The experimental research and production practice show that in the comprehensive agricultural technology measures of tea garden management, the effect of rational fertilization on tea yield and quality improvement is most significant. However, in the production practice, the same amount of fertilizer is often applied, and the effect of increasing production and quality is very different, indicating that the fertilization technology is very particular. The rational fertilization of tea gardens should be based on the age, growth potential and yield of tea trees; the nutrient level, physical and chemical factors of tea garden soil; the type, nature and seasonal weather conditions of tea garden fertilizers, such as seeing trees and seeing fertilizers. Seeing the ground, watching the sky, and rational application can achieve good results. Most of the tea areas in the middle and lower reaches of the Yangtze River in China are in the early summer rainy season ( "Fengmei" or "empty plum" ) . Summer is often accompanied by heavy rains ( thunder showers, typhoon storms ) , high temperature and severe summer droughts, droughts and droughts, and summer tea garden fertilization Technology is especially important. Based on the experience of various places, the tea garden summer fertilization should focus on four key points.
   First, pay attention to fertilization time
   Grasping the season, not breaking the farm is a magic weapon in agriculture. In the tea garden, fertilization in summer should also catch the season. Because of the short interval between spring tea and summer tea, it is better to apply early in the tea garden in summer. The vigorous growth and repeated picking of the tea tree by the spring tea consumes a lot of nutrients in the body, and the nutrient reserves in the tea tree and the tea garden soil will have different degrees of deficit. In addition, summer is the peak season of tea tree reproduction. In the same year, the flower buds were bred in large quantities. The fruit grew rapidly in the previous year, and consumed a lot of nutrients in the tree. If not topdressed in time, it would cause the tea tree nutrients to be out of contact, affecting the germination and growth of the summer shoots, showing the shoots. Less, slow growth, short internodes, yellow leaves, small leaves, thin leaves, multiple buds ( on the leaves ) and other symptoms, affecting both yield and quality, so it is necessary to timely topdress. Summer for the first time at the end of spring and fertilizer, they should be applied immediately, usually in the mid to late May, the southern tea-growing areas in advance to late April or early May, the north tea areas can be extended to early June. The second summer dressing can be at the end of two tea, approximately in late June, early July were. It is customary to call this secondary topdressing "transfer fat" and "severe fat", the importance of which can be imagined.
   Second, pay attention to fertilizer varieties
   The tea tree is the leaf used, and the nitrogen fertilizer is its staple food. The base fertilizer should be sufficient, and the topdressing should be fast. The base fertilizer is rich in phosphorus and potassium fertilizer. In the case of applying the base fertilizer, it is generally unnecessary to apply phosphorus and potassium fertilizer in summer to avoid enhancing reproductive growth and consuming nutrients. In summer, topdressing is based on the selection of high-nitrogen fast varieties. Applying nitrogen fertilizer in summer can enhance the synthesis and accumulation of nitrogen compounds in tea plants, inhibit the formation of carbohydrates in the body, inhibit reproductive growth, accelerate vegetative growth, increase yield and increase amino acid content in buds, reduce phenolic content, and improve green tea. Quality has a good effect. To this end, the majority of green tea production areas should be high-speed available nitrogen fertilizer as the first choice for summer topdressing. Commonly used ammonium sulfate, urea, ammonium bicarbonate, ammonia, ammonium nitrate and high-nitrogen (N:P2O5: K2O is 4:1:1) tea special compound fertilizer, are good varieties of tea garden summer top dressing. Tea plantation soil with low phosphorus and potassium content, tea plantation rate is not high, tea plantation and black tea production area and oolong tea production area, N:P2O5: K2O can be used as a special compound fertilizer for tea : 2:1:1 .
   Green food tea gardens and organic tea gardens should be selected by special agencies to meet the types of fertilizers allowed in green food tea gardens and organic tea gardens, such as manure ( excluding prohibited substances proposed by the certification body ) , human and livestock manure ( by harmless Treatment ) , organic tea special fertilizer, etc.
