Method for predicting spraying time of cotton defoliation ripening agent

Abstract

The invention relates to the technical field of agriculture, in particular to a time prediction method for spraying a cotton defoliation ripening agent. The invention provides a method for predicting time for spraying a cotton defoliation ripening agent. The method comprises the following steps: calculating a temperature threshold value for realizing rapid cotton defoliation in an area to be sprayed according to formulas y1 = 4.81 Tmax-75.65 and y2 = 3.85 GDDs + 28.13; the temperature data of the area to be sprayed with the defoliating ripener in recent 10-15 years are counted, and the corresponding date for spraying the defoliating ripener in the determined area is calculated according to the temperature threshold value of rapid defoliating. According to the method provided by the invention, the optimal time for spraying the defoliation ripening agent for realizing rapid defoliation of the cotton leaves can be determined, the defoliation rate of the cotton leaves is remarkably increased, and the impurity rate of machine-harvested seed cotton is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of agriculture, and in particular to a method for predicting the time for spraying a cotton defoliating and ripening agent. Background Art

[0002] Defoliation and ripening are essential steps in the full mechanization of cotton picking. They can improve cotton picking efficiency, reduce impurity content in seed cotton, and enhance raw cotton quality. Proper application of defoliation and ripening agents not only produces effective defoliation and ripening results, but also reduces negative impacts on yield and quality. Defoliation and ripening agent spraying adheres to the principle of "uneven timing of boll opening, uneven timing of boll opening." A field boll opening rate of 30% to 40% is commonly used as a common method to determine the optimal time to spray defoliation and ripening agents. However, this does not take into account the characteristics of the cotton variety and boll morphology, making it difficult to balance the contradiction between cotton yield and fiber quality under defoliation and ripening conditions. Efficient defoliation and ripening are closely related to the prevailing temperature. The right time to spray defoliation and ripening agents is crucial, but also difficult to determine. Summary of the Invention

[0003] To solve the above problems, the present invention provides a method for predicting the time for spraying a cotton defoliant and ripening agent. The method provided by the present invention can determine the optimal spraying time for the defoliant and ripening agent to achieve rapid defoliation of cotton in different regions.

[0004] In order to achieve the above object, the present invention provides the following technical solutions:

[0005] The present invention provides a method for predicting the time of spraying a cotton defoliant and ripening agent, comprising the following steps:

[0006] (1) According to the formula y1 = 4.81T max -75.65 and y2=3.85GDD s +28.13 Calculate the daily maximum temperature threshold required for the sprayed area to reach y1 and the daily effective accumulated temperature threshold of ≥12℃ required to reach y2; where y1 is the target defoliation rate of cotton 7 days after spraying the defoliation and ripening agent, T max is the daily maximum temperature threshold required under the condition of y1; y2 is the target defoliation rate of cotton 7 days after spraying defoliation and ripening agent, GDD s The daily effective accumulated temperature threshold of ≥12°C required under condition y2;

[0007] (2) Collecting temperature data for the past 10 to 15 years in the area where the defoliant and ripening agent is to be sprayed; the temperature data includes the daily maximum average temperature and the average value of the daily effective accumulated temperature ≥12°C on the same day in different years;

[0008] (3) The date when the daily maximum average temperature is the same as the daily maximum temperature threshold is classified as the high temperature period; the date when the daily average effective accumulated temperature ≥12℃ is the same as the daily effective accumulated temperature threshold ≥12℃ is classified as the accumulated temperature period; if the high temperature period and the accumulated temperature period overlap, the overlapping date is the date for spraying defoliants and ripening agents; if the high temperature period and the accumulated temperature period do not overlap, the subsequent high temperature period or accumulated temperature period is the date for spraying defoliants and ripening agents.

[0009] Preferably, the area to be sprayed includes the northwest inland cotton area.

[0010] Preferably, the northwestern inland cotton region includes the Xinjiang cotton-producing region.

[0011] Preferably, the statistical date of the temperature data in the past 10 to 15 years is from August 20 to September 30.

