Method for direct seeding and multiple cropping of cotton after wheat in southern Xinjiang

Abstract

The invention discloses a method for direct seeding and multiple cropping of cotton after wheat in southern Xinjiang, and belongs to the technical field of cotton planting in southern Xinjiang areas. According to the method, cotton varieties with compact plant types are selected, the plant spacing in a wide-narrow planting mode is shortened, the number of plants is increased, meanwhile, the number of cotton bolls of a single plant is reduced, water and fertilizer integrated management measures are taken in cooperation, and the method adapts to accumulated temperature changes between the winter wheat harvest period and the frost season in June by means of the population effect advantage of cotton crops; high yield of cotton is guaranteed, and double cropping of winter wheat and cotton in one year is realized.

Description

Technical Field

[0001] The present invention relates to the technical field of cotton planting in the southern Xinjiang region, and more specifically, to a method for direct seeding and multiple cropping of cotton after wheat in southern Xinjiang. Background Art

[0002] Due to the geographical location of high latitude and high altitude, the sunshine duration in Xinjiang is much longer than that in other provinces. Also, due to the obstruction of the Tianshan Mountains, warm and humid air currents cannot cross the Tianshan Mountains and enter southern Xinjiang, resulting in scarce rainfall in southern Xinjiang. The annual rainfall is only 20 - 100 millimeters, far lower than the 100 - 500 millimeters in northern Xinjiang. The arid climate and scarce rainfall in southern Xinjiang limit crop planting, making the cultivation mode in southern Xinjiang almost one - crop - per - year, further leading to prominent problems such as low utilization rate of land resources and low agricultural production efficiency in southern Xinjiang. In many areas of southern Xinjiang, the accumulated temperature above 10°C exceeds 4100°C, the frost - free period exceeds 200 days, and the sunshine duration is sufficient. From April to September each year, the sunshine duration reaches 1460 - 1980 hours, and the sunshine percentage is 60 - 80%. The main crops in southern Xinjiang of Xinjiang include cotton, wheat, corn, rice, etc. Among them, cotton is the main crop in southern Xinjiang, and wheat is winter wheat. After the winter wheat is harvested in June, there is still an accumulated temperature of 1900 - 2800°C until the frost period. These conditions provide a relatively long suitable temperature period for crop growth, making it possible for some areas to have two crops a year. If this period can be fully utilized, it will bring great benefits to agricultural production and farmers' income increase.

[0003] However, from June to mid - August, the temperature is high, and from late September to mid - October, the temperature drops rapidly and the effective accumulated temperature is low, with the defect of "one season is more than enough, but two seasons are not enough". For example, after the winter wheat is harvested, if the conventional cultivation method is used for multiple cropping of cotton, the boll - opening rate is extremely low, with a large risk. Farmers not only have no income but also suffer losses. Therefore, how to make full use of the period from the harvest of winter wheat in June to the frost period to achieve two crops a year of winter wheat and cotton is of great significance. Summary of the Invention

[0004] In view of the above problems, the present invention provides a method for direct seeding and multiple cropping of cotton after wheat in southern Xinjiang, which not only realizes two crops a year of winter wheat and cotton but also ensures a relatively high yield of cotton.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] A method for direct seeding and multiple cropping of cotton after wheat in southern Xinjiang, comprising the following steps:

[0007] S1: Land preparation and soil sealing

[0008] After harvesting winter wheat in the first ten days of June, plow and harrow the land to a depth of ≥25 cm to kill stubble and level the land, and conduct soil sealing to reduce weed growth;

[0009] S2: Sowing technology

[0010] a. Variety selection

[0011] Select extra-early maturing cotton varieties with a compact plant type, concentrated boll opening, a starting fruit height of ≥18 cm, a growth period of <120 days, and suitable for mechanical harvesting;

[0012] b. Sowing rate

[0013] After 5 hours of soil sealing, use a density of 21,000 plants per mu for wide-narrow row close planting in holes, with 1 seed per hole. When sowing, lay drip irrigation belts along the planting rows in the middle of the narrow rows and cover with plastic film;

