Vietnam: Reducing soil erosion

Paraquat and no-till methods are minimizing soil erosion and increasing productivity for corn farmers in Northern Vietnam. Corn (maize) is an important crop for the Vietnamese - especially for those living in the hilly northwest region.  180,000 hectares (ha) of corn are grown on hillside fields during the rainy season.

Traditional but time-consuming “slash and burn” farming practices limit crops to one per year and often result in low yields and high soil erosion.

Paraquat applied pre-planting and inter-row reduced soil erosion by 34% and shortened growing time by more than 20 days per season*. This represents a savings of VND **750,000 per ha in manpower costs compared to manual hand-weeding methods.

Erosion is influenced by several factors including gradient, rainfall, surface residue, soil texture, and tillage method. Using traditional tillage methods, the exposed soil surface becomes compacted, increasing rainfall run-off and reducing corn rooting depth.  No-till systems were developed to prevent soil erosion, improve soil fertility, and reduce labor and fuel costs. Paraquat’s contact-only action allows farmers to control weeds without killing the weed root structure, limiting run-off of rain water and soil, and making it an ideal herbicide for use in no-till systems.  In addition, paraquat’s rapid action and unmatched rainfastness enable farmers to plant corn immediately after application, even during the rainy season.

Paraquat used in a no-tillage system offers a wide range of social, economic and environmental benefits to the farmers of Northern Vietnam.  The study’s success has prompted the expansion of field demonstrations to additional provinces together with product stewardship activities to ensure safe use of the product.

Cost-Benefits of Paraquat and No-till

Conventional Method Paraquat and No-till
VND** 1000 Item VND** 1000
Cost for weed slashing before planting     675 Cost of paraquat     450
Cost for hand weeding after 30 days     475 Cost of application     240
Total cost 1,125 Total cost     690
Yield harvested 5,040 Yield harvested 5,400
Benefit gained 3,915 Benefit gained 4,710


** Currency: Vietnam Dong
*As reported at the 20th Asian-Pacific Weed Science Society Conference

“As well as reducing soil erosion and increasing soil fertility, our study showed that paraquat provided excellent weed control, resulting in increased crop yields,” said Mr. Tuan – Deputy Director of Northern Mountainous Agricultural Research Center.

“Time saved by using paraquat makes it possible for these farmers to plant a second crop such as soybean or rice” explains Dr. Nguyen Truong Thanh – Head of Pesticide, Weed and Environment Division of The National Plant Protection Institute.

Ms Pham Thi Rang, a farmer in Minh Bao village, Yen Bai province, said, “This method saved a lot of manpower compared to hand weeding; less hard work in cultivation; reduced soil erosion; increased maize yield. So we expected this method should be widely promoted for farmers to apply.”

Mr. Tran Van Vinh, another farmer in Yen Bai says: “I like this product and method because of no hand weeding; reduce hard work; and less erosion.”

“In the past before planting maize we had to splash weeds, waiting for dry then burning…much manpower and time spent in land preparation. Now we needed only manpower to spray the product that was easy…. Weeding cost was only half of that in the traditional method. We estimated benefit gained was about VND 400,000 – 500,000 per hectare. We suggested that company should supply this product to our area as soon as possible for farmer to apply in the new method,” said Mr. Phung Sinh Hoi, a farmer in Hoa Binh province.