Impact of chronosequence of poplar based agroforestry system on storage of soil organic carbon in active and recalcitrant pools Kaur Ravinder, Singh Baljit*, Dhaliwal S.S. Punjab Agricultural University, Ludhiana-141004, India *Corresponding author e-mail: singh-baljit@pau.edu
Online published on 20 September, 2023. Abstract The study comprised of five land uses viz ., sites having continuous poplar ( Populus deltoides )-based agroforestry system (AFS) for 10, 20 and 30 years, fodder [pearlmillet (Pennisetum glaucum)/ sorghum (Sorghum bicolor) ]-fodder [oats ( Avena sativa )/ berseem ( Trifolium alexandrinum )] (F-F) rotation and fallow land (control) to determine depthwise (0-15, 15-30, 30-60 and 60-90 cm) changes in total C (TC), soil inorganic C (SIC), soil organic C (SOC), total organic C (TOC) and its fractions in different land uses. The TOC pools consisting of very labile C (VLC), labile C (LC), less labile C (LLC) and recalcitrant C (RC) were determined. Fallow land had highest (1.53 Mg m-3) whereas 30 years AFS had lowest bulk density (1.42 Mg m-3) of thesurface soil depth. The TC, SOC and TOC stocks followed the order:AFS > F-F > FL in various soil depths. The active carbon (AC) pools (VLC + LC) were higher in 10-year plantation cycle (62.3% of TOC) than 30-year cycle (32.9% of TOC), whereas the passive carbon (PC) pools (LLC + RC) were higher in 30-year plantation cycle (67.1%) than in 10 years (37.7%) in surface depth. The contribution of LLC to PC was higher in 30-year plantation cycle (65%) than in 10-year plantation cycle (48%). Therefore, long-term adoption of poplar based agroforestry system plays a significant role in sequestration of resistant carbon pools in the soils. Top Keywords Active carbon, Carbon sequestration, Organic carbon fractions, Passive carbon, Poplar plantations. Top |