Professor Le Huy Ham, director general of the Agricultural Genetics Institute in Ha Noi, talks about the potential of cassava, Viet Nam's third most important export crop throughout the last decade.
What is going on with cassava in Viet Nam?
|Professor Le Huy Ham. — Photo hanoimoi
In Viet Nam in recent years, cassava (Manihot esculenta Crantz) is in growing demand as an industrial and food crop. The export value of cassava is about US$1.3-1.5 billion annually, making cassava Viet Nam's third largest export crop, after rice and coffee.
Thanks to its wide adaptability, cassava can be grown across all ecological regions in Viet Nam, even in areas where soil is poor and few other crops grow, contributing significantly to improved income for poor farmers. Cassava production has changed dramatically. Between 1975 and 2000, cassava yields ranged from 6 to 8 tonnes per ha, and the crop was grown mainly as food and animal feed.
Then, in collaboration with the International Centre for Tropical Agriculture (CIAT) – one of five CGIAR Centres for research based in Viet Nam – and national partners in Viet Nam and Thailand, scientists introduced new high-yield breeding lines in 1988.
Between 2000 and 2014, the area under cassava cultivation has doubled from 237,600 to 560,000 ha. Export volumes suggest this number might even be higher. Productivity more than doubled, increasing from 6 to 8 tonnes per ha to 19 tonnes per ha in 2015.
Why are we talking about cassava so much at the moment?
Around 200 million poor farmers in developing countries around the world rely on root and tuber crops (RTCs) for food security and income. These crops – such as cassava, potatoes, sweet potatoes and yams – are excellent sources of energy, and some are rich in vitamins and minerals.
In Viet Nam, cassava is the most important of these for a number of reasons. Farmers cultivate cassava on their small plots of land because they do not have to spend a lot of time looking after it. It can grow in marginal upland conditions and tolerates stress, drought, heat and poor soil, which is especially important as farmers adapt to the impacts of climate change. Farmers can grow cassava alongside other crops to spread their risk, and because the market is diverse, it can bring improved incomes to put food on the table when other crops might not survive.
In today's fast-changing world, rapid economic growth must be balanced with environmental sustainability. Add to this the challenge of climate change – more extreme, more variable weather events – and population increases. Our challenge is to produce more food with fewer resources. Roots and tubers like cassava are relatively well-placed to deal with these challenges – if they are managed properly.
Viet Nam recently hosted a start-up meeting for a new Southeast Asia Cassava Breeders Network, which will work on some future challenges such a capacity building, germplasm exchange and bridging yield gaps. CIAT has facilitated germplasm exchanges in the region for more than 30 years, resulting in numerous new varieties.
How about the concerns about soil erosion caused by planting cassava? What are your solutions for this?
Cassava is relevant to Viet Nam's Ministry of Agriculture and Rural Development's new policy agenda for rural development, which targets poorer regions and marginal areas. However, there are concerns that cassava exacerbates soil erosion and could be costly for the environment.
|Processing cassava for starch. The hardy root crop cassava is among important staples for food security and income in Southeast Asia, but neglected in terms of investment for scientific research. — Pic by: Georgina Smith / CIAT
This is partly because cassava is often grown on sloping land or in poor soil, where few other crops will grow. Cassavas are large and the plants need to be planted far enough apart to get higher root yields. During the two – to three-month period before cassava leaves grow enough to close the crop canopy, the soil between the plants is left exposed to direct rainfall, which in turn results in soil runoff and loss.
It is therefore important that farmers protect the soil surface from the direct impact of rain, and slow runoff and soil loss. Intercropping cassava with fast ground-covering, short-term crops like peanuts protects the soil's surface, diversifies income and controls weeds. It also improves the soil. Mulching with crop residues or grass on the soil's surface protects the soil from direct rain's impact, greatly improving water filtration and further reducing erosion.
Planting strips of forage grasses like Paspalum atratum or shrubs like Tephrosia candida along slopes can also act like a barrier, breaking the slope length, forming terraces and preventing soil loss. The forages can also feed animals as part of integrated crop-livestock smallholdings. In Yen Bai Province, CIAT and local communities are currently testing this integrated cassava-forages practice as part of a climate-smart agriculture plan.
As opposed to most other crops, cassava is capable of growing and providing some yield even when soil fertility is low. That is why it is often a preferred crop for poor farmers. It also has no fixed harvest period, so it can be stored in the soil and harvested when other food has run out. But farmers need to be aware that even though cassava can grow in poor soil, the soil still needs to be improved and nutrients need to be replaced.
Results of cassava trials and demonstrations conducted in Tay Ninh, Dak Lak, Phu Yen and Dong Nai provinces have indicated that farmers have successfully improved their practices, and that new technology has boosted cassava yields. Trials show yield increases from 8.5 tonnes per ha to 36 tonnes per ha in some areas – four times more.
Various methodologies and Farmer Participatory Research (FPR) methods have been introduced, building on collaborative experiences to bring advanced technology to millions of poor farmers. This includes the selection of high-yield cassava varieties, and testing and selection of locally appropriate technologies.
Looking outside, how do you view the potential for cassava demand?
Throughout many communities in Southeast Asia, cassava is still eaten as a staple crop – especially in Indonesia, the Philippines and among ethnic minorities in mountainous areas on the mainland where few other crops grow. Starch, root and tuber crops supply an increasingly diverse and lucrative market. Asia is now the world's largest trader of cassava and cassava products.
Global demand for cassava is on the rise, driving a billion-dollar industry. This burgeoning market represents a huge opportunity for poor smallholder farmers to earn more from a crop that requires little investment and can grow in very poor soil.
Yet, the food security agenda in the Asia-Pacific is dominated by grain crops, rice and wheat, despite the fact that cassava – and other root and tuber crops – are a staple food for millions of poor farming households. — VNS