Declined peat heterotrophic respiration as consequences from zeolite amendment simulation: coupling descriptive and predictive modelling approaches

Abstract

Nowadays, halting greenhouse gasses (GHG) emission is the world's major concern to mitigate global climate change. In oil palm cultivated tropical peatland, GHG emission is primarily constituted of CO<sub>2</sub> flux emitted from aerobic heterotrophic respiration (R<sub>h</sub>), the natural degradation process of organic material in an oxidative environment. By coupling descriptive and predictive statistical approaches, this study attempt to gain an in-depth understanding of the effects of zeolite rates and incubation time on CO<sub>2</sub> emission that came from aerobic R<sub>h</sub> in peat, as well as their decomposition process. This study found that zeolite amelioration up to 30% of the peat at field capacity and starting from the first month of observation (month-1) significantly restricted peat R<sub>h</sub>, denoted by a reduced amount of observed CO<sub>2</sub> flux (0.021 and 0.019-0.012 mg m<sup>-2</sup> sec<sup>-1</sup>, respectively). Both factors and several soil variables exhibited some non-linear relationships with R<sub>h</sub> at different magnitudes and importance, showing the limitation of the traditional linear-based approach to interpreting their complex interrelationships, as well as predicting CO<sub>2</sub> flux. This study highlights the vital role of a polynomial (GAM) and artificial intelligence (Cubist and GBM) -based pedotransfer models in improving our understanding regarding the dynamic of the peat decomposition process as affected by zeolite amendment.