Bio solutions enhance efficiency in shrimp–rice extensive farming

Turning rice straw into nutrients

U Minh Thuong is a key area for rotational farming of one shrimp crop and one rice crop (shrimp-rice) in An Giang Province. In particular, Vinh Hoa Commune, with more than 4,600 hectares under shrimp-rice cultivation, has become the primary livelihood for thousands of households. However, farmers often face difficulties in collecting and treating rice straw after harvest before starting a new shrimp farming cycle. This step is critical but, without appropriate solutions, time-consuming and costly.

Traditionally, rice straw has been either burned directly in the field or soaked in water and then discharged into the environment. While these methods are quick, they cause significant negative impacts. Straw, when soaked under anaerobic conditions, turns the water black and foul-smelling due to the accumulation of organic compounds and toxic gases. When discharged into canals, this water reduces dissolved oxygen levels, causing environmental shocks and potentially mass mortality of aquatic species. In addition, burning straw contributes to air pollution, affects public health, and wastes valuable organic matter that could otherwise enrich the soil.

In response, the An Giang Agricultural Extension Center, in collaboration with TMH Environmental and Services Co., Ltd., has implemented a model using the R3 biological product to treat rice straw directly in the field. This approach does not eliminate organic matter; instead, it promotes controlled decomposition, retaining nutrients while minimizing the release of toxic gases.

The model was piloted on a 3-hectare farm owned by Le Trung Kien in Can Ngon A Hamlet, Vinh Hoa Commune. According to Tran Ha Quang Du, a technical officer from the Aquaculture Extension Division, after harvesting rice, farmers pump water into the fields, apply the R3 biological product, and combine it with lime and dolomite to stabilize pH levels while monitoring environmental parameters. The process is carefully guided to ensure farmers can adopt it easily and effectively.

After just two to three weeks, the water in the fields turns tea-colored, free of foul odors, and key parameters such as pH and alkalinity remain within safe ranges for shrimp growth. More importantly, the process eliminates the need for repeated soaking and drainage, reducing pumping costs, saving labor, and minimizing environmental impacts. As a result, pond preparation time is shortened, allowing farmers greater flexibility in scheduling their production cycles.

Increasing ecological value

Beyond improving environmental conditions, the application of biological products also generates abundant natural feed for shrimp. As rice straw decomposes, microbial communities flourish, forming organic detritus, algae, and plankton that serve as natural nutrient sources, enhancing shrimp growth. This significantly reduces reliance on industrial feed during farming.

Le Trung Kien, the farmer directly involved in the model, noted that thanks to microbial treatment, shrimp post-larvae can be stocked immediately after the first water intake, significantly shortening preparation time. During cultivation, shrimp grow uniformly, survival rates remain high, and feed conversion ratios are low, demonstrating improved feed efficiency compared to traditional methods. This is a key factor in boosting the model's economic performance.

The model follows a polyculture approach, combining brackish water shrimp with mud crab farming on the same area. After 55 days of stocking, Kien harvested 920 kilograms of shrimp, averaging 92 shrimp per kilogram, sold at VND 96,000 per kilogram, generating total revenue of more than VND 88 million. After deducting costs, the initial profit exceeded VND 26 million.

However, this represents only the early-stage economic return of the farming cycle. The remaining three months will allow additional harvests and generate income from integrated crab farming, promising significantly higher overall returns. Diversifying crop species helps reduce risks and maximize resource use within the field ecosystem.

Nguyen Thi Minh, Director of TMH Environmental and Services Co., Ltd., explained that the R3 product contains beneficial microorganisms that accelerate the decomposition of rice straw directly in the field. Compared to traditional methods, this biological approach not only reduces labor but also retains nutrients in the soil, creating a favorable ecological foundation for the development of shrimp and crabs. It also aligns with current trends in green agriculture and circular economy practices.

In the context of increasingly complex climate change, utilizing agricultural by-products through biological solutions is becoming an inevitable direction. This approach not only addresses environmental challenges but also enhances value per unit area, helping shrimp–rice farming in U Minh Thuong evolve toward a greener, more sustainable model that is better adapted to natural conditions. If widely replicated, this model could become a benchmark solution for similar production systems across the Mekong Delta.

$1 = VND 26,358 - Source: Vietcombank.