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Tropentag, September 14 - 16, 2022, Prague

"Can agroecological farming feed the world? Farmers' and academia's views."


The variation in soil carbon storage and emission in different land use systems of the Letaba catchment, Limpopo province, South Africa

Hlengiwe Ntuli1, Lawrance Munjonji2, Kwabena Ayisis3

1University of Limpopo, Department of Plant Production, Soil Science and Agricultural Engineering, South Africa
2University of Limpopo, Department of Plant Production, Soil Science and Agricultural Engineering
3University of Limpopo, Department of Plant Production, Soil Science and Agricultural Engineering


Abstract


Carbon dioxide (CO2) is one of the main greenhouse gases and thus, it is of paramount importance to monitor it and curtail its emission into the atmosphere. Although the highest CO2 emissions are reported by industrial activities, agricultural fields contributes about 10–14% towards total emissions. The influence of land use type on CO2 emission is not well elucidated, thus this study is aimed at attaining a better understanding of the effect of land use type on the emission of CO2 from the soil. The study was conducted at the Letaba catchment under five land use types namely Eucalyptus grandis plantation, banana plantation, communal maize field, forest and natural bushes. The emission of CO2, soil temperature and the moisture content data was collected at a 2-week interval from April 2021 to April 2022. The rate of CO2 emission was highest during summer with an average of 7.53 mg/m2/min making it 76.75%, 46.22%, 57.10% greater than the rates observed in winter, autumn and spring respectively. This was largely aided by the combination of higher soil temperature, moisture content and soil organic carbon (SOC) content. The soil temperature was highest during summer with an average of 33.44°C making it 21.11%, 9.69% and 10.49% greater than the rates observed in winter, autumn and spring respectively. The soil moisture content was highest during summer with an average of 17.01% making it 60.55%, 28.28% and 49.09% greater than the rates observed in winter, autumn and spring respectively. Soil CO2 emission rate was highest under the Forest followed by the Banana plantation, Bush, Maize and the Eucalyptus grandis plantation which had CO2¬ emission rates of 5.84, 4.15, 3.75,3.40 and 2.53 (mg/m2/min) respectively. The Forest also had higher soil temperatures and soil moistures contents while the bush had the lowest. The regression between CO2 emission and the soil moisture content was very low and weak, while that between CO2 emission and soil temperature was strong and positive. The current results show that CO2 emission rates vary significantly with land use as well as with season


Keywords: Carbon dioxide, emission, land use


Contact Address: Hlengiwe Ntuli, University of Limpopo, Department of Plant Production, Soil Science and Agricultural Engineering, 5629/20 chocolate street, 1053 Middelburg, South Africa, e-mail: hlengiwentuli31@gmail.com


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