In agricultural entrepreneur Trang Tran’s native Vietnam, farmers traditionally burn the straw and husks that remain after the rice harvest. This practice happens at least twice a year for two months at a time, releasing noxious smoke and greenhouse gases into the atmosphere. Tran’s solution: using rice straw to cultivate mushrooms. Her social enterprise Fargreen is standardizing the process and teaching farmers how to recycle their own agricultural waste and improve their livelihoods. We asked Tran to tell us about how the idea evolved.
How did you become interested in the burning of rice straw as an environmental problem? Did you come from a farming community?
I’m from a little province called Hà Nam, two hours south of Hanoi, the capital city. My parents are not farmers, but Vietnam is an agricultural country, so everyone is surrounded by rice farms. Even if you live in Hanoi, the nearest farm is only a half an hour away.
Rice straw burning is something that happens every harvest season, and it happens all around us. It’s been done for many years, and it’s considered the most convenient way of getting rid of waste. Straw is perceived as having no value — farmers just want to get it out of the way as soon as possible in order to prepare for the next crop. In Vietnam, 20 to 50 million tons of rice straw are burned annually, releasing greenhouse gases into the atmosphere. Obviously this contributes to climate change, but the more immediate problem is that local people inhale the matter, causing serious health problems in communities — particularly in babies. Poor communities are most affected, and of course they have the least money for health care.
When rice straw is being burned, it’s very smoggy, and it’s hard to breathe. It also blocks visibility. A lot of car accidents happen during harvest season. It’s crazy — whenever I have to travel from my home to Hanoi for work, or come home during harvest season, rice straw is being burned along both sides of the road and it is very dangerous for drivers.
Why is straw burned on roads? Why not just on the field?
The part of the rice plant left in the ground after the harvest is burnt right on the field. But the part left over after threshing is piled by the side of the road. There isn’t much space to store the agricultural waste once it’s been threshed, especially in Northern Vietnam, and roadsides are typically far enough away from houses that the straw can be safely burned. Some people also believe burning straw on the field helps the soil, but it’s actually really damaging because the soil gets drier and drier, and it just gets harder to farm it every year. The straw can’t just be buried because there is too much of it; composting rice straw requires a special technique and takes time. There’s a real need for the farmers to clear the field for the next round of rice cultivation — we plant two crops in Northern Vietnam and three in Southern Vietnam.
How did you come up with the idea to use rice straw to grow mushrooms?
My background is in international development. When I went to get my MBA in Colorado State, I kept thinking about this problem of rice straw waste back home. I had always seen this as an environmental problem, but getting my MBA gave me a way to see the problem differently and find a new way to approach it. My friend Thuy Dao, who was a fellow undergraduate back in Vietnam but in the biotechnology department, shared my fascination. Once I joked with her, “Oh, maybe someday we’ll work together on this problem.” Later, when I was talking to people to find a collaborator, her name popped into my head. So I contacted her and we started doing research.
Of course, we were not the first to tackle this problem. We looked into the various ways other researchers have considered to deal with rice straw. But because we grew up in the community as well as working in development, we could see from the local perspective that the problem is far more complex than just the act of burning. You have to ask, “What is the motivation for farmers? What’s in it for them not to burn?” If there’s nothing in it for them, and burning saves time so they can prepare for their next crop, then you can’t blame them for wanting to continue.
So we tried to think a bit differently — what can we offer the farmers that would make it worth it for them not to burn? In between rice seasons, most of the farmers we work with — many of them women — have to travel to the city to find employment. They don’t have skills to compete in the job market, so all they can get in cities are low-level jobs — picking up trash for recycling and so on. If they can stay on their land and cultivate a profitable crop between rice seasons, it would alleviate a lot of hardship.
One day, we discovered in our research that rice straw can be used to grow mushrooms. We saw that it wasn’t very complex, so we bought some spawn, collected some straw to the back of the house and grew a crop.
What were the varieties of mushrooms that you grew?
We grew paddy straw, oysters and white button. Our first harvest was only a few kilograms, but they were so good! At first we hadn’t even realized that the used straw could then be recycled back to the field. But we saw that the straw had turned into really good compost, because the fungi had helped break it down. Nearby farmers said, “Well, if you want to get rid of it, we’d love to get that to the field for you.” We said OK. We also started to experiment with planting potatoes with the used straw — you put the potatoes in soil, and layer the straw over it to provide more nutrients. We got a really good crop.
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