Source Year: 1998

In Pahang, Peninsular Malaysia, the active root distribution of 3- and 4-year-old rotan manau (Calamus manan) established in a mature rubber plantation, was assessed using isotope tracer technique (32P, applied as a solution with KH2PO4). For the 3-year-old rattan, 3 distances from the plant base (0.5, 1.0 and 1.5 m) at 5- and 30-cm depths were examined. For the 4-year-old plants, 2 distances, vis-a-vis at a centre between 2 rattan plants and another in the middle between 2 rattan plants and another in the middle between 2 rattan plants and 2 rubber trees were studied. High proportions of feeder roots were found at 0.5 and 1.0- m distances at the surface (5-cm depth) for the 3-year-old plants. Uptake of P was also observed for the application at 1.5-m distance for both depths but the counts were small. Statistical analysis gave a highly significant difference within the distances and within the different depths. For a better synchronization between fertilizer application and plant uptake, it seems that application at 0.5-1.0-m distance around the plant is most appropriate at this age. At 4 years after planting, a high uptake was obtained only for the 2 plants located near the application area, indicating to some extent that roots had already extended for another metre compared with 3-year-old plants.