Phosphorus sources: Effect on the tropical cedar nutrition and growth

Many questions remain unanswered regarding the effects of different phosphorus (p) sources and liming on forest species in tropical ecosystems. we investigated: (1) the influence of different p fertilisers and lime on the growth and nutrition of the tropical cedar (cedrela fissilis) in a highly weathered amazon rainforest soil,and (2) the economic viability of the tropical phosphate rock. the four p sources used were single superphosphate (ssp),triple superphosphate (tsp),arad phosphate rock (apr) and yoorin thermophosphate (yt). results show that soil liming has no effect on cedar growth. arad phosphate rock increases nutrient status and growth of cedar when compared with ssp,tsp and yt. the phosphate rock decision support system shows that apr has relative agronomical effectiveness 100% as good as tsp besides being a more economical p source on amazon rainforest soil. © forest research institute malaysia.