[0012] Preferably, when the region is the cotton-producing region of Xinjiang, if the cotton leaf shedding rate is ≥55%, the maximum daily temperature in the region where the defoliation and ripening agent is sprayed is ≥27.2°C and the effective accumulated temperature is ≥12°C / day and ≥7.0°C / day;

[0013] If the cotton leaf shedding rate is ≥60%, the maximum daily temperature in the area where the defoliation and ripening agent is sprayed should be ≥28.2℃ and the effective accumulated temperature should be ≥12℃ / day or ≥8.3℃ / day;

[0014] If the cotton leaf shedding rate is to be ≥65%, the maximum daily temperature in the area where the defoliant and ripening agent is to be sprayed must be ≥29.2°C and the effective accumulated temperature must be ≥12°C per day and ≥9.6°C per day.

[0015] Preferably, the cotton variety is an early maturing variety or a medium early maturing variety.

[0016] Preferably, the defoliation and ripening agent comprises thidiazuron wettable powder and ethephon water-soluble agent; the mass concentration of the thidiazuron wettable powder is 80%, and the concentration of the ethephon water-soluble agent is 40%.

[0017] The present invention provides the application of the time prediction method described in the above technical solution in improving cotton yield.

[0018] The present invention provides the application of the time prediction method described in the above technical solution in improving the quality of cotton fibers.

[0019] Preferably, the cotton fiber quality includes at least one of the following:

[0020] 1) Increase the average length of the upper half of the fiber;

[0021] 2) Improve fiber breaking strength;

[0022] 3) Reduce the leaf impurity rate of seed cotton.

[0023] Beneficial effects:

[0024] The present invention provides a method for predicting the time of spraying a cotton defoliant and ripening agent, comprising the following steps:

[0025] (1) According to the formula y1 = 4.81T max -75.65 and y2=3.85GDD s +28.13 Calculate the daily maximum temperature threshold required for the sprayed area to reach y1 and the daily effective accumulated temperature threshold of ≥12℃ required to reach y2; where y1 is the target defoliation rate of cotton 7 days after spraying the defoliation and ripening agent, T max is the daily maximum temperature threshold required under the condition of y1; y2 is the target defoliation rate of cotton 7 days after spraying defoliation and ripening agent, GDD s The daily effective accumulated temperature threshold of ≥12°C required under condition y2;

[0026] (2) Collecting temperature data for the past 10 to 15 years in the area where the defoliant and ripening agent is to be sprayed; the temperature data includes the daily maximum average temperature and the average value of the daily effective accumulated temperature ≥12°C on the same day in different years;

[0027] (3) The date when the daily maximum average temperature is the same as the daily maximum temperature threshold is classified as the high temperature period; the date when the daily effective accumulated temperature average value ≥12℃ is the same as the daily effective accumulated temperature threshold ≥12℃ is classified as the accumulated temperature period; if the high temperature period and the accumulated temperature period overlap, the overlapping date is the date for spraying the defoliation and ripening agent; if the high temperature period and the accumulated temperature period do not overlap, the subsequent high temperature period or accumulated temperature period is the date for spraying the defoliation and ripening agent. The method provided by the present invention can promote the sustainability of cotton planting and production, achieve a leaf shedding rate of more than 65% to 85% within 7 days after spraying the defoliation and ripening agent, a leaf shedding rate of ≥90% before harvest, and a leaf impurity rate of less than 7.5% for machine-picked seed cotton, greatly reducing the cotton cleaning and processing procedures. The technical solution of the present invention can determine the spraying period and standard of the defoliation and ripening agent, which is of great significance for achieving good defoliation and ripening effects and synergistically improving yield and quality, and meets the needs of modern agricultural development. DETAILED DESCRIPTION

[0028] The present invention provides a method for predicting the time of spraying a cotton defoliant and ripening agent, comprising the following steps:

