Abstract
In the present study, ‘natural 13 C tracer method’ was used to partition the belowground respiration into rhizosphere respiration and soil microbial respiration to test the hypothesis that defoliation affects rhizosphere respiration and rhizosphere priming effect on decomposition of soil organic matter (SOM). A C3 plant species, Helianthus annuus (sunflower), was grown in ‘C4’ soil in microcosms so that the CO2 evolved from plant-soil system can be partitioned. Four levels of defoliation intensities were established by manual clipping. CO2 evolved from plant-soil system was trapped during 0–4 h after defoliation (HAD), 5–22 HAD and 23–46 HAD using a closed circulating system, respectively. We found that both rhizosphere respiration and soil microbial respiration of the clipped plants were either unchanged or significantly enhanced compared to unclipped plants at 45% defoliation level during all sampling intervals. Soil microbial respiration increased significantly at all defoliation levels during 0–4 HAD, however, both rhizosphere respiration and soil microbial respiration decreased significantly during 5–22 HAD or 23–46 HAD when 20% or 74 clearly demonstrated that the defoliation treatments modified the rhizosphere priming effect on SOM decomposition. The total cumulative rhizosphere priming effects on SOM decomposition during 0–46 HAD were 146%, 241%, 204% and 205% when 0%, 20%, 45% and <74%.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.