Greenhouse gas emission implications of small-scale sugarcane farmers’ trash management practices: A case for bioenergy production in South Africa

Abstract

Sugarcane trash is a source of biomass available for energy generation. However, this potential has not been explored in the South African small-scale sugarcane sector. The current trash management practices of farmers, especially, pre-harvest burning, have huge negative environmental implications. Sustainable management of sugarcane trash could help address several challenges in the sugarcane industry including the high cost of irrigation. Therefore, this study is meant to assess small-scale growers’ trash management practices and their implications on greenhouse gas emissions. It also ascertains the potential for using sugarcane trash in the co-generation of electricity. The study was conducted in two communities in KwaZulu-Natal and Mpumalanga provinces with 330 small-scale farmers. A probit regression was used to determine factors that influence farmers’ trash management practices. Other analyses such as estimations of the amount of available trash, burning emissions and potential energy from sugarcane were informed by previous studies. The findings showed that pre-burning of sugarcane is a common practice among smallholder producers in South Africa. However, some farmers have attempted to move away from this practice opting to leave their sugarcane in the field or use it for compost. The farmers’ burning of sugarcane releases an estimated 0.08 tCO2-e per ha into the atmosphere. In total, the estimated greenhouse gas emissions from sugarcane burning of all small-scale growers in the two provinces are 725 tCO2-e per annum. The findings also revealed that having more land, poor endowment with psychological capital, lack of access to extension, limited resources, and working in silos compound the practice of burning sugarcane. The estimated energy potential from small-scale sugarcane producers in the country, using a 50 % recovery efficiency and 36 % energy conversion efficiency is 150,323.3 MWh. The study proposes several recommendations for improving trash management practices and initiating the co-generation of electricity from trash in the small-scale sugarcane industry.