23. What is the effect of ethephon on increasing rubber production?

Hevea brasiliensis is a tall tree with economic life of several decades. Milk is harvested from bark in a special way. Rubber is produced by the laticiferous tissue of the bark of the gum tree. The laticiferous cells use the products of photosynthesis - sugar and other nutrients, through a series of complex enzymatic reactions, to carry out biosynthesis to produce rubber.

The rubber discharge of rubber trees is caused by artificial rubber extraction or natural disasters (such as cold damage, explosion, wind damage and mechanical damage). Under normal circumstances, the influence surface of artificial rubber collection and discharge is limited to a certain extent. The influence surface of rubber discharge is mainly below and on both sides of the cutting line when the rubber is cut by the male knife. The influence surface of rubber discharge is mainly above and on both sides of the cutting line when the rubber is cut by the female knife. The length of the influence is generally 1.25~1.75 meters, and the width of both sides of the influence cutting line is equal to one-ninth of the length. When ethephon is used in rubber trees, it will cause artificial induced callus reaction, which is a method to tap the existing rubber production potential. Its main functions are: (1) to mobilize reserves by a large margin; (2) Strengthen the absorption of water and nutrients and transport them to the milk tube system; (3) Enlarge the rubber discharge surface, block the coagulation mechanism, strengthen the rubber discharge of the latex tube, and make the regeneration function of the latex hyperfunction, resulting in a short-term and substantial increase in production. However, ethephon itself is not a nutrient, nor can it directly improve the ability of photosynthesis to increase new sugar. A large number of experiments have proved that the correct application of ethephon on rubber trees is an effective measure to improve rubber yield.

24. Which rubber trees are suitable to use ethephon?

Like other long-term crops, rubber trees have their seedling stage, yield stage, full yield stage and aging stage. In the seedling stage, it is mainly to promote the growth of rubber trees, and at this time, it can not be stimulated with ethephon; In the initial stage of production, the gum trees need to produce and grow, at this time, it is generally not suitable to stimulate the tapping; Generally, when the rubber trees enter the full production period (generally 15 years after the rubber trees are planted, that is, 5~7 years after the cutting), they can be stimulated to cut; When the rubber tree is aged and renewed, the stimulation intensity should be increased to tap the rubber production potential of the rubber tree.

According to the test in China, it is temporarily stipulated that ethephon tapping is suitable for low-yield seedlings (including low-yield budding trees) over 15 years old and regeneration rubber plantations. As for the high-yield rubber budding trees, they are currently in the experimental stage and cannot be used in large-scale production.

25. How to properly use ethephon to stimulate cutting?

(1) The use scope of ethephon must be strictly controlled: at present, the use of ethephon is only limited to seedling trees (including low-yield budding trees) over 15 years old and the strong cutting of rubber trees before renewal; Except for the experiment, the high-yield budding trees are not suitable for productive use.

(2) The dosage must be strictly controlled: according to the content of ethephon stock solution calibrated in each batch, and then dispensing and coating should be carried out according to the regulations. It is not allowed to arbitrarily increase the dosage and coating times.

(3) Reasonable cutter reduction: generally controlled to reduce the number of rubber cutters by about one third compared with conventional rubber cutting.

(4) Proper shallow cutting: 2/3~1/2 of the yellow skin (about 0.15 cm from the xylem) is usually cut off by conventional rubber cutting; However, the cutting depth of ethrel stimulation was controlled at 1/2~1/3 of the yellow skin (about 0.16~0.20 cm from the xylem).

(5) According to the results of nutrition diagnosis, fertilizer should be added to supplement nutrients.

(6) Master the dynamic analysis of rubber production and conduct scientific rubber cutting;

I. Look at the phenology. The first canopy leaves should be straight and dark green before cutting. In winter, when the leaves turn yellow, cutting should be stopped.

2. Cut the glue according to the weather. Do not cut the glue in rainy days; Do not cut glue when the temperature is lower than 15 ℃ in winter; Do not cut glue when the tree is not dry; Do not cut glue when the ulcer disease is prevalent.

3. When the dry content is less than 28% in the first half of the year and less than 25% in the second half of the year, the cutting shall be suspended temporarily; When there is a sign of dead skin, the cutting should be stopped.

