Khẩu Tan Đón rice is a native type of rice, appears in the local legend of a fairy. In the Thái ethnic’s legend, the fairy, who loved the hard-working Thái people, gave them this exquisite rice, and told them to find suitable soil to grow it. After years of experiments, harvests full of tailings and unbloom crops, finally, the Thái people finally found the “golden soil” on the sides of the clear Nậm Con river.
In the Tày language, “Khẩu” means “type”, “Tan Đón” means “white rice”, “Thẩm Dương” is the name of a commune of Văn Bàn district, Lào Cai province.
The Khẩu Tan Đón Thẩm Dương rice has the scientific name of Oryza sativa l.Glutinosa Tanaka. The seeds are hairless and oval-shaped. Seed length is 0,48cm - 0,63cm, and the width is 0,30cm - 0,41cm. The seeds are white and strongly aromatic. After being cooked, the rice will become sticky, have sweet taste, and leave a layer of oil on the phrynium or banana leaf wrapping.
Khẩu Tan Đón Thẩm Dương rice has the following quality: Total protein content of 6,23% - 7,03%; carbohydrate content of 68,58% - 70,23%; iron content of 15,06mg/kg - 17,93mg/kg; Vitamin B1 content of 0,42mg/100g - 0,63mg/100g; Amylose content of 2,67% - 3,70%.
Khẩu Tan Đón Thẩm Dương rice’s reputation and peculiarity are atttributed to the geographical area and to the accumulated experience of the people throughout the production process
The geographical area is the valley between the two major ridges, which are the Hoang Lien Son ridge to the North West and the Con Voi ridge to the South East, on the altitude of 300 - 500 m above sea level. Due to the area is covered by high mountains, the rice field has the annual average temperature of 23,50C - 24,50C, the highest temperature is in July and August which is 260C - 270C, while other rice fields of Dương Quỳ, Hòa Mạc, Nậm Xây, and Làng Giàng communes have a 10C - 20C higher annual average temperature. On the other hand, due to the valley terrain, the amplitude of temperature variation between day and night of the Thẩm Dương rice fields is considerably high, which is 70C - 80C in July and 50C - 60C in August, while in other Khẩu Tan Đón rice fields, this indicator is 30C - 40C in July and 20C - 30C in August. This is an important condition, formulating the climatic differences between Khẩu Tan Đón rice fields and bringing the peculiarity and quality of Khẩu Tan Đón rice grown in Thẩm Dương. The quality of the rice is decided in the period when the rice switches from vegetative growth stage to reproductive growth stages (bloom splitting), and the amplitude of temperature variation between day and night is the deciding factor to the quality of the rice during the blooming and granulating stage.
Khẩu Tan Đón rice in Thẩm Dương is grown on 04 types of soil: 1) non-drainage Haplic Dystric Fluvisols (FLdy.stha) allocated mainly in Bô Village; 2) non-drainage Haplic Skeletic Acrisols (ACst.skha) allocated mainly in the Thẳm Village area; 3) non-drainage base poor Haplic Acrisols (ACst.vtha) allocated mainly in the Ngoang Village and Thẳm Village area; 4) light-weight, non-drainage Dystric Gleysols (RGdy.star) allocated mainly in Ngoang Village. On the other hand, Khẩu Tan Đón rice in communes of Hòa Mạc, Dương Quỳ, Nậm Xây, etc. are mainly grown on the following types of soil: light-weight Dystric Skeletic Fluvisols (Fldy.arsk); light-weight Dystric Fluvisols (Flar.dyha); Haplic Dystric Gleysols (RGgl.dyha); and light-weight Dystric Skeletic Gleysols (RGar.stsk).
The non-drainage fluvisols in Thẩm Dương which are formulated from the accumulation of alluvial of the river system, the non-drainage acrisols which are formulated on the mountain slopes with medium altitude in communes, and the non-drainage Haplic Gleysols located the valleys form the long-established rice fields of the local farmers. These soils have medium mechanical composition, with high amount of fine sands, which are favourable conditions for the soil to retain the water and accumulate the nutrition. Other areas growing Khẩu Tan Đón rice mainly have light-weight Dystric Skeletic Gleysols and Fluvisols.
Due to valley terrain, alkali and earth alkali washout in Thẩm Dương rarely happen, not as usual as other areas in Văn Bàn district. Therefore, the soil in Thẩm Dương is less acidic than other areas.
The peculiarity of the soil in Thẩm Dương commune for growing Khẩu Tan Đón rice is also presented by the rich total organic carbon amount, which is crucial to the productivity and quality of the rice. The rich total organic carbon amount has significant impact on the ability to provide nutrition of the soil and enhance the activity of useful micro-organisms. The soil, rich in total organic carbon amount, with its distinctive the black-brown colour, non-cohesive and well-moisturized nature, helps Thẩm Dương farmers reducing the use of nitrogenous fertilizer, while still maintain the development and quality of the rice.
The water for Thẩm Dương rice fields is supplied from the Nậm Con stream. From the rich experience of the farmers of Văn Bàn district, rice irrigated by water from the Nậm Con stream shows higher quality than Khẩu Tan Đón rice grown in other areas. Irrigation is validated as a peculiarity affecting Khẩu Tan Đón rice quality, as water from Nậm Con stream has low temperature, rich in minerals, micronutrients, and is organic pollution-free. The water is fed during bloom splitting and formulation of the seed. Therefore, it has significant impact to rice quality.
The harvest season of Thẩm Dương rice starts from middle April of the lunar calendar, when the summer sunlight is as yellow as honey, and the cool water from Nậm Con stream fills the terrace fields, the Thái and the Tày ethnics seed the rice, and plough the fields. When September, October of the lunar calendar come to Thẩm Dương, the aroma can be smelt from the Nậm Con stream. That is the aroma of the new rice, from the sticky rice pot on the fireplace and from the dried rice stubbles.
Long ago, people explained the good taste of Thẩm Dương rice came from the caring hands of the Thái girls. Thẩm Dương rice being considered the “number one rice” is also thanks to the distinctive climate of the areas, and water from the stream.
Clear Nậm Con stream comes from the Pú Hẻo mountain. But when this rice is grown somewhere else, the distinctive taste no longer remains. Unsuitable climate and soil is one reason for it, and the rice not being tended by the Thái, and the Tày ethnics of Thẩm Dương is another. From planting the rice seedlings, then pulling them up and replanting to harvesting, the rice of Thẩm Dương has received the love and care of the Thái and Tày couples. The husband pulls the seedlings, the wife replants them, then the wife harvests the rice and the husband carries them back home. Therefore, the rice gets the aroma from the soil and water, but the taste from the love of the people.
Geographical area consists of Villages of Ngoang, Thẳm, and Bô of Thẩm Dương communes, Văn Bàn district, Lào Cai province.