Contents - Akademi Sains Malaysia

ASM Sci. J., 7(1), 23–26Cellulolytic, Nitrogen-fixing and PhosphatesolubilizingMicro-organisms as BiologicalIndicators of Forest Soil RehabilitationA. Tang 1 , S.K. Wong 1 *, O.H. Ahmed 2 and N.M. Majid 3Widespread deforestation has resulted in soil degradation that is often linked to environmental and ecologicalchanges. Rehabilitation of degraded forest is essential to prevent further degradation of the soil. Abundanceof soil microbiota could serve as an essential biological indicator of soil health for rehabilitation success. Aninvestigation was conducted to study the relationship between cellulolytic, nitrogen-fixing and phosphatesolubilizingmicrobial counts and age of rehabilitated forest. A random sampling design was used to obtainfour replicates of five composite soil of 0–10 cm depth soil samples of 4, 9, 14 and 19-year-old rehabilitatedforest. Three selective media: Congo red cellulose, nitrogen-free malate and calcium phosphate media wereused for the enumerations of cellulolytic, nitrogen-fixing and phosphate-solubilizing microbes, respectively.Cellulolytic and phosphate-solubilizing microbes were counted based on the formation of clearing zones, whilenitrogen-fixing microbes were based on the formation of blue halo on the respective media. There was positivelinear relationship between age of the rehabilitated forest and microbial count. These findings revealed that thepotentials of cellulolytic, nitrogen-fixing and phosphate-solubilizing microbial populations could be used asbiological indicators of forest soil rehabilitation.Key words: cellulolytic; phosphate solubilising; nitrogen-fixing; soil micro-organisms; forest age; forest soilrehabilitationDeforestation often results in land degradation in the tropics.In such degraded areas, the native plant species are proneto fail in surviving because the degraded soil conditionsare different from the original conditions (Kanowskiet al. 2005). Thus, rehabilitation and regeneration of forestis essential to restore the natural ecosystem (Azani et al.2001). In some cases, forest rehabilitation is designatedto regenerate the environmental protection functionsof deforested areas, in which economic gains from theplanting is not a major aim. Micro-organisms are partof the natural characteristics of forest soils, which is theactive composition of the organic matter, as the reservoirof soil nutrients (Singh et al. 1989). Rehabilitation successhas been demonstrated by the use of plant native speciesusing beneficial micro-organisms as described for gypsummine spoil in India (Matias et al. 2007). Studies done byMatias et al. (2007) also indicated that soil cellulolytic andphosphate solubilizing population of micro-organisms maybe used as rehabilitation indicators of iron-ore mined land.This result supposedly has the same potential to be appliedin other degraded lands, such as of rehabilitated forestsoils. According to Mummey et al. (2002), the makeup ofsoil microbiota is an important biological indicators of soilhealth as an aspect for determining the reclamation success.Microbial characteristics of soil are increasingly beingexamined as sensitive indicators of soil health because ofthe clear relationship between microbial diversity, soil andplant quality and ecosystem sustainability (Mabuhay et al.2003). This research was aimed to study the relationshipbetween cellulolytic, nitrogen-fixing and phosphatesolubilizingmicrobial counts and age of a rehabilitatedforest.Soil SamplingMATERIALS AND METHODSThis study was conducted at the rehabilitated forest areas atUniversiti Putra Malaysia, Bintulu Sarawak Campus. Soil1 Department of Animal Science and Fisheries, Faculty of Agriculture and Food Sciences, Universiti Putra Malaysia, Bintulu SarawakCampus, 97008 Bintulu, Sarawak, Malaysia.2 Department of Crop Science, Faculty of Agriculture and Food Sciences, Universiti Putra Malaysia, Bintulu Sarawak Campus, 97008 Bintulu,Sarawak, Malaysia.3 Department of Forest Management, Faculty of Forestry, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia.* Corresponding author (e-mail: wongsk@btu.upm.edu.my)23