In this study we examined the effect of conversion from
grassland to oil palm on soil microbial diversity and nitrogen
cycling gene abundance. The study site was on the coastal plain of
Oro Province in Papua New Guinea, where recent expansion of oil
palm plantations has been mostly on grasslands. Conversion of
3500 ha of grassland to oil palm is planned for 2015–2018 in this
region. We undertook analysis of abundance of several genes
involved in soil N cycling, as we considered alteration in plant
composition and/or C inputs into the soil system were likely to
impact on soil N cycling and thereby have important implications
for both ecosystem fertility (soil mineral N) and off-site impacts
(e.g. denitrification to N2O). We hypothesized that changes in land
use would be reflected in (1) alteration of soil microbial
community composition and (2) the abundance of representative
N-cycling taxa, due to the demonstrated effects of land use on soil
physicochemical properties. Following from this study, a future
goal is to develop microbial indicators for sustainable land use in
Papua New Guinea and elsewhere