[0014] c. Row and plant spacing configuration

[0015] Six rows per film, with row spacing of (13 + 63 + 13 + 63 + 13) cm and plant spacing of 7.5 cm. After sowing, drip water in time to emerge;

[0016] S3: Management after sowing

[0017] a. Releasing seedlings

[0018] When the emergence rate reaches 60%, break the film to release the seedlings;

[0019] b. Rational chemical regulation

[0020] Conduct chemical regulation 4 times during the whole growth period. Spray 0.3 - 0.5 g / mu of mepiquat chloride on the 5th - 6th true leaves, 0.8 - 1 g / mu on the 7th - 8th true leaves, 5 - 6 g / mu 7 days after topping, and 8 - 10 g / mu 14 days after topping;

[0021] c. Topping

[0022] Strictly determine the topping time according to the number of fruiting branches. Control the number of fruiting branches after topping at about 4, that is, remove the top when the number of fruiting branches per plant reaches 6;

[0023] d. Integrated water and fertilizer management

[0024] Start integrated water and fertilizer irrigation treatment 7 - 8 days after breaking the film to release the seedlings.

[0025] Preferably, the soil sealing in S1 is as follows: when the soil type is sandy soil, after spraying the soil surface with 33% pendimethalin emulsifiable concentrate at a dosage of 150 - 180 ml / mu, immediately mix the soil shallowly by 2 - 3 cm; when the soil type is clayey soil, after spraying the soil surface with 33% pendimethalin emulsifiable concentrate at a dosage of 130 - 150 ml / mu, immediately mix the soil shallowly by 2 - 3 cm.

[0026] Preferably, the specific method of drip irrigation for seedling emergence in step c of S2 is: conduct the first drip within 48 hours after sowing, conduct the second drip 3 - 5 days later, with a total of 2 drips, and the drip volume for each time is 15 m 3 / mu, and the drip head flow rate is 2.0 - 2.4 L / h.

[0027] Preferably, the integrated water and fertilizer management in step d of S3 is: a total of 13 drip irrigations are carried out, and the total water consumption is m 3 / mu. For the first to twelfth irrigations, urea, monoammonium phosphate, and potassium sulfate are applied with water droplets each time. No fertilizer is applied in the thirteenth irrigation, and the total dosages are 28.5 kg / mu, 17.5 kg / mu, and 17.7 kg / mu respectively.

[0028] The integrated water and fertilizer management directly transports water and fertilizers to the vicinity of the cotton roots. Not only does it reduce water evaporation and nutrient loss, significantly improving the utilization efficiency of water and fertilizers, but also reduces the loss and volatilization of fertilizers, reducing environmental pollution; more importantly, the integrated water and fertilizer irrigation can precisely irrigate and fertilize, meeting the water and nutrient requirements of cotton at different growth stages, ensuring both the number of effective cotton bolls and promoting the weight gain of single bolls, thereby improving the quality and total yield of cotton.

[0029] Preferably, the drip irrigation interval is as follows: for the first to seventh irrigations, irrigate once every 4 days; after the seventh irrigation, irrigate the eighth and ninth irrigations successively every 5 days; after the ninth irrigation, irrigate the tenth, eleventh, and twelfth irrigations successively every 6 days; the interval between the thirteenth irrigation and the twelfth irrigation is 8 days.

[0030] Preferably, the drip irrigation water volume is as follows: the irrigation volumes for the first and second irrigations are 20 m 3 / mu, the irrigation volume for the third irrigation is 22 m 3 / mu, the irrigation volumes for the fourth to eighth irrigations are 25 m 3 / mu, the irrigation volumes for the ninth to eleventh irrigations are 20 m 3 / mu, and the irrigation volumes for the twelfth and thirteenth irrigations are 15 m 3 / mu.

[0031] The above settings of the drip irrigation frequency and drip irrigation water volume changing with the number of drip irrigation times can meet the water requirements of cotton at different stages.

