Edaphic influences on soil organic carbon in the forest systems of southern Western Ghats, India.

Abstract

Listen

Translate article

Spatial distribution and edaphic influences on soil organic carbon (SOC) are key determinants of carbon sequestration potential, and analysis of aggregate-protected SOC gives an in-depth understanding of the stability of carbon stored in soils. The present study evaluated the edaphic effects on the SOC in four different forest types-tropical evergreen forest, tropical moist deciduous forest, tropical dry deciduous forest and shola forest-in the southern high hills agro-ecological zone of Western Ghats, India. SOC stocks at depths of up to 1m varied significantly across forest types, with the highest levels observed in the shola forest type (441.08Mg C/ha) and the lowest in the dry deciduous forest (138.17Mg C/ha). Around 70% of SOC was found in upper layers (0-30cm) in all the studied forest types. Evaluation by a fixed-effect model showed that forest type, soil depth and aggregate size significantly affected SOC storage in these systems. An assessment of the relative importance and effect of 14 edaphic factors on SOC content in different forest types using the random forest model showed that the algorithm could explain 93.68%, 41.72%, 45.53% and 75.2% variability of SOC concentration across shola, dry deciduous, moist deciduous and evergreen systems, respectively. Across all forest types, except for dry deciduous forests, soil texture was found to be the primary factor influencing SOC, surpassing all other edaphic parameters. Ionic interactions by way of metal oxides like Ca2+, Al3+, Fe3+, Mg and H+ influenced the SOC in tropical forest systems. The insights into SOC dynamics and the edaphic factors regulating them offer valuable guidance for forest management in tropical regions, particularly regarding climate change mitigation.