Cambodia assesses new technologies for safe and sustainable rice straw management

BATTAMBANG, Cambodia, 30 April—Cambodian rice farmers will soon have access to sustainable rice straw management techniques that will curtail the air pollution and potential health risks associated with rice straw burning.

The Cambodian Ministry of Agriculture, Forestry and Fisheries (MAFF), the Don Bosco Agro-Vocational School (DABVS), and the Postharvest and Mechanization Unit of the International Rice Research Institute (IRRI) organized a technology demonstration event for extension agents, government agencies, the private sector, and NGOs in Cambodia to help promote better options for rice straw management.

The event (photos), conducted at the DABVS model farm, showcased a rice straw baler machine for collecting the straw in the field, spraying urea or Trichoderma fungi to hasten the decomposition of rice straw, and mechanical equipment for chopping and dispersing rice straw into mulch. These technologies drew a lot of interest from the participants. The rice straw baler technology from Vietnam, in particular, opened a possibility of developing business models to add value for farmers on the use of rice straw either as feedstock or for mushroom production.

Another technology aims to transform rice straw into renewable energy. “The huge energy potential that can be derived from rice straw through the use of an anaerobic digester can generate fuel for cooking and electricity for home lighting,” said Nguyen Van Hung, an IRRI postdoctoral fellow working on renewable energy from rice residues. “This technology on anaerobic digestion of rice straw is being piloted at IRRI to generate sufficient data before further delivering it to farmers.”

Sustainable rice straw management technologies are becoming more important as rice farming produces millions of tons of the material every year. “The increase in mechanization for rice production, through the wide adoption of combine harvesters in Cambodia has been a game changer that has resulted in more rice straw being left in the field, especially in intensive production systems,” said Martin Gummert, IRRI senior scientist and head of IRRI’s Postharvest and Mechanization Unit. “Farmers opted for burning as the cheapest option due to a lack of technology for collection and the short turn-around time between cropping seasons that is not sufficient for decomposition before the next seedbed preparation.”

However, smoke from burning rice straw contributes to air pollution that causes acute and potentially serious health problems. “Moreover, burning rice straw in the field brings minimal benefits to the soil with the addition of potassium silica from charred straw and ash,” said Walter Zwick, senior expert on agronomy from Germany, who is helping in the operation and management of the DABVS model farm.

The project team discussed the next steps for Cambodia, Vietnam, and the Philippines, which will focus on the promotion of a rice straw baler and further studies on Trichoderma and mushroom production.

The project, Scalable straw management options for improved farmer livelihoods, sustainability, and low environmental footprint for rice-based production systems, is funded by the Federal Ministry for Economic Cooperation and Development of Germany (BMZ), which supported the technology demonstration.

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