Greenhouse gaseous emission and energy analysis in rice production systems in Ghana.
Agriculture in Africa is associated with low food production. The attempt to increase food productivity has the potential to generate some environmental concerns such as greenhouse emissions and energy impacts. The environmental impact of the rice production in the tropics, especially Africa, has not received much attention from the research community. Therefore, analysing the environmental performance of rice (Oryza sativa) production in Ghana provides an effective first step to develop, implement and improve its environmental management. The objective of this study was to assess greenhouse gas (GHG) emissions and energy impacts of rice production in Ghana. Among the three main components of greenhouse gases (GHGs), N2O accounted for the highest value, followed by CO2. Approximately, 477 kg CO2-equivalents of greenhouse gas was emitted per hectare of rice production. Among the activities that generated greenhouse gases, fertiliser application ranked first (72%), with transportation to mills as the second with a relative emission of 10%. Fertiliser application and transportation were the major contributors to SO2 emission. Energy used (mainly from diesel usage) in rice production amounted to 0.2 MJ per hectare. With regards to options to reduce environmental impact of rice production in Ghana, practices that recover investment cost and generate a profit in the short term are preferred by rice farmers over practices that require a long-term to recover investment costs. Practices that have a high probability associated with expected profits are desired over practices that have less certainty about their returns.
Key Words: Carbon dioxide, nitrous oxide, Oryza sativa