Mungbean in rice systems

Date released

19 February 2024

World Pulses Day, on 10 February 2024, was declared by the United Nations General Assembly to highlight the importance of pulse crops, such as chickpeas, dry beans, lentils and mungbean, as a global food.

ACIAR has a long history of supporting research on pulse production in the Indo-Pacific region, and mungbean in particular. It has supported research into mungbean, which is an important crop in South and South-East Asia.

ACIAR Research Program Manager, Crops, Dr Eric Huttner said despite its value, mungbean has often received less research attention than other pulses.

Since 2016, ACIAR has supported the International Mungbean Improvement Network, led by the international agricultural research centre, WorldVeg. The aim of the network is to unlock the potential of mungbean to improve system productivity and livelihoods (CIM/2014/079 and CROP/2019/144).

‘The crop itself is quite valuable,’ said Dr Huttner. ‘It has a short duration, it has a good market value and has good nutritional content. When it fits into a cropping system well, there are good prospects for economic returns.’

Because of its short growing season, mungbean commonly fits well in rotation with rice. Integrating it into a rice cropping system has been the focus of 2 ACIAR-supported projects in Timor-Leste and Cambodia.

Mungbean in Timor-Leste

The work to improve mungbean productivity in Timor-Leste began in 2000 through the Seeds of Life program. This major initiative of the Timor-Leste Ministry of Agriculture and Fisheries was supported by ACIAR, and backed by the Timorese and Australian governments. It aimed to improve the crop varieties available to farmers in Timor-Leste, including grains, vegetables and pulses.

Through Seeds of Life, two mungbean varieties were released for production in Timor-Leste in 2016: a dull seed coat variety from Indonesia and a shiny seed coat variety from Australia. Both varieties had a shorter season and were higher yielding than the traditional varieties.

Following on from Seeds of Life, the ACIAR-supported ‘Agricultural innovations for communities’ project launched in 2016, looked at ways to help smallholder farmers make the most of new crop varieties, including mungbean, to sustainably intensify their farming.

Mr Robert Williams, Technical Director of the project, now in its second phase (CROP/2021/131), said a key feature of new mungbean varieties is their shorter growing period. They take just over 2 months to mature rather than the 3 to 4 months of previously used varieties, and better fit the timing between rice crops.

Other features include a shorter crop height, ensuring plants do not fall over as often and are easier to harvest, and higher yield production.

From variety selection, the new research focused on improving agronomy and farm practices to encourage more farmers to grow mungbean.

Hand holding a crop mungbean — Mungbean crops in Timor-Leste are usually planted and harvested by hand. Photo: ACIAR

Reducing farm labour needs

Mr Williams said there was a particular focus on reducing labour requirements.

‘In Timor-Leste, everything is very manual. You plant by hand, you weed by hand, you harvest by hand, so reducing workload was attractive to farmers,’ said Mr Williams.

‘But we observed that it took 40 people one day to plant a hectare of mungbean because of the close spacing (20 x 20 cm). It was a lot of manual work stabbing the soil and planting seeds.’

In addition to the significant effort of planting, Mr Williams said it became clear that the amount of weeding required is really what made mungbean too laborious to be attractive.

However, after some trial and error and working closely with local farmers, a low-labour program came to light.

‘While we were testing with farmers, a woman named Juliana suggested that after harvesting rice, you do a herbicide spray, and then broadcast your mungbean into the soil and then you barely have to touch it until harvest.’

Testing with farmers verified this as the best low-labour approach. There was residual moisture in the soil from the rice, available for the mungbean. By broadcasting the seed, the soil was not disturbed, and the labour required was minimal; by spraying weeds, only minimal in-season weeding was required. The remaining rice straw also acted as a mulch.

The Timor-Leste Government has supported the new approach with a subsidy on herbicides and by buying the mungbean when it is harvested.

This has helped to accelerate the adoption of new mungbean varieties. The price of mungbean almost doubled over a 12-month period during the COVID-19 pandemic, which also increased the level of adoption.

The key to the success of the ACIAR-supported projects in Timor-Leste has been testing with farmers and listening to their observations of what is and isn’t working.

Mr Robert Williams,
Technical Director of the Agricultural Innovations for Communities

Mungbean in Cambodia

In Cambodia, ACIAR-supported research (CSE/2015/044) on intensifying production from lowland rice systems has included diversification with crops such as mungbean.

Project leader Professor Daniel Tan, from The University of Sydney, said that mungbean was a good candidate for diversification from rice in the Cambodian context.

‘Rice can be a poverty trap for smallholder farmers, as they do not usually make a large profit. We found that farmers who were doing well were growing rice on the side of other businesses,’ said Professor Tan.

Diversification options explored included watermelon, fish and fingerling production, and mungbean.

‘Mungbean was a good option with rice. It leaves residual nitrogen in the soil and creates a disease break for the rice, resulting in a higher yielding rice crop following on from mungbean,’ said Professor Tan.

In discussions with farmers, they highlighted the need for mungbean varieties with pods that would not shatter when mechanically harvested. They also wanted a variety that met the expectations of Cambodian consumers: large, green and shiny.

Of 22 varieties evaluated against these criteria, the Australian varieties Delta and Emerald were the recommended choices. These varieties met the qualities required by the market and can be harvested via an initial handpick and then a machine harvest in the second round.

Filed of mungbean crop rows — Twenty-two varieties of mungbean were evaluated for Cambodia and 2 Australian varieties were recommended. Photo: The University of Sydney

Beyond varieties

The project also provided training and better access to information for farmers, with 2 mobile apps developed: one to identify weeds and one to identify pests in mungbean crops.

This has helped farmers to make use of beneficial insects in managing crop pests and reduce their pesticide use.

These apps are free to download for iOS and Android, are available in English and Khmer, and also contain spoken voiceover for improved accessibility for those unable to read.

The project also explored options for improving the source of rhizobium, the bacteria that allow pulses to fix nitrogen to the soil, by trialling rhizobium imported from Thailand. It also explored the use of drones for spraying pesticides to reduce farmer exposure to toxicity.

‘One of the most successful outcomes of the project was how the farmers have picked what they took away from our research. They built their own businesses from it to serve other farmers and the results are becoming self-sustaining, essentially carrying on the work of the project even when it is over,’ said Professor Tan.

Mungbean Congress

In supporting the development of mungbean cropping, ACIAR is sponsoring the International Mungbean Congress in Bangkok, Thailand on 5 to 7 March 2024.

The findings of ACIAR-supported research will be presented at the event, along with projects being undertaken by mungbean researchers who have developed their expertise through participation in ACIAR projects.

ACIAR Projects: ‘Intensified and Diverse Farming Systems for Timor-Leste (AI-Com 2)’ (CROP/2021/131); ‘Sustainable intensification and diversification in the lowland rice system in Northwest Cambodia’ (CSE/2015/044);'International Mungbean Improvement Network 2' (CROP/2019/144)