Method for evaluating influence of irrigation amount and coronatine on cotton field soil and cotton growth

Abstract

The invention discloses a method for evaluating the influence of irrigation amount and coronatine on cotton field soil and cotton growth, which comprises the following steps: on the basis of a two-factor split area experiment, setting the irrigation amount as a main area, and setting the coronatine amount as an auxiliary area for experiment; measuring the physical and chemical properties of the soil and the growth condition of the cotton in a split area test mode with two factors of irrigation amount and coronatine dosage; the influence of the irrigation amount and the coronatine dosage on cotton field soil and cotton growth is evaluated. The method has the beneficial effects that the change rule of the physical and chemical properties of the cotton field soil under different treatments and the influence on the cotton growth condition are explored, an irrigation amount and coronatine optimal combination scheme suitable for the arid region is provided, and the response mechanism of cotton growth and development to different irrigation amounts and coronatine dosages is explained; the method is expected to provide a theoretical basis for optimizing the water dripping amount and the coronatine dosage in the seedling stage in a cotton dry-sowing and wet-out planting mode.

Description

Technical Field

[0001] The present invention belongs to the field of bio-agricultural technology, and more specifically, relates to a method for evaluating the effects of irrigation amount and coronatine on cotton field soil and cotton growth. Background Art

[0002] Cotton is a major cash crop in my country and a crucial raw material for the textile industry, playing a vital role in the development of the national economy. Arid regions generally face water shortages, with extremely low rainfall and enormous evaporation. Secondary salinization of cotton soil is severe, and water shortages and the hazards of soil salinization have become major constraints on drought-resistant cotton production. To address water shortages and soil salinity, the "dry seeding and wet emergence" technique was developed. This technique requires minimal or no winter or spring irrigation before sowing, and a small amount of drip irrigation after sowing to ensure normal emergence. This technique offers significant advantages in water conservation. It is crucial for improving emergence rates in saline-alkali soils, increasing production and income, ensuring precise water and fertilizer management, and reducing costs and increasing efficiency.

[0003] Coronatine is a new plant growth regulator with physiological functions such as enhancing crop stress resistance, promoting growth and development, and improving crop quality. However, the effectiveness of coronatine in dry-seeding and wet-out cotton fields remains unclear. Research domestically and internationally has primarily focused on the effects of irrigation volume and coronatine under conventional irrigation systems. However, there is limited research on the specific effects of irrigation volume and coronatine under dry-seeding and wet-out systems, and relevant reports are relatively limited. Therefore, studying the effects of irrigation volume and coronatine on soil physical and chemical properties and cotton growth in dry-seeding and wet-out cotton fields is of great significance for optimizing cotton cultivation techniques and improving water resource utilization efficiency. Summary of the Invention

[0004] An object of the present invention is to solve at least the above problems and / or disadvantages and to provide at least the advantages which will be described hereinafter.

[0005] To achieve these objectives and other advantages of the present invention, a method for evaluating the effects of irrigation amount and coronatine on cotton field soil and cotton growth is provided, comprising:

[0006] Based on a two-factor split-plot experiment, the irrigation amount was set as the main plot and the coronatine dosage was set as the secondary plot.

[0007] In a split-plot experiment with two factors, irrigation volume and coronatine dosage, the physical and chemical properties of the soil and the growth status of cotton were measured.

[0008] The effects of irrigation amount and coronatine dosage on cotton field soil and cotton growth were evaluated by the physical and chemical properties of the soil and the growth status of cotton.

[0009] Preferably, the main area has 4 irrigation volumes: P1-375m 3 / hm 2 、P2-450m 3 / hm 2 、P3-225+150m 3 / hm 2 and P4-225+225m 3 / hm 2 The sub-plots consisted of three coronatine dosages: C0 (no coronatine spraying), C1 (3000-fold 0.006% coronatine solution), and C2 (2000-fold 0.006% coronatine solution). The plots were divided into 12 zones: P1C0, P1C1, P1C2, P2C0, P2C1, P2C2, P3C0, P3C1, P3C2, P4C0, P4C1, and P4C2. Each zone was replicated four times, for a total of 48 zones.

[0010] Preferably, the physical and chemical properties of the soil include: soil moisture content, soil electrical conductivity, and soil temperature.

[0011] Preferably, the cotton growth status indicators include: cotton emergence rate, cotton growth index, cotton leaf area index, cotton leaf SPAD value, cotton root index, dry matter dry weight and cotton yield.

[0012] Preferably, when evaluating the effect of irrigation amount on cotton field soil by the physical and chemical properties of the soil, the method specifically includes:

[0013] The effect of irrigation amount on soil moisture content was evaluated by the dynamic changes of soil moisture content at different depths and the spatial distribution characteristics of soil moisture content.

[0014] The effect of irrigation amount on soil electrical conductivity was evaluated by the dynamic changes of soil electrical conductivity at different depths and the spatial distribution characteristics of electrical conductivity.

[0015] The effect of irrigation amount on soil temperature was evaluated by the average temperature and effective accumulated temperature of different soil layers.

[0016] Preferably, when evaluating the effect of irrigation amount on cotton growth based on the growth condition of cotton, the method specifically includes:

[0017] The effect of irrigation amount on cotton emergence rate was evaluated by the cotton emergence rate in different treatment areas.

[0018] Preferably, when evaluating the effects of irrigation amount and coronatine on cotton growth based on the growth status of cotton, the method specifically includes:

[0019] The effect of the interaction between irrigation amount and coronatine dosage on cotton growth and development was evaluated by measuring cotton plant height, stem diameter, root morphology, leaf area index, and leaf SPAD value in different treatment areas.

[0020] Preferably, when evaluating the effects of irrigation amount and coronatine on cotton growth based on the growth condition of cotton, the method specifically includes:

[0021] The effects of the interaction between irrigation amount and coronatine dosage on cotton dry matter and yield were evaluated by measuring the underground dry matter weight, aboveground dry matter weight, dry matter distribution rate, and cotton yield in different treatment areas.

[0022] Preferably, the soil moisture content is determined by: using a drying method at 105±2°C for 12 hours to determine the soil mass moisture content, and converting the soil volume moisture content into the soil volume moisture content by multiplying the soil dry bulk density by the mass moisture content;

[0023] The soil conductivity is determined by grinding a dried soil sample to remove plant debris, stones, and other intrusive materials. When the sample is ground into powder, 18 g of the sample is added to a conical flask, 90 ml of purified water is added, and a mixture having a soil-water mass ratio of 1:5 is prepared. The mixture is shaken using an oscillator for 10 minutes, allowed to rest for 15 minutes, and the supernatant is obtained. Finally, the conductivity of the supernatant is measured using an F3 conductivity meter.

[0024] The soil temperature is measured by using a curved tube thermometer to locate and observe the temperature changes of the 0-5 cm and 5-10 cm soil layers near the edge of the mulch near the cotton seedlings. The soil temperature is monitored every 2 hours from 9:00 to 21:00 on each observation day, and the average value is used as the measured value for the day. The effective accumulated soil temperature is calculated using the following formula:

[0025] K=N(TC)

[0026] Where: K is the effective accumulated soil temperature during the seedling growth period, expressed in °C; T is the ground temperature of one day, expressed in °C; N is the number of days of soil temperature measured from sowing to emergence, d; C is the minimum temperature required for growth and development, 14 °C.

