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| Drouillon,M.; Merckx,R.. |
| Exudation of low molecular weight carboxylates is an important phosphorus (P) acquisition strategy for plants in strongly P-fixing soils. The effect of citrate exudation on P availability was studied in five acid soils with a large organic matter content and a low available P pool. The amount of molybdate reactive P extracted by citric acid 10 mM (0.1-2 mg kg-1) was larger than the molybdate reactive P (MRP) extracted by CaCl2 10-3 M (0.007-0.07 mg kg-1). Both extractants were adjusted to soil pH prior to extraction. Also, the total P content of citric acid extracts (2-44 mg kg-1) far exceeded the total P content of CaCl2 (0.2-1.5 mg kg-1). However, ratios of MRP to total dissolved P (TDP) remained constant. When citric acid was added to the CaCl2-extracts... |
| Tipo: Journal article |
Palavras-chave: Andosols; Citric acid; Phosphorus availability. |
| Ano: 2003 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-66432003000100009 |
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| Brouwere,Katleen De; Thijs,Ann; Hens,Maarten; Merckx,Roel. |
| This study investigated the different forms and availability of P in soil profiles from temperate forests in southern Chile (two sites: Nothofagus obliqua (Mirb.) Bl. and Nothofagus betuloides (Mirb.) Oerst.) and Flanders, Belgium (two sites: Pinus nigra Arnold and Betula pendula Roth). Soils were sampled according to genetic horizonation and analysed for organic matter, oxalate-extractable P, Al and Fe, total inorganic P and total organic P. Phosphorus availability was assessed using an isotopic exchange technique and anion exchange membranes. The total P content was higher for the Chilean andosols and remained relatively high in the whole soil profile (1413-187 mg P kg-1) whereas total P decreased sharply in the lower horizons of the Flemish podzols... |
| Tipo: Journal article |
Palavras-chave: Andosols; Phosphorus availability; Podzols. |
| Ano: 2003 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-66432003000100004 |
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| 谷, 昌幸; 溝田, 千尋; 八木, 哲生; 加藤, 拓; 小池, 正徳; TANI, Masayuki; MIZOTA, Chihiro; YAGl, Tetsuo; KATO, Taku; KOIKE, Masanori. |
| 本研究では，十勝地域の農耕地，とくに普通畑土壌にお ける肥培管理などが土壌へのリン酸蓄積量とその形態に及ぼす影響を明らかにすることを目的とした.畑地およひ隣接する未耕地において土壌断面調査と試料採取を行い，土壌中の全リン酸含量および各種形態別リン酸含量の垂直分布を調べたさらに，仮比重および未耕地と農耕地における土壌の層厚差を考慮し正味のリン酸蓄積量を調べた. 1)淡色黒ボク土，厚層黒ポク土，および普通褐色低地 土のいずれの農耕地土壌においても，施肥などに由来する余剰リン酸は耕起の影響を受けた表層30~40cm までの 作土層に蓄積し，物理的に撹拌および混和されることにより作土層全体に比較的均一に分布した. 2)未耕地土壌との垂直分布の比較から，黒ボク土では 余剰リン酸が下層へ溶脱せず作土層にのみ蓄積し，褐色低地土では一部が下層へ溶脱していると考えられた. 3) 農耕地における正味のリン酸蓄積量は，黒ボク土で 著しく多く，年平均130kgha-1以上であった. 大部分は，フッ化物イオンの配位子交換能により抽出され，活性アルミニウムなどに特異吸着されていると考えられた褐色低地土では蓄積量が少なく，弱酸可溶のリン酸水素カルシウムや，弱い配位子交換反応で抽出可能な非品質リン酸アルミニウムなどの沈殿として蓄積していると考えられた.Heavy application of phosphate fertilizer and subsequent phosphate accumulation in arable soilsï¼ especially Andosolsï¼ are critical issues for sustainable agriculture in ]apan. The effects of... |
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Palavras-chave: リン酸蓄積; 黒ボク土; 褐色低地土; 層厚差; 垂直分布; Andosols; Brown Lowland soils; Soil thickness; Phosphate accumulation; Vertical distribution. |
| Ano: 2010 |
URL: http://ir.obihiro.ac.jp/dspace/handle/10322/2696 |
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