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Bruno Delvaux - One of the best experts on this subject based on the ideXlab platform.
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porosity and soil water properties of caribbean volcanic ash soils
Soil Use and Management, 2006Co-Authors: Marc Dorel, Jean Rogerestrade, Hubert Manichon, Bruno DelvauxAbstract:Volcanic ash soils are generally recognized as soils with excellent and stable physical properties. Here we characterized the porosity and water properties of volcanic ash Andosols and Nitisols from Guadeloupe in contrasting banana systems: (1) perennial crop without mechanization, (2) mechanized and regularly replanted crop. Desiccation from 1 kPa to 1550 kPa moisture tension leads to significant shrinkage in the Andosol, representing a 50% reduction of the void space. The clayey Nitisol exhibited limited shrinkage. Soil clods from the mechanized plots had a significantly smaller macroporosity than that from perennial plots. The soil hydraulic conductivity was also drastically reduced in the compacted layers of the mechanized plots. However, Nitisols appeared to be less affected than Andosols. Laboratory compression tests showed that both soils were susceptible to compaction at soil moisture close to field capacity. The shrinkage properties of the Andosol were due to microaggregation of non-crystalline components upon drying. The relative stability of the macroporosity in the Nitisol was probably related to the presence of stable microaggregates made of halloysite and iron oxide. Two major processes promote soil structure degradation in the Andosol under mechanized banana cropping, surface desiccation and soil compaction. They are both induced by repeated tillage after clearing.
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contribution of so3 to the acid neutralizing capacity of Andosols exposed to strong volcanogenic acid and so2 deposition
European Journal of Soil Science, 2005Co-Authors: Thomas Delfosse, Pierre Delmelle, Anne Iserentant, Bruno DelvauxAbstract:Soil response to acid and sulphur inputs is influenced largely by the soil's physico-chemical properties. We studied the effects of such depositions in two types of Andosols exposed to volcanogenic emission (Masaya, Nicaragua), namely Eutric Andosols rich in allophanic constituents, and Vitric Andosols rich in volcanic glass. Small mineral reserves and large contents of secondary short-range ordered minerals indicate a more advanced weathering of the Eutric than the Vitric Andosols. Strong correlations between soil specific surface and oxalate-extractable Al, Si and Fe contents highlight the predominant contribution of short-range ordered minerals to surface area. Both types of Andosols showed a decrease in pH upon acid input. Sulphur deposition increased the soil's S content to 5470 mg S kg(-1). However, the acid neutralizing capacity of the soil solid phase (ANC(s)) was not significantly affected by the acid and S inputs. Non-exchangeable (mineral reserve) and exchangeable cations and total contents of sulphur and phosphorus dictate most of the ANC(s) variation. In the Vitric Andosols, mineral reserves contributed up to 97% to these four additive pools, whereas the exchangeable cations accounted for 1-4%. In the Eutric Andosols, the contribution of mineral reserves was less (71-92%), but the exchangeable cation content was greater (1-20%), whereas the contribution of sulphur and phosphorus was significant at 1-15% and 2-7%, respectively. The main process involved in H+ consumption is mineral weathering in Vitric Andosols and ion exchange in Eutric Andosols.
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selective sorption of potassium in a weathering sequence of volcanic ash soils from guadeloupe french west indies
Catena, 2004Co-Authors: Samuel Ndayiragije, Bruno DelvauxAbstract:Volcanic ash soils are usually associated within the weathering sequence glass --> allophane --> 4 halloysite. On the eastern slopes of the volcano La Soufriere, Guadeloupe, this sequence occurs in a toposequence Molli-silicic Andosol-Humic Andosol-Haplic Andosol-Haplic Nitisol, where the average annual rainfall decreases from 4000 mm at 420 m a.s.l. to 2500 mrn at 30 m a.s.l. Of this sequence, we selected four profiles and examined the relationships between weathering stage, clay mineralogy and exchangeable K+-Ca2+ selectivity. With increasing weathering, the total content of alkaline and alkaline-earth cations of the B horizon steadily decreased from 185 cmol(c) kg(-1) soil in the Molli-silicic Andosol to 24 cmol(c), kg(-1) soil in the Nitisol. K+ selectivity was small in the Molli-silicie Andosol, but significantly increased with increasing weathering stage and increasing content of halloysite. In the Haplic Andosol and Nitisol, the very strong selectivity for K+ ions may be linked with the presence of a 2:1 clay mineral, but could not be attributed unequivocally to this mineral or to halloysite. The 2:1 mineral occurred as a discrete phase mixed with halloysite and exhibited X-ray diffraction features, suggesting its vermiculitic nature. (C) 2003 Elsevier B.V. All rights reserved.