(7) In addition to regeneration and strong cutting, the increase in yield should be controlled within the reasonable balance between gum production and gum discharge.

(8) In order to improve the effect of stimulating production and reduce the occurrence of side effects, try to use the method of alternating cutting face and high and low cutting line to stimulate rubber cutting.

26. What are the methods of using ethephon in rubber trees?

Depending on the carrier (dosage form), there are currently three main methods:

(1) Emulsion: hang the skin under the secant (male knife) or above the secant (female knife). The width depends on the number of knives. Generally, the skin is scraped along the secant for 1.2~1.5 cm, and the rough skin is scraped off. Then evenly apply the prepared ethephon emulsifiable concentrate on the scraping belt with a brush.

(2) Water or paste: instead of scraping, after the glue line is removed, apply the prepared ethephon water (or paste) evenly along the secant on the bark of two centimeters wide on the secant with a brush.

(3) Colloid: The use is the same as emulsion. It can be used after purchase without having to prepare itself, but its concentration is only one specification.

After 48 hours of application, vinyl has completely entered the gum tree and can be cut.

In case of heavy rain or rainstorm within 5 hours after the application of the medicine, because ethephon did not enter the gum tree, it should be repainted. In case of heavy rain after 5 hours, it should not be repainted.

27. What dosage forms should be used for the use of ethephon in rubber trees?

The selection of dosage form should consider the source of materials, the exertion of efficacy, the effect of increasing production, the cost and the safety of rubber trees. Generally, carriers with wide source of materials, low price, strong adhesion and small side effects are required. In recent years, 40% of ethephon produced by the factory is water and alcohol, and 5~10% is colloid; Generally, pastes and emulsions are prepared on the farm.

Water agent: It is made by mixing ethephon stock solution directly with water as required.

Colloid: In recent years, Shanghai Pengpu Chemical Plant has successfully developed 5~10% colloidal ethephon based on the materials used in foreign rubber parks, which has strong adhesion, is not easy to be washed away by rain, and is convenient to use. It has been tested in the affiliated farm of South China Tropical Crop Research Institute.

Paste: add 0.5 kg of starch in 50 kg of water, stir it evenly, boil it to paste, cool it to normal temperature, add ethephon stock solution and stir it evenly to form paste.

Emulsion: use palm oil to rosin 1:1.50, or gum seed oil to rosin 1:2 as the carrier, first boil and melt the oil and rosin, cool to normal temperature, and then add ethephon stock solution and stir evenly to form the emulsion.

The emulsion is relatively thick, with strong adhesion, long efficacy time and good yield increase effect, but it has serious side effects, high cost and difficult source. The water agent is not so viscous, has poor adhesion, short efficacy time, and has poor yield increase effect, but has light side effects, low cost, and convenient source. Paste is between emulsion and water. The colloid has strong adhesion and can be purchased out of the box. It does not need to be prepared by itself, so it is convenient to use, but the cost is high.

28. How to calculate the amount of ethephon used by rubber trees?

The application amount of ethrel stimulation for rubber trees is mainly determined by the dosage form, tree age, length of secant and length of cycle.

Generally, emulsion is applied once a month, while water and paste are applied twice a month; The dosage of chemicals for young trees should be less, and that for mature trees should be more, and the number of regeneration and strong cutting trees should be increased gradually. In principle, the dosage of emulsion for each young tree should be 0.1 g of ethephon stock solution (effective concentration 2%), and the dosage of water or paste for each tree should be 0.05 g of ethephon stock solution (effective concentration 1%); The dosage of mature tree emulsion is 0.2g of ethephon stock solution (effective concentration 4%) of 40% per plant; 0.1 g of 40% ethephon stock solution (effective concentration 2%) is used for each water or paste; Use 0.4-0.5g of 40% ethephon stock solution (i.e. effective concentration 8-10%) for each time of renewal and strong tree cutting emulsion, and 0.25g of 40% ethephon stock solution (i.e. effective concentration 5%) for each time of water or paste.

calculation:

(1) Concentration preparation method:

Required quantity of technical drug=(weight to be dispensed × Use concentration%) ÷ (technical concentration%)