[0032] Preferably, the urea application rates for the first and second irrigations are 1 kg / mu and 1.5 kg / mu respectively. After the second irrigation, the urea application rate increases by 1 kg / mu successively until the fourth irrigation. The urea application rates for the fifth and sixth irrigations are both 4 kg / mu. After the sixth irrigation, the urea application rate decreases by 0.5 kg / mu successively until the ninth irrigation. The urea application rate for the tenth irrigation is 1.5 kg / mu, and then it decreases by 0.5 kg / mu successively until the twelfth irrigation. The monoammonium phosphate application rates for the first, second, third, and fourth irrigations are 0.5, 0.7, 0.8, and 1.5 kg / mu respectively. The monoammonium phosphate application rates for the fifth and sixth irrigations are both 2.5 kg / mu. The monoammonium phosphate application rates for the seventh to ninth irrigations are both 2 kg / mu. After the ninth irrigation, the monoammonium phosphate application rate decreases by 0.5 kg / mu successively until the twelfth irrigation. The application rate of potassium sulfate for the third irrigation is 1 kg / mu, and the application rates for the remaining drip irrigations are the same as those of monoammonium phosphate.

[0033] The above settings of the nitrogen, phosphorus, and potassium application rates varying with drip irrigation are aimed at meeting the fertilizer types and amounts required by cotton at different growth stages.

[0034] Preferably, the planting method further includes the following steps:

[0035] S4: Field management

[0036] a. Weeding

[0037] After emergence, manual weeding is mainly adopted. If the soil becomes hard and compact after the emergence irrigation, deep tillage should be carried out in a timely manner, with a tillage depth of 18 - 20 cm.

[0038] b. Ripening and defoliation

[0039] When the boll stage reaches 45 days, a defoliant is sprayed for ripening.

[0040] S5: Pest and disease control

[0041] For fusarium wilt and verticillium wilt: Before sowing cotton, soak and mix the seeds with pesticides, or choose coated cotton seeds; for lightly diseased fields, diseased plants should be removed in a timely manner, and soil disinfection should be carried out; during the budding stage, spray nutrients such as potassium dihydrogen phosphate and fulvic acid salts on the leaf surface to improve the disease resistance of cotton plants and reduce the occurrence of diseases; drip-feed Bacillus subtilis pesticides with water.

[0042] For aphids: Timely search for the central plants damaged by cotton aphids, and insert yellow sticky boards in the field for trapping; use 3 - 5 g / mu of 70% imidacloprid or 2000 - fold dilution of 20% Confido EC, 3 - 5 g / mu of 40% acetamiprid, or 10 g / mu of 50% flonicamid for manual spraying; when a large number occur, mechanical spraying can be used with the above-mentioned drugs, and each drug is used only once to prevent the generation of drug resistance, and they are used alternately.

[0043] For cotton bollworms: Use insecticidal lamps, sex attractants, etc. to trap and kill adult insects; when a large number occur, choose 5000 - 6000 - fold dilution of 1.8% abamectin or 2000 - fold dilution of 4.5% cypermethrin for leaf surface spraying.

[0044] Against spider mites: Spray the leaf surface with 2000 - fold solution of 15% pyridaben emulsifiable concentrate;

[0045] S6: Harvest:

[0046] Harvest cotton with a cotton picker in November. Harvest when the boll cracking rate reaches 95%.

[0047] As can be seen from the above - mentioned technical solutions, the present invention discloses a method for direct seeding and multiple cropping of cotton after winter wheat in southern Xinjiang. By selecting cotton varieties with a compact plant type, shortening the plant spacing in the wide - narrow planting mode, increasing the number of plants while reducing the number of cotton boll stands per plant, and cooperating with the integrated fertilization management measures, taking advantage of the population effect of cotton crops to adapt to the accumulated temperature change between the harvest of winter wheat in June and the frost period, ensuring a relatively high yield of cotton and achieving two - crop a year of winter wheat and cotton. Brief Description of the Drawings

[0048] Figure 1 : Schematic diagram of cotton after the last chemical regulation in step S3b of Example 1;

[0049] Figure 2 : Example 1 Schematic diagram after topping cotton in step S3c of . Detailed Embodiment

[0050] The technical solutions in the embodiments of the present invention will be described clearly and completely below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0051] The reagents involved in the embodiments of the present invention are all purchased through commercial channels, and the methods not mentioned are conventional experimental methods, which will not be elaborated here one by one.

