The weed-smart rice system changing livelihoods

There is a stark difference between these two rice fields at the village of Khanthajan in Laos.

On one side of the farmer the plants are barely knee-high, patchy and overrun by yellowing weeds, while the other is taller, bright green and healthy.

The lush green plants are a trial patch for a University of Queensland-led project that has significantly improved yields and profits while reducing weeds and herbicide use. 

The project, which has been running for 5 years on smallholder farms in Cambodia and Laos, has been recognised by the Laos government with a national honour and extended for a further year. 

Professor Jaquie Mitchell from UQ’s School of Agriculture and Food Sustainability, along with Dr Gomathy Palaniappan, Dr Jhoana Opena and Professor Ammar Abdul Aziz, has been a driving force of the project funded by the Australian Centre for International Agricultural Research (ACIAR) and implemented with the National Agriculture and Forestry Research Institute, Lao PDR.  

Facing up to weeds

Professor Mitchell said farmers who had changed from transplanting rice seedlings to using direct-seeded rice (DSR) to save time and labour suddenly found they were dealing with increased weed infestations in their fields.

“More weeds meant less rice, harvests contaminated with weed seeds, and the situation was pushing farmers to increase their herbicide use,” Professor Mitchell said.

“Our goal was to co-design and implement practical, weed-smart DSR packages that worked for farmers, and build national capacity in integrated weed management so these solutions could keep evolving long after the project ends.

“Our international team tested different combinations of practices on 57 farms, which ultimately led to big changes.” 

• In the rainfed lowlands of Laos, intercropping rice and mung beans reduced weed pressure and weed seed banks, increased rice yield by around 30 per cent and boosted profits by approximately 150 per cent compared with farmers’ usual practice.
• In irrigated areas of Laos, certified seed and early flooding halved the volume of weeds, reduced the weed seed bank by nearly a third and delivered up to 30 per cent higher yield and 55 per cent higher profits.
• In Cambodia, good land preparation, drill- or drum-seeded certified seed, early flooding and, where appropriate, well-timed herbicides reduced weeds by around 50 per cent and increased profits by 40–120 per cent.

Benefits beyond farms

Away from the fields, the project has had significant impact on communities as well as agricultural education.

Weed management has been included in undergraduate courses at Cambodia’s Royal University of Agriculture and new scientific and technological tools are being generated as Laos and Cambodia lead weed-smart, climate-resilient rice systems.

“Capacity building was a core pillar of the project,” Professor Mitchell said.

“More than 400 people participated in field days, demonstrations and discussions so they could take the ideas and practices home to try.

“Agriculture officers – both men and women – were trained in weed identification and the principles of integrated weed management, so they can effectively advise and support farmers in key rice-growing regions.” 

Gender considerations were embedded in all co-design and training activities, as women in Laos and Cambodia play a central role in rice growing, weeding and post-harvest activities. 

“Changes to farm practice helped reduce the drudgery and time burden of weed control which women told us meant they had time to redirect to other farm tasks or to family and off-farm work,” Professor Mitchell said.

“So, as well as the sustainable farming goals, the project has supported more flexible livelihood choices and more diverse household incomes.”

Building on success

The project has been extended to run to the end of 2026, and the UQ project team was invited along with more than 100 collaborators to accept a Friendship Medal from the Lao People’s Democratic Republic at an event celebrating 35 years of ACIAR involvement with the country. 

Professor Mitchell said the honour draws attention to the outcomes so far and the extension will help the team continue to support Laos with its clean and green agricultural goals. 

“Over the next 12‑months we will extend the proven weed‑smart DSR packages to other communities enabling more farmers to adopt these sustainable and profitable practices,” she said. 

“We will deliver targeted training on safe and effective herbicide use to ensure women and men benefit equally from improved weed management. 

“And there’ll be more opportunities to share the project’s findings with government and other stakeholders to aid the development of herbicide regulation and drone spraying standards.”

Collaboration and acknowledgements