[0029] (1) According to the formula y1 = 4.81T max -75.65 and y2=3.85GDD s +28.13 Calculate the daily maximum temperature threshold required for the sprayed area to reach y1 and the daily effective accumulated temperature threshold of ≥12℃ required to reach y2; where y1 is the target defoliation rate of cotton 7 days after spraying the defoliation and ripening agent, T maxis the daily maximum temperature threshold required under the condition of y1; y2 is the target defoliation rate of cotton 7 days after spraying defoliation and ripening agent, GDD s The daily effective accumulated temperature threshold of ≥12°C required under condition y2;

[0030] (2) Collecting temperature data for the past 10 to 15 years in the area where the defoliant and ripening agent is to be sprayed; the temperature data includes the daily maximum average temperature and the average value of the daily effective accumulated temperature ≥12°C on the same day in different years;

[0031] (3) The date when the daily maximum average temperature is the same as the daily maximum temperature threshold is classified as the high temperature period; the date when the daily effective accumulated temperature average value ≥12℃ is the same as the daily effective accumulated temperature threshold ≥12℃ is classified as the accumulated temperature period; if the high temperature period and the accumulated temperature period overlap, the overlapping date is the date for spraying the defoliant and ripening agent; if the high temperature period and the accumulated temperature period do not overlap, the subsequent high temperature period or accumulated temperature period is the date for spraying the defoliant and ripening agent. If the high temperature period and the accumulated temperature period have overlapping dates, the overlapping date is the corresponding date for regional spraying of the defoliant and ripening agent. If the high temperature period and the accumulated temperature period do not have overlapping dates, the subsequent date shall prevail. For example, if the high temperature period is August 25 and the accumulated temperature period is August 27, then August 27 is the date for regional spraying of the defoliant and ripening agent. The defoliant and ripening agent of the present invention is sprayed only once.

[0032] According to the formula y1=4.81T max -75.65 and y2=3.85GDD s +28.13 When the daily maximum temperature threshold required for the spraying area to reach y1 and the daily effective accumulated temperature threshold required to reach y2 of ≥12°C are calculated, the values ​​of y1 and y2 are the target defoliation rate of cotton. For example, if the target defoliation rate of cotton is 55%, the values ​​of y1 and y2 are both 55 when substituted into the formula. max -75.65 and y2=3.85GDD s +28.13 was calculated using a linear function fit based on the temperature and leaf drop rate within 7 days after spraying the defoliant and ripening agent. Temperature is a key environmental factor affecting leaf drop rate, showing a significant positive correlation with the maximum daily temperature and daily effective accumulated temperature ≥12°C. The two formulas above were derived using linear fitting.

[0033] The technical solution of the present invention can determine the optimal spraying time for different areas, so as to spray the defoliation and ripening agent in a timely manner to promote rapid leaf shedding, concentrated cotton boll ripening and concentrated cotton boll opening, and improve mechanical harvesting efficiency and cotton quality.

[0034] As an optional embodiment, the cotton variety of the present invention is an early-maturing variety or a medium-early-maturing variety.

[0035] As an optional embodiment, the target defoliation rate of cotton of the present invention is divided into three conditions: ≥55%, ≥60%, and ≥65%. The range of the target defoliation rate of cotton is divided according to the defoliation rate 7 days after spraying the defoliation and ripening agent in practice. When determining the temperature condition based on the target defoliation rate of cotton, the temperature condition with the smallest difference with the leaf shedding rate is used as the standard. For example, when determining the temperature condition with a leaf shedding rate of 70%, the temperature condition with a leaf shedding rate of ≥65% is used as the standard.

[0036] As an optional embodiment, when the area to be sprayed includes the Northwest Inland Cotton Area, the statistical date of the temperature data of the present invention for the past 10 to 15 years is from August 20 to September 30. As an optional embodiment, the Northwest Inland Cotton Area includes the Xinjiang cotton-producing area. In a specific embodiment of the present invention, the effect is verified by taking the Xinjiang cotton-producing area as an example. In a specific embodiment of the present invention, when the area is the Xinjiang cotton-producing area, if the cotton leaf shedding rate is ≥55%, the present invention requires that the daily maximum temperature of the area where the defoliation and ripening agent is sprayed is ≥27.2°C and the daily effective accumulated temperature of ≥12°C is ≥7.0°C / day; if the cotton leaf shedding rate is ≥60%, the daily maximum temperature of the area where the defoliation and ripening agent is sprayed is ≥28.2°C and the daily effective accumulated temperature of ≥12°C is ≥8.3°C / day; if the cotton leaf shedding rate is ≥65%, the daily maximum temperature of the area where the defoliation and ripening agent is sprayed is ≥29.2°C and the daily effective accumulated temperature of ≥12°C is ≥9.6°C / day.