   Third, pay attention to the amount of fertilizer applied
   The amount of topdressing in summer tea gardens depends on the age of the trees, the growth potential, the high and low yield of tea, the soil nutrient level in tea gardens, and the management level of tea gardening. The tea yield is the main basis for determining the amount of fertilizer. Generally, 100kg of dry tea is produced per mu (667 m2 ) , and the amount of pure nitrogen applied is about 15kg per year . The amount of topdressing accounts for about 50% of the annual nitrogen application . Topdressing the summer about 25 to 30% of the annual amount of nitrogen, i.e., the first summer dressing (5 months late), accounted for 10% nitrogen; 6 dressing after the second summer (two tea in late May - early July), accounting for 15 to 20% of the annual amount of nitrogen. In production, three teas are often classified as autumn tea, so the second summer fertilizer is also called autumn fertilizer. For the general production of tea gardens, such as the special compound fertilizer for tea, 50 to 100 kg can be applied after spring tea and after two teas .
   In the tea garden with water source, foliar fertilizer can be sprayed once before the two teas and three teas in the summer. The foliar fertilizer concentration is: ammonium sulfate 1% , urea 0.5 to 1.0% , Ai Nong 300 times liquid, and rich spring 300 times. Liquid, EM1000 times solution, linolein 10000 times solution, etc., as a supplement to the root top dressing. Spray about 150kg per mu of fertilizer .
   Fourth, we must pay attention to fertilization methods
   Under the condition that the amount of fertilization in the tea garden is not very sufficient, the effect of relatively concentrated application is greater. That is, the ground is ditched and concentrated along the vertical position of the outer edge of the crown. The application of ditching is more effective than spraying the soil between the tea rows. It can avoid the loss of rainwater, and can avoid the loss of high temperature volatilization and reduce the fertilizer efficiency. The fertilization ditch is 10 to 15 cm deep , and most of the nitrogen fertilizers are unstable in ammonium. When fertilizing, they should be fertilized and covered with soil. Applying water and fertilizer, the soil is dried and covered with soil. The application method varies depending on the individuality of the fertilizer. For example, ammonium sulfate contains 20 to 21% nitrogen . It is an ideal variety for tea gardening. It is not only a nitrogen fertilizer but also a sulfur fertilizer. It is a physiological acid fertilizer and is a soil acidifier. Applicable to tea gardens with insufficient acidity in soil; ammonia water contains 12 to 20% nitrogen , fertile , applied with water diluted 10 to 20 times, ammonia is unstable, easy to leak and run, lose fat, and apply deep control when applied The side cover is applied; the ammonium chloride contains 25 to 26% of nitrogen , but the chlorine content is high. The tea tree is a bogey of chlorine plants. In order to avoid the accumulation of poisonous tea trees in the soil, it should be avoided in the dry period. It is suitable to use no more than 15kg per acre , and it is applied when there is more rainwater; ammonium bicarbonate contains about 17% nitrogen , which is extremely unstable under high temperature conditions and is easy to decompose and volatilize. According to the measurement of exposure to above 20 °C for one day, the loss of nitrogen is 8.86% , the exposure is 10 days, the loss is 74.09% . At 32 °C, exposure for half a month, all lose the fertilizer effect. Therefore, it is not suitable to expose to storage under high temperature conditions. When applying, it is especially important to emphasize the application of soil while applying fertilizer and deep application. However, if nitrogen fertilizer such as ammonium nitrate is applied, it can be applied as appropriate; urea contains about 45 to 46 nitrogen. % is a neutral fertilizer. After being applied to the soil, it is ammoniated to ammonium carbonate under the action of urease to be absorbed by the tea tree. Therefore, the application time is a few days earlier than ammonium sulfate. Because urea contains a small amount of biuret and other substances, it has a certain toxic effect on tea trees. It should not be too much in each dose. In addition, urea is a weakly polar molecule before being decomposed, and the soil has poor adsorption to it. It is leached by rain, so avoid applying it before heavy rain.
   Fertilizers applied to tea gardens must first be dissolved in water before they can be absorbed by roots. For example, if the soil is dry, the range of fertilizer movement is small, and the fertilizer effect should not be fully exerted. Therefore, wet application should be applied; dry application should end in the rainy season, while soil is more It is suitable when wet.
   The concentration of foliar fertilizer should be appropriate. The concentration is too low and the fertilizer is not effective. The concentration is too large to burn the buds and harm the tea tree. When the temperature is high, it is better to spray it in the morning and evening to avoid the increase of the fertilizer concentration and the occurrence of fertilizer damage. It does not rain for 24 hours after spraying . When the fish leaf is spread to the first leaf exhibition, the spray on the leaf back is the best.
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