Nutrient utilisation efficiencies of two Central Himalayan tree species.

BARGALI, K. & BARGALI, S. S. 2000. Nutrient utilisation efficiencies of two Central Himalayan tree species. The nutrient utilisation efficiencies of two Central Himalayan species, one from nutrient-rich sites, Quercus leucotrichophora, and another from nutrient-poor sites, Pinus roxburghii, were compared at different nutrient and moisture levels. For this, seedlings of these two species were grown at four soil nutrient levels and each nutrient level was kept under four watering frequencies. Pinus roxburghii showed greater relative growth rate and greater relative retranslocation of nutrients before leaf senescence; however, nutrient concentrations in mature leaves were always higher for Q. leucotrichophora. Pinus roxburghii also had greater uptake, recovery and use efficiency for each nutrient examined compared to Q. leucotrichophora. However, in both species, nutrient uptake, recovery and nutrient use efficiency decreased with increasing nutrient availability. It seems that greater nutrient utilisation efficiencies of P. roxburghii should not only enable its seedlings to rapidly invade nutrient-rich Q. leucotrichophora forest sites, but also help to resist reinvasion of the site by Q. leucotrichophora as reported for large areas for Central Himalaya.