[0027] Preferably, the cotton emergence rate is determined by observing and recording the emergence of all cotton seedlings in each area 16 days after sowing, and calculating the cotton emergence rate, which is: emergence rate (%) = number of emerged seedlings / total number of sowing holes × 100;

[0028] The cotton growth indicators include plant height, stem diameter, and leaf number, and the measurement method is as follows: in the early stage of treatment, 10 representative plants in each area are marked with special markers, and the plant height, stem diameter, and leaf number are measured during the cotton boll opening period;

[0029] The leaf area index was determined by selecting three representative cotton plants from each test area at the seedling, bud, boll, and boll-opening stages. All leaves were removed, flattened, and laid on a scaled white paper. The leaves were photographed vertically with a digital camera, and the leaf area was measured using a digital image processing method. The leaf area index was calculated using the following formula:

[0030] LAI = leaves per unit land area / area per unit land area

[0031] Where, LAI is leaf area index;

[0032] Preferably, the method for determining the SPAD value of the leaf is: using a SPAD instrument to determine the SPAD value of the leaf in the seedling stage, bud stage, boll stage and boll opening stage, respectively, during the period of clear weather from 11:00 to 12:00 noon, repeating three times in each area, selecting 5 cotton plants in each area, cleaning the dirt on the surface of the leaves with a soft brush, and taking a leaf from the upper, middle and lower parts of the cotton plant respectively, and then measuring the upper, middle and base of the leaf respectively, calculating the average value of the three parts, and obtaining the final SPAD value.

[0033] Preferably, the cotton root system indicators include total root length, projected area, total root surface area, total root volume, average root diameter, and number of root tips. The determination method is: root drilling is used to sample cotton at the seedling stage, bud stage, boll stage, and boll opening stage, and three representative plants with uniform growth and continuous distribution are selected. Three sampling points are set for each cotton plant, namely, the taproot, 25 cm from the taproot on the side of the film-covered row, and 25 cm from the taproot on the side between the films; at each sampling point, the sample taken every 10 cm is soaked in clean water for 8 to 10 hours, then impurities are filtered out with a 0.1 mm mesh, and the image is scanned with a scanner. Finally, the image is input into the WinRHIZO root analyzer for analysis to calculate the total root length, projected area, total root surface area, total root volume, average root diameter, and number of root tips.

[0034] Preferably, the dry matter weight determination method is as follows: 10 cotton plants are sampled at the seedling stage, and 3 representative cotton plant samples are selected from each test area at the bud stage, boll stage, and boll opening stage. The samples are divided into 6 parts according to the root, stem, leaf, bud, flower, and boll. The samples are placed in an oven at 105°C for 30 minutes to fix the green part, and then dried at 80°C to constant weight. The dry matter mass of each component is weighed using an electronic balance with an accuracy of 0.001g.

[0035] The cotton yield was determined by randomly selecting 6.67 m2 of cotton per area after cotton boll opening. 3The sample points were collected and repeated 3 times to calculate the seed cotton yield of each area; the seed cotton yield of each area was determined by collecting one film, and the number of plants with film production in each area and the number of bolls of 10 consecutive plants were investigated to obtain the number of bolls per plant; 30 bolls were collected from the upper, middle and lower parts respectively, and the weight was weighed before ginning and weighing the lint weight to calculate the single boll weight and lint percentage.

[0036] The present invention has at least the following beneficial effects: exploring the changing patterns of cotton field soil physical and chemical properties under different irrigation rates and coronatine treatments and their impact on cotton growth; proposing an optimized irrigation rate and coronatine combination suitable for arid areas; and explaining the response mechanism of cotton growth and development to different irrigation rates and coronatine dosages, thereby providing a theoretical basis for optimizing seedling drip rate and coronatine dosage under the dry-seeding and wet-emergence cotton planting model.

[0037] Other advantages, objectives and features of the present invention will be reflected in part from the following description and will be understood by those skilled in the art through study and practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 It is the technical roadmap of the present invention;

[0039] Figure 2 This is a dynamic change diagram of soil moisture content under different irrigation amounts;

[0040] Figure 3 This is the spatial distribution characteristic map of soil moisture under different irrigation amounts;

[0041] Figure 4 This is a graph showing the dynamic changes of soil electrical conductivity under different irrigation amounts;

[0042] Figure 5 This is the spatial distribution characteristic map of soil electrical conductivity under different irrigation amounts;

[0043] Figure 6 This is a graph showing the dynamic changes in soil temperature under different irrigation amounts;

[0044] Figure 7 This is a graph of cotton emergence rate under different irrigation amounts;

[0045] Figure 8 This is the correlation analysis diagram between cotton emergence rate and soil physical and chemical properties;

[0046] Figure 9 This is a graph showing the effects of different treatments on cotton plant height;

[0047] Figure 10 This is a graph showing the effects of different treatments on cotton stem diameter;

[0048] Figure 11 This is a diagram showing the effects of different treatments on cotton leaf area;

[0049] Figure 12 This is a graph showing the effects of different treatments on the dry weight of the underground part of cotton;

[0050] Figure 13 This is a graph showing the effects of different treatments on the aboveground dry weight of cotton;

[0051] Figure 14 This is a diagram showing the effects of different treatments on the dry matter distribution rate of cotton. DETAILED DESCRIPTION

[0052] The present invention will be described in further detail below in conjunction with the accompanying drawings so that those skilled in the art can implement the invention with reference to the description.

[0053] It should be understood that terms such as “having”, “including” and “comprising” used herein do not preclude the existence or addition of one or more other elements or combinations thereof.

[0054] The technical route of the present invention is as follows Figure 1 As shown, the following embodiments are based on this technical route.

[0055] Example:

[0056] 1. Experimental Area

[0057] The experiment was conducted from April to November 2024 in an arid and semi-arid region with a dry climate and scarce rainfall. The average annual precipitation in this region is only 75 mm, the average annual temperature is 10.5 °C, and the average annual solar radiation is 534-622 kJ / cm 2 The soil is sandy loam with a pH of approximately 7.8, 174 mg / kg N, 142 mg / kg P, and 154 mg / kg K.

[0058] 2. Experimental Design

[0059] The cotton variety 'Tahe No. 2' was used as the test material. The irrigation amount and frequency at the seedling stage and the dosage of coronatine at the seedling stage, bud stage and early flowering stage were used as experimental factors. A two-factor split-plot design was adopted. The main plot had four irrigation amounts: P1 (375m 3 / hm 2 )、P2(450m 3 / hm 2 )、P3(225+150m 3 / hm 2 ) and P4(225+225m 3 / hm 2) and three coronatine application rates in the sub-plots: C0 (no coronatine spraying), C1 (0.006% coronatine 3000 times solution), and C2 (0.006% coronatine 2000 times solution). Each plot had one film, a row length of 15 m, and a plot area of ​​34.5 m. 2 , each area is 30 cm apart, each repetition is 5 m apart, each area is repeated 4 times, and there are 48 areas in total.

[0060] The experiment adopted a "dry sowing and wet out" planting pattern with one film, six rows and three pipes. The drip irrigation tape was placed between the narrow rows. The drip irrigation tape was patch-type with a flow rate of 2.4L / h and 5 holes / m. The cotton planting density was 261,000 plants / hm2. 2 The average row spacing was 30 cm, and the plant spacing was 13 cm. The experiment was replicated four times, with replicates 1-3 used for destructive sampling and the fourth for final yield determination. Each replicate was 5 m apart, with guard rows around each edge. All treatments were watered for the first time within 48 hours of sowing, and the second time six days later. Field management after seedling emergence was the same as for the field. Planting was done on April 26th and harvested on October 12th, with a growing period of 120 days.

