@article{fdi:010008810,
  title = {{S}oil isotopically exchangeable phosphorus : a comparison between {E} and {L} values},
  author = {{F}rossard, {E}. and {F}ardeau, {J}.{C}. and {B}rossard, {M}ichel and {M}orel, {J}.{L}.},
  editor = {},
  language = {{ENG}},
  abstract = {{T}his study was designed to explain the apparent discrepancies often reported in the literature between {E} and {L} values, two parameters obtained from isotopic exchange experiments and commonly used to quantify available soil phosphate. {T}he {E} and {L} values of the surface horizons of 10 soils from tropical, mediterranean, and temperate regions were determined. {T}he {L} value was measured from a 13-wk pot experiment with common bentgrass (#{A}grostis capillaris$ {L}.) where the available soil {P} was labeled with 32{PO}4 ions in the presence of a carrier (25-50 mg 31{P}/kg soil). {T}o determine the {E} value, the isotopic exchange kinetic experiment was carried out on each soil. {C}arrier-free 32{PO}4 was added to the soil-solution system at a steady state and the quantity of isotopically exchangeable soil phosphate at time t, {E}(t), was calculated from the kinetic equation describing the decrease of radioactivity in solution with time. {R}esults showed that {L} values determined after 13 wk were not significantly different from {E}(t) values extrapolated to the same period (t = 131 040 min). {I}t was concluded that the {L} value is a particular point of the kinetic equation and isotopically exchangeable phosphate is the available {P} for common bentgrass. {A} strict equality between {E}(13 wk) and {L} values was not, however, reached for all samples. {P}ossible causes for the differences were : an overestimation of the water-soluble phosphate due to the presence of silica and disturbance of the steady state following a too large uptake of phosphate by the crop or the application of too large quantities of carrier compared with the initial quantity of exchangeable soil phosphate. ({R}{\'e}sum{\'e} d'auteur)},
  keywords = {{SOL} ; {PHOSPHORE} ; {PHOSPHATE} ; {SOLUTION} {DU} {SOL} ; {ECHANGE} {D}'{IONS} ; {RELATION} {SOL} {PLANTE}},
  booktitle = {},
  journal = {{S}oil {S}cience {S}ociety of {A}merica {J}ournal},
  volume = {58},
  numero = {},
  pages = {846--851},
  ISSN = {0361-5995},
  year = {1994},
  URL = {https://www.documentation.ird.fr/hor/fdi:010008810},
}