[0037] As an optional embodiment, the time prediction method of the present invention further includes generating a regional schedule for spraying the defoliant and ripening agent based on the spraying areas and the dates for spraying the defoliant and ripening agent. This regional schedule provides intuitive information to agricultural production managers, helping them rationally plan spraying operations, including personnel deployment, equipment preparation, and agent procurement, thereby improving the efficiency and scientific nature of production management.

[0038] In a specific embodiment of the present invention, using temperature data from 2008 to 2017 in Xinjiang as an example, if a leaf drop rate of ≥55% is achieved within 7 days after spraying a defoliant and ripening agent, the spraying time for all cities and counties in Xinjiang is generally between September 9th and 17th. Shawan City sprayed the defoliant and ripening agent the earliest, on August 31st, and Turpan City sprayed the latest, on October 7th. Bole City, Kuqa County, Hutubi County, Shihezi City, Jinghe County, Wusu City, and Wujiaqu City sprayed the defoliant and ripening agent between September 5th and 10th. Yuli County, Shule County, Shaya County, Luntai County, Qiemo County, Maigaiti County, and Bachu County sprayed the defoliant and ripening agent between September 16th and 20th. The remaining counties and cities in Xinjiang sprayed the defoliant and ripening agent between September 11th and 15th.

[0039] If the cotton defoliation rate target of 60% or higher is achieved, the earliest spraying time for defoliation and ripening agents in Shawan, Bole, Kuqa, Hutubi, Aksu, and Shache counties in Xinjiang is August 27 to September 5. Application of defoliation and ripening agents in Luntai, Qiemo, and Bachu counties can be delayed to September 11 to 12. Turpan's spraying time is the latest, October 2. The rest of Xinjiang's counties and cities should spray defoliation and ripening agents from September 6 to 10.

[0040] If leaf shedding rate reaches 65% or higher within 7 days after spraying, all cities and counties should apply defoliants and ripening agents around September 1. The earliest spraying time in Shawan City, Kuqa County, Shache County, Bole City, Hutubi County, Aksu City, Aral City, and Maigaiti County is August 24-31; the latest in Turpan City is September 27. The rest of Xinjiang's cities and counties should spray defoliants and ripening agents between September 1 and 5.

[0041] As an optional embodiment, the present invention has no particular limitation on the type of the defoliant and ripening agent, and conventional products can be used. In a specific embodiment of the present invention, the defoliant and ripening agent comprises 80% wettable powder thidiazuron and 40% aqueous ethephon.

[0042] The present invention provides the application of the time prediction method described in the above technical solution in improving cotton yield.

[0043] The present invention provides the application of the time prediction method described in the above technical solution in improving cotton quality.

[0044] As an optional embodiment, the cotton fiber quality of the present invention includes at least one of the following: 1) increasing the average length of the upper half of the fiber; 2) increasing the fiber breaking strength; 3) reducing the seed cotton leaf impurity rate.

[0045] The method provided by the present invention can determine the optimal spraying time for a cotton defoliant and ripening agent, promoting the sustainability of cotton cultivation and production. It can achieve a leaf shedding rate of 65% to 85% or higher within 7 days after spraying the defoliant and ripening agent, a leaf shedding rate greater than 90% before harvest, and a leaf impurity rate of less than 7.5% for machine-picked seed cotton, thereby improving cotton fiber quality. The present invention is of great significance for determining the spraying time of a defoliant and ripening agent, achieving a good defoliation and ripening effect and synergistically improving yield and quality, meeting the needs of modern agricultural development.