Carrier weight=required weight - technical requirement

(2) Dose allocation method:

Technical drug demand=drug consumption per plant × Number of plants

Carrier weight=number of plants × Required capacity per plant

29. How to conduct ethephon stimulation tapping for abnormal rubber trees?

The rubber trees were attacked by typhoons and cold waves, the branches, leaves and trunks were damaged to varying degrees, and the stored organic nutrients were also consumed to varying degrees. Therefore, it is not allowed to apply medicine and cut glue according to the method of normal rubber tree. No ethephon shall be used for wind and cold damage trees of grade 3-5 in the year of injury; The trees with Grade 3 wind and cold damage that reach the normal tapping standard in the second year of injury can be sprayed with medicine to stimulate tapping; Grade 4~5 wind and damaged trees can only be used with ethephon if they meet the re-cutting standard, but the number of times and concentration of application should be reduced. In the period of no application, the knife should be reduced, which is 1/3~1/2 of the normal tree.

There are also some dead bark trees and canker trees. Their gum production mechanism (milk tube system and bark) has been damaged, and local nutrition deficiency has occurred. These trees should not use ethephon during the disease expansion period; After the second year of ulcer disease, when the focus has stabilized, the dead skin disease tree can use ethephon appropriately after the stabilizer, but the number of times of applying medicine and the number of glue cutting knives should be appropriately reduced, or the method of cutting and stopping should be adopted.

30. Why should the rubber trees be fertilized with ethephon? How should they be added?

Rubber synthesis requires a lot of nutrients. Fertilizer is the food intake of rubber trees. Under normal circumstances, regular rubber cutting requires a certain amount of nutrients every year. After the use of ethephon, the amount of glue discharged from the rubber tree will be multiplied, and the need for nutrient supplement will be increased. According to the measurement, the gum tree loses 8 grams of nitrogen, 2 grams of phosphorus, 7 grams of potassium and 3 grams of magnesium for each kilogram of dry gum added; Therefore, it is necessary to apply more fertilizer to rubber trees to stimulate ethephon, so as to ensure the nutrient requirements of rubber trees. It has been measured that when ethephon stimulates the increase of dry rubber yield by 10-15%, the nutrient consumption discharged with latex increases by 20-30%. If no fertilizer is applied, it will not only affect the yield increase effect, but also reduce the nutrient content of leaves, inhibit the growth of rubber trees, affect the normal metabolic activities of rubber trees, and reduce the ability of rubber production. Therefore, the application of ethephon-stimulated rubber trees requires a large amount of organic fertilizer. Organic fertilizer not only contains nitrogen, phosphorus and potassium, but also can improve soil structure and promote root growth. Its effect is better than chemical fertilizer. Generally, 100 kg of organic fertilizer should be applied to each plant every year, and 0.5~1 kg of ammonium sulfate and 0.25~0.5 kg of superphosphate should be applied when conditions permit. Organic fertilizer and phosphorus fertilizer shall be applied from the end of cutting in winter to the beginning of cutting in the next year, and 60% of nitrogen fertilizer and potassium fertilizer shall be applied from the beginning of cutting to the first application of ethephon to promote the growth of the first canopy leaf and produce more nutrients. The remaining nitrogen fertilizer can be applied 10 to 15 days before the high-yield season. Water and fertilizer should be applied in dry season.

31. Why should rubber trees be shallowly cut when using ethephon?

The bark of rubber tree is usually divided into outer bark, hard bark, soft bark, water sac skin and cambium from outside to inside. The soft bark layer is composed of parenchyma cells, sieve tubes and milk tubes, with few stone cells, soft skin and light yellow color, so it is also called yellow bark layer, which is the main cortex for latex production.

Conventional tapping usually requires deep tapping to obtain yield. After using ethephon, shallow tapping can obtain much more yield than conventional tapping. Due to the large increase in the amount of glue after application, the regeneration of latex needs to supplement a large amount of water and nutrients. Their transportation in the rubber tree is mainly through the sieve tubes of the ducts, and the sieve tubes with functional functions are in the water sac bark of the bark. Deep cutting not only causes a large loss of nutrients, but also partially cuts off the transportation. The sugar and nutrients mobilized by ethylene cannot be transported into the latex tube in time, which weakens the rubber production function of the latex tube. Experience has proved that deep cutting after coating will cause dry skin on the cutting surface, shrink the rubber discharge line, and even dry the cutting line. Therefore, in order to protect the health of rubber trees and long-term high and stable yield, rubber trees must be shallowly cut after using ethephon.

