Impact of Soil Organic carbon on Bulk Density and plasticity index of Arid Soils of Raichur, India

Abstract

To assess the impact of soil organic carbon (SOC) on Bulk density (BD) and plasticity index (PI) of arid soils, a laboratory study was conducted on four of the arid soils namely black cotton, red, marshy and mountainous, obtained from organic farms. Wastes like humus, pressmud, bagasseash and flyash were used as a source of SOC to amend with the soils. SOC inputs were made volumetrically up to 70% in the increments of 10% of the soil columns which resulted in 0.08 gm/gm4.18 gm/gm for black cotton, 0.06 gm/gm-2.99 gm/gm for red, 0.06 gm/gm -3.16 gm/gm for marshy and 0.07 gm/gm -3.57 gm/gm for mountainous soil. There was also a control column without any external addition of SOC. The relation between SOC, BD and PI was analyzed by series of experiments carried in triplicate in three different phases based on the mode of application of SOC. The lowest PI were 3.00%, 2.97%, nil and 1.83% similarly lowest BD were 0.73 gm/cc, 0.81 gm/cc, 0.75 gm/cc and 0.83 gm/cc for black cotton, red, marshy and mountainous soils respectively. Phase I performed better for red soil, phase II for black cotton, and phase III for mountainous soils with respect to PI; while it was phase I that performed better for red, phase III for back cotton, mountainous and marshy soils with respect to BD. The positive relation between SOC and BD was observed. Thus, organic carbon input will be a suitable key for sustainable soil management.