02309nam a2200193 a 450000100080000000500110000800800410001910000210006024501330008126001510021430000080036552016180037365000150199170000220200670000200202870000230204870000230207170000210209419796702015-03-31       2013    bl uuuu     u00u1 u    #d1 aCASTRO, R. C. de  aAnalyzing the mobility in granular forms of P fertilizer in brazilians soils under laboratory conditions.h[electronic resource]  aIn: INTERNATIONAL NUCLEAR ATLANTIC CONFERENCE/INAC, 2013. Recife/PE. Anais... Rio de Janeiro, RJ: Associação Brasileira de Energia Nuclearc2013  a8p.  aPhosphorus is an essential nutrient for plant growth. Million of tones of P are applied to the soils annually. However, only a small fraction of the P applied with fertilizers is taken up by crops in the year of application, and the effectiveness of any residual P fertilizer declines with time. To improve our understanding of the mechanisms underlying this response to P in the field, we have studied the mobility of P from 3 different fertilizes: monoammonium phosphate (MAP), polymer coated monoammonium phosphate (MAPp) and Organomineral phosphate (OMP) applied on high weathered soil samples in a Petri dish experiment. Total Reflection X-Ray Fluorescence (TXRF) was used to determine the P diffusive flux at different distances (0 - 7.5, 7.5 ? 13.5, 13.5 ? 25.5 and 25.5 ? 43 mm) from granular fertilizer. TXRF analyses were performed at the X-Ray Fluorescence Beamline D09B at Brazilian National Synchrotron Light Laboratory (LNLS), in Campinas, São Paulo, using a polychromatic beam with maximum energy of 20 keV for the excitation and an Ultra-LEGe detector with resolution of 148 eV at 5.9 keV. Besides that, the detections were performed in a high vacuum chamber (2.5 x 10-5 mbar) to avoid air absorption. After a period of five weeks, the total P concentration increased in the soil sampled 7.5 to 13.5 mm from the fertilizer showing a diffusive flux of P. About 20% (considering MAP and MAPp) of the total P applied diffused out of the central soil ring. Different sources showed differences in diffusive flux of P. Soil pH also influenced diffusive flux of P showing higher flux on lower pH soils.  aphosphorus1 aBENITES, V. de M.1 aTEIXEIRA, P. C.1 aOLIVEIRA, D. F. de1 aOLIVEIRA, L. F. de1 aANJOS, M. J. dos