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coexistence of allophane gibbsite kaolinite and hydroxy al interlayered 2 1 clay minerals in a perudic Andosol
Geoderma, 2003Co-Authors: Samuel Ndayiragije, Bruno DelvauxAbstract:Allophane and halloysite are the most common secondary aluminosilicate minerals in Andosols developed in pyroclasts in humid tropical areas. We studied the composition and the charge properties of the clays extracted from the weathered B horizon of a perhydrated Andosol developed in andesitic ash in Guadeloupe, French West Indies, by selective dissolution, X-ray diffraction (XRD), thermal analysis and characterization of ion exchange properties. The Bw horizon contained weatherable minerals and exhibited an allophane content of 25%. Its clay fraction contained gibbsite, allophane, kaolinite and hydroxy-Al interlayered 2:1 clay minerals. The occurrence of gibbsite, allophane and kaolinite was linked with intense leaching of silica. After oxalate dissolution of allophane, the cation exchange capacity (CEC) was 11.8 cmol(c) kg(-1) clay, i.e. a typical value for low-activity clays. Subsequent citrate treatment completely dissolved gibbsite, but partly extracted Al interlayers from the hydroxy-Al-interlayered phase. This extraction led to a 5.6-fold increase of the cation exchange capacity (62.3 cmol(c) kg(-1) clay) and a 2.3-fold increase in K+ selectivity. The 2:1 clay minerals involved a combination or continuum of high-charge beidellite and vermiculite. From our data, we believe that the 2:1 clay minerals first acted as a sink for aluminium and might have expressed an anti-gibbsitic effect. After substantial Al interlayering of 2:1 clay minerals mimicking low-activity clay, gibbsite might have formed in a second stage. (C) 2003 Elsevier Science B.V. All rights reserved.
Cut Fajrina - One of the best experts on this subject based on the ideXlab platform.
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KAJIAN FRAKSI FE DAN AL HUMUS PADA BEBERAPA JENIS TANAH DI LAHAN KERING ACEH BESAR
Fakultas Pertanian Universitas Syiah Kuala, 2018Co-Authors: Cut FajrinaAbstract:Kabupaten Aceh Besar memiliki lahan kering seluas 278,581 hektar yang terbentukatas beberapa jenis tanah seperti Litosol, Regosol, Aluvial, Renzina, Mollisol, Andosol,Kambisol, Podsolik dan Oksisol. Beberapa permasalahan yang sering di temukan pada sistempertanian lahan kering di wilayah tropika basah antara lain pH tanah rendah, kandungan Corganik rendah, miskin unsur hara, kapasitas tukar kation dan kejenuhan basa rendah, fiksasifosfat yang tinggi, masalah erosi dan ketersediaan air. Tanah-tanah yang berada di daerahiklim tropis tersebut digolongkan sebagai tanah dengan sistem muatan variabel dan memilikiliat aktivitas rendah (low activity clay).Penelitian ini bertujuan untuk mengetahui kadar Fe- dan Al-humus serta C-organikmenurut horison pada setiap ordo tanah dan mengetahui distribusi dan pola distribusi Fe- danAl-humus serta C-organik pada masing-masing ordo tanah. Penelitian ini menggunakanmetode survai deskriptif yaitu melalui kegiatan observasi lapangan dan analisis laboratoriumuntuk mengumpulkan data.Hasil penelitian didapatkan bahwa kandungan tertinggi baik Fe-humus maupun Alhumus terdapat pada ordo Mollisol. Fe-humus terdapat pada horison Ap, Bk1 dan Bk2 yaitu0,14%, sedangkan Al-humus terdapat