[0052] Example 1

[0053] A method for direct seeding and multiple cropping of cotton after winter wheat in southern Xinjiang, comprising the following steps:

[0054] S1: Land preparation and soil sealing

[0055] After the winter wheat is harvested in the first ten days of June, plow and disk the land to a depth of ≥25 cm to eliminate stubble and level the land, then conduct soil sealing to reduce weed growth. Generally, select corresponding insecticides according to soil type. For example, when the soil type is sandy soil, spray 33% pendimethalin EC at a rate of 150 - 180 ml / mu on the soil surface, and then immediately mix the soil shallowly by 2 - 3 cm; when the soil type is clay soil, spray 33% pendimethalin EC at a rate of 130 - 150 ml / mu on the soil surface, and then immediately mix the soil shallowly by 2 - 3 cm.

[0056] S2: Sowing Technique

[0057] a. Variety Selection

[0058] Select a very early-maturing cotton variety with a compact plant type, concentrated boll opening, a starting fruit height of ≥18 cm, a growth period of <120 days, and suitable for mechanical harvesting.

[0059] b. Sowing Rate

[0060] After 5 hours of soil sealing, conduct wide-narrow row close planting and hole sowing at a density of 21,000 plants / mu, with 1 seed per hole. During sowing, lay drip irrigation tapes along the planting rows in the middle of the narrow rows and cover with plastic film.

[0061] c. Row and Plant Spacing Configuration

[0062] There are 6 rows per film, with row spacings of (13 + 63 + 13 + 63 + 13) cm and a plant spacing of 7.5 cm. After sowing, irrigate promptly to emerge. Specifically: conduct the first irrigation within 48 hours after sowing, and the second irrigation 3 - 5 days later. A total of 2 irrigations are carried out, with an irrigation amount of 15 m 3 / mu each time, and the drip emitter flow rate is 2.0 - 2.4 L / h.

[0063] S3: Management after Sowing

[0064] a. Seedling Liberation

[0065] When the emergence rate reaches 60%, use a simple seedling releaser or manually break through the film to release the seedlings that emerge through the hole under the film.

[0066] b. Rational Chemical Regulation

[0067] Conduct chemical regulation 4 times during the whole growth period. Spray mepiquat chloride at 0.3 - 0.5 g / mu on the 5th - 6th true leaves, 0.8 - 1 g / mu on the 7th - 8th true leaves, 5 - 6 g / mu 7 days after topping, and 8 - 10 g / mu 14 days after topping (for the schematic diagram of cotton after the last chemical regulation, see Figure 1 ).

[0068] c. Topping:

[0069] Determine the topping time strictly according to the number of fruiting branches, and control the number of fruiting branches after topping at about 4, that is, remove the top tip when the number of fruiting branches per plant reaches 6 (see the schematic diagram after cotton topping in Figure 2 );

[0070] d. Integrated water and fertilizer management:

[0071] Start the integrated water and fertilizer irrigation treatment 7 - 8 days after breaking the film and releasing the seedlings. A total of 13 drip irrigations are carried out, and the total water consumption is 277 m 3 / mu. The first to seventh waters are irrigated every 4 days, and after the seventh water, the eighth and ninth waters are drip irrigated every 5 days in sequence. After the ninth water, the tenth, eleventh, and twelfth waters are drip irrigated every 6 days in sequence. The interval between the thirteenth water and the twelfth water is 8 days; the irrigation amounts of the first and second waters are 20 m 3 / mu, the irrigation amount of the third water is 22 m 3 / mu, the irrigation amounts of the fourth to eighth waters are 25 m 3 / mu, the irrigation amounts of the ninth to eleventh waters are 20 m 3 / mu, and the irrigation amounts of the twelfth and thirteenth waters are 15 m 3 / mu;