[0061] 3. Measurement items and methods

[0062] 3.1 Soil moisture content

[0063] The determination method is: use the drying method at 105±2℃ for 12 hours to determine the soil mass moisture content, and convert it into soil volume moisture content by multiplying the soil dry bulk density by the mass moisture content.

[0064] 3.2 Soil conductivity

[0065] The determination method is as follows: grind the dried soil sample to remove plant residues, stones and other intrusive bodies, grind it into powder, take 18g and add it to a conical flask, add 90ml of pure water, and prepare a mixture with a soil-water mass ratio of 1:5. Use an oscillator to shake for 10 minutes, let it stand for 15 minutes to obtain the supernatant, and finally use an F3 conductivity meter to measure the conductivity of the supernatant.

[0066] 3.3 Soil temperature

[0067] The measurement method is as follows: a curved tube thermometer is used to locate and observe the temperature changes of the 0-5 cm and 5-10 cm soil layers near the edge of the mulch near the cotton seedlings. The soil temperature is monitored every 2 hours from 9:00 to 21:00 on each observation day, and the average value is used as the measurement value for the day. The effective accumulated soil temperature is calculated using the following formula:

[0068] K=N(TC)

[0069] Where: K is the effective accumulated soil temperature during the seedling growth period, expressed in °C; T is the ground temperature of one day, expressed in °C; N is the number of days of soil temperature measured from sowing to emergence, d; C is the minimum temperature required for growth and development, 14 °C.

[0070] 3.4 Cotton emergence rate

[0071] The determination method is: 16 days after sowing, observe and record the emergence of all cotton seedlings in each area, and calculate the cotton emergence rate, emergence rate (%) = number of seedlings emerged / total number of sowing holes × 100.

[0072] 3.5 Cotton Growth Indicators

[0073] The growth indicators of cotton include plant height, stem diameter, and number of leaves. The measurement method is: in the early stage of treatment, 10 representative plants in each area are marked with special markers, and the plant height, stem diameter, and number of leaves are measured during the cotton boll opening period.

[0074] 3.6 Leaf area index

[0075] The measurement method is as follows: At the seedling, bud, boll, and boll-opening stages of cotton, three representative plants were selected from each test area. All leaves were removed, flattened, and laid on a white paper marked with a scale. The leaves were photographed vertically with a digital camera and the leaf area was measured using digital image processing methods. The leaf area index was calculated using the following formula:

[0076] LAI = leaves per unit land area / area per unit land area

[0077] Where LAI is the leaf area index.

[0078] 3.7 Leaf SPAD value

[0079] The measurement method is as follows: the SPAD value of the leaves is measured using a SPAD meter at the seedling stage, bud stage, boll stage and boll opening stage, respectively. The measurement is performed three times in each area during the sunny weather period from 11:00 to 12:00 noon. Five cotton plants are selected from each area. The dirt on the surface of the leaves is cleaned with a soft brush. A leaf is taken from the upper, middle and lower parts of the cotton plant respectively, and then the upper, middle and base parts of the leaves are measured respectively. The average value of the three parts is calculated to obtain the final SPAD value.

[0080] 3.8 Cotton root system indicators

[0081] Cotton root system indicators include total root length, projected area, total root surface area, total root volume, average root diameter, and number of root tips. The measurement method is as follows: root drilling is used to take samples at the seedling, bud, boll, and boll-opening stages of cotton, and three representative plants with uniform growth and continuous distribution are selected. Three sampling points are set for each cotton plant, namely, the main root, 25 cm away from the main root on the side of the film-covered row, and 25 cm away from the main root on the side between films; at each sampling point, the sample taken every 10 cm is soaked in clean water for 8 to 10 hours, then filtered with a 0.1 mm mesh to remove impurities, scanned with a scanner, and finally input into the WinRHIZO root analyzer for analysis to calculate the total root length, projected area, total root surface area, total root volume, average root diameter, and number of root tips.

[0082] 3.9 Aboveground dry matter

[0083] The determination method is as follows: 10 cotton plants were sampled at the seedling stage, and 3 representative cotton plant samples were selected from each test area at the bud stage, boll stage and boll opening stage. The samples were divided into 6 parts according to roots, stems, leaves, buds, flowers and bolls. The samples were placed in an oven at 105°C for 30 minutes for sterilization, and then dried at 80°C to constant weight. The dry matter mass of each component was weighed using an electronic balance with an accuracy of 0.001g.

[0084] 3.10 Cotton Production

[0085] The determination method is as follows: After the cotton bolls are opened, 6.67m 3 The sample points were collected and repeated 3 times to calculate the seed cotton yield of each area; the seed cotton yield of each area was determined by collecting one film, and the number of plants with film production in each area and the number of bolls of 10 consecutive plants were investigated to obtain the number of bolls per plant; 30 bolls were collected from the upper, middle and lower parts respectively, and the weight was weighed before ginning and weighing the lint weight to calculate the single boll weight and lint percentage.

[0086] 4. Data statistics and analysis

[0087] Excel 2021 was used to organize the raw data and generate tables. A two-factor split-plot design was used for analysis of variance in DPS 9.01, and the Duncans new multiple range method was used to test statistical significance. Graphs were generated in Origin 2021, and location maps were drawn using Quantum GIS 3.8.3. Structural equation modeling was performed in AMOS 22.0.

[0088] 5. Results and Analysis

[0089] 5.1 Effects of different irrigation amounts on soil physical and chemical properties and cotton emergence rate in “dry sowing and wet emergence” cotton fields

[0090] 5.1.1 Effects of different irrigation amounts on soil moisture content

[0091] 5.1.1.1 Dynamic changes in soil moisture under different irrigation rates

[0092] Effects of different irrigation amounts and frequencies on soil moisture content Figure 2 As shown in Figure 2a, the soil moisture contents P1 and P2 at 10 cm (Figure 2a), 20 cm (Figure 2b), and 30 cm (Figure 2c) from the drip irrigation tape showed the same change pattern, showing a single-peak curve, with the peak appearing after the first irrigation. The soil moisture contents P3 and P4 at 10 cm, 20 cm, and 30 cm from the drip irrigation tape showed the same change pattern, showing a double-peak curve, with the peak appearing after the first and second drips. After the first drip, the soil moisture contents at 10 cm, 20 cm, and 30 cm from the drip irrigation tape in the P3 treatment were 22.86%, 22.33%, and 21.97%, respectively. The soil moisture contents at 10 cm, 20 cm, and 30 cm from the drip irrigation tape in the P4 treatment were 23.55%, 23.01%, and 22.80%, respectively. After the second drip irrigation, soil moisture content in P1 and P2 gradually decreased due to the absence of water irrigation. The first drip volume was greater than the second drip volume. In P3 and P4, soil moisture content after the second drip irrigation was lower than after the first drip irrigation. The soil moisture content in the P3 treatment at 10 cm, 20 cm, and 30 cm from the drip tape was 21.54%, 20.01%, and 19.70%, respectively. The soil moisture content in the P4 treatment at 10 cm, 20 cm, and 30 cm from the drip tape was 22.39%, 22.25%, and 21.79%, respectively. Soil moisture content in P3 and P4 gradually increased after the second drip irrigation and then gradually decreased, remaining higher than in P1 and P2. In summary, irrigation volume and frequency significantly affected soil moisture content. Under the same irrigation quota, soil moisture content was higher in split irrigation than in single irrigation.

