Variation in soil organic carbon stock in different land uses and altitudes in Bagrot Valley, Northern Karakoram

ABSTRACT

Soil organic carbon tends to respond more sensitively to climate change and land use intensification in ecologically fragile and economically marginal regions of mountainous areas. This study aims to evaluate the soil organic carbon stock dynamic across various land uses at different altitudes in the Bagrot valley, Northern Karakoram, Gilgit-Baltistan, Pakistan. Soil samples from 0–20, 20–40 and 40–60 cm depth were collected from three land uses: pasture, forest, and adjacently located arable land at different altitude (ranging from 2100–4163 m). The variables investigated were soil bulk density (BD), soil organic carbon concentration (SOC), soil organic carbon stock (SOCS) and pH. A significant variation in all tested variables were found across the land uses and altitudes. Likewise, soil under forest had significantly higher values of SOCS (59.35 Mg ha⁻¹) than pasture (42.48 Mg ha⁻¹) and arable land (23.63 Mg ha⁻¹). Similarly, SOCS increased with increasing altitude and decreased with soil depth in all land uses. In addition, SOCS had a negative relationship with BD and pH. Overall results indicated that the land use intensification and climate change (increase in temperature and decrease in precipitation) were associated with declining SOCS. These results suggest restoration of degraded agricultural land to the forest, especially at higher altitude, and decrease in intensity of land use could increase SOCS in the study area as well as other similar mountainous regions.

KEYWORDS:

• Bagrot valley
• climate change
• Gilgit-Baltistan
• mixed mountain agriculture
• vegetation density

Disclosure statement

No potential conflict of interest was reported by the authors.

Notes on contributors

Shamsher Ali, Ph.D., is a Lecturer and Environmental Chemist at the Karakoram International University, Pakistan, working on the response of soil organic carbon to land use intensification and environmental change.

Farida Begum, Ph.D., is an Assistant professor and Environmental Scientist at the Karakoram International University, Pakistan, working on Carbon Dynamics and Sequestration potential under different land use systems for sustainable management of agro ecosystem and mitigation of climate change.

Rifat Hayat, Ph.D., is an Associate Professor and Soil Scientist at the Pir Maher Ali Shah Arid Agriculture University, Pakistan, working on Soil microbiology/Systematic/Soil Metagenomics under different cropping systems.

Brendan J. M. Bohannan, Ph.D., is a Professor of Biology and Environmental Studies at the University of Oregon, Eugene, USA, working on causes and consequences of microbial biodiversity and the response of bacterial and archaeal communities to environmental change. Prof. Bohannan is especially interested in promoting the integration of microbial ecology into the general science of ecology.