Nitrogen nutrition considerably influences the process of growing and producing potato crops. The aim of this study was to determine the effects of nitrogen nutrition on the pattern of biomass and nitrogen partitioning during the growth of potato crop in Mérida, Mérida, Venezuela. Experimental land plots were set, with a randomized blocks design, and with three different fertilization treatment settings for the "Granola" cultivar. The first one without nitrogen (0-N), the next one with 133 Kg N Ha-1 (133-N), and the last one with 400 Kg N Ha-1 (400-N). In the main phenological stages of the crop, biomass and nitrogen levels were measured for each organ. The performance of the tubers and the total biomass are strongly influenced by the availability of nitrogen and assimilatory biomass. The total biomass production, as well as the biomass and nitrogen partitioning to each organ, showed the following sequence: 400-N > 133-N > 0-N. However, biomass and nitrogen partitioning to the roots and stolons was higher in the treatment with limited nitrogen levels. Proportional changes among aboveground and belowground biomass are adaptive responses to nitrogen deficit conditions, which, in their turn, are determining factors in crop production.
Allometric equations to estimate aboveground and belowground biomass of Pinus patula Schiede ex Schltdl. & Cham