[0072] Urea, monoammonium phosphate, and potassium sulfate are applied with water for each of the first to twelfth waters, and no fertilizer is applied for the thirteenth water. The total amounts are 28.5 kg / mu, 17.5 kg / mu, and 17.7 kg / mu respectively. Among them, the urea application amounts for the first and second waters are 1 kg / mu and 1.5 kg / mu respectively, and then increase by 1 kg / mu successively after the second water until the fourth water. The urea application amounts for the fifth and sixth waters are both 4 kg / mu, and then decrease by 0.5 kg / mu successively after the sixth water until the ninth water. The urea application amount for the tenth water is 1.5 kg / mu, and then decreases by 0.5 kg / mu successively until the twelfth water; the monoammonium phosphate application amounts for the first, second, third, and fourth waters are 0.5, 0.7, 0.8, and 1.5 kg / mu respectively. The monoammonium phosphate application amounts for the fifth and sixth waters are both 2.5 kg / mu. The monoammonium phosphate application amounts for the seventh to ninth waters are all 2 kg / mu, and then decrease by 0.5 kg / mu successively after the ninth water until the twelfth water; the application amount of potassium sulfate for the third water is 1 kg / mu, and the application amounts for the other drip irrigations are the same as those of monoammonium phosphate.

[0073] S4: Field management

[0074] a. Weeding

[0075] After emergence, mainly adopt manual weeding. If the soil becomes hard after dripping the emergence water, timely tillage should be carried out, with a tillage depth of 18 - 20 cm;

[0076] b. Ripening and defoliation

[0077] When the boll stage reaches 45 days, spray a defoliant for ripening;

[0078] S5: Pest and Disease Control

[0079] For Fusarium wilt and Verticillium wilt: Before sowing cotton, soak and mix the seeds with pesticides, or choose coated cotton seeds; in lightly diseased fields, promptly remove diseased plants and disinfect the soil; during the budding stage, spray nutrient agents such as potassium dihydrogen phosphate and fulvic acid salts on the leaf surface to improve the disease resistance of cotton plants and reduce the occurrence of diseases; drip-apply Bacillus subtilis pesticides with water;

[0080] For aphids: Promptly search for the central plants damaged by cotton aphids and insert yellow sticky boards in the field for trapping; use 70% imidacloprid at 3 - 5 g / mu or 20% Confido EC 2000 - fold dilution, 40% acetamiprid at 3 - 5 g / mu, 50% flonicamid at 10 g / mu for manual spraying; when a large number occur, use mechanical spraying with the above-mentioned drugs, and each drug is used only once to prevent the generation of drug resistance and alternate their use;

[0081] For cotton bollworms: Use insecticidal lamps, sex attractants, etc. to trap and kill adult insects; when a large number occur, choose 1.8% abamectin at 5000 - 6000 - fold dilution or 4.5% cypermethrin at 2000 - fold dilution for leaf surface spraying;

[0082] For spider mites: Spray the leaf surface with 15% pyridaben EC at 2000 - fold dilution;

[0083] S6: Harvesting

[0084] Harvest cotton with a cotton picker in November and harvest when the boll cracking rate reaches 95%.

[0085] Taking Zhongmian 113 as an example, in the wide - narrow row pattern with 6 rows per film and row spacing of (13 + 63 + 13 + 63 + 13) cm, set the planting densities at two plant spacings. Respectively, for low density: plant spacing is 10.5 - 11.5 cm, planting density is 16,000 plants / mu (theoretical), and the number of bolls per plant is 8 (theoretical); for high density: plant spacing is 7.5 - 8.5 cm, planting density is 21,000 plants / mu (theoretical), and the number of bolls per plant is 6 (theoretical).

