Labile carbon fractions build-up and dynamics under vertical stratification of Populus deltoides and Eucalyptus tereticornis based agroforestry systems in Trans-Gangetic plains of India

Abstract

Populus deltoides and Eucalyptus tereticornis based agroforestry systems are credited for stocking significant amounts of soil carbon and hence have the potential to mitigate climate change. In this study, four different land uses were compared in terms of labile carbon fractions build up in varying soil depths. Soil organic carbon under 4-year Populus and Eucalyptus based agroforestry system was 22.9 and 6.30% higher, respectively than sole wheat crop. Microbial biomass carbon under 4-year Populus and Eucalyptus based agroforestry system was 10.6 and 12.3 % higher than sole wheat crop. Permanganate oxidizable carbon under 4-year Populus and Eucalyptus based agroforestry system was 4.4 and 23.1% higher than sole wheat crop. In Populus and Eucalyptus based agroforestry systems, significant positive correlations were recorded between POXC and MB-C (r=0.809 and 0.889), POXC and SOC (r=0.903 and 0.793) and SOC and MB-C (r=0.765 and 0.852), respectively. The relationship between POXC and SOC under Populus (4-year) + wheat (R2 = 0.845) had stronger relationship than Eucalyptus (4-year) + wheat (R2 = 0.712). This study demonstrated the usefulness of POXC in assessing changes in the labile soil C pools quickly and inexpensively under Populus and Eucalyptus based agroforestry systems in Trans-Gangetic plains of India.