[0093] 5.1.1.2 Spatial distribution characteristics of soil moisture under different irrigation rates

[0094] The spatial distribution characteristics of soil moisture content under different irrigation amounts and frequencies are as follows: Figure 3As shown, the drip tape is positioned at 0 cm on the horizontal axis. Horizontally, the distance from the drip tape increases from 10 cm to 20 cm to 30 cm. Vertically, soil moisture increases irregularly with increasing soil depth. At the same irrigation frequency, soil moisture in the P2 treatment was higher in all soil layers than in the P1 treatment, and the moisture distribution was relatively uniform across depths and horizontal distances. The P4 treatment had higher soil moisture in all soil layers than the P3 treatment. The soil moisture content in the P4 treatment ranged from 21% to 24%, with the highest values ​​at 23% to 24% at a horizontal distance of 25 cm to 30 cm from the drip tape and at a vertical depth of 30 cm to 40 cm. At the same irrigation rate, soil moisture in split irrigation was higher than in single irrigation. In the P3 treatment, the average soil moisture contents of the soil layers at 10 cm, 20 cm and 30 cm away from the drip irrigation tape were 20.23%, 19.92% and 20.21%, respectively, which were 59.42%, 56.97% and 57.52% higher than those in the P1 treatment; in the P4 treatment, the average soil moisture contents of the soil layers at 10 cm, 20 cm and 30 cm away from the drip irrigation tape were 22.11%, 21.41% and 22.19%, respectively, which were 9.72%, 8.19% and 15.81% higher than those in the P2 treatment.

[0095] 5.1.2 Effects of different irrigation amounts on soil conductivity

[0096] 5.1.2.1 Dynamic Changes in Soil Electrical Conductivity under Different Irrigation Rates

[0097] Effects of different irrigation amounts and frequencies on soil electrical conductivity Figure 4 As shown, 10cm away from the drip irrigation belt ( Figure 4 a) 20cm( Figure 4 b) 30cm( Figure 4c) Soil conductivity showed consistent V-shaped changes in treatments P1 and P2, while treatments P3 and P4 exhibited a single-peak curve. After the first drip irrigation, conductivity decreased in all treatments. This is likely because the dripping water diluted conductive substances such as salt in the soil, resulting in a decrease in conductivity. Soil conductivity reached its lowest point from May 3rd to May 5th. Over time, soil water gradually distributed and evaporated, causing soil conductivity to gradually recover. After the second drip irrigation, conductivity increased in treatments P1 and P2 at 10, 20, and 30 cm from the drip tape, due to the absence of drip irrigation. On May 12th, soil conductivity in treatment P1 at 10, 20, and 30 cm from the drip tape was 561 μs / cm, 616 μs / cm, and 673 μs / cm, respectively. In treatment P2, soil conductivity at 10, 20, and 30 cm from the drip tape was 499 μs / cm, 600 μs / cm, and 638 μs / cm, respectively. The conductivity of the P3 and P4 treatments decreased, and the conductivity of the P4 treatment was the lowest. The soil conductivity at 10 cm, 20 cm, and 30 cm away from the drip irrigation tape was 226 μs / cm, 401 μs / cm, respectively. / cm, 499μs / cm, the range of change varies with the distance from the drip irrigation tape, 10cm>20cm>30cm from the drip irrigation tape.

[0098] 5.1.2.2 Spatial distribution characteristics of soil electrical conductivity under different irrigation rates

[0099] Soil electrical conductivity is related to soil fertility, structure and other properties. The spatial distribution characteristics of soil electrical conductivity under different irrigation amounts and irrigation frequencies are as follows: Figure 5As shown, the drip tape position is 0 cm on the horizontal axis. Overall, soil conductivity across all treatments was highest at a depth of approximately 30 to 40 cm and approximately 30 cm from the drip tape. Soil conductivity was lowest near the soil surface and 0 to 10 cm from the drip tape. Horizontally, the distance from the drip tape was 10 cm less than 20 cm, and less than 30 cm. Vertically, soil conductivity showed an irregular decreasing trend with increasing soil depth. At the same irrigation frequency, soil conductivity in treatment P2 was lower in all soil layers than in treatment P1, and the conductivity distribution was relatively uniform across depths and horizontal distances. Soil conductivity in treatment P4 was lower in all soil layers than in treatment P3. Soil moisture content in treatment P4 ranged from 294 to 588 μS / cm, with the lowest conductivity (294 μS / cm) occurring at 5 cm horizontally from the drip tape and 25 cm vertically. Under the same irrigation quota, soil conductivity under split irrigation was lower than that under single irrigation. The average soil conductivity at 10, 20, and 30 cm from the drip tape in the P3 treatment was 326 μs / cm, 431 μs / cm, and 567 μs / cm, respectively. In the P1 treatment, the average soil moisture content at 10, 20, and 30 cm from the drip tape was 460 μs / cm, 651 μs / cm, and 688 μs / cm, respectively. The P3 treatment was lower than the P1 treatment. In the P4 treatment, the average soil moisture contents of the soil layers at 10 cm, 20 cm, and 30 cm away from the drip irrigation tape were 291 μs / cm, 400 μs / cm, and 518 μs / cm, respectively. In the P2 treatment, the average soil moisture contents of the soil layers at 10 cm, 20 cm, and 30 cm away from the drip irrigation tape were 257 μs / cm, 483 μs / cm, and 652 μs / cm, respectively. The soil electrical conductivity of the P4 treatment was lower than that of the P2 treatment.

[0100] 5.1.3 Effects of different irrigation amounts on soil temperature

[0101] Depend on Figure 6 As shown, irrigation amount and frequency significantly affected soil temperatures at 13:00, 15:00, and 21:00 in the 0-5 cm soil layer (using May 12 as an example), and at 15:00 in the 5-10 cm soil layer. In the 0-5 cm soil layer, split irrigation significantly increased soil temperatures at 13:00 and 21:00, with increases of 5.84% (at 13:00) and 1.12% (at 21:00) compared to single irrigation. The 15:00 soil temperature pattern was P3 > P4 > P2 > P1. P1 significantly reduced soil temperature in the 5-10 cm soil layer by 2.63% and 4.03% compared to P3 and P4, respectively, but showed no significant difference compared to P2.

[0102] Table 1 shows the average soil temperature and effective accumulated temperature in the 0–5 cm and 5–10 cm soil layers from the first irrigation to seedling emergence. Treatment P3 increased the average soil temperature and effective accumulated temperature in the 0–5 cm and 5–10 cm soil layers. Under single irrigation, treatment P1 increased effective accumulated temperature in the 0–5 cm soil layer, while under split irrigation, treatment P3 increased effective accumulated temperature by 3.18% compared to treatment P4. Under the same irrigation quota, treatment P4 increased effective accumulated temperature by 7.50% compared to treatment P2, and treatment P3 increased effective accumulated temperature by 9.22% compared to treatment P1. Under single irrigation, treatment P2 increased effective accumulated temperature in the 5–10 cm soil layer, while under split irrigation, treatment P3 increased effective accumulated temperature by 1.91% compared to treatment P4. Under the same irrigation quota, treatment P4 increased effective accumulated temperature by 3.16% compared to treatment P2, and treatment P3 increased effective accumulated temperature by 4.12% compared to treatment P1. In summary, under the single irrigation level, P1 is beneficial to increasing the effective accumulated temperature of the soil in the 0-5 cm and 5-10 cm soil layers, and under the same irrigation quota, the divided irrigation level P3 is beneficial to increasing the effective accumulated temperature of the soil in the 0-10 cm soil layer.

