Root Respiration from Rubber Trees Developed on Peat Soil Under Different Climatic Conditions

Climate phenomena such as an El Niño event that is associated with drought usually have a negative impact on water availability. On peat soil, the reduction of water level is potentially accelerating the peat soil emissions. One critical part of soil respiration on peat soil is root respiration. However, the study of root respiration during the El Niño years is limited in plantations on tropical peatland. The study aimed to estimate the contribution of root respiration from rubber trees developed on peat soil under different climatic conditions, normal and El Niño years. The research was carried out on peat soil under smallholder rubber plantation, in Central Kalimantan, from July through October, during the dry season of 2014 (normal year) and 2015 (extreme El Niño year). Root respiration was calculated from the differences between total and heterotrophic respiration. The root respiration showed no significant difference between a normal and an extreme El Niño year. However, during four months of the measurements, the trend of root respiration was different. The highest root respiration in 2015 was found in September, while in September 2014, the root respiration showed the lowest condition. The root respiration is likely to follow the typical annual phenology of the vegetation rather than the climatic conditions. Further research is needed to understand the contribution of root to total peat soil respiration on peatland.