The  soil  organic  carbon  (SOC)  and  its  various  fractions  vary  significantly  under  different  forest  categories  and  understanding these  variations  is  important  for  assessing  the  carbon  balance and dynamics of  these systems. These  factors or  indicators can depict  the extent of  vulnerability  of  forest  systems  as  potential  sources  or  sinks  of  carbon(C).  The  study  was  conducted  in four  typical  forest  types  in  the Chinnar wild  life  sanctuary  of  Idukki  district, Kerala,  India, a part of  the high ranges of Southern Western Ghats. The results showed  that there were obvious variations  in  the content and  stock of SOC among  the  forest categories. Maximum  SOC  content was  observed  in  Shola  Forest  (SF)  site whereas  the minimum  in Riparian  Forest  (RF).  The  prominence  of  subsoil  layer  (10-30cm)  as  a  better  C  sink was recognized for the entire forest types, irrespective of its category. Variations in the labile and non labile C counterparts were significant among the categories and similar variational trends were  observed  between  the  Particulate  organic  carbon(POC)  and  water  stable  aggregates (WSA)  proportion  for  various  forest  systems.  The  various  soil  carbon  fractions  indicate different  aspects  of  soil  carbon  dynamics  and  sequestration, with  the more  active  (labile) carbon component reacting moresensitively to landuse changes as observed in thorny forest (TF)  site.  The  proportion  of  carbon  labile,  micro  aggregation  and  potential  carbon mineralization (PCM) were comparatively high in TF site making it a vulnerable soil carbon pool. Significant positive correlations were observed between the soil carbon sink indicators like  SOC,  POC,  and macro  aggregation.  The  soil  carbon  source  indicators  like  PCM  and micro-aggregation showed significant negative correlation with the sink indicators. The study thus highlights the role of selected parameters or factors as potential indicators of soil carbon pool vulnerability  in  forest ecosystems. Understanding  the mechanisms and  factors of SOC dynamics  in  forest soils  is  important  in  their  role as natural sinks  for C sequestration  in  the climate change perspective. 

Type: Research Article
Year: 2013
URL: http://www.ipublishing.co.in/ijesarticles/thirteen/articles/volthree/EIJES31153.pdf