[0103] Table 1 Average temperature and effective accumulated temperature of 0-5cm and 5-10cm soil layers under different treatment conditions

[0104]

[0105] 5.1.4 Effects of different irrigation amounts on cotton emergence rate

[0106] Depend on Figure 7 It can be seen that, for the same irrigation quota, split irrigation increased the cotton emergence rate compared with single irrigation, and the P3 treatment had the highest emergence rate, which was significantly increased by 89.88% and 18.26% compared with P1 and P2 respectively. Under the single irrigation condition, the amount of irrigation had no significant effect on the emergence rate. In summary, under the same irrigation quota, split irrigation was beneficial to cotton emergence and increased the cotton emergence rate, indicating that split irrigation (225+150m 3 / hm 2 ) is more conducive to the growth of cotton.

[0107] 5.1.5 Correlation Analysis between Cotton Emergence Rate and Soil Physical and Chemical Properties

[0108] Depend on Figure 8 The results show that soil moisture content, soil temperature and cotton emergence rate are significantly positively correlated, while soil moisture content, soil temperature, cotton emergence rate and soil electrical conductivity are significantly negatively correlated. This indicates that increasing soil moisture content and soil temperature and reducing soil electrical conductivity are beneficial to cotton emergence under the dry seeding and wet emergence model.

[0109] 5.2 Effects of irrigation amount and coronatine on the growth and development of “dry-sown and wet-emerged” cotton

[0110] 5.2.1 Effects of irrigation amount and coronatine on cotton plant height

[0111] Effects of different treatments on cotton plant height Figure 9 Irrigation rate and coronatine dosage significantly affected cotton plant height, while the interaction between irrigation rate and coronatine dosage was not significant (P>0.05). At the same irrigation rate, different coronatine dosages significantly affected cotton plant height. With increasing coronatine dosage, cotton plant height showed an increasing trend, specifically C2 > C1 > C0. Plant height in the C2 treatment increased by 6.21%-9.19% and 3.13%-5.43% compared to treatments C0 and C1, respectively. This indicates that, within a certain range, appropriately increasing coronatine dosage can promote cotton plant height growth. At the same coronatine dosage, irrigation rate significantly affected cotton plant height, with P3 > P4 > P2 > P1. At the same irrigation quota, split irrigation significantly increased cotton plant height compared to single irrigation. Plant height in the P3C2 treatment increased by 19.42% and 8.53% compared to the P1C2 and P2C2 treatments, respectively. Under single irrigation, there was no significant difference in cotton plant height among different treatments.

[0112] In conclusion, split irrigation with high coronatine concentrations at the same irrigation quota can promote cotton plant height growth. The cotton plant height in the P3C2 treatment was the highest, reaching 104.3 cm, an increase of 29.40% compared with the P1C0 treatment.

[0113] 5.2.2 Effects of irrigation amount and coronatine on cotton stem diameter

[0114] Effects of different treatments on cotton stem diameter Figure 10 As shown, irrigation amount and coronatine dosage significantly affected cotton stem diameter, while the interaction between irrigation amount and coronatine dosage was not significant (P>0.05). At the same irrigation amount, different coronatine dosages had a significant effect on cotton stem diameter. With increasing coronatine dosage, cotton stem diameter showed an increasing trend, specifically C2 > C1 > C0. The C2 treatment increased stem diameter by 9.60%-25.46% and 3.16%-22.82% compared to the C0 and C1 treatments, respectively. This indicates that, within a certain range, appropriately increasing the coronatine dosage can promote cotton stem diameter growth. At the same coronatine dosage, irrigation amount significantly affected cotton stem diameter, with P3 > P4 > P2 > P1. At the same irrigation quota, fractional irrigation significantly increased cotton stem diameter compared to single irrigation. The P3C2 treatment increased stem diameter by 33.13% and 31.12% compared to the P1C2 and P2C2 treatments, respectively. Under single irrigation, there was no significant difference in cotton stem diameter among different treatments.

[0115] In conclusion, split irrigation with high coronatine concentrations at the same irrigation quota can promote the growth of cotton stem diameter. The cotton stem diameter in the P3C2 treatment was the highest, reaching 14.5 mm, an increase of 47.62% compared with the P1C0 treatment.

[0116] 5.2.3 Effects of irrigation amount and coronatine on cotton roots

[0117] Table 2 shows the effects of different irrigation rates and coronatine dosages on cotton root morphology. The results indicate that irrigation rate significantly affected total root volume, while coronatine, irrigation rate, and the interaction between coronatine and cotton root morphology showed no significant effect.

[0118] Under the same coronatine dosage and at the same irrigation quota, split irrigation increased total root length, projected area, total root surface area, total root volume, average root diameter, and number of root tips compared to single irrigation. Total root volume significantly increased by 179.35% in the P4C0 treatment compared to the P2C0 treatment, and by 180.12% in the P4C1 treatment compared to the P2C1 treatment. Total root length and projected area significantly increased by 74.68% and 117.59% in the P3C2 treatment compared to the P1C2 treatment. There was no significant effect of irrigation volume on total root length, projected area, total root surface area, total root volume, average root diameter, or number of root tips under single or split irrigation. At the same irrigation quota, higher coronatine concentrations increased total root length in cotton, with P3C2 significantly increasing total root length by 64.22% compared to P3C0. In summary, under the same irrigation quota, two-time irrigation is beneficial to the growth of cotton roots, and the two-time irrigation P3 increases the total root length and projected area. Under the same irrigation quota, higher concentrations of coronatine can increase the total root length of cotton. The total root length of P3C2 is 568.72 cm, indicating that the two-time irrigation (225+150m 3 / hm 2 ) Adding high concentration of coronatine C2 (2000 times dilution of 0.006% coronatine) is more conducive to the growth of cotton roots.

[0119] Table 2 Effects of different irrigation amounts and coronatine on cotton root morphology

[0120]

[0121] Note: Different lowercase letters in the same column indicate significant differences (P<0.05), the same below.

[0122] 5.2.4 Effects of irrigation amount and coronatine on cotton leaf area index

[0123] Depend on Figure 11 The results show that the leaf area index (LAI) of cotton populations under different irrigation rates and coronatine dosages showed a single-peak curve throughout the growth cycle. The dynamic changes in LAI were basically consistent among the treatments, showing a continuous increase from the seedling stage to the flowering and boll stage, reaching a peak at the flowering and boll stage, and then gradually decreasing during the boll opening stage.

[0124] There were no significant differences in leaf area index among treatments at the seedling, bud and boll stages, but significant differences at the flowering and boll stages. The study showed that the average leaf area index of the P2C0, P2C1, and P2C2 treatments throughout the entire growth period increased by 34.81%, 2.88%, and 0.43% compared with the P1C0, P1C1, and P1C2 treatments, respectively. The average leaf area index of the P4C1 and P4C2 treatments throughout the entire growth period increased by 0.92% and 13.45% compared with the P3C1 and P3C2 treatments, respectively. This indicates that at the same irrigation frequency and coronatine dosage, a greater amount of irrigation results in a higher leaf area index. At the flowering and boll stage, the leaf area index of the P3C0 treatment increased by 86.61% compared with P1C0, and the leaf area index of the P4C0, P4C1, and P4C2 treatments increased by 6.67%, 2.93%, and 8.19% compared with P2C0, P2C1, and P2C2, respectively. This indicates that at the same irrigation quota and coronatine dosage, split irrigation resulted in a higher leaf area index than single irrigation. Under the same irrigation amount, the coronatine dosage was C2>C1>C0. The leaf area index of the P1C2 treatment at the flowering and boll stage was significantly increased by 41.13% and 19.54% compared with the P1C0 and P1C1 treatments.

