Sankar Mariappan

Department: Department of Geography
Discipline: Geography
Research Centre/Unit: University of Exeter

Project Summary

PhD title on An Assessment of fate of eroded Soil carbon under various landscape positions: A source or sink for atmospheric CO2

My PhD thesis focus on assess the Soil erosion-induced redistribution alters soil organic carbon (SOC) dynamics at various landscape positions; however, there is as yet no clear consensus regarding the net effect on the terrestrial carbon budget. Existing studies undertaken and  quantifying erosion-induced carbon redistribution on agricultural land have identified a carbon sink. However, these have mainly examined temperate and mechanized farming systems. Therefore, there is need to investigate these processes in subtropical and low productivity farm lands, where net return of biomass are expected to differ from those systems already studied, to generate data and improve understanding of the mechanisms involved in erosion induced changes on SOC flux. Therefore, my study aims to : (1) undertake a retrospective assessment of the effect of soil redistribution on the net flux of C between soil and the atmosphere within the landscape using 137Cs fallout and SOC inventories, (2) characterise the influence of erosion induced soil redistribution on the spatial (vertical and horizontal) distribution of SOC pools, (3) investigate the spatial variation in soil respiration through incubation studies using topsoil and subsoil samples from a range of landscape positions, (4) characterise the soil morphological properties at various landscape positions,  (5) determine the soil respiration changes following water erosion in controlled erosion flume studies and (6) characterize the restoration of SOC at eroded landscape by adopting no-till practice. The focus of this work with respect to the first 5 aims is on low input and low productivity farming lands around the Himalayan foothill regions of India where the highest sediment flux and SOC flux is occurring and the sixth aim will be addressed in the study of restoration of SOC at one of the long- term erosion studies in Ohio, USA.


Supervisory Team

Prof. T. A. Quine, Iain A. Hartley  from University of Exeter and Jennifer Dungait from Rothamested Research, North Wyke

Wider Research Interests

·         Soil Science, Soil Carbon dynamics , soil erosion, and  soil respiration

Authored Publications/Reports

K Manikandan, P Kannan, M Sankar (12th October 2012) Evaluation and Management of Groundwater in Coastal Regions, Earth Science India, 5, 1-11

KS Dadhwal, D Mandal, SS Srimali, SC Mohan, A Raizada, M Sankar (5th March 2012) Impact of different land use systems on soil properties in a watershed of lower Himalayan region, Indian Journal of Soil Conservation, 40, 129-134

M Sankar, R Sivasamy, and KS Dadhwal, (2010) Land resource data and its evaluation for village level land use planning, Agropedology, 20, 1-06