Tea cultivation requires specific soil conditions in order to promote the growth of tea trees and improve the yield and quality of the tea. The following are key characteristics of soil in high-yield tea gardens:

1. The soil is deep and loose. Tea plants have a deep root system, with the majority of absorbing roots located in the top 15 cm of soil. Therefore, the soil layer in a tea garden must be deep enough to accommodate the normal growth of the tea tree's root system.

Loose soil also promotes the growth, yield, and quality of the tea.

2. The soil texture is sandy and sticky. Tea thrives in loose sandy loam soil.

3. The soil has proper moisture and air coordination. Tea plants require a moist environment, and the soil should have a high water content, around 90% of its field capacity.

4. The soil acidity is suitable, and the amount of base is sufficient. Tea plants require acidic soil with a pH of less than 6.5. They also need a certain amount of calcium as a nutrient.

If there is a lack of calcium, the tea tree will not grow well and will exhibit symptoms of yellowing.

5. The soil conditions are affected by the local climate and topography. Tea-growing areas are mostly located in mountainous regions, where the topography is complex and affects microclimate and soil conditions.

Altitude, topographic orientation, and slope direction all play a role in determining the climate and soil conditions.

6. The soil is well-drained. Tea plants require well-drained soil in order to prevent waterlogging and root rot. This can be achieved by ensuring that the soil has a good structure, is not compacted, and has an adequate organic matter to improve water-holding capacity.

7. Adequate fertility is maintained. Tea plants require a range of nutrients to grow, including nitrogen, phosphorus, and potassium. Proper fertilization can be achieved through a combination of organic and inorganic fertilizers.

8. The soil is protected from erosion. Tea gardens are often located on steep slopes and are vulnerable to erosion. Measures such as terracing, mulching, and planting cover crops can help to protect the soil and prevent erosion.

9. The soil is regularly tested. Regular soil testing is an important aspect of maintaining the health and fertility of the soil. This can help to identify any deficiencies and ensure that the right amount of nutrients is being added to the soil.

Overall, maintaining the right soil conditions is crucial for the successful cultivation of tea. Adequate attention to soil preparation, fertilization, and soil conservation can help to improve the growth, yield, and quality of tea.

Regular soil testing can also help to ensure that the soil stays healthy and fertile over time.