[0046] In order to further illustrate the present invention, the technical solutions provided by the present invention are described in detail below in conjunction with the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0047] Example 1

[0048] 1. Based on the temperature indicators in Xinjiang over the past 10 to 15 years, the maximum temperature from August 20 to September 30, the daily effective accumulated temperature ≥12°C and the daily sequence, and the temperature and defoliation rate within 7 days after spraying defoliants and ripening agents were linearly fitted using Excel to calculate the date (daily sequence) corresponding to the target defoliation rate, that is, the appropriate time to spray defoliants and ripening agents in various cities and counties in Xinjiang.

[0049] The resulting formula is y1 = 4.81T max -75.65 and y2=3.85GDD s +28.13. Among them, y1 is the target defoliation rate of cotton 7 days after spraying defoliation and ripening agent, T max is the maximum daily temperature required under the condition of y1; y2 is the target defoliation rate of cotton 7 days after spraying the defoliation and ripening agent, GDD s It is the daily effective accumulated temperature ≥12℃ required under the y2 condition.

[0050] According to the formula y1=4.81T max -75.65, y2=3.85GDD s +28.13, it is calculated that within 7 days after spraying the defoliant, in order to achieve a leaf shedding rate of ≥55%, the daily maximum temperature must be ≥27.2℃ and the daily effective accumulated temperature must be ≥12℃ or ≥7.0℃ / day; to achieve a leaf shedding rate of ≥65%, the daily maximum temperature must be ≥29.2℃ and the daily effective accumulated temperature must be ≥12℃ or ≥9.6℃ / day.

[0051] Table 1 Temperature conditions required to achieve different leaf defoliation rates within 7 days after spraying defoliants

[0052]

[0053] 2. Based on the cotton planting area in Xinjiang, China from 2008 to 2017, we selected 21 cities and counties (Bole City, Jinghe County, Wusu City, Shawan City, Shihezi City, Hutubi County, Wujiaqu City, Turpan City, Hami City, Korla City, Yuli County, Luntai County, Qiemo County, Aksu County, Kuche County, Shaya County, Aral City, Bachu County, Makit County, Shache County, and Atushi County) and collected temperature data for each city and county (China Meteorological Data Network: http: / / data.cma.cn / site / index.html). Daily maximum temperatures and effective accumulated temperatures ≥12°C from 2008 to 2017 were calculated.

[0054] Based on the temperature indicators in Xinjiang from 2008 to 2017, the daily maximum temperature and the daily effective accumulated temperature ≥12℃ from 2008 to 2017 were calculated. The statistical time range is from August 20 to September 30.

[0055] The daily maximum temperature and daily effective accumulated temperature ≥12°C in each city and county in Xinjiang were linearly fitted with the daily sequence using Excel. Combined with the thresholds of daily maximum temperature and daily effective accumulated temperature ≥12°C in Table 1, the corresponding date (daily sequence) was calculated using Excel linear function, that is, the time suitable for spraying defoliants and ripening agents in each city and county.

[0056] 3. According to the corresponding dates (daily sequence) of spraying defoliants, see Table 2.

[0057] If a leaf drop rate of 55% or higher is achieved within 7 days of spraying defoliants and ripening agents, spraying should generally be carried out between September 9th and 17th in all cities and counties in Xinjiang. Shawan City sprayed the earliest, on August 31st, while Turpan City sprayed the latest, on October 7th. Bole City, Kuqa County, Hutubi County, Shihezi City, Jinghe County, Wusu City, and Wujiaqu City sprayed between September 5th and 10th. Yuli County, Shule County, Shaya County, Luntai County, Qiemo County, Makit County, and Bachu County can delay spraying to September 16th and 20th. The remaining cities and counties in Xinjiang sprayed between September 11th and 15th.

[0058] If the cotton defoliation rate target of 60% or higher is achieved, the earliest spraying time for defoliation and ripening agents in Shawan, Bole, Kuqa, Hutubi, Aksu, and Shache counties in Xinjiang is August 27 to September 5. Application of defoliation and ripening agents in Luntai, Qiemo, and Bachu counties can be delayed to September 11 to 12. Turpan's spraying time is the latest, October 2. The rest of Xinjiang's counties and cities should spray defoliation and ripening agents from September 6 to 10.

