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.