Dilute acid-soluble phosphorus in fresh air-borne tephras and fixation with an increase in active aluminum and iron

Masami Nanzyo, Tomoko Takahashi, Atsushi Sato, Sadao Shoji, Ichiro Yamada, Tomoko Takahashi, Atsushi Sato, Sadao Shoji

Research output: Contribution to journalArticlepeer-review

9 Citations (Scopus)


Fresh rhyolite-to-andesite tephras ground to less than 0.15 mm particles contained dilute acid-soluble phosphorus (P) as in the case of cultivated upland soils in Japan. The amount of P determined by Truog extraction (Truog P) ranged between 119 and 784 mg P2O5 kg-1 in 12 rhyolite-to-andesite tephras, and that determined by a modified Bray P2 extraction method (modified Bray P2) ranged between 133 and 812 mg P2O5 kg-1. In contrast, the Truog P-content in fresh basaltic andesite-to-basalt tephras was only 3.4–23 mg P2O5 kg-1, and the modified Bray P2-content was in the range of 41–185 mg P2O5 kg-1, although the total P-content of the two tephra groups was in almost the same range. Among 12 rhyolite-to-andesite tephras, those from Mt. Usu that erupted in 1977 and from Mt. Pinatubo that erupted in 1991 were selected for detailed studies. Fine particle size fractions of these tephras showed higher Truog P values than the coarse ones. The Truog P values further increased in the heavy fraction with a particle density of 2.8 or greater. In this heavy fraction, apatite was detected by energy dispersive X-ray (EDX) analysis, indicating the contribution of the mineral to the high Truog P. Dilute sulfuric acid treatment of the tephras at 80°C for 15 d followed by neutralization increased the amount of active Al and Fe and decreased the Truog P values of these tephras. These results suggested that the amount of apatite rapidly decreased with weathering in volcanic ash soils.

Original languageEnglish
Pages (from-to)839-848
Number of pages10
JournalSoil Science and Plant Nutrition
Issue number4
Publication statusPublished - 1997 Dec 1
Externally publishedYes


  • Andisols
  • Apatite
  • Fresh tephra
  • Plant-available P
  • Volcanic ash soils

ASJC Scopus subject areas

  • Soil Science
  • Plant Science


Dive into the research topics of 'Dilute acid-soluble phosphorus in fresh air-borne tephras and fixation with an increase in active aluminum and iron'. Together they form a unique fingerprint.

Cite this