Tree Genetics and Molecular Breeding 2025, Vol.15, No.1, 33-43 http://genbreedpublisher.com/index.php/tgmb 35 2.2 The influence of planting density The relationship between planting density and tea yield is rather complex and is influenced by factors such as the type of tea tree variety and environmental conditions. Studies have found that a higher planting density can increase the total output per unit area. However, the yield of a single tea tree may decrease due to the competition for resources such as sunlight, water and nutrients. For example, in Tanzania, the yield of the AHP S15/10 variety has always been higher than that of the BBK35 variety under different planting densities, which indicates that some tea tree varieties are more suitable for high-density planting (Kigalu, 2007). The planting density also affects the quality of tea. High-density planting may make each tea leaf thinner and poorer in quality, thereby affecting the contents of components such as chlorophyll and catechins in tea (Sano et al., 2018). These changes will alter the taste and quality of the tea, so it is necessary to reasonably control the planting density and strike a balance between yield and quality. 2.3 Theoretical basis The theory that supports high-density planting can optimize resources mainly focuses on the efficient utilization of sunlight, water and soil nutrients. The core of high-density planting is to cultivate dense tree crowns to absorb as much sunlight as possible, thereby enhancing photosynthesis, increasing the growth of tea trees and improving the efficiency of sunlight utilization (Phukan et al., 2018). Studies have observed that tea trees with larger canopies absorb carbon dioxide more efficiently, which is very helpful for maintaining high yields and also confirms this theory (Phukan et al., 2018). Water efficiency is also a key point in high-density planting. In water-scarce areas, such as arid regions, high-density planting will make the competition for water among tea trees more intense. However, tea tree varieties like AHP S15/10 can have relatively high yields even with less rainfall. This indicates that when planting at high density, choosing the right tea tree varieties is very important for making good use of water resources (Kigalu, 2007). In addition, nutrient management is also indispensable. If it is not managed properly, high-density planting will cause the nutrients in the soil to be absorbed dry. Using reasonable fertilization methods and choosing tea tree varieties that can efficiently utilize nutrients can help solve these problems and ensure sustainable tea production (Ruan et al., 2023). 3 High-Density Tea Planting Implementation Technology 3.1 Planning and layout: design of planting distance In high-density tea gardens, planning the planting spacing properly is the key to making full use of space and ensuring the healthy growth of tea trees. A commonly used method is to plant tea trees in single rows, keeping the distance between rows at 1.2 to 1.5 meters and the distance between tea trees within the same row at 0.8 to 1.0 meters. In this way, 800 to 1 000 tea tree seedlings can be planted per unit area, which not only creates a sustainable growth environment but also reduces the risk of disease transmission among tea trees (Fang et al., 2014). Another method is row sowing, where tea seeds are sown in furrows with a row spacing of 180 cm and a plant spacing of 20~25 cm. This approach can effectively prevent tea trees from over-competing for nutrients and improve the quality of tea (Cui et al., 2014). Intercropping methods such as camphor trees and ryegrass between tea houses can make the ecological balance of the tea garden more balanced. Doing so is not only beneficial to the growth of each tea tree, but also can help reduce pests and contribute to the sustainable development of tea gardens (Fang et al., 2014). Reasonable arrangement of tea tree spacing and the adoption of intercropping are conducive to enhancing the ecological and economic benefits of high-density tea gardens. 3.2 Selection of tea tree varieties Selecting the right tea tree varieties is crucial for high-density planting, as it will affect the tea yield and the disease resistance of the tea trees. High-yielding and disease-resistant varieties like Liangye Huangjiao are particularly suitable for close planting. By applying techniques such as plastic film mulching and reasonable planting density, both the growth and yield of this variety of tea trees can be improved (Shi, 2014). Similarly, Anji
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