Studies On Weed Ecological Control Of Biodiversity In Tea Plantation In Subtropical Hilly Region

In China, tea is mainly distributed in the subtropical region in which Red-soil Hilly is especially important in tea yielding. However, such kind of soil in subtropical area is very poor and pests are rampant. High temperature and seasonal droughts are frequent. In addition, in poor natural condition, fertilization is till irrational. All these cut down the quantity and quality of tea. The dwindling economy restrains sustainable development of tea production in this area.This experiment is carried out in typical subtropical red-soil hilly tea areas-Chinese Academy of Science test base for organic tea in Jinjing County, Changsha, Hunan, viz. tea plantations of Hunan Xiang Feng Tea Co., Ltd. The experiment is conducted in spring, summer and autumn. It is divided into interplanting Dutch clover, mulching straw and cleaning tillage (conventional regulation). It analyses and compares effects of two biological measures on the category of weeds in tea plantations, dynamic structural changes of weed communities and quantity and quality of tea production. The main findings are as follows:1.During covering straw, the Total species richness (S) and Community diversity (H) in spring, summer and autumn in experiment tea plantation are higher than other tea plantations during cleaning tillage, Evonness (J) in spring and summer is higher and Concentration(C) in spring, summer and autumn is lower. Straw mulching stabilizes weed community where dominance of weed population is not obvious. It has little influence on the growth tea trees. The control of weeds in spring and summer is effective, but in autumn, since the covered straw has been degraded and decayed, there are more weeds in tea plantations and comparison of weed biomass between experiment plantations and other plantations is not so significant.2.It can reduce fluctuations in soil temperature by interplanting Dutch clover in tea plantations. In addition, light for weed seeds on the soil surface can also be obstructed. Roots of Dutch clover distribute in layers of Soil Depth 0-20 cm. In dense surface, stolons produce strong mechanical resistance on weed seed germination, so some of weeds on the surface soil will gradually die due to lack of nutrients, light and water after germination. As a result, occurrence and development of weeds are under thumb.3.Interplanting Dutch clover and straw mulching significantly increase the water extracts, amino acids and water content, while reducing ammonia content of tea Polyphenols and Phenol Ammonia ratio. Main sensory qualities of tea, such as tea color, liquor color, aroma, taste of tea and holding tenderness, are improved, which is especially obvious in autumn tea. The effects are more prominent by interplanting Dutch clover. The maximum value of net output in this area is produced by interplanting Dutch clover, followed by mulching straw. Evidently, interplanting Dutch clover not only improves tea quality, but increases tea production. Moreover, it enhances economic benefits of tea plantations. Meanwhile, it confirms that methods of weed control are significant for increasing tea production and assuring tea quality.