Organic Carbon Stock and its Relationship with Soil Properties in Coastal Agroecosystem of Puducherry, India

Abstract

This study in coastal agroecosystem was conducted to evaluate the soil organic carbon Stock (SOC) in different farm management practices (conventional, sustainable and organic) and to develop its relation to soil physical, chemical and biological parameters. Three composite soil samples were collected from each of the 9 farms from the surface (0-15 cm depth). Soil organic carbon (SOC) stock was significantly higher in organic farming (28.14 t ha^-1) compared to sustainable and conventional farming. Soils from organic farms had significantly higher level of moisture content (4.40 %(w/w)), water holding capacity (50.33%),clay (13%) total N (3.67 g kg^-1), total P (2.38 g kg^-1), soil respiration (6.33 mg CO₂ 100 g of soil^-1 day^-1), microbial biomass C (779.87 mg kg^-1) and N microbial biomass (74.90 mg kg^-1) compared to conventional and sustainable farming systems. SOC stock showed a significant positive correlation with soil moisture content (r = 0.80), volume of soil particle (r = 0.68), water holding capacity (r = 0.91), EC (r = 0.68), silt (r = 0.86), clay (r = 0.82), total N (r = 0.93), total P (r = 0.95), soil respiration (r = 0.67), microbial biomass C (r = 0.87) and N (r = 0.84). The highest amount of SOC stock was in organic farming due to continuous use of farm yard manure and organic fertilizers.