[0086] Among them, the low - density group uses the conventional planting method, denoted as the control group. Conventional planting adopts integrated water and fertilizer management 7 - 8 days after breaking the film and releasing the seedlings, with a total of 9 times of drip irrigation, 255 m 3 / mu. The drip irrigation interval is: the first to fifth waters are irrigated every 7 days, after the fifth water, the seventh and eighth waters are drip - irrigated every 8 days in sequence, and the interval between the eighth and ninth waters is 10 days; the irrigation amounts of the first and second waters are both 25 m 3 / mu, the irrigation amounts of the third, fourth, and fifth waters are both 35 m 3 / mu, the irrigation amounts of the sixth and seventh waters are both 30 m 3 / mu, and the irrigation amounts of the eighth and ninth waters are both 20 m 3 / mu;

[0087] For the first to eighth irrigation waters, urea is applied with each water droplet, and no fertilizer is applied for the ninth irrigation water. Among them, the urea application rates for the first to third irrigation waters are 3 kg / mu, 5 kg / mu, and 8 kg / mu respectively, the urea application rates for the fourth and fifth irrigation waters are both 10 kg / mu, the urea application rates for the sixth and seventh irrigation waters are both 6 kg / mu, and the urea application rate for the eighth irrigation water is 3 kg / mu.

[0088] For the second to eighth irrigation waters, urea is applied with each water droplet, and no fertilizer is applied for the first and ninth irrigation waters. Among them, the monoammonium phosphate application rates for the second and third irrigation waters are 2 kg / mu and 3.5 kg / mu respectively, the monoammonium phosphate application rates for the fourth and fifth irrigation waters are both 5 kg / mu, and the monoammonium phosphate application rates for the sixth to eighth irrigation waters are 3 kg / mu, 2 kg / mu, and 1 kg / mu respectively; the drip irrigation application rate of potassium sulfate is the same as that of monoammonium phosphate.

[0089] For high density, the planting method of Example 1 is adopted, denoted as the experimental group.

[0090] From 2023 to 2024, cotton planting experiments were carried out at multiple test sites in Region 1, Region 2, Region 3, Region 4, Region 5, etc. in southern Xinjiang (correspondingly denoted as Test Sites 1-5), and the cotton yield per mu and boll opening rate of the two planting methods were statistically analyzed. The results are shown in Table 1.

[0091]

[0092]

[0093] As can be seen from Table 1, in 2023 and 2024, the number of bolls per plant in the experimental group in different regions was less than that in the control group, but the number of plants harvested per mu, the total number of bolls per mu, the seed cotton yield per mu, and the boll opening rate in the experimental group were all higher than those in the control group. It can be seen that the method of the present invention not only realizes the double cropping of winter wheat and cotton in one year, but also ensures a relatively high yield of cotton.

[0094] In this specification, each embodiment is described in a progressive manner. The key point of each embodiment is to illustrate the differences from other embodiments. For the same or similar parts among the embodiments, reference can be made to each other.

[0095] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be obvious to those skilled in the art. The general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to these embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for direct seeding and multiple planting of cotton after wheat in southern Xinjiang, characterized in that: The following steps are involved: S1: Land preparation, soil sealing After winter wheat is harvested in early June, the land is plowed to a depth of ≥25 cm to remove stubble, level the land, seal the soil, and reduce weed growth; S2: Seeding Technology a. Variety selection Select early-maturing cotton varieties with compact plant shape, concentrated boll opening, initial fruit height ≥ 18 cm, growth period ≤ 120 days, and suitable for mechanical harvesting; b. Seeding rate After the soil is sealed for 5 hours, the density of 21,000 plants / mu is used for wide and narrow row dense planting, one seed per hole. At the same time of sowing, a drip irrigation belt is laid along the planting row in the middle of the narrow row and covered with film; c. Plant spacing configuration One film has 6 rows, the row spacing is (13+63+13+63+13) cm, the plant spacing is 7.5 cm, and water is dripped in time after sowing; S3: Management after sowing a.Liberation seedlings When the germination rate reaches 60%, break the film and release the seedlings; b. Rational adjustment Chemical regulation was applied 4 times during the whole growth period: spraying 0.3-0.5g / mu of DCP on the 5th to 6th true leaves, 0.8-1g / mu of DCP on the 7th to 8th true leaves, 5-6g / mu of DCP 7 days after topping, and 8-10g / mu of DCP 14 days after topping; c. Topping: The topping time is strictly determined according to the number of fruit branches. The number of fruit branches after topping is controlled at about 4 branches, that is, the top is removed when the number of fruit branches per plant reaches 6. d. Integrated water and fertilizer management: 7-8 days after the film is broken and the seedlings are planted, start the integrated water and fertilizer irrigation treatment.

