Basic Information of Japanese Tea and OSADA TEA
Tea is said to have been brought to Japan 1200 years ago. Since then, until the mid-20th century, when modern agriculture flourished, organic farming was naturally pesticide-free and chemical-free.The concept of organic farming was devised in 1971, and guidelines were established in 1992. Osada Seicha (Osada Tea Japan) began handling organic tea around 1990.
Suitable areas for tea cultivation are those with an average annual temperature of 14-16℃ or higher, a minimum winter temperature of -5-6℃, and a maximum summer temperature of no higher than 40℃. Rainfall should be moderate from February to April and from mid-July to early September after the end of the rainy season, with an annual precipitation of about 1,500 mm.The topsoil should be rich and well drained, and the soil should be slightly acidic. Tea produced in areas where there is a clear difference in temperature between day and night is of superior quality.
The area of tea harvested in 2021 is 25,300Ha and is on a declining trend. However, production efficiency has increased and there is no significant change in tea production yield. Due to changing tastes, the domestic consumption is on declining trend and, small-scale farmers cannot invest to increase production efficiency. This is thought to be the main reason for the declining trend in harvested area. Large-scale farmers are increasing and practicing organic farming methods.
It is said that more than 1,500 mm of precipitation is required annually for tea cultivation, especially more than 1,000 mm during the growing season from March to October. The moisture required by tea is retained and used by the soil. However, because of evapotranspiration, more than 1,000 mm of precipitation per year is needed to cover it with rainfall. But considering the rate of flow over the surface, infiltration into the soil, and utilization by the tea plants, 1,500mm of precipitation per year is required to produce the tea. Especially in the case of heavy summer evaporation, a lot of soil moisture is required, and if the number of days without rainfall exceeds 20 days during this period, drought will be a factor. High rainfall can retain water if it is within the soil's tolerance, but drought is likely to be fatal if it continues for a long period of time.