Peat subsidence in a tropical rubber plantation during a strong El Ninõ year

Abstract

El Ninõ usually induces peat fires because dry season was prolonged and rainfall was low. This event potentially increases soil CO2 emissions and peat subsidence on tropical peat due to low groundwater level. Despite this, El Ninõ impacts on peat soil subsidence is understudied in Indonesia. To fill the gap, we measured peat surface elevation to determine peat soil subsidence at monthly basis during dry season, from June to November, in the strong El Ninõ year of 2015 and the normal year of 2014. A rubber plantation cultivated on peat soil was selected as a representative area for this research. Subsidence (in cm) was determined by calculating the difference in ground elevation between June and November for 2014 and 2015. Measurement was done by inserting three steel pipes vertically until underlying mineral substrate. We found that peat soil subsidence in strong El Ninõ year was larger than that of normal year. This finding can be further exploited as the baseline information for peatland management under climate change and or in extreme weather.