The study sought to investigate the internal cycling of phosphorus (P) in Clementine mandarin (Citrus reticulata Blanco “Clementine”). The biomass formation, P concentration, P uptake and accumulation of different organs (bud, flower, fruit, leaf and branches) identified as active organs and found on 1-year-old shoots on fruit trees of bearing age were periodically examined for 2 years. The biomass value was similar between both production seasons. At the beginning of shoot activity, the biomass of annual shoots had a very low rate in the total biomass (0.4%). The biomass increased from 9.7 kg/tree at the beginning of the production season to 62.8 kg/tree at harvest. The P concentrations were in the ranges of 0.11–0.22% in the branches of
