. No calibrated phosphorus (P) soil test exists to guide Florida citrus fertilization. Applying P fertilizer to citrus when it is not needed is wasteful and may cause undesirable P enrichment of adjacent surface water. The objective of this study was to establish guidelines for P management in developing Florida grapefruit (Citrus paradisi Macf.) and orange (Citrus sinensis L. Osb.) orchards by determining the effect of P fertilizer rate on soil test P and subsequently calibrating a P soil test for citrus yield and fresh fruit quality. Two orchards were planted on sandy soil with 3 mg.kg^-1 (very low) Mehlich 1 soil test P. In Years 1 through 3, P fertilization increased soil test P up to 102 mg.kg^-1 (very high). In Years 4 through 7, canopy volume, yield, and fruit quality did not respond to available soil P as indexed by soil testing. As tree size and fruit production increased, leaf P was below optimum where soil test P was below 13 mg.kg^-1 (grapefruit) or 31 mg.kg^-1 (oranges). Total P in the native soil at planting was ≃42 mg.kg^-1, which was apparently available enough to support maximum tree growth, fruit yield, and fruit quality for the first 7 years after planting. Trees were highly efficient in taking up P from a soil considered very low in available P. Citrus producers can likely refrain from applying P fertilizer to young trees on Florida sandy soils if soil test P is very high or high and probably medium as well.

EXPLOR_STEP=$WICRI_ROOT/Wicri/Bois/explor/OrangerV1/Data/Main/Merge

HfdSelect -h $EXPLOR_STEP/biblio.hfd -nk 002276 | SxmlIndent | more

HfdSelect -h $EXPLOR_AREA/Data/Main/Merge/biblio.hfd -nk 002276 | SxmlIndent | more

{{Explor lien
   |wiki=    Wicri/Bois
   |area=    OrangerV1
   |flux=    Main
   |étape=   Merge
   |type=    RBID
   |clé=     Pascal:09-0022736
   |texte=   Managing Phosphorus for Citrus Yield and Fruit Quality in Developing Orchards
}}