32. Why can rubber trees save gum bark by using ethephon?

The latex tube is contained in the bark, and the bark of the rubber tree is an important basis for the production of rubber. In a sense, the bark is the workshop for manufacturing latex, and the latex tube is the machine for manufacturing latex. Saving the bark is to preserve the plants and machines that produce rubber, and wasting the bark is to destroy the plants and machines that produce rubber.

For conventional tapping, the cutting time is 15 knives per month, the bark consumption is 2~2.5 cm, and the bark consumption is about 20 cm per year; After using ethylene, rubber trees generally cut rubber by 9 to 10 knives per month, consuming 1.5 cm of bark, and only 13 to 15 cm of bark per year. It can be seen that the use of ethephon in rubber trees can significantly save the production of rubber bark and prolong the economic life of rubber trees due to the reduction of rubber cutting trees.

33. Why can rubber trees use ethephon to save rubber cutting labor?

Under conventional rubber cutting, the rubber latex regeneration generally takes 24 hours to complete, so the s/2 and d/2 cutting systems are usually adopted (that is, the secant of one-half of the tree circumference is cut once a day). The use of ethephon in rubber trees has expanded the influence area of rubber drainage, and the amount of rubber drainage has increased significantly. However, the regeneration of rubber latex needs to supplement a lot of water and nutrients, so it takes 48 hours to complete the regeneration of rubber latex. Therefore, the s/2 and d/3 cutting systems are usually used (that is, the cutting line of one-half of the tree circumference is cut every three days).

The use of ethephon for rubber trees generally reduces the cutting times by one third, so it can save a lot of rubber cutting labor. People can also use the saved rubber cutting labor to strengthen the management of rubber trees, so as to improve the rubber production potential of rubber trees and better improve the rubber production of rubber trees.

34. How about the economic benefits of using ethephon correctly to stimulate tapping?

The effect of ethephon on increasing yield of rubber trees is satisfactory. According to the statistics of the 12-year (1972-1983) experiment of 28.70 mu rubber seedlings in the fifth team of the South China Tropical Crop Research Institute, the average annual tapping of trees stimulated by ethephon was 76.80, and the average annual tapping of trees stimulated by ethephon was 106.50, and the average annual tapping of trees stimulated by ethephon was 29.70 times less than that of the control, with a reduction of 28%; The average annual yield of dry gum per mu of the stimulation tree is 54.50 kg, and the dry gum per plant is 3.73 kg, while the average yield of dry gum per mu of the control tree is 31.30 kg, and the dry gum per plant is 2.35 kg, which is 54.50% higher than that of the control tree; After deducting costs such as ethephony, the net income of each mu of rubber park can be increased by 70 yuan per year.

In addition, according to the statistics of 23000 mu of state-owned Nanmao Farm, 480000 rubber seedling trees have been used in a large area for eight years (1975-1982) to stimulate the tapping of ethephon, the average annual tapping of ethephon trees is 98, 142.30, 45% less than that of the control trees; The average annual yield of dry rubber per mu of pesticide application is 48.90 kg, and the average annual yield of dry rubber per mu of control tree is 32.70 kg, with an average increase of 24.40%; In the eight years, a total of 1957.66 tons of dry rubber have been increased. In addition to processing costs, a total of 1096300 yuan of income has been increased by 5600 yuan per ton of dry rubber. After deducting 109000 yuan of ethephony cost, the net profit was 10.854 million yuan, with an average annual net profit of 1.35 million yuan and an annual increase of 58.70 yuan per mu of rubber.

At present, the low-yield rubber plantation trees in the national agricultural reclamation system generally use ethephon to stimulate tapping, which generally increases the yield by more than 15%. In the future, if the high-yield rubber budding trees can use ethephon to stimulate tapping, the economic benefits will be higher.