Dry matter accumulation and seasonal partitioning in matureOpuntia ficus-indica (L.) Mill. fruiting trees

Aim of this study was to understand the allocation of biomass intodifferent canopy and root components and to measure the stem areaindex and its partitioning by cladode functionality (age), for fruitingOpuntia ficus-indica (OFI) Gialla trees, spaced 6¥5 m apart andtrained to a globe. The net primary productivity (NPP), calculated takinginto account dry weight gain for above-ground vegetative componentsof OFI trees was 3.6 t C ha–1. Including the fruit component and1st flush current-year cladodes, NPP of above-ground componentsbecomes 12 t ha–1, equivalent to 5.4 t C ha–1. Current-year cladodeswere the highest C sink (49% of total annual C fixed in the canopy),secondary growth accounted for 22% of C fixation and the fruit componentfor 29%. This study demonstrated that OFI trees, grown in a commercialfruit orchard, couple high productivity, in terms of fruit yieldand harvest index, with relevant C fixed in the canopy.