2. The method for direct seeding and multiple planting of cotton after wheat harvest in southern Xinjiang according to claim 1, characterized in that: The dripping seedlings described in step S2 c are specifically: the first dripping is carried out within 48 hours of sowing, and the second dripping is carried out 3-5 days later, for a total of 2 drippings, and the dripping amount each time is 15m 3 / mu, the dripper flow rate is 2.0-2.4L / h.

3. The method for direct seeding and multiple planting of cotton after wheat harvest in southern Xinjiang according to claim 1, characterized in that: The integrated water and fertilizer management described in step d of S3 is: drip irrigation is performed 13 times in total, with a total water consumption of 277m 3 / mu, urea, monoammonium phosphate and potassium sulfate are applied with water drops from the first to the twelfth watering, and no fertilizer is applied at the thirteenth watering. The total dosage is 28.5kg / mu, 17.5kg / mu and 17.7kg / mu respectively.

4. The method for direct seeding and multiple planting of cotton after wheat harvest in southern Xinjiang according to claim 3, characterized in that: The drip irrigation interval is as follows: the first to seventh waterings are irrigated every 4 days, the eighth and ninth waterings are drip irrigated every 5 days after the seventh watering, the tenth, eleventh and twelfth waterings are drip irrigated every 6 days after the ninth watering, and the thirteenth and twelfth waterings are separated by 8 days.

5. The method for direct seeding and multiple planting of cotton after wheat harvest in southern Xinjiang according to claim 4, characterized in that: The drip irrigation water volume is: the first and second water irrigation volume is 20m 3 / mu, the irrigation volume of the third water is 22m 3 / mu, the irrigation volume of the fourth to eighth water is 25m 3 / mu, the irrigation volume from the ninth to the eleventh water is 20m 3 / mu, the irrigation volume of the twelfth and thirteenth water is 15m 3 / mu.

6. The method for direct seeding and multiple planting of cotton after wheat harvest in southern Xinjiang according to claim 4, characterized in that: The urea application rate of the first and second waterings is 1kg / mu and 1.5kg / mu respectively. After the second watering, the urea application rate increases by 1kg / mu to the fourth watering. The urea application rate of the fifth and sixth waterings is 4kg / mu. After the sixth watering, the urea application rate decreases by 0.5kg / mu to the ninth watering. The urea application rate of the tenth watering is 1.5kg / mu, and then decreases by 0.5kg / mu to the twelfth watering. The application rates of monoammonium phosphate in the first, second, third and fourth waterings are 0.5, 0.7, 0.8 and 1.5 kg / mu respectively, the application rates of monoammonium phosphate in the fifth and sixth waterings are both 2.5 kg / mu, the application rates of monoammonium phosphate in the seventh to ninth waterings are all 2 kg / mu, and after the ninth watering, the application rates are gradually reduced by 0.5 kg / mu to the twelfth watering; The application rate of potassium sulfate in the third water is 1kg / mu, and the application rate of the remaining drip irrigation is the same as that of monoammonium phosphate.

7. The method for direct seeding and multiple planting of cotton after wheat harvest in southern Xinjiang according to claim 1, characterized in that: The following steps are also included: S4: Field management a. Weeding After the seedlings emerge, weeding is mainly done manually. If the soil becomes compacted after the seedling water drips out, it should be tilled in time with a tillage depth of 18-20cm. b. Ripening and defoliation When the cotton boll stage reaches 45 days, spray defoliants to accelerate ripening; S5: Pest and disease control S6: Harvest: Cotton is picked in November using a cotton picker, and is picked when the boll opening rate reaches 95%.

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