@article{fdi:010069271,
  title = {{G}eochemical and microbial controls of the effect of citrate on phosphorus availability in a ferralsol},
  author = {{H}enintsoa, {M}. and {B}ecquer, {T}hierry and {R}abeharisoa, {L}. and {G}erard, {F}.},
  editor = {},
  language = {{ENG}},
  abstract = {{T}he secretion of organic anions, particularly citrate, by plant roots may be an effective process to mobilize phosphate ({PO}4) from solid constituents. {H}owever, microbial growth and corresponding phosphorus ({P}) immobilization can act adversely. {T}his experimental study was aimed at studying the relative influence of geochemistry and microbiology on the influence of citrate on {P} availability in a tropical soil. {W}e carried out water extractions with different citrate concentrations (0-500 mu {M}. {A} first set of experiment was performed at low temperature ({T} = 2 degrees {C}) in order to have only geochemical effects. {W}e performed two other set of experiments at room temperature ({T} = 25 degrees {C}), without and with addition of glucose and nitrate, in order to investigate the influence of an increase of microbial activity. {W}e measured an overall increase of {P} availability with citrate concentration in all the treatments. {R}esults obtained at low temperature were consistent with the lack of significant {P} immobilization by microbial activity. {T}he concomitant increase of dissolved {S}i, {A}l and {F}e suggested that citrate enhanced the dissolution of {PO}4-adsorbing minerals. {T}his geochemical process should release {PO}4 and increase {P} availability. {T}he overall increase of {P} availability with temperature further suggested that the dissolution of {A}l- and {F}e-{PO}4 minerals was also responsible of the effect of citrate. {L}astly, results obtained at 25 degrees {C} without addition of glucose and nitrate exhibited a weak effect of microbial activity, as a decrease of {P} availability was only observed at the lowest citrate concentration (2 mu {M}). {T}he addition of glucose and nitrate enhanced microbial activity as a net immobilization of {PO}4 was observed up to 20 mu {M} of citrate. {B}eyond this threshold, microbial growth appeared limited by other factors as time. {O}ur study revealed that the effect of citrate on {P} availability was mainly controlled by complex geochemical interactions in a range of temperature conditions. {T}he adverse influence of microbial growth increased with temperature and nutrient supply but revealed limited. {T}he nature and intensity of controlling geochemical processes depend on soil type and fertilization.},
  keywords = {{D}issolution ; {I}mmobilization ; {T}emperature ; {G}lucose ; {N}itrate ; {F}ertilization ; {MADAGASCAR}},
  booktitle = {},
  journal = {{G}eoderma},
  volume = {291},
  numero = {},
  pages = {33--39},
  ISSN = {0016-7061},
  year = {2017},
  DOI = {10.1016/j.geoderma.2016.12.020},
  URL = {https://www.documentation.ird.fr/hor/fdi:010069271},
}