Turning by-products into resources: Green path of agriculture

During harvest season in the Red River Delta, smoke from burning straw no longer blankets the dikes as it did a few years ago. Instead, collection trucks line up to transport the straw to organic fertilizer factories in Ninh Binh, Hung Yen, Hai Phong, or to dairy farms.

In the Mekong Delta, rice husks and sugarcane bagasse are compressed into bio-pellets for export to Japan. Decades ago, these materials were considered agricultural waste, but today they have become a new resource for circular agriculture.

The concept of circularity is not unfamiliar to Vietnamese farmers. In the past, agricultural by-products were commonly used as fuel, animal feed, or returned to the fields as fertilizer. But in the low-emission era, circular agriculture has reached a new level: a closed-loop production model that wastes no resources and imposes no burden on the environment.

This has become increasingly urgent as Vietnam’s agriculture generates hundreds of millions of tons of by-products each year, according to the Ministry of Agriculture and Environment. Crop production alone produces about 160 million tons of by-products: straw, corn stalks, coffee husks, sugarcane bagasse, cashew shells, livestock manure, etc., equivalent to 20% of the country’s total methane emissions.

In recent years, these by-products and agricultural wastes have become “gold” when repurposed as organic fertilizers, bio-materials, renewable fuels, and raw materials for processing industries. In Ninh Binh, several post-harvest straw collection models implemented by the provincial Extension Center have reduced open-field burning by 80%, generating 1.5-2 million VND per hectare from selling straw.

The benefits have multiplied with a model implemented from mid-2024 by the International Rice Research Institute (IRRI) in collaboration with Nam Cuong Agricultural Production, Business, and Services Cooperative (Ninh Binh). Farmers are trained to process straw into organic fertilizer using a mixture of 60% straw, 30% cow manure, and 10% soil, sprayed with microbial inoculants, and composted for about 45 days at 50–60% moisture and 50-70°C temperature.

Using self-propelled mixers with a capacity of 138-300 m³ per batch, the composting time is reduced by half compared to traditional methods. Properly composted material achieves a C/N ratio of about 13-14.5 and a pH of 6.8–7.2, after which it can be pelletized or packaged for direct use in the fields.

Such by-product utilization methods are increasingly widespread. In Soc Trang, the “three-benefit” model, which has no straw burning, organic fertilizer production, and rotational vegetable cultivation, reduces emissions by more than 5 tons of CO2 per hectare. In Dak Lak, coffee cooperatives invest in systems to compost coffee husks and pulp into bio-fertilizer, saving costs while improving soil quality. These closed-loop systems are spreading across cropping areas, from lowlands to midlands, and from rice to industrial crops.

According to the Plant Production and Protection Department, if 50% of agricultural by-products are efficiently processed and reused, Vietnam could reduce about 40 million tons of CO2 annually. This is one of the key measures to achieve the Net Zero 2050 commitment. The Ministry of Agriculture and Environment has incorporated circular agriculture into its green growth strategy, aiming to have, by 2030, at least 30% of agricultural by-products collected and recycled, with 20% used for organic fertilizer and 10% for biofuel.

In practice, many localities have demonstrated that this is feasible. In Dong Nai, Vinamilk and TH True Milk dairy farms apply the “from pasture to milk” model. Grass is grown using organic fertilizer composted from cow waste; liquid waste is treated into biogas, and the remaining solids are used as fertilizer for crops. This model saves 25% of input costs while reducing methane emissions.

In Bac Ninh, several cooperatives utilize livestock by-products combined with fruit cultivation, forming a “3F Circular” chain (Feed – Farm – Fruit). In An Giang and Tay Ninh, the program “No Straw Burning - Keep the Air Clean” has been widely embraced by farmers who realize that burning straw is both wasteful and harmful to their own health.

More important than the numbers is the change in mindset. Farmers no longer see by-products as waste but as an extension of the harvest. When straw is collected to produce fertilizer, people say, “the field lives another cycle.” When coffee husks and sugarcane bagasse become industrial raw materials, people say, “the soil has learned to regenerate.” In each of these closed-loop processes, there is not only economic benefit but also an ethical dimension of farming returning to the land what has been taken.

To promote this process, research institutes are developing rapid composting technologies, microbial fermentation, and biofertilizer production from by-products. The Institute of Agricultural Environment is collaborating with JICA and FAO to test a process for producing biochar from straw, which improves soil moisture retention and nutrient absorption. The Ministry of Agriculture and Environment also encourages the establishment of “agricultural by-product processing clusters” in specialized crop regions, where businesses, cooperatives, and farmers participate together. The goal is not only to reduce emissions but also to create new industries and rural jobs.

Challenges remain, particularly in collection and investment in processing infrastructure. Crop by-products are often dispersed, bulky, low-value, and difficult to transport over long distances. Incentive mechanisms such as carbon credits, tax benefits for biomass processing enterprises, and technical guidance for farmers are needed. Early successes indicate that this approach is highly promising.

From the fields to the factories, from straw to bio-pellets, the journey of turning by-products into resources continues to write the story of sustainable agriculture in Vietnam. It is also a way for people to reshape their relationship with nature - respecting, regenerating, and coexisting with it. After 80 years, the crop production and plant protection sector has not only learned how to create wealth but also how to safeguard the health of the soil, the plants, and the environment.

* Currency exchange: 1$ = 26.083 VND (source: Vietcombank)