In situ and Ex situ Conservation of Commercial Tropical Trees - ITTO

445Biological properties of the soils indicated that growing plants hadsignificantly improved biological activities in the soil. Populations of bacteria,fungi, and mycorrhizal fungi in the planted soils were, respectively, at least 40,100 and 1000 times higher than those in soil prior to planting (Table 7).Accumulation of litter might also have enhanced biological activity in the soil.Field observation showed that leaf litter of turi took less than two weeks tocompletely decompose, suggesting that biological processes in the soil had beenvery active. Litter production for two plant species - sengon and turi - is shownin Table 6. Within 8 weeks, sengon produced more litter than turi. However,soil analysis showed that this difference had not significantly contributed to thedifferences in soil properties under these two plants.Table 6. Litter Weight of Sengon and Turi StandsPlant Species Treatments Plant Parts Litter weight (gm -2 ) at sampling time Total LitterNov.6,1998 Nov.21 st , 1998 Dec.5 th , 1998 Dec. 18,1998 Jan.3.,1999 (g m -2 )Rip Leaves 34.81 21.41 23.92 15.36 17.03 112.53Twigs 27.49 29.91 17.09 8.16 12.81 95.16Sengon No-Rip Leaves 14.90 3.92 6.16 8.25 4.60 37.83Twigs 6.24 2.86 3.59 1.39 4.90 19.16Total 264.16Rip Leaves 4.43 6.57 8.58 9.26 7.64 36.48Twigs 17.80 7.57 5.85 4.76 7.09 43.07Turi No-Rip Leaves 4.05 6.30 9.48 10.44 5.58 35.85Twigs 10.29 6.94 5.37 3.49 6.66 32.75Total 148.15Notes:Rip. = Ripped-soilNo-Rip = Non-ripped soilTable 7. Type and population soil microbes in mine soil and forest soilType of Microbes Soil depths PopulationMine soil *) Forest soil **)Bacteria 0 – 30 cm 71.75 x 10 4 162.00 x 10 4(cel/g dry soil) 30 – 60 cm 90.97 x 10 4 139.60 x 10 4Fungi 0 – 30 cm 7.11 x 10 4 5.80 x 10 4(cfu/g dry soil) 30 – 60 cm 5.33 x 10 4 2.00 x 10 4Mycorrhizal fungi 0 – 30 cm 77.15 91.10(spore/g dry soil) 30 – 60 cm 49.65 35.64Notes : *) Average values of 18 samples**) Average values of 5 samples