Author(s)

Md. Sadiqul Amin¹, Md. Zulfikar Khan^1,2*, Tutul Laskar¹, Sheikh Mohammad Fazle Rabbi³

¹Soil, Water and Environment Discipline, Khulna University, Khulna, Bangladesh.
²Forestry and Environmental Science, University of Tuscia, Viterbo, Italy.
³School of Life and Environmental Sciences, University of Sydney, Sydney, Australia.

Land use change and cropping patterns are important factors for controlling carbon sequestration in soils and they may also change the relative importance of different mechanisms of soil organic matter stabilization. The study was conducted to investigate the state of carbon sequestration in soil aggregates under different cropping patterns of Khulna, Jessore and Chapainawabganj districts in Bangladesh. Thirty-six soil samples were collected from (0 - 100 cm depth) above mentioned regions of three physiographic regions: Ganges Meander Floodplain, Ganges Tidal Floodplain and High Barind Tract. The texture of the samples varied within three soil texture groups, Silt Loam, Silty Clay Loam and Silty Clay. The highest NSI value (0.89) was found under Wheat-Fallow-T. Aman cropping pattern in Silty Clay soils (sample No 15) and lowest value (0.59) was found Vegetables/Mustard-Fallow-T. Aman cropping pattern in Silt Loam soils (sample No 17). The highest value (735.20 mg•kg⁻¹) of active C was observed under Chickpea/mustard-T. Aman (Sample No 31) and the lowest value (619.23 mg•kg⁻¹) was found in case of Wheat-Fallow-T. Aman cropping pattern (Sample No 30). The highest SOC stock (1.62 Kg C m⁻²) was found in Silty Clay Loam soil under Mungbean/Ash gourd-T. Aman cropping pattern (Sample no 4) and the lowest SOC stock (0.35 Kg C m⁻²) was found in Silt Loam soil under Cauliflower/Pumkin/Spinach-T. Aman Cropping pattern (Sample No 2). Soil organic carbon associated with different size aggregates was the highest (3.14%) under Mungbean/Ash gourd-T. Aman (Sample No 20) and was the lowest (0.36%) under Cauliflower/Pumkin/Spinach-T. Aman cropping pattern (Sample No 2). Organic carbon content in aggregate size ranges > 2000 μm (SOC1), 2000 - 250 μm (SOC2), 250-53 μm (SOC3), and <53 μm (SOC4) varied from 0.36% - 1.90%, 0.52% - 2.10%, 0.50% - 2.60% and 0.50% - 1.62%, respectively. The percentages of SOC associated with <53 μm aggregates were higher than those of >2000 μm, 2000 - 250 μm and 250 - 53 μm, aggregates. Significant positive correlations were found between SOC stock and SOC1, SOC stock and SOC2, SOC stock and SOC3, SOC stock and SOC4.

Carbon Sequestration, Carbon Stock, Soil Aggregate, Cropping Patterns, Climate Change

Amin, M. , Khan, M. , Laskar, T. and Rabbi, S. (2020) Carbon Sequestration in Soil Aggregates under Different Cropping Patterns of Bangladesh. Open Journal of Soil Science, 10, 459-485. doi: 10.4236/ojss.2020.1010024.