Carbon dioxide emissions from spring ploughing of grassland in Ireland

Grassland re-seeding or land-use change requires ploughing, which may enhance carbon dioxide (CO2) emissions from soil. This study observed the short to intermediate-term (37 days) effects of ploughing on CO2 emissions from poorly drained grassland using automated soil respiration chambers. Immediately after ploughing, a brief peak in CO2 emissions from soil occurred with a maximum observed flux of 6.91 g CO2 m−2 h−1. Contradictory to other reported results, ecosystem respiration after ploughing was lower on the ploughed than on the grass site. After including estimates of photosynthesis in the analysis, ploughing led to significantly higher net CO2 emissions than from grassland. The main mechanism of C loss during ploughing was most likely due to a reduction in gross primary production rather than enhanced soil respiration.

► CO2 emissions were monitored from ploughed and unploughed Irish grassland.
► Ploughing led to higher net CO2 emission compared to permanent grassland.
► C loss during ploughing was due to reduced GPP rather than enhanced soil CO2 loss.