Johannes Reiner G. Asio1* and Marlito Jose M. Bande1
The successful establishment of dipterocarp tree species especially in problematic lands is a challenge since it is still poorly understood. The study was conducted to evaluate the effects of the addition of N, P, and K to Yakal-yamban (Shorea falciferoides Foxw.), a critically endangered dipterocarp tree species, grown in a soil derived from an ophiolitic rock. The seedlings were grown in pots inside a screenhouse and then subjected to the following treatments: control, NPK, NP, PK, and NK. Results revealed that NPK addition generally enhanced the growth of Yakal-yamban in the problematic soil, six (6) months after transplanting, particularly in terms of leaf area, biomass increment and allocation in the leaves. The allocation was enhanced in treatments that receive P, in addition to N, NK, or K suggesting that P was the most limiting nutrient in the problematic soil used. The study also revealed the occurrence of ectomycorrhiza in Yakal-yamban where P was not applied. The results imply that NPK addition is a potential nutrient management strategy for the seedling establishment of Yakal-yamban in problematic soils.
Keywords: Dipterocarp trees, Yakal-yamban, fertilization, problem soil, ophiolite