Influence of Arbuscular Mycorrhiza and Source of Phosphorus on Root Development and Nodulation of Acacia mangium Seedlings on Degraded Soils

Abstract

A pot study on the effect of arbuscular mycorrhiza (AM) and phosphate rock (PR) on root development and nodulation of Acacia mangium seedlings on degraded (tin tailing) soils was conducted in the glasshouse of Universiti Putra Malaysia (UPM), Malaysia. Two arbuscular mycorrhiza (AM) inoculation treatments, viz., (i) with AM and (ii) without AM in combination with three P sources like Gafsa phosphate rock (GPR), China phosphate rock (CPR) and triple superphosphate (TSP) including a control (without P) were studied in split plot design. Six sets of this treatment combination were established for destructive sampling at 60, 75, 90, 105, 120 and 135 days after planting (DAP). Root biomass yields and root volume of inoculated seedlings given TSP and GPR were identical and superior to that with other treatments throughout the study. The P sources were in the order of TSP>GPR>CPR for enhancing root development irrespective of AM inoculation. The uninoculated seedlings required 15 to 20 more days to produce an equivalent root biomass to that of inoculated seedlings. Number and weight of nodules of AM inoculated seedlings given TSP and GPR were also higher than those with other treatments. As a cheaper source GPR in combination with AM might be used for growing A. mangium seedlings on degraded tin tailings.