Reaction conditions control soil colloid facilitated phosphorus release in agricultural Ultisols

Allison Rick VandeVoort, Ken J. Livi, Yuji Arai

Research output: Contribution to journalArticlepeer-review


Colloid (typically < 1 μm) facilitated phosphorus (P) transport in agricultural soils has received much research attention in recent decades due to the possibility of a mobile solid form of P, which may increase P runoff in some soils. The existing literature reports inconsistent results of colloidal P release as a percentage of total P in soil solution, separated at operationally defined size definitions by various centrifugation and/or filtration methods. The amount of total soil P attributed to colloidal particles remarkably ranges from 0 to 95%. The cause of colloidal P release has been difficult to assess since their experimental/environmental conditions (e.g., soil type, pH) vary from study to study. The case study presented here aims to focus on three controllable reaction conditions: ionic strength (I), pH and added P concentration, to elucidate their effect on P colloid release. Our case study showed that these reaction conditions do not largely alter the release of colloidal P in Ultisols of the southeastern United States (mildly acidic native pH, low organic C). However, the availability of colloidal P was slightly enhanced at near neutral pH in high [P] or high I (0.1. M) solutions. We further discussed these reaction conditions in selected literature studies to better assess the occurrence of colloid facilitated P transport in a wide variety of soil types and conditions.

Original languageEnglish (US)
Pages (from-to)101-111
Number of pages11
StatePublished - Sep 1 2013
Externally publishedYes


  • Colloid facilitated transport
  • Nanoparticles
  • Phosphate
  • Reaction conditions
  • Sorption

ASJC Scopus subject areas

  • Soil Science

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