pada horison Bk1 yaitu 7,53% dan C-organik tertinggiterdapat pada horison Ap ordo Andisol yaitu 4,44%. Kandungan C-organik di lahan keringKabupaten Aceh Besar pada jenis tanah Entisol, Inceptisol, Mollisol dan Ultisol tergolong kedalam kriteria sangat rendah sampai rendah, sedangkan pada Andisol tergolong sangat rendahsampai tinggi dan pada tanah Oxisol tergolong sangat rendah. Sebaran Fe-humus, Al-humusdan C-organik pada enam ordo tanah di lahan kering Aceh Besar membentuk pola yangbervariasi. Pola distribusi Fe-humus pada kedalaman 80 - 125 cm ordo Inceptisol, Andisol,Mollisol dan Ultisol semakin menurun, sedangkan pada Entisol dan Oxisol semakinmeningkat. Pola distribusi Al-humus pada kedalaman 85 - 125 cm pada enam ordo tanahsemakin menurun, sedangkan pada kedalaman 20 - 125 cm pola distribusi C-organik semakinmenurun dengan bertambahnya kedalaman tanah.Banda Ace
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KAJIAN FRAKSI FE DAN AL HUMUS SERTA C ORGANIK PADA BEBERAPA JENIS TANAH DI LAHAN KERING ACEH BESAR
'Badan Penerbitan Fakultas Pertanian (BPFP) Universitas Bengkulu', 2018Co-Authors: Cut FajrinaAbstract:Kabupaten Aceh Besar memiliki lahan kering seluas 278,581 hektar yang terbentuk atas beberapa jenis tanah seperti Litosol, Regosol, Aluvial, Renzina, Mollisol, Andosol, Kambisol, Podsolik dan Oksisol. Beberapa permasalahan yang sering di temukan pada sistem pertanian lahan kering di wilayah tropika basah antara lain pH tanah rendah, kandungan C organik rendah, miskin unsur hara, kapasitas tukar kation dan kejenuhan basa rendah, fiksasi fosfat yang tinggi, masalah erosi dan ketersediaan air. Tanah-tanah yang berada di daerah iklim tropis tersebut digolongkan sebagai tanah dengan sistem muatan variabel dan memiliki liat aktivitas rendah (low activity clay). Penelitian ini bertujuan untuk mengetahui kadar Fe- dan Al-humus serta C-organik menurut horison pada setiap ordo tanah dan mengetahui distribusi dan pola distribusi Fe- dan Al-humus serta C-organik pada masing-masing ordo tanah. Penelitian ini menggunakan metode survai deskriptif yaitu melalui kegiatan observasi lapangan dan analisis laboratorium untuk mengumpulkan data. Hasil penelitian didapatkan bahwa kandungan tertinggi baik Fe-humus maupun Al-humus terdapat pada ordo Mollisol. Fe-humus terdapat pada horison Ap, Bk1 dan Bk2 yaitu 0,14%, sedangkan Al-humus terdapat pada horison Bk1 yaitu 7,53% dan C-organik tertinggi terdapat pada horison Ap ordo Andisol yaitu 4,44%. Kandungan C-organik di lahan kering Kabupaten Aceh Besar pada jenis tanah Entisol, Inceptisol, Mollisol dan Ultisol tergolong ke dalam kriteria sangat rendah sampai rendah, sedangkan pada Andisol tergolong sangat rendah sampai tinggi dan pada tanah Oxisol tergolong sangat rendah. Sebaran Fe-humus, Al-humus dan C-organik pada enam ordo tanah di lahan kering Aceh Besar membentuk pola yang bervariasi. Pola distribusi Fe-humus pada kedalaman 80 - 125 cm ordo Inceptisol, Andisol, Mollisol dan Ultisol semakin menurun, sedangkan pada Entisol dan Oxisol semakin meningkat. Pola distribusi Al-humus pada kedalaman 85 - 125 cm pada enam ordo tanah semakin menurun, sedangkan pada kedalaman 20 - 125 cm pola distribusi C-organik semakin menurun dengan bertambahnya kedalaman tanah.Banda Ace
Tadashi Takahashi - One of the best experts on this subject based on the ideXlab platform.
