Characteristics of CO2 Emission on Peatland Under Oil Palm Trees

Abstract

The research aim was studying the characteristic CO₂ emission from peatland under oil palm trees as a relationship with environmental factors of specific locations in the Labuhan Batu District of North Sumatra. CO₂ gasses were sampling by closed chamber technique and their concentration was measured by portable micro Gas Chromatograph CP 4900. The observation of environmental factors as the variable that affected to CO₂ emission included soil temperature (TS), atmosphere temperature (TA), soil moisture on 0-5 cm of soil depth (SM5), soil moisture on 0-30 cm of soil depth (SM30), and pH of peat (A). The relationship model of CO₂ emission with environmental factors analyzed by Spearman correlation and multivariant regression. Stepwise regression was applied for multivariant regression to identify the environmental factors that have a relationship with CO₂ emission with significant analysis in 5 % of the threshold. Variance inflation factor (vif) was applied to identify the multicollinearity problem of the model from multivariant regression. The Spearman correlation showed the A (pH) of environmental factors have the highest correlation coefficient with the middle category (R=0.637). The stepwise regression showed the CO₂ emission have been significantly affected by soil moister SM30 and A (n = 216; p < 0.05) with vif value < 3. The regression model from multivariant regression was CO₂ = 7.394*A – 0.008*SM30 – 16.659 with R2 = 0.420. In the partial, there was a relationship of CO₂ with soil moisture in the field capacity condition. The highest CO₂ emission occurred at soil moisture of 354 – 376% w w-1 and decreased while the soil moisture increases overring the field capacity condition. The CO₂ emission was decreased while the peat soil was drying at under the critical of water content caused the peat soil hydrophobicity was increasing.