A B S T R A C TSustainability criteria for palm oil production guide new planting toward non-forest land cover on mineral soil, avoiding carbon debts caused by forest and peat conversion. Effects on soil carbon stock (soil C stock ) of land use change trajectories from forest and non-forest to oil palm on mineral soils include initial decline and subsequent recovery, however modeling efforts and life-cycle accounting are constrained by lack of comprehensive data sets; only few case studies underpin current debate. We analyzed soil C stock (Mg ha À1 ), soil bulk density (BD, g cm À3 ) and soil organic carbon concentration (C org , %) from 155 plots in 20 oil palm plantations across the major production areas of Indonesia, identifying trends during a production cycle on 6 plantations with sufficient spread in plot age. Plots were sampled in four management zones: weeded circle (WC), interrow (IR), frond stacks (FS), and harvest paths (HP); three depth intervals 0-5, 5-15 and 15-30 cm were sampled in each zone. Compared to the initial condition, increases in C org (16.2%) and reduction in BD (8.9%) in the FS zone, was compensated by decrease in C org (21.4%) and increase in BD (6.6%) in the HP zone, with intermediate results elsewhere. For a weighted average of the four management zones and after correction for equal mineral soil basis, the net temporal trend in soil C stock in the top 30 cm of soil across all data was not significantly different from zero in both forest-and non-forest-derived oil palm plantations. Individual plantations experienced net decline, net increase or U-shaped trajectories. The 2% difference in mean soil C stock in forest and nonforest derived oil palm plantations was statistically significant (p < 0.05). Unless soil management changes strongly from current practice, it is appropriate for C footprint calculations to assume soil C stock neutrality on mineral soils used for oil palm cultivation. 2015 Z. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http:// creativecommons.org/licenses/by-nc-nd/4.0/).

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