Finding a local solution for deforestation

Research into finding sustainable curing fuels for tobacco is being undertaken by the University of Zimbabwe’s Industrial Engineering and Mechatronics department. They have been working on the development of a furnace and stoker designed to burn maize cobs to provide supplementary heating needed for tobacco curing. This may be crucial for mitigating the environmental impact of tobacco farming, namely deforestation.

The Department of Industrial and Mechatronics Engineering (UZ) invited all stakeholders driving the sustainability goal within the tobacco supply chain to attend a live demonstration for the newly designed and constructed maize-cob renewable energy system which was commissioned and was being tested at the University of Zimbabwe.

At the event, UZ’s Engineer Nelson Shati explained that maize cobs as a source of biomass fuel, are widely available here and may very well be a sustainable option to supplement curing fuel for flue-cured Virginia tobacco. In Zimbabwe, maize cobs are usually regarded as residue with no value. They are abundant and can be sourced locally and cheaply, reducing the need for long-distance transport.

As modifications to the curing barns and heating systems can be costly and time-consuming, a significant part of the research for this working model has been based on addressing challenges and limitations such as capital expenditure, modifying existing stokers and furnaces and ease of use (with this system, farmers do not need to bend their backs to load curing fuel into the furnaces).

The system includes an energy charging cart and a furnace, of which furnace charges go to barn furnace modification on existing structures. The system is detachable to allow farmers to detach it should they need. It comes with a guide for maize they will need to grow to supplement their sustainably sourced woodlot output without having to resort to buying the maize cobs. To cure one hectare of tobacco, three tons of cob are needed. A ton of cobs currently fetches USD 55. Two hectares of maize will yield two tons of cobs.

Using maize cobs as fuel for tobacco curing can help to reduce the environmental impact of tobacco farming and promote sustainable practices. By providing farmers with the necessary training, equipment, and support, sustainable tobacco farming can be made a reality.

Tobacco curing is a highly energy-intensive process, but the burning of indigenous wood to cure tobacco is unsustainable, not to mention illegal, and has contributed to massive deforestation over the years. An increased annual hectarage of tobacco means increased inputs will be needed, chief among them curing fuels and finding options for viable alternative energy sources are a matter of the utmost urgency. According to latest Tobacco Industry and Marketing Board (TIMB) figures, tobacco seed sales for this season amounted to 673 kg with the capacity to cover to 112,104 ha. Last year, 647 kg had been sold and the national hectarage stood at 110,063 ha.