Soil carbon stock and emission: estimates from three land-use systems in Ghana

Abstract Background Land-use systems that sequester carbon and reduce CO 2 emissions are key in the global mitigation strategies of climate change. Greenhouse gas emission from agro-ecosystems in sub-Saharan Africa is little studied. Here, we quantified soil carbon stock (SCS) and CO 2 emissions from three land-use systems viz. arable land, oil palm plantation and forestland in the semi-deciduous forest zone of Ghana. Results Soil organic carbon concentration at the 0–15 cm layer in the forestland was 62 and 23% greater than that in the arable land and palm plantation, respectively. The SCS along the 1.0-m profile was 108.2, 99.0 and 73.5 Mg ha −1 in the forestland, palm plantation and arable land, respectively. Arable land emitted 30–46% more CO 2 than palm plantation and forestland. In the dry season, CO 2 emissions were respectively 0.93, 0.63 and 0.5 kg ha −1  h −1 from the arable land, palm plantation and forestland. Positive relationships were observed between CO 2 emissions and SCS, soil temperature, and moisture. The SCS greatly influenced CO 2 emission in the dry season more than in the wet season in the relatively higher carbon-input systems (forestland and palm plantation). Soil temperature accounted for more than 55% of CO 2 emissions in both seasons, which has implications in the era of rising global temperatures. Conclusions The study provides relevant information on carbon storage abilities of the three land-use types in tropical climate and calls for drastic climate change actions to reduce degradation of forest cover and soil disturbance in agro-ecosystems in sub-Saharan Africa.