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nature properties and function of aluminum humus complexes in volcanic soils
Geoderma, 2016Co-Authors: Tadashi Takahashi, Randy A. DahlgrenAbstract:© 2015 Elsevier B.V. Andosols (or Andisols) possess several distinctive properties that are rarely found in other groups of soils. These properties are largely due to the dominance of short-range-ordered minerals (allophane, imogolite and ferrihydrite) and/or metal-humus complexes (Al/Fe-humus complexes) in their colloidal fraction. While several papers have extensively reviewed the nature and properties of short-range-ordered minerals, there is no comprehensive review of the genesis, characteristics and management implications of Al-humus complexes, the dominant form of active Al in non-allophanic Andosols. In this review, we survey the chemical characteristics of Al-humus complexes and discuss the pedogenic environment favoring their formation in non-allophanic Andosols. The role of Al-humus complexes in carbon cycling and soil organic carbon accumulation is emphasized as an important mechanism controlling organic dynamics in Andosols. While non-allophanic Andosols share many common properties with allophanic Andosols, they display several distinct characteristics associated with Al-humus complexes, such as strong acidity and high exchangeable Al content that impair agricultural productivity due to Al phytotoxicity. Thus, we focus on the role of Al-humus complexes in regulating aqueous Al3+ solubility and release/retention kinetics, Al phytotoxicity, phosphorus dynamics, and suppression of soil-borne diseases. Knowledge of these soil properties as related to Al-humus complexes is necessary to develop effective soil management practices to assure sustainable agricultural productivity in non-allophanic Andosols. Finally, future research needs are identified concerning the role of Al-humus complexes in regulating soil biogeochemical processes.
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aluminum toxicity of synthetic aluminum humus complexes derived from non allophanic and allophanic Andosols and its amelioration with allophanic materials
Soil Science and Plant Nutrition, 2009Co-Authors: Kiyoshi Ito, Tadashi Takahashi, Masami NanzyoAbstract:Abstract Natural non-allophanic Andosols often show aluminum (Al) toxicity to Al-sensitive plant roots. The significance of Al–humus complexes to Al toxicity has been emphasized. Allophanic Andosols also possess Al–humus complexes, but they rarely show any toxicity. In the present study, using model substances, we tested the toxicity of Al–humus complexes and its amelioration with allophanic materials. We extracted humic substances from the A horizons of a non-allophanic Andosol and an allophanic Andosol using a NaOH solution, and reacted the humic substances and partially neutralized AlCl3 solution at pH 4. Allophanic material was purified from commercial Kanuma pumice. Plant growth tests were conducted using a medium containing the Al–humus complexes (50 g kg−1), the allophanic material (0, 90, 180 and 360 g kg−1) and perlite. The root growth of barley (Hordeum vulgare L.) and burdock (Arctium lappa) was reduced in the media containing the Al–humus complexes derived from both the non-allophanic and allo...
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changes in element concentrations during Andosol formation on tephra in japan
European Journal of Soil Science, 2007Co-Authors: Masami Nanzyo, S Yamasaki, Toshimasa Honna, I Yamada, S Shoji, Tadashi TakahashiAbstract:Andosol formation involves the rapid, abundant and in situ formation of non-crystalline materials from tephra deposits. A large amount of humus complexed with Al also accumulates in the A horizons. As these materials are rich in Al or Fe compared to the parent tephra, the concentrations of the major and minor elements change significantly during Andosol formation. The objectives of this study were to examine how the rock type of the tephra and its weight loss during the formation process affect the changes in the element concentrations of Andosols. A total of 95 samples with different rock types from 18 pedons of Andosols in Japan were used to determine the total concentrations of 54 elements. Principal component analysis suggested that the degree of weathering and the rock types of parent tephra are the important factors in the variation of the element concentrations in Andosols. Three rock types, dacitic, andesitic and basaltic-andesitic, were identified from the V and Zn contents of ferromagnetic minerals separated from the Andosol samples. Basaltic Andosols were identified from the abundant coloured volcanic glass and olivine in the sand fraction. Regarding concentrations of 41 elements, at least one group based on rock type was significantly different from one to three other groups at the P = 0.05 level. The content of oxalate-extractable Si (Si o ), Al (Al o ) and Fe (Fe o ) was used as an index to show the extent of Andosol development. Relatively strong correlations between the element concentrations and Si o , Al o and Fe o as well as other weathering indices were found in the andesitic samples. Among these elements, at least 27 (Be, Al, Ti, Fe, Y, Zr, Nb, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Hf, Ta, Tl, Pb, Th and U) were enriched in the Andosols and the increases in these concentrations were related to total weight loss due to soil formation processes.
