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Sumber : www.environment.ualberta.ca/ Soils ERM/lecture6/Lecture6. ppt ‎

pH -TANAH & REAKSI TANAH. Sumber : www.environment.ualberta.ca/ Soils ERM/lecture6/Lecture6. ppt ‎ . Reaksi Tanah. Soil reaction is the degree of acidity or alkalinity of a soil, usually expressed as a pH value. Soil pH = -log [H + ]

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Sumber : www.environment.ualberta.ca/ Soils ERM/lecture6/Lecture6. ppt ‎

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  1. pH -TANAH & REAKSI TANAH Sumber: www.environment.ualberta.ca/SoilsERM/lecture6/Lecture6.ppt‎

  2. Reaksi Tanah • Soil reaction is the degree of acidity or alkalinity of a soil, usually expressed as a pH value. • Soil pH = -log [H+] • Soil pH is an indicator of physical, chemical and biological properties in soil. • Soil pH is also related to the cations present on the exchange complex. Sumber: www.environment.ualberta.ca/SoilsERM/lecture6/Lecture6.ppt‎

  3. Nilai pH beberapa material • Milk of magnesia: ~10.5 • Bicarbonate of soda: ~8.3 • Pure water: 7.0 • Milk: ~6.8 • Natural rain: 5 to 6 • Beer/coffee: ~4 • Lemon Juice: ~2 Sumber: www.environment.ualberta.ca/SoilsERM/lecture6/Lecture6.ppt‎

  4. Deskripsiuntukkisaran pH tanah Sumber: www.environment.ualberta.ca/SoilsERM/lecture6/Lecture6.ppt‎

  5. Tanah mempunyaiciri yang khas Dark Gray Luvisol Orthic Humo-Ferric Podzol Orthic Black Chernozem Sumber: www.environment.ualberta.ca/SoilsERM/lecture6/Lecture6.ppt‎ Credit: Pedosphere.com

  6. pH Tanah vs. KomposisiKation • Total cation exchange capacity (TCEC) is a function of quantity of clays, organic matter and iron and aluminum oxides. • TipeLiatternyatasangatpentingpengaruhnya. Sumber: www.environment.ualberta.ca/SoilsERM/lecture6/Lecture6.ppt‎

  7. pH Tanah vs. KomposisiKation • Base cations (Ca++, Mg++, K+, Na+) concentration decreases as soil becomes more acidic (pH decreases) • Kejenuhanbasaberkaitaneratdengan pH tanah Sumber: www.environment.ualberta.ca/SoilsERM/lecture6/Lecture6.ppt‎

  8. PersenKejenuhanBasa (KB) • Basic cations: Ca++, Mg++, Na+, K+ • Acidic cations: Al+++, H+ • Percent base saturation: A measure of the proportion of basic cations occupying the exchange sites of a soil Sumber: www.environment.ualberta.ca/SoilsERM/lecture6/Lecture6.ppt‎

  9. Formula • Cation exchange capacity is the sum of all cations on the exchange complex • % Base saturation =  (Ca++, Mg++, K+, Na+) x 100 Cation Exchange Capacity Sumber: www.environment.ualberta.ca/SoilsERM/lecture6/Lecture6.ppt‎

  10. Impact of soil pH on net charge of noncrystallinealuminum oxide. At low pH, H ions become bound to Al and Fe oxides Sumber: www.environment.ualberta.ca/SoilsERM/lecture6/Lecture6.ppt‎ Credit: Pedosphere.com

  11. pH Tanah vs. KationpadaKompleksPertukaran(Brady and Weil, 1996) Sumber: www.environment.ualberta.ca/SoilsERM/lecture6/Lecture6.ppt‎

  12. Pelarutan Al(OH)3 Amorf • Al(OH)3 + H+ Al(OH)2++ H2O • Al(OH)2++ H+ Al(OH)+++ H2O • Al(OH)+++ H+ Al++++ H2O • The equilibrium reactions result in buffering of soil Sumber: www.environment.ualberta.ca/SoilsERM/lecture6/Lecture6.ppt‎

  13. MekanismePenyangga (Buffering) • Oxidation of pyrite and reduced S minerals; dissolution of minerals: pH 2 to 4 • Aluminum compounds: pH 4.0 to 5.5 • PertukaranKation : pH 5.5 to 6.8 • Organic matter and minerals: pH 6.8 to 7.2 • Karbonatdari Ca danMg : pH 7.2 to 8.5 • Na+tukar; pelarutan Na-karbonatpadatan : pH 8.5 to 10.5 Sumber: www.environment.ualberta.ca/SoilsERM/lecture6/Lecture6.ppt‎