[0059] If leaf shedding rate reaches 65% or higher within 7 days after spraying, all cities and counties should apply defoliants and ripening agents around September 1. The earliest spraying time in Shawan City, Kuqa County, Shache County, Bole City, Hutubi County, Aksu City, Aral City, and Maigaiti County is August 24-31; the latest in Turpan City is September 27. The rest of Xinjiang's cities and counties should spray defoliants and ripening agents between September 1 and 5.

[0060] Table 2 Regional distribution of timely defoliant spraying in cotton-producing areas of Xinjiang

[0061]

[0062] Note: The areas in Table 2 basically cover all cotton-growing areas in Xinjiang.

[0063] Example 2 carried out a four-year field trial of defoliation and ripening agents

[0064] The cotton variety is Xinluzao No. 74.

[0065] From 2019 to 2022, a four-year field trial of defoliants and ripening agents was carried out in Shihezi City, Shuanghe City, and Aral City. The defoliant was thiadiazole (80% wettable powder) and ethephon (40% aqueous solution), with the dosage per hectare being 450g and 1350mL respectively.

[0066] Shuanghe City sprayed defoliants on August 29, Shihezi on September 1, and Alaer on August 30. Shuanghe City was chosen because it is somewhat representative of Bole City, and the two urban areas are only about 20 kilometers apart.

[0067] Comparative Example 1

[0068] From 2019 to 2022, a four-year field trial of defoliants and ripening agents was carried out in Shihezi City, Shuanghe City, and Aral City. The defoliant was thiadiazole (80% wettable powder) and ethephon (40% aqueous solution), with the dosage per hectare being 450g and 1350mL respectively.

[0069] The defoliant spraying time of comparative example 1 was consistent with the local management time. The specific spraying time was: September 12 in Shihezi City, September 13 in Shuanghe City, and September 17 in Aral City.

[0070] Table 3 shows the statistical data of the defoliation rate 7 days after spraying, the defoliation rate 21 days after spraying, the average length of the upper half of the cotton fiber (length), the breaking strength, the micronaire value and the cotton seed yield of Example 2 and Comparative Example 1.

[0071] Investigation and calculation of leaf shedding rate:

[0072] Select 10 to 20 representative and continuous cotton plants in each plot for fixed-point investigation. Starting from the day of spraying defoliant, the number of leaves per plant was investigated every 7 days. i ) refers to the difference between the number of leaves per plant on the day of defoliant spraying (L0) and the number of leaves per plant on the ith day after spraying (L i ) is the percentage of L0, and the calculation method is shown in formula (1).

[0073]

[0074] Fiber quality: 30 to 50 cotton bolls of uniform size were collected and air-dried and ginned uniformly. The lint cotton samples were sent to the Cotton Quality Supervision, Inspection and Testing Center of the Ministry of Agriculture and Rural Affairs (Urumqi, Xinjiang and Anyang, Henan) to measure the average length of the upper half of the cotton fiber (length) and breaking strength (specific strength).

[0075] Yield: Field yield surveys were conducted during the cotton boll-opening period. Three 3m x 2.3m plots were randomly selected in each plot. The total number of plants and bolls was counted to determine the boll number per unit area. Seed cotton was collected from each plot and converted to seed cotton yield per unit area.

[0076] The Shihezi Fiber Inspection Institute was commissioned to test the machine-picked seed cotton leaf impurity rate of Example 2, which was less than 7.5%.

[0077] It can be seen that compared with the comparative example 1 (traditional spraying time), the defoliation rate of Example 2 (the time predicted by the present invention) increased by 6.5% to 12.0% 7 days after spraying, and the defoliation rate before harvest increased by 9.4% to 10.9%; the average length of the upper half of the cotton fiber and the breaking strength increased by an average of 0.4 mm and 1.1 cN tex. -1 , seed cotton yield increased by 5.1% to 13.0%.The regional time distribution map of the suitable spraying time of the defoliant and ripening agent determined according to the present invention can accurately predict and guide the application of the defoliant.

