Soil carbon pools and carbon management index under different land use systems in the Central Himalayan region

Abstract

We investigated different land use and cropping systems in the Almora region of Central Himalaya to assess total organic carbon (TOC), microbial biomass carbon (MBC), particulate organic carbon (POC), labile carbon (LC), microbial quotient (MQ) (i.e., ratio of MBC to TOC) and measured the carbon management index (CMI). The TOC content recorded the highest value in undisturbed forest (45.4 g kg−1 soil) and lowest in barren land (18.4 g kg−1 soil). The MBC values varied from 146 mg kg−1 in barren land to 783 mg kg−1 in undisturbed oak forest. Land under organic farming showed higher LC values (4.0 g kg−1) than soya bean–wheat and fodder crops. The average POC values ranged from 0.9 g kg−1 in barren land to 11.0 g kg−1 in undisturbed oak forest. Variation of these parameters with season and depth was also observed. The CMI was highest under the forest ecosystem and lowest in barren land. Our study thus revealed that cultivation of Himalayan soils has significantly reduced the soil organic carbon pools and thus maintenance of natural forest or eco-friendly practices such as inclusion of legumes and application of organics is urgently needed for sustainable use of these ecosystems.