  14. TipeKemasaman Tanah • KemasamanAktif (Active acidity):Aktivitaskation H+ dalamlarutantanah • KemasamanCadangan (Reserve acidity):The acidity that is associated with the exchange complex. It is neutralized by lime or other alkaline material Sumber: www.environment.ualberta.ca/SoilsERM/lecture6/Lecture6.ppt‎

  15. KlasifikasiKemasaman Tanah - + - + + - - + + + - - + - + + - Clay surface + - + Bulk solution + + - - + + - + + - + - - + - Hydrogen is part of the crystal lattice, and can be present as an exchangeable cationand in the soil bulk solution Sumber: www.environment.ualberta.ca/SoilsERM/lecture6/Lecture6.ppt‎

  16. Ketersediaan Hara • Ketersediaanharasangatberhubunganeratdengankelarutannyapadaberbagainilai pH • At extreme pH values, solubility of some nutrients increases tremendously, leading to toxicity of plants Sumber: www.environment.ualberta.ca/SoilsERM/lecture6/Lecture6.ppt‎

  17. Pengasaman Tanah Pengasaman Tanah Use of ammonium-based fertilizers (NH4)SO4 + 4O22HNO3 + H2SO4 + 2H2O DeposisiAsam Nitric (HNO3) + Sulfuric (H2SO4) acids Sumber: www.environment.ualberta.ca/SoilsERM/lecture6/Lecture6.ppt‎

  18. Pengasaman Tanah Drainage of some coastal wetlands leads to the oxidation of pyrite (FeS2), iron sulfide (FeS) and elemental S and formation of sulfuric acid Sumber: www.environment.ualberta.ca/SoilsERM/lecture6/Lecture6.ppt‎

  19. Influence of Soil Moisture on Soil Solution Chemistry and Concentrations ofMinerals in the CalcicolesPhleumphleoides and Veronica spicata Grown on aLimestone SoilAPARNA MISRA and GERMUND TYLER . Veronica spicata dan Phleum phleoides adalah tanaman calcicole , terutama terjadi pada tanah netral atau alkali . Eksperimen 16 minggu dilakukan di rumah kaca untukmengelusidasi pengaruh tingkat kelembaban tanah thdkimia larutan tanah , dan konsentrasi biomassa dan penyerapan haraoleh tanaman .Tujuh tingkat kelembaban tanah, sesuai dengan 35 ± 85 % kapasitas menahan air ( WHC ) dari tanah diuji . KonsentrasilarutantanahHCO3 , P dan Mn, dan pH meningkat , sedangkan konsentrasi Ca , Mg , dan Zn menurun denganmeningkatkan kelembaban tanah.Konsentrasi K yang tertinggi di 50 ± 70 % WHC . Konsentrasi dan jumlah P , Zn dan Mn dalam dua spesies berhubungan dengan konsentrasi larutan tanah ; haraini kelarutannyarendah dan ketersediaannyarendahpadatanah berkapur . Konsentrasi haradalam biomassa lebih dipengaruhi oleh kelembaban tanah untukV. spicata daripada P. phleoides . Hal ini menunjukkan bahwa P. phleoides lebih mampu mengendalikan serapan hara, sedangkan V. spicata sensitif terhadap variasi kelembaban tanah . Hal ini menyimpulkan bahwa variasi rejim kelembaban tanah sangat mempengaruhi konsentrasi haralarutan tanah berkapur dan serapan haraolehtanaman . Sumber: Annals of Botany 84: 401±410, 1999

  20. The effect of soil water content, soil temperature, soil pH-value and theroot mass on soil CO2 efflux – A modified modelSascha Reth, Markus Reichstein & Eva Falge. Untuk mengukur efek suhu tanah ( Tsoil ) , dan kadar air tanah relatif ( RSWC ) thdrespirasi tanah , makadilakukanpengukuranCO2 tanah di lapangan dan diruang iklim percobaan . Pengaruh suhu tanah thd emisi CO2 sangat signifikan pd semua penggunaan lahan , kecuali untuk lapangan terbukadengan hujan terus menerus . Suhu tanah berpengaruh yang signifikan , persentase ragam yang dapatdijelaskan oleh suhu tanah berkisar13-46 % di lapangan dan 35-66 % di ruang percobaan. Perubahan kelembaban tanah mempengaruhipelepasanCO2 pada tanah padang rumput di lapangan dan ruang percobaan ( 14-34 % ragam) , sedangkan dilahan gundul dan tanah hutan tidak ada efek yang terlihat . Variasi spasial emisi CO2 tanah di lapanganberkorelasi secara signifikan dengan pH tanah dan massa akar halus , halinidapatmenjelaskan hingga 24 % dan 31 % dari ragam. Model regresi non - linear dikembangkan untuk menggambarkan pelepasanCO2 tanah sebagai fungsi dari suhu tanah , kelembaban tanah, pH tanahdan biomasa akar . Dengan model inikita dapat menjelaskan 60 % dari variabilitas emisi CO2 tanahdari semua individu pengukuran ruang danlapangan . Model mengestimasialiran CO2 secaraberlebihan selama dan dalam waktu empat jam dari peristiwa hujan terakhir .Sebaliknya, setelah lebih dari 72 jam tanpa hujan ternyataestimasimodel underestimated. Antara empat dan 72 jam setelahcurah hujan , model regresi emisi CO2 tanah menjelaskan sampai dengan 91 % ragam. Sumber: Plant and Soil (2005) 268: 21–33