[0078] Table 3 Analysis of the difference in leaf removal rate, yield and quality between Example 2 and Comparative Example 1

[0079]

[0080]

[0081] In summary, the predicted spraying time of the present invention can improve the defoliation rate, cotton yield and quality of cotton.

[0082] Although the above embodiment provides a detailed description of the present invention, it is only a part of the embodiments of the present invention, not all of the embodiments. People can also obtain other embodiments based on this embodiment without creativity, and these embodiments all fall within the scope of protection of the present invention.

Claims

1. A method for predicting the time of spraying a cotton defoliant and ripening agent, characterized in that: The following steps are involved: (1) According to the formula y1 = 4.81T max -75.65 and y2=3.85GDD s +28.13 Calculate the daily maximum temperature threshold required for the sprayed area to reach y1 and the daily effective accumulated temperature threshold of ≥12℃ required to reach y2; where y1 is the target defoliation rate of cotton 7 days after spraying the defoliation and ripening agent, T max is the daily maximum temperature threshold required under the condition of y1; y2 is the target defoliation rate of cotton 7 days after spraying defoliation and ripening agent, GDD s The daily effective accumulated temperature threshold of ≥12°C required under condition y2; (2) Collecting temperature data for the past 10 to 15 years in the area where the defoliant and ripening agent is to be sprayed; the temperature data includes the daily maximum average temperature and the average value of the daily effective accumulated temperature ≥12°C on the same day in different years; (3) The date when the daily maximum average temperature is the same as the daily maximum temperature threshold is classified as the high temperature period; the date when the daily average effective accumulated temperature ≥12℃ is the same as the daily effective accumulated temperature threshold ≥12℃ is classified as the accumulated temperature period; if the high temperature period and the accumulated temperature period overlap, the overlapping date is the date for spraying defoliants and ripening agents; if the high temperature period and the accumulated temperature period do not overlap, the subsequent high temperature period or accumulated temperature period is the date for spraying defoliants and ripening agents.

2. The time prediction method according to claim 1, characterized in that The area to be sprayed includes the northwest inland cotton area.

3. The time prediction method according to claim 2, characterized in that The statistical date for temperature data in the past 10 to 15 years is from August 20 to September 30.

4. The time prediction method according to claim 2 or 3, characterized in that: The northwestern inland cotton area includes the Xinjiang cotton-producing area.

5. The time prediction method according to claim 4, characterized in that: When the area is the cotton-producing area of ​​Xinjiang, if the cotton leaf shedding rate is ≥55%, the area where the defoliation and ripening agent is sprayed must have a daily maximum temperature ≥27.2°C and a daily effective accumulated temperature ≥12°C ≥7.0°C / day; If the cotton leaf shedding rate is ≥60%, the maximum daily temperature in the area where the defoliation and ripening agent is sprayed should be ≥28.2℃ and the effective accumulated temperature should be ≥12℃ / day or ≥8.3℃ / day; If the cotton leaf shedding rate is to be ≥65%, the maximum daily temperature in the area where the defoliant and ripening agent is to be sprayed must be ≥29.2°C and the effective accumulated temperature must be ≥12°C per day and ≥9.6°C per day.

6. The time prediction method according to claim 1, characterized in that The defoliation and ripening agent comprises thidiazuron wettable powder and ethephon water agent; the mass concentration of the thidiazuron wettable powder is 80%, and the concentration of the ethephon water agent is 40%.

7. The time prediction method according to claim 5, characterized in that: The cotton variety is an early-maturing variety or a medium-early-maturing variety.

8. Use of the time prediction method according to any one of claims 1 to 7 in increasing cotton yield.

9. Use of the time prediction method according to any one of claims 1 to 7 in improving cotton fiber quality.

10. The use according to claim 8 or 9, characterized in that: The cotton fiber quality includes at least one of the following: 1) Increase the average length of the upper half of the fiber; 2) Improve fiber breaking strength; 3) Reduce the leaf impurity rate of seed cotton.

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