Growth stimulation of Acacia mangium Willd by Pisolithus sp. in some Senegalese soils

Functional compatibility between one provenance of Acacia mangium Willd see dlings and one fungal isolate of Pisolithus sp. COI 007 was evaluated in fo ur Senegalese soils. This was measured to mycorrhizal formation, root colon ization, shoot and root dry weight and mineral nutrient contents in the lea ves of A. mangium seedlings. Mycorrhizal formation occurred on A. mangium i n all the soils. However, percentage of root colonization of A. mangium by Pisolithus sp. varied from 90% to 10%. It reached no more than 10% in soil having the highest available P (Olsen P 20 ppm) and at least 60% in soils c ontaining low available P (from Olsen P 2.3-6.8 ppm). Shoot and root dry we ight of inoculated plants significantly increased as a consequence. P, N, K , Ca, Mg, Na, S, Cu and Zn concentrations in leaves of A. mangium contribut ed significantly to inoculated plant growth in soils having the lower avail able P. These results are discussed in the light of management techniques o f multiple types of symbiotical microorganisms in nursery and field conditi ons. (C) 1999 Elsevier Science B.V. All rights reserved.