Provenance-related Growth Response of Populus ciliata Wall. ex Royle to Nitrogen Fertilization

Clonal material of Populus ciliata Wall. ex Royle, collected from two provenances Karain Bibal (1800 m, 32.14°N, 77.11°E) and Kangni (2400 m, 32.19°N, 77.10°E) in the Kulu Forest Division, was tested for responsiveness to nitrogen fertilization in a nursery trial. Soil of the experimental area was medium in N, P and K supplies with a sandy loam texture. Calcium ammonium nitrate was used as a source for four levels (0,30, 60, 90 kg/ha) of nitrogen. Both the provenances exhibited enhanced growth with the application of nitrogen. Plant height, collar diameter, internodal length, total biomass, foliar nitrogen and fibre length significantly Increased upto the application of 60 N/ha. The specific gravity was maximum with 30 kg N/ha and decreased wilh higher levels. On an average application of 90 kg N/ha resulted in an insignificant decrease in all the growth characters. Karaln Bihal provenance, representing the lower range of distribution of the species with better growth performance, tended to be more responsive to nitrogen fertilization in all growth characters studied except specific gravity, as compared to Kangni provenance, inhibiting higher zone with coniferous association. Karain Bihal provenance, representing the lower range of distribution of the species with better growth performance, tended to be more responsive to nitrogen fertilization in all growth characters studied except specific gravity, as compared to Kangni provenance, inhibiting higher zone with coniferous association.