Carbon mitigation potential of different landuse systems in Northwest Himalayas of India

Abstract

The alarming increase of CO2 from pre-industrial time has made scientists of every corner to evolve technology to harness this anthropogenic gas and balance the system. A landuse can be a source or sink for carbon depending on the process experienced by the system. The proportion of carbon stored in landuse varies widely depending on their components and climate conditions. More accurate estimates of global or continental CO2 emission from landuse/cover change can only be obtained from extrapolation of reliable local estimates. Northwest Himalayan region has variety of land management practices and landuse systems. In the present research at Department of Silviculture and Agroforestry, Dr. Y. S. Parmar University of Horticulture and Forestry, India, all possible land use systems of Northwestern Himalayas (India) viz.  Agri-silvi-horticulture (ASH), Agri-horti-silviculture (AHS), Agri-silviculture (AS), Agri-horticulture (AH), Silvi-pasture (SP), Pure agriculture  (PA), Pure grassland  (PG) and Abandoned land  (AL) / undisturbed lands were taken to assess the relative carbon mitigation (RCM) potential by calculating carbon mitigation in plant biomass as well as in soil component of the system. The carbon inventory in plants were estimated by calculating the above and below ground biomass using non-destructive method for different plant parts while in the soil the carbon expressed as mega grams per hectare (Mg/ha) for soil depths (0-20 cm and 0-40 cm) was computed by multiplying the soil organic carbon (g kg-1) with bulk density (g cm-3) and depth (cm). The results showed that all land use systems had higher relative carbon mitigation potential than agriculture system. For the soil layer 0-20 cm, the relative carbon mitigation potential ranged from 1.33-2.32 (taking value for agriculture LU system as 1). The lowest value was obtained for AH whereas, the maximum for abandoned land. Further, the study shows that the relative carbon mitigation potential of AL was obtained 2.32 times higher than agriculture followed by SP, ASH, AS, PG=AHS and AH. Considering the RCM values for cumulative soil layer 0-40 cm over 0-20 cm only, different land use systems showed slightly higher carbon mitigation potential values except PG. The different land use systems in terms of RCM potential were ranked as: AL > SP > ASH > AS > AH > AHS > PG and ranging from 1.16-2.40.