Detailed Explanation of Key Points for Pollution-Free Management Techniques of Tea Plants

Tea garden soil should be ploughed frequently to facilitate microbial activity, accelerate soil maturation, promote the release of mineral elements, and facilitate root absorption. Depending on the soil structure, carry out shallow ploughing several times a year, with a depth of 5-10 cm; medium ploughing 2-3 times, with a depth of 10-15 cm; deep ploughing once a year or every other year, with a depth of 25-30 cm. Shallow ploughing and medium ploughing can be carried out in combination with weeding and topdressing in each tea season, while deep ploughing is carried out in combination with garden cleaning or applying organic fertilizer. Tea gardens should be given more organic fertilizer to improve soil physical and chemical properties and the capacity for sustained nutrient supply; appropriately stock @#@254@#@, use earthworms to loosen the soil, increase soil porosity, facilitate tea root growth, strengthen tree vigor, and improve yield and quality. On the basis of building high-standard "three-preservation" tea gardens, spread grass as mulch between tea rows before the dry season and rainy season each year, which can both preserve water and buffer erosion, and also use the decomposed mulch to increase organic matter and improve the soil.

I. Fertilize according to soil physical and chemical properties. Sandy loam has relatively poor water- and fertilizer-holding capacity, so more fertilizer should be applied, with appropriately more nitrogen fertilizer; red soil, because the soil acidity is relatively strong, is prone to relative phosphorus deficiency, so phosphorus fertilizer should be applied in small amounts and multiple times; while black soil formed from humus has a relatively high organic matter content, better physical and chemical properties, and strong soil fertility, so less fertilizer can be applied.

II. Fertilize according to the type of tea picked and processed. For oolong tea, spring and autumn tea have the highest yield and the best quality, so the proportion of topdressing before spring and autumn tea picking should be increased. The amount of topdressing for spring and autumn tea should account for more than 70% of the annual fertilization amount to increase the yield of spring and autumn tea. For tea picked and processed in four seasons a year, the topdressing ratio is 4:2:3:1; for tea picked and processed in five seasons a year, the topdressing ratio is 3:1.5:15:3:1.

III. Fertilize according to tea plant variety. Varieties with low sprouting ability and many buds, such as Shuixian and Maoxie, should be given more fertilizer; varieties with strong sprouting ability and few buds, such as Foshou and Tieguanyin, can be given less fertilizer.

IV. Fertilize according to tree age and tree vigor. Tea gardens with older trees and weak growth should be given more fertilizer, and appropriately more nitrogen fertilizer, to strengthen tree vigor; tea gardens with younger trees and strong growth can be given less fertilizer, but should be appropriately given more phosphorus and potassium fertilizer.

V. Fertilize according to yield level. Tea plants are leaf crops. According to estimates, for every 50 kg of dry maocha harvested, about 2.25 kg of pure nitrogen is removed from the tree body (equivalent to the pure amount of 5 kg of urea). However, fertilization should be carried out at at least 2-3 times that amount to ensure the overall metabolic activity of the tea plant.

VI. Fertilize according to fertilizer type. Nitrogen mainly promotes vegetative growth, and tea gardens in production should be appropriately given more nitrogen fertilizer. Phosphorus and potassium have a good effect on root and framework branch formation, so young tea gardens should be appropriately given more phosphorus and potassium fertilizer. At the same time, the fertilization amount should be determined by referring to fertilizer use efficiency; generally, nitrogen use efficiency is 30-40%, potassium is about 20%, while phosphorus is only a little more than 10%.

VII. Balanced fertilization and formula fertilization should be determined according to the needs of tea plants for the three major elements at different stages and their content in the soil. Generally, for young trees 1-2 years old it is 1:1.5:1.5, and for 3-4 years old it is 2:1:1. In the full production period it is 3:1:1. As tree age increases, the proportion of nitrogen application can be appropriately gradually increased. In addition, on the basis of applying sufficient nitrogen, phosphorus, and potassium, trace elements such as copper, magnesium, zinc, molybdenum, and boron should be appropriately supplemented.