Trial results showed a 12 per cent increase in grain yield compared to farmers’ traditional practices.

String Bio, a technology company building sustainable, low-carbon solutions for global agriculture, has successfully completed its first field trials in Vietnam in collaboration with the Cuu Long Delta Rice Research Institute (CLRRI), located in the heart of the Mekong Delta.

The trial focused on CleanRise®, String Bio’s patented foliar microbial biostimulant, which enhances nutrient-use efficiency and stimulates systemic plant responses to boost productive tillering and reduce grain sterility. In prior Indian studies, CleanRise has demonstrated reductions of up to 50 per cent in methane and nitrous oxide emissions. It is compatible with a wide range of cultivation systems including AWD (Alternate Wetting and Drying), TPR (Transplanted Rice), DSR (Direct-Seeded Rice), and Single Drainage systems.

During the Summer-Autumn 2025 season, the CLRRI team tested CleanRise on paddy fields under four treatment scenarios involving two nitrogen levels (100 per cent and 75 per cent of standard N dose), both with and without CleanRise. Results showed:

A 12 per cent increase in grain yield compared to farmers’ traditional practices.

Use of CleanRise with a 25 per cent reduction in nitrogen fertilizer produced yields comparable to full nitrogen application, confirming improved nitrogen-use efficiency.

Up to 30–40 per cent lower greenhouse gas emissions, as measured through in-field instrumentation.

Enhanced grain quality, particularly reduced sterility and improved grain fullness, contributing to market value.

Dr. Thach and Dr. Cuong from CLRRI highlighted, “CleanRise is compatibile with existing cultivation techniques and aligns with Vietnam’s national “One Million Hectare Low-Carbon Rice Program.” Its ease of use and infrastructure-free adoption position it as a promising tool for scale-out across diverse rice farming landscapes in Vietnam.”

Dr. Ezhil Subbian, CEO from String remarked, “The validation data from CLRRI extends the consistent performance, scaling and benefits of CleanRise witnessed with rice farmers across India. To have studies completed with Dr.Cuong’s lab at CLRRI in the Mekong delta provides a high level of confidence for us to bring CleanRise, a first-of-a-kind solution, to the rice farmers of Vietnam.”

Dr. Tran Ngoc Thach, Director General of CLRRI, recommends conducting additional multi-season and multi-location trials to confirm and strengthen the evidence for the product’s performance.

String Bio is currently expanding partnerships to further validate and deploy CleanRise, supporting Vietnam’s climate resilience goals and efforts to improve smallholder farmer livelihoods.