SHIZUOKA, March 4 — Shizuoka Prefecture is Japan’s top producer of wasabi — the quintessential seasoning of Japanese cuisine that the country boasts to the world.
The native Japanese plant, whose lower part of the stems are grated to make spice that stimulates the nose with a sharp flavor, has been grown in a traditional way in Shizuoka, and the wasabi cultivation making use of abundant spring water, geological features and weather conditions has been added to the list of Globally Important Agricultural Heritage Systems by the United Nations Food and Agriculture Organization.
The Ikadaba wasabi fields in the city of Izu in the central Izu Peninsula are made up of 1,500 fields on 15-hectare terraces of stacked stone built by reclaiming streams along mountain slopes.
The terraces are surrounded by waterfalls and streams of the Amagi mountain range, and the refreshing sounds of spring water flowing down can be heard.
While it is said that 2 tons to 5 tons of water is needed to produce a kilogram of rice, more than 30 tons of water is necessary to grow the same amount of wasabi.
Constant flow of spring water coming from the mountains and the cool, shady environment are essential for wasabi production.
The wasabi terraces are created using the so-called “Tatamiishi (rock matting) style,” with large rocks used in the bottom layer, small stones in the middle layer and sand and gravels on the surface.
A flow of spring water through the fields keeps the water temperature stable and supplies the nutrients and oxygen, enabling stable cultivation of high-quality wasabi plants with thick stems all year round without using fertilizers as much as possible.
Because the water is purified by filtering through the stone layers, clear water spreads all the way to downstream areas, leading to an increase in overall yields.