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Hani and Yi technique of irrigation has always been a secret since their rice terraced fields were built from mountain top to deep valley. Many friends also wrote me asking for the Hani & Yi method of rice cultivation but not until recently I was lucky to locate a valuable field survey by Adachi Shimpei. I hope his work helpful to all of us who are willing to learn. Today text is continued from previous post.

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Terraced Rice Cultivation

Multi-function of the Rice Terrace

Terraced paddy field is not only a place for cultivating rice but also a place for producing many kinds of supplementary foods.

In terraced paddy fields where dikes and dike walls occupy the greater portion of the total farmland area, utilization of the dike and dike wall has been highly developed. At rice transplanting, soybean is sown on the dike. Since the dike soil is renewed at least twice in a year by farming works, the soil is very fertile and produces soybean with good taste. In the village, one variety of soybean (nebenu) is sown especially on the dikes of paddy fields. Since this variety is only suitable for lower altitudes, seedlings of finger millet are planted on the dikes of upper paddy fields (both mio and mifa). Seedlings of finger millet are grown in upland nursery fields and are transplanted onto the paddy dike. In addition, the villagers often pick up many kinds of edible wild herbs grown on the dike of both terraced fields and irrigation channels. The period between May and June (one or two months after the transplanting), is considered the best season for picking these wild herbs since tender and delicious plant shoots come out in this season. Dry season farming works, described in the previous section, such as repairing the dike and shaving dike wall can create suitable soil conditions for those edible herbs to sprout each year.

In terraced fields that are kept under deep-flooded conditions on most days of the year, the villagers catch many kinds of shellfish and aquatic insects for food. Moreover, in some paddy fields, young fish are released for pisciculture during the transplanting period, and are harvested usually along with the rice. The slight inclination of the paddy field bottom is also considered by the villagers to be suitable for pisciculture, as well as for preserving physical structure of the terrace. Flooded terraced fields also provide feeding grounds for the ducks that are raised by most of the households.

The Change in Agricultural Technologies with the Introduction of Improved Varieties

A major change in terraced rice cultivation in recent years is the rapid increase of improved rice varieties. According to the author’s survey conducted in 2002, only three out of 10 randomly sampled households grew improved varieties (two grew non-hybrid and one grew hybrid varieties), but in 2004, 20 out of 30 sampled households cultivated improved varieties (seven grew non-hybrid, 10 grew hybrid variety, and three grew both).

The influence of introducing improved varieties on water management seems to be limited. In order to maximize the yield potential of the improved varieties, different water management is recommended. However, the introduction of improved varieties has led to little change in the water management of terraced paddy fields. Ideally, because the seedlings of improved varieties are short, field water levels should not be high during the early parts of the growing season. Most of the villagers, however, prefer to keep the water deep enough to cultivate fish or to save irrigation water for subsequent growing season, even though deep water retards the growth of rice seedlings. In addition, when chemical fertilizer is applied, it is recommended to drain the terraced field in order to heighten the effect of fertilizer. However, very few villagers drain the fields for the same reason. The villagers also know that applying pesticide or too much chemical fertilizer at once can kill the fish in the field, therefore, they apply them by spreading the application over several times.

It seems that the improved rice varieties have been adapted to the conventional agricultural practices, rather than having brought about drastic changes on the existing system. Again, agricultural technologies, including water management, are closely related not only to rice cultivation, but also to the physical maintenance of terraced fields and the production of supplementary food sources. The cultivation of improved varieties has been incorporated into the unique agricultural system of the terraced paddy field.

By Adachi Shimpei, ASAFAS, Kyoto University

(To be continued)

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