[0125] In summary, at the same irrigation frequency and coronatine dosage, the greater the irrigation amount, the higher the leaf area index; at the same irrigation quota and coronatine dosage, the leaf area index is higher with split irrigation than with single irrigation; at the same irrigation amount, the greater the coronatine dosage, the higher the leaf area index.

[0126] 5.2.5 Effects of irrigation amount and coronatine on SPAD value of cotton leaves

[0127] Table 3 shows the effects of different irrigation rates and coronatine on leaf SPAD values ​​at various cotton growth stages. The results showed that irrigation rate had a significant effect on leaf SPAD values ​​at the seedling stage, an extremely significant effect on leaf SPAD values ​​at the boll opening stage, and an extremely significant effect of the interaction between irrigation rate and coronatine on leaf SPAD values ​​at the boll opening stage.

[0128] For the same irrigation quota, split irrigation increased leaf SPAD values ​​at the seedling and bud stages compared with single irrigation. The leaf SPAD values ​​of treatment P3 at the seedling, bud, and boll-opening stages increased by 0.47%, 2.04%, and 11.22% compared with treatment P1, respectively. At the boll-opening stage, the leaf SPAD values ​​of treatments P3C0, P3C1, and P3C2 significantly increased by 9.89%, 11.14%, and 12.66% compared with treatments P1C1, P1C2, and P1C3. The leaf SPAD values ​​of treatment P4 at the seedling and bud stages increased by 1.23% and 2.87% compared with treatment P2, respectively. Under single irrigation conditions, the leaf SPAD values ​​of treatment P1 at the seedling, bud, and boll-opening stages increased by 15.50%, 10.26%, and 9.28% compared with treatment P2, respectively. The leaf SPAD value of treatment P2 at the boll-opening stage increased by 9.72% compared with treatment P1. Under split irrigation conditions, leaf SPAD values ​​in the P3 treatment at the seedling, bud, boll, and boll-opening stages increased by 14.64%, 9.37%, 2.18%, and 2.28% compared to the P4 treatment, respectively. Under the same irrigation quota, higher concentrations of coronatine increased leaf SPAD values ​​at the seedling and boll-opening stages. The P1C2 treatment significantly increased leaf SPAD values ​​by 30.19% compared to the P1C0 treatment at the seedling stage. At the boll-opening stage, the P2C2 treatment significantly increased leaf SPAD values ​​by 10.62% and 16.97% compared to the P2C1 and P2C0 treatments, respectively. The P4C2 treatment significantly increased SPAD values ​​by 14.98% compared to the P4C0 treatment.

[0129] In summary, under the same irrigation quota, two irrigations are beneficial to improving the SPAD values ​​of leaves at the seedling and bud stages; under the same irrigation quota, higher concentrations of coronatine can improve the SPAD values ​​of leaves at the seedling and boll-opening stages, indicating that two irrigations (225+150m 3 / hm 2 ) Adding high concentration of coronatine C2 (0.006% coronatine 2000 times solution) is more conducive to improving the SPAD value of cotton leaves at all stages.

[0130] Table 3 Effects of irrigation amount and coronatine on SPAD value of cotton leaves

[0131]

[0132]

[0133] 5.3 Effects of irrigation amount and coronatine on dry matter and yield of cotton grown in dry-sowing and wet-out conditions

[0134] 5.3.1 Effects of irrigation amount and coronatine on underground dry matter

[0135] Effects of different irrigation amounts and coronatine dosages on the dry weight of cotton underground parts Figure 12The results showed that underground dry matter accumulation in cotton showed dynamic changes: aboveground dry matter increased continuously from the bud stage to the boll opening stage, reaching a peak at the boll opening stage. Irrigation rate and coronatine had no significant regulatory effect on underground dry matter accumulation during the bud stage.

[0136] During the flowering and boll-opening stage, the P3C1 and P3C2 treatments showed significant growth promotion. The P3C1 treatment achieved an average growth increase of 89.78% compared to the other treatments, while the P3C2 treatment showed even more significant increases, ranging from 42.30% to 139.16%. Notably, the P1C0 treatment decreased growth by 68.07% and 66.55% compared to the P4C0 and P2C2 treatments, respectively, while the P3C0 treatment increased growth by 69.77% to 105.78% compared to the P1C1 and P1C2 treatments, indicating that moderate irrigation promotes underground growth. During the boll-opening stage, the P3C2 treatment increased growth by 20.17% to 55.03% compared to the other treatments, with an average increase of 43.93%. P3C0 and P3C1 significantly increased growth by 23.38% to 40.34% and 30.19% to 48.08%, respectively, compared to the other treatments. Furthermore, the P4C2 treatments increased belowground dry matter accumulation by 23.37% to 29.01% compared to some control groups. Comprehensive analysis showed that split irrigation, under the same irrigation quota, consistently promoted belowground dry matter accumulation: The P3 treatment increased belowground dry matter accumulation by 87.59%, 104.55%, and 43.78% compared to the P1 treatment at the bud, boll, and boll opening stages, respectively. The P4 treatment increased belowground dry matter accumulation by 11.16% and 13.34% compared to the P2 treatment at the bud and boll opening stages, respectively. Notably, under the same irrigation rate, the coronatine dosage had no significant effect on belowground dry matter accumulation at the bud and boll opening stages, but exhibited a dose-response effect at the boll opening stage. In summary, split irrigation, under the same irrigation quota, effectively promoted belowground dry matter accumulation in cotton, with the regulatory effect of coronatine dosage primarily manifesting in the later growth stages.

[0137] 5.3.2 Effects of irrigation amount and coronatine on aboveground dry matter

[0138] Figure 13The effects of different irrigation rates and coronatine dosages on the aboveground dry matter of cotton were analyzed. The results showed that aboveground dry matter increased continuously during the bud, boll, and boll-opening stages, reaching its maximum during boll-opening. At the bud stage, the P1C0 treatment significantly decreased by 69.38%, 84.11%, and 76.16% compared to the P3C1, P3C2, and P4C2 treatments, respectively. At the boll-opening stage, the P3C2 treatment significantly increased by 81.77% and 107.47% compared to the P1C0 and P2C0 treatments, respectively. At the boll-opening stage, the P2C0 treatment significantly decreased by 24.90%, 27.34%, 33.33%, and 24.89% compared to the P3C0, P3C1, P3C2, and P4C2 treatments, respectively. At the same irrigation rate and coronatine dosage, the aboveground dry weight of the P3 treatment at the bud, boll, and boll opening stages was 36.55%, 21.41%, and 12.51% higher than that of the P1 treatment, respectively. The aboveground dry weight of the P4 treatment at the bud, boll, and boll opening stages was 18.94%, 38.13%, and 4.93% higher than that of the P2 treatment, respectively. This indicates that split irrigation, at the same irrigation quota, is more conducive to increasing aboveground dry weight. At the same irrigation quota, there were no significant differences in aboveground dry weight between treatments using different coronatine dosages at the bud, boll, and boll opening stages. In summary, at the same irrigation quota and coronatine dosage, split irrigation resulted in greater aboveground dry matter accumulation than single irrigation.

