IN THE FIELD: Sand, sand everywhere–but it’s Vietnam, not the Sahara!

Dr Evan Christen, ACIAR’s Research Program Manager for Land and Water Resources, recently travelled to Vietnam to scope for an upcoming project on effectively farming in sandy soils. He explains the process involved in identifying the farmers’ needs and developing the project’s focus...

Dr Evan Christen with Vietnamese farmer, Mr Tuyen

Crops struggle in sandy soils

The Central Coast of Vietnam (around Quy Nhon city) is an interesting area for research, as the greatest problem for developing agriculture and increasing smallholder farmer incomes is the almost-pure sand soil there (90-95% sand). Although this makes for great beaches for tourists, it makes farming difficult, as sandy soils don’t retain water or nutrients, and this results in poor crop yields.

To try and address this, the farmers apply large amounts of cow manure and commercial fertiliser, which costs a lot, doesn’t necessarily lead to high yields, and contaminates the groundwater used for drinking. Farmers also irrigate from this groundwater, but they’re unsure of what techniques to use or how much to apply. This has led to overuse and also salinisation of the groundwater. These problems then threaten the whole agricultural system.

Workshop group brought together to discuss sandy soil research

So, what type of research can Australia support to try to improve the incomes of these smallholder farmers and ensure a sustainable system?

The first step is to talk to the local agriculture researchers and the people whose job it is to manage the groundwater. We held a 1-day workshop at the Agricultural Science Institute for Southern Central Coastal Vietnam (ASISOV) in Quy Nhon to discuss the issues and plan research activities.

The next step is to go out and talk to the farmers. They see the world differently from researchers and government organisations, being at the sharp end of having to deal with all the problems of growing a crop – the weather, pests and disease, credit for fertilisers, labour shortages and the market ups and downs.

Farmer Thai Thi Hanh
(far right)

We first visited Thai Thi Hanh. She has to farm on her own, as her husband has passed away and her two sons are away in the city. She farms 2 hectares of cassava and peanuts and has a well to pump the groundwater, and she irrigates the peanuts once a week until the whole area is flooded. She also has 4 cows, so she uses their manure plus fertiliser on the crops. She doesn’t really know how much fertiliser she applies or why; she just follows the lead of the other farmers and fertiliser seller (on credit). She ends up spending about half of the crop income on fertiliser. 

From this meeting, our perception that the management of irrigation and fertiliser can be much improved is confirmed. We could potentially trial some options on part of her farm, to demonstrate how to irrigate efficiently, and how and when to fertilise.

Farmer Mr Trung,
eggplant and peanut grower

Our next visit was to see Mr Pham Van Trung in Phu Yen. Mr Trung is a farmer growing peanut and eggplant. He had a nice plot of eggplant, and all looked good, but after talking with him we found out he spends at least 1.5hrs every day hand watering his eggplant with a hosepipe, and he also watered his fodder crop from his groundwater well. He applies fertiliser (by watering can) 12 times during the crop’s growth. So there are clearly large amounts of labour involved here; time that could be being spent more productively. This farmer’s case might be suitable for trialling a simple drip system, or possibly sprinklers would be better.

Previous ACIAR-funded research found that the groundwater nitrate level in this area is relatively high, and this is a concern for groundwater used for drinking. Clearly, any research here will need to focus on the most effective combination of watering and fertiliser to protect the groundwater from more contamination, whilst keeping the eggplant coming! 

For Mr Trung, hand watering is both time-consuming and inefficient. More effective methods are being explored.

Women onion farmers with their harvest

We also visited several intensive onion production sites using groundwater. Here, the groundwater is very salty due to the sea being only 1 to 2 km away. One farmer reported that her groundwater bore runs dry after 3 hours pumping in the summer, so clearly things are out of balance: there is not enough rainwater recharging the groundwater, so too much pumping has led to groundwater salinisation and bores running dry. This is not an encouraging situation.

The last visit of the trip was more positive. We went to an area where a development program has recently introduced sprinkler systems to 15 farmers.

One farmer we met (Mr Tuyen, a Cham minority person) had been curious about the program and learnt about sprinklers from the other farmers. He could see the benefits compared to his hand hosepipe watering. He invested $650 (half to 2/3 of his annual income) on a pump and sprinklers for his whole farm. He changed from growing about just half the farm of peanuts to now growing the whole farm with a mix of peanuts, onions, cabbage and fodder for his 2 cows and 4 calves.

Mr Tuyen's calves.
Mr Tuyen is also pictured with Dr Christen top.

Mr Tuyen (pictured top) is a good example of a dynamic young farmer, and  is happy with the results from his investment. This area appears to be an example of successful intensification and diversification of cropping. But there are still research questions about how efficiently the sprinklers are being used and the amounts and types of fertiliser. Also, there is a broader research question: With many farmers upgrading and using more groundwater, will it be sustainable? The overuse and/or pollution of groundwater could be a real risk.

These visits and extensive discussions with researchers in Vietnam and Australia are leading to the development of a new project due to start early next year “Integrated water use, soil and nutrient management for sustainable farming systems in south central coastal Vietnam and Australia”. The project will look at water and fertiliser management and improving the sandy soils. It will also involve studies of the amount of groundwater that can be safely used, and how to prevent the groundwater quality from degrading.

By Dr Evan Christen, ACIAR’s Research Program Manager for Land & Water Resources 

More information:
ACIAR's Research strategy for Vietnam
ACIAR's Soil Management and Crop Nutrition program