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proposed revisions to the diagnostic criteria for andic and vitric horizons and qualifiers of Andosols in the world reference base for soil resources
Soil Science and Plant Nutrition, 2004Co-Authors: Tadashi Takahashi, Masami Nanzyo, Sadao ShojiAbstract:Abstract World Reference Base for Soil Resources (WRB) was published in 1998 and has begun to be used all over the world. We examined the definitions of andic and vitric horizons and qualifiers (lower-level units) of Andosols in the WRB by using the Tohoku University World Andosol Database (TUWAD) and proposed several revisions. Among 5 items of the definition for the andic horizon, we considered that the requirements of clay and volcanic glass contents should be deleted due to the difficulty in their accurate determination with the progression of soil weathering. In relation to this revision, correction of vitric horizon was also proposed. Although two major types of andic horizons, silandic and aluandic, are specified in the andic horizon definition, the aluandic type is not included in the qualifiers. Because aluandic volcanic ash soils have unique properties and are extensively distributed, the aluandic qualifier should be included in the lower level units of Andosols. Soil texture is used for the def...
Randy A. Dahlgren - One of the best experts on this subject based on the ideXlab platform.
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nature properties and function of aluminum humus complexes in volcanic soils
Geoderma, 2016Co-Authors: Tadashi Takahashi, Randy A. DahlgrenAbstract:© 2015 Elsevier B.V. Andosols (or Andisols) possess several distinctive properties that are rarely found in other groups of soils. These properties are largely due to the dominance of short-range-ordered minerals (allophane, imogolite and ferrihydrite) and/or metal-humus complexes (Al/Fe-humus complexes) in their colloidal fraction. While several papers have extensively reviewed the nature and properties of short-range-ordered minerals, there is no comprehensive review of the genesis, characteristics and management implications of Al-humus complexes, the dominant form of active Al in non-allophanic Andosols. In this review, we survey the chemical characteristics of Al-humus complexes and discuss the pedogenic environment favoring their formation in non-allophanic Andosols. The role of Al-humus complexes in carbon cycling and soil organic carbon accumulation is emphasized as an important mechanism controlling organic dynamics in Andosols. While non-allophanic Andosols share many common properties with allophanic Andosols, they display several distinct characteristics associated with Al-humus complexes, such as strong acidity and high exchangeable Al content that impair agricultural productivity due to Al phytotoxicity. Thus, we focus on the role of Al-humus complexes in regulating aqueous Al3+ solubility and release/retention kinetics, Al phytotoxicity, phosphorus dynamics, and suppression of soil-borne diseases. Knowledge of these soil properties as related to Al-humus complexes is necessary to develop effective soil management practices to assure sustainable agricultural productivity in non-allophanic Andosols. Finally, future research needs are identified concerning the role of Al-humus complexes in regulating soil biogeochemical processes.
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evaluation and proposed revisions of criteria for Andosols in the world reference base for soil resources
Soil Science, 1996Co-Authors: Sadao Shoji, Randy A. Dahlgren, Masami Nanzyo, Paul QuantinAbstract:The proposed criteria for Andosol classification in the World Reference Base (WRB) of Soil Resources were evaluated using the Tohoku University World Andosol Database (TUWAD). The WRB proposal defines a diagnostic andic horizon comprised of vitr-andic, alu-andic, and sil-andic subtypes, and eight
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aluminum release rates from allophanic and nonallophanic Andosols
Soil Science and Plant Nutrition, 1994Co-Authors: Randy A. Dahlgren, Masahiko SaigusaAbstract:Abstract Aluminum release rates were studied for subsoil horizons of allophanic and nonallophanic Andosols and for imogolite gel films. Release rates were determined using a stirred, flow-through reaction vessel with a 10−3 M acetate buffer adjusted to pH 3.3, 3.8, or 4.2. To determine the sources of dissolved AI, soils were pretreated with Kel, Na-pyrophosphate, citrate-bicarbonate-dithionite, and acid oxalate to remove various solid-phase pools of active AI. Rates of Al release for imogolite gel films during the first minute of reaction ranged from 74.8 nmol/gls at pH 4.2 to 113.3 nmol/g/s at pH 3.3. Rates of AI release for nonallophanic Andosols were greater than for allophanic Andosols due to the rapid release of exchangeable Al from nonallophanic Andosols. Aluminum release rates showed fractional order H+ -dependence ranging from 0.23 to 0.54. The primary source of dissolved Al in allophanic Andosols was from AI-humus complexes and allophane/imogolite. In nonallophanic Andosols, exchangeable Al and A...
