Turning agricultural by-products into resources

Each year, Viet Nam's agricultural sector produces a substantial volume of by-products, including rice straw, crop stalks and leaves, cassava pulp, fruit peels, livestock waste, shrimp shells, rice husks, etc. However, for many years, much of this biomass has been burned, buried, or discarded into the environment, resulting not only in a waste of valuable resources but also in increased environmental pollution, higher greenhouse gas emissions, and rising production costs.

As requirements for emission reduction, traceability, and environmental standards become increasingly stringent, agricultural by-products can no longer be regarded as mere waste left behind after production. When properly collected, sorted, and treated by appropriate technologies, they can become raw materials for animal feed, organic fertilizers, bioenergy, and a wide range of value-added products.

According to experts, shifting the mindset from "waste management" to "resource recovery" is one of the keys to unlocking new growth opportunities for Viet Nam's agricultural sector, reducing input costs, and moving toward a low-emission, circular production model.

Vast potential

Prof. Dr. Nguyen Huy Khang, Director of the Research and Technology Transfer Center at the Ho Chi Minh City University of Agriculture and Forestry, said that global agricultural development has clearly shifted toward circular and low-emission production. This direction also aligns with Viet Nam's commitment to achieving net-zero emissions by 2050.

According to Prof. Khang, agricultural by-products and waste will become an environmental burden if not properly managed. Conversely, when collected and treated by suitable technologies, by-products once regarded as waste can be transformed into valuable inputs for new production cycles, creating additional value across value chains.

Many agricultural by-products have already been successfully reused. Cassava pulp is used as livestock feed or raw materials for bioproducts; cow manure is utilized for vermiculture; rice straw is processed into organic fertilizer or mushroom-growing substrate; and seafood shells are converted into raw materials for the biotechnology industry. Fruit peels, crop stalks and leaves, and other organic by-products can be composted into fertilizers or blended into feed for livestock.

Another approach is the use of livestock manure and organic by-products to rear black soldier flies. The larvae can be used as animal feed, while the remaining material is applied as organic fertilizer. As a result, nutrients are recycled within an almost closed-loop production cycle.

Viet Nam generates more than 40 million tons of rice straw each year. If burned directly in the fields, this biomass contributes to environmental pollution and greenhouse gas emissions. However, when collected and composted with microbial inoculants, rice straw can be converted into livestock feed, organic fertilizer, mushroom-growing substrate, or raw materials for a range of other industries.

According to Dr. Pham Viet Thuan, Director of the Institute of Resources Economics and Environment, the adoption of a circular economy has significantly increased the market value of rice straw for mushroom growing, from around VND 57,000/30 kg to VND 107,000/30 kg. "This demonstrates that the value of agriculture lies not only in its primary products but also in the ability to fully utilize all materials generated throughout the production process. When organized into value chains, agricultural by-products can create additional income for farmers, lower environmental treatment costs, and reduce dependence on external production inputs," Dr. Thuan said.

According to MSc. Ngo Xuan Chinh, Director of the Center for Agricultural Technology Research and Transfer under the Institute of Agricultural Science for Southern Viet Nam, the productivity of many of Viet Nam's key crops, including rice, coffee, and pepper, has already reached high levels. Achieving even a 1% increase in yield now requires producers to invest substantially more in fertilizers, pesticides, and labor. Meanwhile, post-harvest losses remain at 15–20%. This has created a paradox: the agricultural sector continues to consume increasing amounts of resources to raise output, yet a significant share of value is still lost during harvesting, storage, and processing.

According to Mr. Chinh, rather than continuing to push agricultural land to its limits in pursuit of higher yields, the sector should focus on reducing post-harvest losses, improving storage capacity, expanding deep processing, and fully utilizing agricultural by-products. These measures would unlock new opportunities for sustainable growth in the years ahead.

Building a circular economic chain

Despite their enormous potential, bringing agricultural by-products back into production continues to face legal, technological, and market barriers. According to Mr. Nguyen Chi Cong, Chairman of the Dong Nai Livestock Association, the province supplies around 15,000 pigs to the market each day, along with large volumes of poultry, fruits, and other agricultural products. This level of production also generates a substantial amount of by-products.

Durian peels, jackfruit rinds, mango peels, and other fruit residues can be processed into low-cost cow feed. However, when businesses or livestock producers seek to collect and treat these materials, they may be classified as waste, triggering environmental licensing requirements for waste treatment.

According to Mr. Cong, this is a major bottleneck that needs to be addressed. The legal framework should clearly distinguish between by-products that can be reused and waste that must be treated. If all such materials are managed as waste, businesses will have little incentive to invest in their collection, processing, and reuse.

With a clear legal framework, agricultural by-products could become not only a low-cost source of animal feed but also contribute to reducing methane emissions from livestock production when incorporated into properly formulated feed rations. Biogas generated from livestock manure can be collected for energy production, while the digestate can be used for crop production.

Prof. Khang noted that the essence of a circular economy lies in recycling nutrients and extending the life cycle of raw materials. However, each model must be carefully calculated in terms of technology, costs, and product output. "The utilization of agricultural by-products can only be truly sustainable when it delivers both environmental benefits and economic efficiency," Prof. Khang said, emphasizing that science and technology play a decisive role in this process.

To turn agricultural by-products into resources at scale, Prof. Khang stressed the need for close collaboration among scientists, management agencies, businesses, and farmers. Research should be driven by practical needs, targeted toward specific applications, and closely linked to commercialization.

He also called for the completion of standards and technical regulations on circular production, emission reduction, and by-product utilization; the development of demonstration models that allow farmers to observe, learn, and master technical processes; and strong application of digital tools for nutrient management, carbon inventory, and data traceability.

"For the circular economy to become an integral part of agricultural production, research alone is not enough. Technologies must be transferred, farmers must receive proper training, and businesses must see economic efficiency. Only then will agricultural by-products truly become resources," Prof. Khang emphasized.

$1 = VND 26,490 - Source: Vietcombank.