Ben Ke is the name of one of the four hamlets in Thuy Dong commune that was formed quite early compared to the history of the Dong Thap Muoi region (established in 1836, according to the Nguyen Dynasty records), located at the edge of the Dong Thap Muoi basin. Since ancient time, this place is a gulf ingrained deeply in the mainland, due to the impact of the marine regression receding from 6,000 years ago, this area was filled with alluvium and sediments of the Tien River and Vam Co Dong and Vam Co Tay Rivers. Since 1975, Ben Ke has been known as the land of yams. The Yam plants of indigenous varieties are incorporated into the local main crop structure by the local people to contribute to diversifying local crops and increasing production. Up to now, the entire Thanh Hoa district has focused on producing yams with more than 2,799 hectares with average productivity of 15 tons/ha, an output of 41,506 tons, an average selling price of 8,000 VND/kg, and the lowest profit of 40 million VND/ha. Yam products are not only distributed within a small local area but also reach out to Europe, Taiwan, China, Japan, and Cambodia,  being the pride of Thanh Hoa. Every year during the yams season from November to July, Thanh Hoa - Long An area  along the National Highway N2 which connects Ho Chi Minh City to the Western provinces and the Highway 62 which connects Tan An city to the Cambodian border through Binh Hiep border gate,  boats full of yams waiting to be transported by traders to localities and factories for consumption can be seen everywhere. 

 

Ben Ke white yam 

  

 

Ben Ke purple yam 

Ben Ke yam is cilyndrical in shape, elongated in shape, with little branching, and have a large tuber weight (1.7 - 2.5 kg/tube with white yams, 0.9 - 1.7 kg/tube with purple yams), the tuber has many accessory roots, the  cross section is viscous and has a lot of mucus starch granules are circular in shape, evenly distributed, with clear boundaries. Ben Ke white yam tubers have water content: 66.2 – 69.6%; starch content: 24.4 – 27.9%; Potassium content: 3.1 – 4.9 mg/100g; Manganese content: 1.9 - 8.4 mg/100g. Ben Ke purple yam tubers have water content: 70.3 – 72.8%; starch content: 17 – 22.2%; Potassium content: 2.1 – 4.9 mg/100g; Manganese content: 1.6 - 10.5 mg/100g. 

Ben Ke yam has such specific properties and quality thanks to the typical natural conditions of the geographical area. The geographical area has a flood season from September to November of the solar calendar. The flood water from upstream along the tributaries and canals has risen and flooded most of the farming areas of some communes in Thanh Hoa district, except for the high mounds. The yearly periodic flood intrusion has brought many significant benefits, including fertile alluvium and mineral deposits that enrich the soil and inhibit the growth of plant pests. In addition, the season of yam production of the people in Ben Ke is also affected by the flood season, which makes it different from other yam production areas. People in Ben Ke will start planting in December, tending the Yam  from December to May, and harvesting from June to August. When the flood season returns in September, the productive land will be left fallow and flooded until the end of the flood season in November. 

The geographical area also has low-lying terrain that is difficult to drain, the terrain tends to be lower in the northeast-southwest direction. Low terrain: altitude < 0.9m accounts for about 95.1% of the natural land area of the whole area. The lowest place has an altitude of <0.6m, accounting for about 5.3% of the area. Due to the low-lying, the soil of the geographical area has  the presence of both alum and humus simultaneously. The soil for growing yam has a mechanical composition of acid sulfate and slightly acidic soil: pH H2O from 3.53 to 3.77, pH KCl from 3.15 to 3.99. Fe content of surface exchange: 0.68%; floor 20 – 40cm: 0.67%; exchange Al content in the surface exchange: 0.78%; floor 20 – 40cm: 0.69%; organic matter content (humus): surface layer 0 – 20cm: 8.37%; floors from 20 to 40cm: 3.57%. H+ ions; Fe3+; Al3+ available in the soil help to fix and balance the amount of P and Mg in the soil to match the low P, and Mg needs of plants. This makes yams not deficient or redundant in important nutrients, which help the plant to have good growth, and fully absorb nutrients, so that, the nutritional composition of Ben Ke yams is maximized, and the Ben Ke yams are rich in starch, low in water content, and rich in minerals. In addition, the high amount of humus in the soil has created a porous structure, overcomes the phenomenon of compaction, the soil retains water, and maintains a stable moisture level. This is completely beneficial for the development of tubers in general and yams in particular. 

In addition to the specific natural conditions, the people of Ben Ke also have their own knowhow, contributing to the unique characteristics and quality of yams. The yam varieties used are Mong Linh white yams, purple yams, and native purple cotton yams. The selected bulbs are cut into small blocks with a size of 6-8 cm. The section of the bulbs after cutting are permeated with dry cement (except for the tuber shell), the cement will absorb the water from the section to reduce moisture, inhibit the activity of harmful fungi, help the surface tubers not rot during incubation, and ultimately increased germination rates. In addition, unlike other yam growing areas, the Ben Ke yam growing area in Thanh Hoa district is a low-lying area, affected by floods from river systems every year, yams are planted consecutively to adapt to the inherent natural conditions. After the flood subsided, the yam fields were plowed up to form parallel areas with a surface of 3-4m wide, interspersed with ditches with a width of 2 - 3.5m, and a depth of 60 - 70cm. The water level in the ditch is kept fixed at a distance of 20-30 cm from the mulch surface to maintain the necessary humidity of the yam field. In addition, after planting, local people also use grass growing around the ditches to dry and cover with a thin layer on the surface of the mulch bed before or immediately after planting, creating a cover for the yams in the early stages and making a grounding barrier between the yams and the soil surface. 

  

 

Ben Ke yam field 

Geographical area: Thanh Hoa town and Thuy Tay, Thuy Dong, Thanh An, Thuan Binh, Tan Hiep, Tan Tay, Tan Dong, Thuan Nghia Hoa, Thanh Phu, Thanh Phuoc communes in Thanh Hoa district, Long An province./. 

  

Center for Examining Geographical Indication and International Trademark.