Paulina Schuller - One of the best experts on this subject based on the ideXlab platform.
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Radiocaesium transfer from volcanic soils to Swiss chard, cabbage and sweet corn.
Journal of environmental radioactivity, 2018Co-Authors: Paulina Schuller, Alejandra Castillo, Gabriele Voigt, Natalia SemioshkinaAbstract:Abstract The root uptake of radiocaesium by different plant parts of Swiss chard (Beta vulgaris L. var. cicla), cabbage (Brassica oleracea L. var. capitata) and sweet corn (Zea mays L. var. saccharata ) and the potential influence of K-fertilising on the transfer behaviour was studied in allophanic volcanic soils (umbric Andosol and dystric fluvisol) in Chile under temperate climate and heavy rainfall conditions (∼2660 mm y −1 ) over several vegetation periods. The soils were spiked homogeneously to 0.20 m depth with 100 kBq 134 Cs m −2 and activity concentrations measured. The transfer factor (TF, on a dry mass basis) to Swiss chard had a clear exponential decrease within each crop year for both soil types, either K-fertilised or unfertilised. The highest values of the TFs to Swiss chard were at the beginning of the harvests, and the half-times of TF decrease ranged between 52 and 137 d for umbric Andosol and between 40 and 164 d for dystric fluvisol. Over the five seasons there was no consistent ageing effect based on TF in either soil types for the three studied crops. The effect of 134 Cs foliar uptake by Swiss chard from resuspended soil was estimated to account for about 70% (external leaves) and 30% (internal leaves) increase in the TF for the K-unfertilised umbric Andosol, and showed an ambiguous behaviour for the K-fertilised umbric Andosol. Consequently foliar uptake does not explain the 370 and 500% increase of the TF to Swiss chard leaves determined during the third growing period in the umbric Andosol without and with K-fertilisation, respectively. Therefore an uncertainty factor of 3–5 is recommended to be taken into account when using this parameter for dose calculations. The TF to Swiss chard was found to be higher than previously reported values. The TF to cabbage and sweet corn plant parts was found to be within the range of previously reported values. Normal K-fertilisation resulted in about 2.4-fold reduction in 134 Cs TF to Swiss chard, 2.3-fold to sweet corn and 3.0-fold to cabbage.
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seasonal variation of the radiocaesium transfer soil to swiss chard beta vulgaris var cicla l in allophanic soils from the lake region chile
Journal of Environmental Radioactivity, 2004Co-Authors: Paulina Schuller, K Bunzl, G Voigt, A Krarup, Alejandra CastilloAbstract:Abstract The transfer factor (TF) of radiocaesium from soil-to-Swiss chard ( Beta vulgaris var. cicla L.) was studied in two different characteristic allophanic soils (umbric Andosol and dystric fluvisol) of the Lake Region, an important agricultural region situated in central-south Chile. To investigate especially the time dependence and the effect of K-fertilisation on the TF, field experiments were conducted. Plots of 7.6 m 2 were labelled with 100 kBq 134 Cs m −2 at Santa Rosa Experiment Station close to the city of Valdivia characterised by a temperate climate and high precipitation rates. The variation in time of the radiocaesium TF soil-to-Swiss chard was observed during two consecutive years after soil contamination by sequential harvests and radiocaesium analyses of the plants. The TFs showed no significant ageing effect, but a pronounced seasonal decrease with effective half-lives of about 140 and 160 days for the umbric Andosol without and with K-fertilisation, respectively, and of 50 and 60 days for the dystric fluvisol without and with K-fertilisation, respectively. The effect of K-fertilisation on the absolute values of the TF was determined by the ratio between the median TF values obtained for corresponding dates without and with use of K-fertiliser. A ratio of TF without K TF with K =1.8 for the umbric Andosol and TF without K TF with K =2.9 for the dystric fluvisol was obtained, indicating a reduction of the TF by applying 90 kg K ha −1 . The maximal values of the TF to chard predicted by the equation characterising the seasonal decrease of the TF at the beginning of the harvest periods are 0.19 for the umbric Andosol and 0.11 for the dystric fluvisol, both values for soil treated with common K-fertilisation.