  21. Soil pH and Mineral Nutrition of Vitisvinifera Varieties. Padatanah-tanah yang pHnyarendah, ion Al+++ mendominasikation. Kalau pH tanahmendekati 4.5, Al-tukarmulaiberkurangdanpada pH lebihdari6 hanyasedikitsekali ion Al+++ yang tersediabagitanaman. Sumber: http://www.fruit.cornell.edu/grape/pool/nutrition.html

  22. .pH danToksisitas Cu Cu menjadilebihtersediapadakondisi pH rendah. Toksisitas Cu biasanyaberkaitandneganaplikasifungisida Cu ketanahmasam. Olehkarenaituuntukmengendalikangangguanpenyakittidakharustergantungpadafungisida Cu. Sumber: http://www.fruit.cornell.edu/grape/pool/nutrition.html

  23. .pH Tanah pH is defined as the negative logarithm of the hydrogen ion (H+) concentration. When water ionizes to H+ and OH- (a neutral solution), both H+ and OH- ions are in equal concentrations of 0.0000001 moles per liter. That is a very small concentration. HOH <—> H+ + OH- [H+] = [OH-] = 1 x 10-7 moles/liter. The H+ ion and OH- concentrations in water are very small. The pH scale has been devised for conveniently expressing these small concentrations by expressing pH = Log 1/[H+] Sumber: http://www.swac.umn.edu/classes/soil2125/doc/s12ch1.htm

  24. .pH Tanah When the hydrogen concentration isgreater, such as 0.0001 moles per liter, the pH is 4; when it is smaller, such as 0.00000001, the pH is 8. One thing to remember is that when the pH changes from one unit to another, the change in the hydrogen ion concentration is a ten-fold change, not just one. So a pH of 5 is ten times more acid than a pH of 6 and 100 times more acid than a pH of 7. Sumber: http://www.swac.umn.edu/classes/soil2125/doc/s12ch1.htm

  25. .pH Tanah Sources of H+ ions in the soil : Dissociation of carbonic acid (H2CO3), which forms readily in soils when CO2 is present;--- H2CO3- ---> CO2 + H + +HCO3- Asamorganikformed during the decomposition of organic matter; Pembakaranbatubarain electrical power plants releases sulfur to the atmosphere which is added to soils during precipitation as sulfuric acid, and fertilizers containing sulfur, which adds H+ ; KonversiNH4+menjadi NO3-melepaskan H+ selamasiklus N atauketikapemupukan nitrogen. (5) uptake of positive ions by plant roots and the resulting release of H+ by the root to balance internal charge. pH is < 4.0=indicates that the soil contains free acids probably as a result of sulfide oxidation pH is < 5.5=indicates that the soil's exchange complex is dominated by Al pH is < 7.8=soil pH is controlled by a range of factors pH is > 7.8=indicates that the soil contains CaCO3 Sumber: http://www.swac.umn.edu/classes/soil2125/doc/s12ch1.htm

  26. .pH Tanah Tanah-tanahcenderungmenjadilebihmasamkarena: Air Hujanmencucikationbasa (calcium, magnesium, potassium dansodium); CO2 daridekomposisi BOT danrespirasiakar yang larutdalam air-tanahmembentuklarutanasamlemah; Penyerapankationby plant roots and the resulting release of H+ by the root to balance internal charge; Pembentukanasamkuatorganikdananorganik, such as nitric and sulfuric acid, from decaying organic matter and oxidation of ammonium and sulfur fertilizers. Strongly acid soils are usually the result of the action of these strong organic and inorganic acids. Sumber: http://www.swac.umn.edu/classes/soil2125/doc/s12ch1.htm

  27. .pH Tanah Pertanian Sumber: Hardy DH, Tucker MR, Stokes CE. 2014. Crop fertilization based on North Carolina soil tests. Raleigh (NC): North Carolina Department of Agriculture and Consumer Services, Agronomic Division. Circular No. 1.

  28. Efek pH Tanah thdKetersediaan Hara Sumber: http://www.summitfertz.com.au/agronomy_soil_pH.html

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