu.cn/land/ppt/4.Soil%20texture%20and%20structure.ppt‎

  19. LIAT - Clay • Pores spaces are very small • Movement of water and air very slow • Water holding capacity • Tremendous capacity to adsorb water- not all available for plants. • Soil strength- shrink/swell affects buildings, roads and walls. • Chemical adsorption is large SUMBER: jpkc.njau.edu.cn/land/ppt/4.Soil%20texture%20and%20structure.ppt‎

  20. LEMPUNG - Loam • < 0.02 mm to > 0.002 mm • Not visible without microscope • Quartz often dominant mineral in loam since other minerals have weathered away. SUMBER: jpkc.njau.edu.cn/land/ppt/4.Soil%20texture%20and%20structure.ppt‎

  21. LEMPUNG - Loam • Does not feel gritty • Floury feel • Wet loam does not exhibit stickiness / plasticity / malleability SUMBER: jpkc.njau.edu.cn/land/ppt/4.Soil%20texture%20and%20structure.ppt‎

  22. LEMPUNG - Loam • Smaller size allows rapid weathering of non quartz minerals • Smaller particles – retains more water for plants and have slower drainage than sand. • Easily washed away by flowing water – highly erosive. • Holds more plant nutrients than sand. SUMBER: jpkc.njau.edu.cn/land/ppt/4.Soil%20texture%20and%20structure.ppt‎

  23. Silt is responsible for silting over gravel beds in rivers that are needed by fish for spawning. SUMBER: jpkc.njau.edu.cn/land/ppt/4.Soil%20texture%20and%20structure.ppt‎

  24. Loess Cliff in China Silt if often left as a vertical face since in this condition the landscape is less prone to water erosion than if the area was graded to a slope. SUMBER: jpkc.njau.edu.cn/land/ppt/4.Soil%20texture%20and%20structure.ppt‎

  25. Menggunakandanmemperbaikiteksturtanah ① Foreign soil methods Soil texture can be changed only by mixing with another soil with a different textural class in small quantities ② Deep ploughing, deep turn over etc. 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!! SUMBER: jpkc.njau.edu.cn/land/ppt/4.Soil%20texture%20and%20structure.ppt‎

  26. Soil Structure 一、Soil structureness （一）Concept of soil structure Soil structure- The combination or arrangement of primary soil particles into secondary units or peds. The secondary units are characterized on the basis of size, shape, and grade (degree of distinctness). (二) Classes and types of soil structure Types of structure describe the ped shape with the terms granular, crumb, platy, blocky, subangular blocky, prismatic, and columnar. Structure classes are the ped sizes such as very fine, fine, medium, coarse (or thick), and very coarse (or very thick). SUMBER: jpkc.njau.edu.cn/land/ppt/4.Soil%20texture%20and%20structure.ppt‎

  27. Soil structureness SUMBER: jpkc.njau.edu.cn/land/ppt/4.Soil%20texture%20and%20structure.ppt‎

  28. Struktur yang Jelek: platy, blocky, subangular blocky, prismatic, and columnar Struktur yang baik: Granular • Genesis Struktur Granular • Prosespembentukanstruktur granular • Cohesion aggregation • ① Condense • ②Cohesion of inorganic matter • ③ Cementation and compound of organic matter • ④ Complex of organic-mineral • ⑤ Earthworms and other small animals SUMBER: jpkc.njau.edu.cn/land/ppt/4.Soil%20texture%20and%20structure.ppt‎

  29. 2. ProsesPengirisandanPemodelan ① Root ②Wetting and drying cycle ③ Alternate freezing and thawing ④ Tillage The arrangement of soil particle SUMBER: jpkc.njau.edu.cn/land/ppt/4.Soil%20texture%20and%20structure.ppt‎

  30. Prosespembentukanagregattanah PARTIKEL TANAH Agregat AGREGAT MIKRO ProsesAgregasi SUMBER: jpkc.njau.edu.cn/land/ppt/4.Soil%20texture%20and%20structure.ppt‎

  31. Humus (BOT) & Liatsebagaiperekat PASIR BOT LIAT PASIR DEBU SUMBER: jpkc.njau.edu.cn/land/ppt/4.Soil%20texture%20and%20structure.ppt‎

  32. Ca++ dansenyawaorganiksebagaiperekat Ca2+ SENYAWA ORGANIK SEBAGAI PEREKAT PARTIKEL TANAH PARTIKEL TANAH PARTIKEL TANAH SUMBER: jpkc.njau.edu.cn/land/ppt/4.Soil%20texture%20and%20structure.ppt‎

  33. Fe dan Al, dansenyawaorganiksebagaiperekat Fe2+ SENYAWA ORGANIK SEBAGAI PEREKAT PARTIKEL TANAH PARTIKEL TANAH Fe3+ PARTIKEL TANAH Al3+ SUMBER: jpkc.njau.edu.cn/land/ppt/4.Soil%20texture%20and%20structure.ppt‎

  34. MekanismeMikrokosmikpembentukanagregattanah 1. TeoriLiat SUMBER: jpkc.njau.edu.cn/land/ppt/4.Soil%20texture%20and%20structure.ppt‎

  35. 2. Keseimbangan air danUdaradalamtanah 3.Coordinated to keep and apply fertilizer 4. Pengolahantanah yang sesuai 5. Lapisanolah-tanah yang bagus SUMBER: jpkc.njau.edu.cn/land/ppt/4.Soil%20texture%20and%20structure.ppt‎

  36. Pengelolaanstrukturtanah • Aplikasipupukorganik • Rotasi (pergiliran ) tanaman yang sesuai • Reasonable tillage, water management and soil reclamation • Aplikasibahanperbaikanstrukturtanah • The electric current reclamation of saline-alkali soil SUMBER: jpkc.njau.edu.cn/land/ppt/4.Soil%20texture%20and%20structure.ppt‎

  37. Pori Tanah danTubuh Tanah Porositas Tanah: Perhitunganporositastanah 1. Soil porosity = pore volume/soil volume = (soil volume – soil particle volume)/soil volume = 1-（ soil particle volume/ soil volume） = 1-[（ soil particle volume×soil weight）/（ soil volume× soil weight）] = 1-[（ soil weight/ soil volume）×（ soil particle volume/ soil weight ）] =1-[（ soil weight/ soil volume）/（ soil weight / soil particle volume）] = （1 – BI / BJ) SUMBER: jpkc.njau.edu.cn/land/ppt/4.Soil%20texture%20and%20structure.ppt‎

  38. 2. Scope of soil porosity Sandy soil 30－45％ Loam soil 40-50% Clay soil 45-60% Peaty soil 〉80％ 3. Loose and tight arrangement of soil particles SUMBER: jpkc.njau.edu.cn/land/ppt/4.Soil%20texture%20and%20structure.ppt‎

  39. 2. KlasifikasiPorositas 3. PorositasAerasi The porosity model of granular structure (Studied by yourself) Equivalent pore diameter (effective aperture) Aeration pores- Greater than 0.1 mm average diameter. Size of medium sands. Capillary pores- 0.1-0.03 mmaverage diameter. Size of silt particles. Storage pores-Less than 0.03 mm average diameter. Size of clay particles. SUMBER: jpkc.njau.edu.cn/land/ppt/4.Soil%20texture%20and%20structure.ppt‎

  40. ProfilPorositas Tanah The suitable porosity for plant growth: Plowed layer soil : total porosity in 50% to 56%, aeration pores in 8% to 10%. SUMBER: jpkc.njau.edu.cn/land/ppt/4.Soil%20texture%20and%20structure.ppt‎

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