[0139] 5.3.3 Effects of irrigation amount and coronatine on dry matter distribution

[0140] Effects of different irrigation amounts and coronatine on dry matter distribution rate of cotton Figure 14 As shown in the study, dry matter distribution in crops shows regular changes during different growth stages. During the bud stage, stems and leaves are the primary dry matter distributors, with stems accounting for 35% to 40% and leaves for 30% to 35%, providing the material basis for vegetative growth. During the flowering and boll stage, the reproductive organs' demand for dry matter increases significantly, with bolls accounting for 25% to 35% and flowers for 5% to 10%, reflecting the material distribution characteristics of the reproductive growth stage. During the boll opening stage, the boll's dry matter distribution further increases to 40% to 50%, the highest proportion among stems, leaves, bolls, and cotton, indicating that the reproductive organs increase their share in the later growth stages.

[0141] Dry matter distribution did not differ significantly among treatments during the bud stage. The proportion of stems, leaves, and buds among treatments was leaf > stem > bud. Leaves accounted for 53%-61%, stems for 35%-41%, and buds for 3%-6%. Buds accounted for bud-to-bud ratios in P3 > P4 > P1 > P2. In the P3 treatment, C2 > C0 = C1. During the flowering and boll stage, dry matter distribution followed the order of stem > leaf > boll > bud > flower, with stems accounting for 33%-55%, leaves for 18%-29%, bolls for 16%-36%, buds for 3%-6%, and flowers for 1%. The proportion of bolls in P3 differed significantly from those in the P1, P2, and P3 treatments, with C2 > C1 > C0 in the P3 treatment. During boll opening, the boll-to-cotton ratio was boll > stem > cotton > leaf, with bolls accounting for 29%-43%, stems for 24%-40%, leaves for 10%-18%, and cotton for 13%-23%. The proportion of cotton and boll in P3 during boll opening differed significantly from that in P1, P2, and P3 treatments, with C2 > C1 > C0 in P3.

[0142] In summary, crop dry matter distribution follows a common pattern of shifting from vegetative to reproductive growth, and differences in distribution across different treatments during each growth stage significantly influence plant growth and yield formation. Dry matter distribution to vegetative organs should be balanced during the bud stage, while dry matter supply to reproductive organs should be enhanced during the flowering and boll formation and boll opening stages. Treatments C1 and C2 showed significant differences in dry matter distribution among bolls, stems, and leaves.

[0143] 5.3.4 Effects of Irrigation Amount and Coronatine on Cotton Yield and Yield Components

[0144] The effects of different irrigation amounts and coronatine on cotton yield and its components are shown in Table 3-4. The results show that irrigation amount significantly affected the number of bolls per plant and seed cotton yield, while the interaction between coronatine, irrigation amount, and coronatine had no significant effect on cotton yield and its components.

[0145] For the same irrigation quota, split irrigation increased the number of bolls per plant, boll weight, lint percentage and seed cotton yield compared with single irrigation. The number of bolls per plant in P3C2 treatment was significantly increased by 39.32%, 44.40% and 42.50% compared with P1C0, P1C1 and P1C2 treatments, and the seed cotton yield in P3C2 treatment was significantly increased by 20.50%, 18.80% and 18.61% compared with P1C0, P1C1 and P1C2 treatments. Under single irrigation conditions, the number of bolls per plant, boll weight and seed cotton yield in P2 treatment were increased by 3.71%, 1.55% and 3.47% compared with P1 treatment, respectively, and the lint percentage in P2 treatment was increased by 1.93% compared with P1 treatment. Under split irrigation conditions, the number of bolls per plant, boll weight, lint percentage and seed cotton yield in P3 treatment were increased by 18.55%, 3.19%, 2.30% and 7.30% compared with P4 treatment, respectively. Under the same irrigation quota, higher coronatine concentrations increased boll number per plant, boll weight, lint percentage, and seed cotton yield, but there were no significant differences between treatments. In summary, under the same irrigation quota, two-step irrigation is beneficial for increasing boll number per plant, boll weight, lint percentage, and seed cotton yield. The effects of different irrigation rates and coronatine dosages on cotton yield and yield components are primarily independent, with no significant synergistic effects.

[0146] Table 3-4 Effects of different irrigation amounts and coronatine on cotton yield and its components

[0147]

[0148] In summary, the evaluation conclusions of the method for evaluating the effects of irrigation amount and coronatine on cotton field soil and cotton growth are as follows:

[0149] 1. Fractional irrigation optimizes the soil water, heat, and salt environment, significantly increasing the cotton emergence rate

[0150] Through the comparative study of split irrigation (P3, P4 treatments) and single irrigation (P1, P2 treatments), it was found that:

[0151] (1) Soil moisture and salt regulation: Split irrigation in the P3 and P4 treatments significantly increased soil moisture content in the 0-40 cm soil layer by 57.93% and 12.83% compared to the single irrigation in the P1 and P2 treatments, respectively. It also reduced soil electrical conductivity by 23.89% and 3.26%. High-frequency, low-volume irrigation effectively alleviated soil salinization in arid regions by reducing surface evaporation and salt accumulation.

[0152] (2) Soil temperature and soil effective accumulated temperature accumulation: Under the split irrigation treatment, the effective accumulated temperature of the soil at 0-5 cm and 5-10 cm increased by 9.25% and 3.79% respectively compared with that of single irrigation, providing stable heat conditions for seed germination. The cotton emergence rate increased to 90.7% (71.3% and 76.7% for P1 and P2 treatments, respectively).

[0153] (3) Advantages of water saving and salt suppression: Compared with traditional single irrigation, split irrigation can save water at the same irrigation quota (P3 and P1 are both 375m 3 / hm 2 ) can achieve water conservation effect and inhibit salt accumulation at the same time, providing new ideas for water-saving and salt-inhibiting technologies in arid areas.

[0154] 2. Coronatine and irrigation amount synergistically promote cotton morphological development and stress resistance

[0155] The synergistic effect of coronatine (C2 treatment, 0.006% coronatine 2000 times diluted) and fractional irrigation (P3) significantly enhanced cotton growth potential:

[0156] (1) Optimization of aboveground morphology: Under the P3C2 treatment, cotton plant height, stem diameter, and leaf area index reached 103.2 cm, 14.5 mm, and 2.33, respectively, representing increases of 19.44%, 33.03%, and 0.43% compared to the single irrigation plus coronatine treatment (P1C2). Coronatine can regulate the expression of proteins involved in the ABA signaling pathway and drought response factors, alleviating the inhibitory effects of drought stress on plants.

[0157] (2) Spatial expansion of root system: fractional irrigation maintains soil moisture continuity and stimulates lateral root proliferation. The total root volume of P3C2 treatment is 32.21m 3 , total root length 568.72cm and projected area 84.88cm 2 The increases were 167.30%, 75.76%, and 117.59% compared with P1C2. The enhanced root absorption capacity drove the accumulation of aboveground biomass.

[0158] (3) Improved leaf function: The SPAD value of leaves at the seedling stage reached 33.99 under the P3 treatment, which was significantly higher than that under single irrigation (P1 and P2). The interaction effect between coronatine and irrigation amount was significant at the flowering and boll stage (P < 0.05). The leaf area index of P3C2 increased by 5.54% compared with P3C0. Coronatine promoted the accumulation of photosynthetic products by delaying leaf senescence (inhibiting chlorophyll degradation).

