Mapping Spatial Variation of Soil Carbon Concentration and Assessment of Carbon Stocks in an Agricultural Farm of Semiarid Region of India

Abstract

Soil carbon is a major indicator for sustainability of agricultural productivity and crucial for climate change studies. Spatial modeling and prediction map of surface soil (0.0 -0.15 m) carbon concentration in a semiarid agricultural farm, New Delhi, India was generated using geo-statistical techniques. Average concentration of total carbon at surface soil was 5.7 g kg-1, ranging from 0.72 to 14.49 g kg-1. Spatial ranges of soil organic carbon (SOC) and total carbon (TC) concentration were 180 m and 83 m respectively, as identified through semivariogram modeling. Depth-wise carbon density and stock were also assessed for five soil families under subgroup of Fluventic Haplustepts (1), Typic Haplustepts (3) and Calcic Haplustepts (1) in the farm (number of soil family within parenthesis). SOC density within 1.5 m depth ranged from 35.11 Mg ha-1 (in Calcic Haplustepts) to 57.16 Mg ha-1 (in Fluventic Haplustepts). Contrarily, soil inorganic carbon (SIC) density within 1.5 m depth varied from 16.98 Mg ha-1 (in Fluventic Haplustepts) to 403.68 Mg ha-1 (in Calcic Haplustepts). The farm having 293.1 ha of cultivated area had 27.94 Gg TC stock within 1.5 m depth, of which proportion of SIC stock (i.e. 51.1%) was higher than SOC stock (i.e. 48.9%), indicative of calcification process in semiarid ecosystem. The assessment of soil carbon concentration, density or stock assessment with georeferenced location of nationally important agricultural farm will be useful for spatiotemporal analysis of soil carbon changes, carbon emission and sequestration studies in context of global warming sceniario.