Creating value after the harvest from rice straw

For many farmers, rice straw is one of the most difficult byproducts to manage after harvest. Left in piles, it obstructs the next cropping season. When burned in the field, it creates smoke and air pollution. Even collecting it for sale is not always a viable option due to uncertain market demand.

But at the Green Agriculture Innovation Center on the morning of July 8, straw was no longer treated as agricultural waste. Instead, it was fed into a mixing machine, sprayed with microbial inoculants, and set on its way to becoming organic fertilizer, returning nutrients to the very fields where it was produced.

The demonstration also marked the beginning of a new phase of Vietnam's Crop Production Emissions Reduction Program for 2025-2035, with a Vision to 2050, which promotes circular and low-emission farming practices.

Following the successful pilot models in Hung Yen, Ninh Binh, and Hai Phong, which demonstrated that row seeding combined with deep fertilizer placement can reduce production costs, increase farmers' profits, and lower greenhouse gas emissions, the International Rice Research Institute (IRRI), in partnership with Vietnam Green Agriculture Investment and Development Group (VAG Group), has launched a sustainable rice production and circular agriculture initiative centered on straw utilization. The program aims to scale up the model through public-private partnerships.

When straw is no longer meant to be burned

For years, rice production has faced a persistent paradox: while farmers strive to increase the value of every grain of rice they harvest, the remaining biomass is often treated as a burden.

According to Associate Professor Nguyen Van Hung, Senior Scientist at IRRI, only a small proportion of rice straw is used for mushroom cultivation or livestock feed. Straw for mushroom production must meet strict quality requirements, while market demand remains limited. Straw used as cattle feed must be clean, dry, and free from pesticide residues. As a result, most of the remaining straw, accounting for as much as 80%, particularly in low-quality or waterlogged fields, has little or no commercial value, leaving farmers with little choice but to burn it or allow it to decompose in the field.

Burning straw may save time, but it also removes valuable organic matter from the soil and generates additional greenhouse gas emissions. Leaving straw to decompose naturally in the field, meanwhile, is a slow process that can delay land preparation and affect the following crop.

This gap has become the next challenge that IRRI aims to address.

In fact, this is not the first time the technology has been introduced to rice-growing areas in northern Vietnam. Since 2024, under the framework of the Fertilize Right Project, IRRI has worked with local authorities to pilot mechanized straw treatment in Nam Dinh Province, now part of Ninh Binh Province following the administrative merger, before expanding the model to neighboring localities.

With a processing capacity of up to 300 cubic meters of rice straw per hour, the technology featured in the partnership between IRRI and VAG Group is far more than a demonstration of new equipment. It represents the integration of a field-tested solution into the low-emission rice production system in the Red River Delta. The goal is to transform straw management from a pilot initiative into a scalable service that can be adopted by cooperatives and agribusinesses, laying the foundation for wider deployment in future cropping seasons.

Unlike conventional composting methods, which typically require up to three months and depend heavily on farmers' experience, the new process begins with mechanization. The mixing machine simultaneously chops and turns the straw while spraying microbial inoculants directly onto each layer of material. This process breaks the straw into smaller pieces, increases its surface area, and creates favorable conditions for microorganisms to accelerate decomposition.

According to the IRRI expert, turning rice straw into high-quality organic fertilizer requires careful control throughout the entire composting process. The compost pile must maintain a moisture content of around 60%, while the temperature initially rises to nearly 70°C to eliminate pathogens and weed seeds before stabilizing at 50-55°C, the optimal range for cellulose-degrading microorganisms.

The carbon-to-nitrogen ratio is also carefully adjusted to create favorable conditions for decomposition. As a result, the composting period is reduced to about 40 days to produce finished organic fertilizer, or just 25-30 days when the material is intended for direct soil improvement in the field.

Beyond eliminating emissions from open-field burning, organic fertilizer produced from rice straw helps increase soil organic matter, improve the soil's capacity to retain water and nutrients, and gradually reduce reliance on synthetic fertilizers.

For IRRI, this represents the next step in advancing low-emission crop production. While earlier efforts focused on reducing seed rates, fertilizer use, and pesticide applications during cultivation, the next phase aims to keep carbon in the field by converting post-harvest straw into a valuable resource instead of allowing it to be lost after harvest.

Businesses step in to close the post-harvest gap

During the recent spring rice season, IRRI, in collaboration with local authorities, piloted row seeding combined with deep fertilizer placement in Hung Yen, Hai Phong, and Ninh Binh. The results showed that seeding costs were significantly lower than those of conventional transplanting. Seed use was reduced by more than 30%, while nitrogen fertilizer application declined by over 30%.

Overall production costs fell by more than 25%, while average profits reached approximately VND 21 million per hectare. These results demonstrate that reducing greenhouse gas emissions can go hand in hand with improving economic returns.

This is also why IRRI has chosen a public-private partnership approach to accelerate the adoption of low-emission farming. Rather than simply transferring technology, the model in Nghia Son brings together research institutions, government agencies, suppliers of agricultural machinery, fertilizers, and biological products, cooperatives, and farmers within a single production value chain.

The role of businesses extends well beyond supplying agricultural inputs. They are involved in developing cultivation protocols, investing in mechanization, processing agricultural residues, establishing raw material production zones, and building market linkages for agricultural products.

Nguyen Quang Truong, Chief Executive Officer of VAG Group, echoed this view, saying the company aims to provide an integrated solution that covers every stage of production, from row seeding with deep fertilizer placement and nutrient management to post-harvest straw treatment. The ultimate goal is to reduce input costs, improve yields, and increase farmers' incomes, with measurable on-farm results serving as the benchmark before expanding the model to other localities.

"Businesses are the missing link needed to scale the model from a few dozen hectares of pilot fields to large-scale production," said former Deputy Minister Ho Xuan Hung. He noted that most farmers lack the capacity to invest in integrated technologies and equipment. In contrast, businesses can organize production services, develop supply chain partnerships, provide market outlets, and improve value chain transparency. To successfully expand green agriculture, he added, businesses must work alongside farmers rather than simply investing in farmland.

IRRI shares the same perspective. Nguyen Van Hung, the institute's senior scientist, said new technologies can only transform farming practices when they are incorporated into regular commercial services provided by businesses. Once farmers see tangible benefits in their own fields and have reliable access to these services, the transition to sustainable farming can progress much more rapidly than through pilot projects alone.

*$1 = VND 26,466 - Source: Vietcombank.