[0159] 3. Split irrigation and coronatine synergistically regulate dry matter distribution, driving yield increases

[0160] (1) Dynamic accumulation of dry matter: At the same irrigation quota, fractional irrigation significantly promoted underground dry matter accumulation, with increases of 87.59%, 104.55%, and 43.78% at the bud, boll, and boll-opening stages, respectively, compared with single irrigation. Dry matter accumulation per plant in the P3C2 treatment reached 16.28 g, a 55.05% increase compared with the P1C2 treatment.

[0161] (2) Optimization of dry matter distribution: Dry matter distribution showed significant differences across growth stages—stems and leaves accounted for >60% of the total dry matter during the bud stage, shifting to reproductive organs during the flowering and boll stage, and boll organs accounted for 48.3% of the total dry matter during the boll opening stage. Coronatine promoted the transport of photosynthetic products to bolls by regulating endogenous hormones (JA / ABA balance). Boll dry matter distribution in P3C2-treated cotton increased by 5.2% to 8.7% compared to the control (P3C0).

[0162] (3) Synergistic improvement in yield and resource efficiency: P3C2 treatment yields 6123.67 kg / hm2 of seed cotton 2 Compared with other treatments, the yield increased by 3.30% to 14.69%, and the boll weight increased by 6.51% to 11.43%. Split irrigation optimizes water supply during the flowering and bolling period to meet cotton's critical water needs. Coronatine delays leaf senescence and prolongs the photosynthetic cycle, ultimately achieving a dual increase in yield and water use efficiency.

[0163] 4.Technology Model and Application Value

[0164] This study proposes an optimized technology combination suitable for "dry sowing and wet extraction" cotton fields in arid areas:

[0165] Technical parameters: Drip irrigation twice during seedling stage (225+150m 3 / hm 2 ), spray 2000 times diluted 0.006% coronatine (C2) during the seedling stage, bud stage and early flowering stage.

[0166] Application effect: On the basis of water conservation and soil moisture conservation, this model achieved a seedling emergence rate of >90.7% and a seed cotton yield of >6123.67kg / hm, a 20.50% increase in yield compared with traditional single irrigation (P1C0), and an additional seed cotton yield of 1041.67kg per hectare.

[0167] The number of devices and processing scales described herein are intended to simplify the description of the present invention. Applications, modifications, and variations of the present invention will be readily apparent to those skilled in the art.

[0168] Although the embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the description and implementation methods. They can be fully applied to various fields suitable for the present invention. For those familiar with the art, additional modifications can be easily implemented. Therefore, without departing from the general concept defined by the claims and the scope of equivalents, the present invention is not limited to the specific details and illustrations shown and described herein.

Claims

1. A method for evaluating the effects of irrigation volume and coronatine on cotton field soil and cotton growth, characterized in that: include: Based on a two-factor split-plot experiment, the irrigation amount was set as the main plot and the coronatine dosage was set as the secondary plot. In a split-plot experiment with two factors, irrigation volume and coronatine dosage, the physical and chemical properties of the soil and the growth status of cotton were measured. The effects of irrigation amount and coronatine dosage on cotton field soil and cotton growth were evaluated by the physical and chemical properties of the soil and the growth status of cotton.

2. The method for evaluating the effects of irrigation volume and coronatine on cotton field soil and cotton growth according to claim 1, wherein: The main area has 4 irrigation volumes: P1-375m 3 / hm 2 、P2-450m 3 / hm 2 、P3-225+150m 3 / hm 2 and P4-225+225m 3 / hm 2 The sub-plots consisted of three coronatine dosages: C0 (no coronatine spraying), C1 (3000-fold 0.006% coronatine solution), and C2 (2000-fold 0.006% coronatine solution). The plots were divided into 12 zones: P1C0, P1C1, P1C2, P2C0, P2C1, P2C2, P3C0, P3C1, P3C2, P4C0, P4C1, and P4C2. Each zone was replicated four times, for a total of 48 zones.

3. The method for evaluating the effects of irrigation volume and coronatine on cotton field soil and cotton growth according to claim 1, wherein: The physical and chemical properties of the soil include: soil moisture content, soil electrical conductivity, and soil temperature.

4. The method for evaluating the effects of irrigation volume and coronatine on cotton field soil and cotton growth according to claim 1, wherein: The cotton growth status indicators include: cotton emergence rate, cotton growth index, cotton leaf area index, cotton leaf SPAD value, cotton root index, dry matter dry weight and cotton yield.

5. The method for evaluating the effects of irrigation volume and coronatine on cotton field soil and cotton growth according to claim 3, wherein: When evaluating the effect of irrigation on cotton field soil through the physical and chemical properties of the soil, the following are included: The effect of irrigation amount on soil moisture content was evaluated by the dynamic changes of soil moisture content at different depths and the spatial distribution characteristics of soil moisture content. The effect of irrigation amount on soil electrical conductivity was evaluated by the dynamic changes of soil electrical conductivity at different depths and the spatial distribution characteristics of electrical conductivity. The effect of irrigation amount on soil temperature was evaluated by the average temperature and effective accumulated temperature of different soil layers.

6. The method for evaluating the effects of irrigation volume and coronatine on cotton field soil and cotton growth according to claim 4, wherein: When evaluating the effect of irrigation on cotton growth through cotton growth conditions, the following are the specific factors to consider: The effect of irrigation amount on cotton germination rate was evaluated by the germination rate of cotton in different treatment areas.

7. The method for evaluating the effects of irrigation volume and coronatine on cotton field soil and cotton growth according to claim 4, wherein: When evaluating the effects of irrigation and coronatine on cotton growth based on cotton growth conditions, the following are specifically included: The effect of the interaction between irrigation amount and coronatine dosage on cotton growth and development was evaluated by measuring cotton plant height, stem diameter, root morphology, leaf area index, and leaf SPAD value in different treatment areas.

8. The method for evaluating the effects of irrigation volume and coronatine on cotton field soil and cotton growth according to claim 4, wherein: When evaluating the effects of irrigation and coronatine on cotton growth based on cotton growth conditions, the following are specifically included: The effects of the interaction between irrigation amount and coronatine dosage on cotton dry matter and yield were evaluated by measuring the underground dry matter weight, aboveground dry matter weight, dry matter distribution rate, and cotton yield in different treatment areas.

9. The method for evaluating the effects of irrigation volume and coronatine on cotton field soil and cotton growth according to claim 3, wherein: The soil temperature is measured by using a curved tube thermometer to locate and observe the temperature changes of the 0-5 cm and 5-10 cm soil layers near the edge of the mulch near the cotton seedlings. The soil temperature is monitored every 2 hours from 9:00 to 21:00 on each observation day, and the average value is used as the measured value of the day. The effective accumulated soil temperature is calculated using the following formula: K=N(TC) Where: K is the effective accumulated soil temperature during the seedling growth period, expressed in °C; T is the ground temperature of one day, expressed in °C; N is the number of days of soil temperature measured from sowing to emergence, d; C is the minimum temperature required for growth and development, 14 °C.

10. The method for evaluating the effects of irrigation volume and coronatine on cotton field soil and cotton growth according to claim 4, wherein: The leaf area index was determined by selecting three representative cotton plants from each test area at the seedling, bud, boll, and boll-opening stages. All leaves were removed, flattened, and laid on a scaled white paper. The leaves were photographed vertically with a digital camera, and the leaf area was measured using a digital image processing method. The leaf area index was calculated using the following formula: LAI = leaves per unit land area / area per unit land area Where LAI is the leaf area index.

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