@article{1260503,
  abstract     = {{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 (the pH of citric acid being adjusted to the pH of CaCl2 , and thus eliminating release of P through acidification) a significant pH increase was noted. Simultaneously, MRP increased significantly in all but one soil. This suggests that the P availability enhancing properties of citric acid are not only due to acidification of the plant rhizosphere, but also to its Al and Fe complexing capacity.}},
  author       = {{Drouillon, Margriet and Merckx, Roel}},
  issn         = {{0016-5301}},
  journal      = {{GAYANA. BOTANICA}},
  keywords     = {{phosphorus availability,citric acid,Andosols}},
  language     = {{eng}},
  number       = {{1}},
  pages        = {{55--62}},
  title        = {{The role of citric acid as a phosphorus mobilization mechanism in highly P-fixing soils}},
  volume       = {{60}},
  year         = {{2003}},
}