Rationalized Layout of Improved Tea Cultivars in Liandu District

Liandu District of Lishui City is located in the heart of southwestern Zhejiang, in the middle reaches of the Ou River. The area is embraced by green mountains and clear waters, with extremely rich ecological resources. It is a national ecological demonstration zone with a forest coverage rate of over 80%, and is known as "Green Liandu." Liandu District has four distinct seasons and a mild climate, belonging to the mid-subtropical monsoon climate zone. The soil is mainly red-yellow soil and lithological soil, with a pH value mostly between 4.5 and 6.5, which is very suitable for tea cultivation, and the tea produced is of excellent quality.

1. Overview of tea production and improved tea cultivar structure in Liandu District

The district currently has a tea garden area of 21,400 mu (1 mu = 667 sq m, the same below). Of this, the producing area is 17,300 mu, accounting for 80.8% of the total area. In 2006, the output was 356 tons, with an output value of nearly 33 million yuan. Of this, the output of famous and premium tea reached 276 tons, accounting for 78.8% of the total annual output, with an output value of over 28.8 million yuan, accounting for 84.7% of the total annual tea output value. Tea processing types include flat tea, Biluochun, fragrant tea, etc. In recent years, newly developed tea garden cultivars include Wuniuzao, Longjing 43, white tea, Yingshuang and other improved cultivars. The district's improved cultivar tea garden area has reached 12,900 mu, of which Wuniuzao is 4,000 mu, Longjing 43 is 3,000 mu, white tea is 3,000 mu, and Yingshuang is 2,900 mu, with an improved cultivar rate of 60.36%. In 2006, it was rated by the Zhejiang Provincial Department of Agriculture as an advanced county and district for the promotion of improved tea cultivars.

2. Rational layout of improved tea cultivars

An excellent tea cultivar should possess the characteristics of achieving high and stable yields under the climate and geographical conditions, cultivation, and harvesting and processing systems of a certain region, producing tea of excellent quality, having strong adaptability, and having strong resistance to pests, diseases and natural disasters, that is, it should have good yield performance, processing suitability, adaptability and stress resistance. The layout of improved tea cultivars must be determined according to the local natural conditions, cultivation characteristics and tea type requirements.

The tea gardens in Liandu District are mainly mountainous, with the majority at elevations of 100 to 900 m. As elevation increases, temperature decreases, relative humidity rises, and there is abundant cloud and mist, sufficient water vapor, and cool temperatures year-round. The river valley basins are hot in summer with high temperatures, and extreme high temperatures can reach 42°C. Along the Ou River and in the Bihu Plain below 100 m elevation, temperatures rise relatively late in early spring and frost damage is very likely. Based on the above characteristics, the improved tea cultivars in Liandu District can be laid out as follows.

(1) Mountainous areas at elevations of 200 to 500 m are more suitable for cultivating the Wuniuzao cultivar. At this elevation, spring temperatures in mountainous areas rise early, and spring frost can be effectively avoided, making production relatively safe and allowing the cultivar's early-sprouting advantage to be fully utilized. Wuniuzao can generally be picked around February 15, and is one of the early teas with the most prominent early-sprouting advantage in Zhejiang Province, with strong competitiveness in the market. When this cultivar is cultivated in mountainous areas below 200 m and along the Ou River, it is very prone to spring frost damage, and it also fails to demonstrate its early tea advantage, resulting in low production efficiency, so it is generally not suitable for adoption. Liandu District has already formed an early tea production area of nearly 4,000 mu centered on Maotian. The early tea produced there is "early-sprouting and high-quality, with lasting high aroma, rich and refreshing," and its "early tea" advantage is particularly prominent. Every year it attracts a large number of out-of-town merchants, with booming transactions and considerable benefits.

(2) Mountainous areas below 500 m can also develop the early tea cultivar "Lizaoxiang," which shows strong adaptability and stress resistance, and produces tea of excellent quality. This tea was developed in 1993 through single-plant selection from the local Jiukeng population. It sprouts early, with picking beginning in late February in Lishui, about one week later than Wuniuzao and 15 days earlier than Longjing 43 and Yingshuang. It has good processing suitability; the dried tea has a good appearance, a mellow and refreshing taste, an especially excellent aftertaste, a lasting chestnut aroma, and a clear and bright liquor color. In recent years it has been welcomed by the market.

(3) Mountainous areas above 500 m are more suitable for developing white tea production. White tea was selected from Tianhuangping in Anji at an elevation of 800 m, and is suitable for planting in higher-elevation, cool-climate areas. Lower temperature conditions can fully bring out the characteristics and quality traits of this cultivar. Judging from production in previous years, cultivation in low-elevation areas and plains fails to show the cultivar's "albinism" characteristic, and during high-temperature periods leaf scorching commonly occurs, along with poor tolerance to fertilizer and barren conditions, making it rather "delicate." However, in places such as Shangzhuang and Hengkeng in Dagangtou Town above 500 m elevation, it shows good traits, and a number of examples of rapid high yield have emerged. For example, Hengkeng Village in Dagangtou is at an elevation of 550 m and began planting white tea in 2003 (the village currently has more than 200 mu of white tea). After planting and with strengthened management, the output value per mu reached 2,400 yuan in the second year; in the third year, the output value of white tea fresh leaves per mu reached 4,800 yuan, and more than 3,000 yuan worth of cutting stems could also be harvested, bringing income per mu to nearly 8,000 yuan.

(4) Longjing 43 and Yingshuang have strong adaptability and good economic traits, and are suitable for cultivation throughout Liandu District, where they can achieve relatively good economic benefits.