A soil micro-habitat regulation method beneficial to seedling emergence of saline cotton field

Abstract

The application provides a soil micro-habitat regulation method for seedling emergence in a saline cotton field, and belongs to the technical field of soil improvement. After land preparation, a simple strip electrode system is laid at a predetermined sowing row position, an anode is arranged at the center of the sowing row, cathodes are arranged at positions 10-20 cm away from both sides of the sowing row, a direct current electric field is applied for electrodialysis, a 2-4 cm deep ditch is opened at the sowing row, a chlorella fungus composite buffer is scattered and applied, cotton is sown after soil covering, underground and aboveground drip irrigation belts are laid, degradable bio-membranes are covered, and micro-nano bubble water filling drip irrigation is adopted. The method can significantly improve the seedling emergence rate and yield of cotton in a saline cotton field, simultaneously improve the physical and chemical properties of soil, and provide technical support for efficient utilization of salinized farmland.

Description

Technical Field

[0001] This invention belongs to the field of soil improvement technology, and in particular relates to a method for regulating soil microenvironment that is beneficial to seedling emergence in saline cotton fields. Background Technology

[0002] my country has a vast area of ​​saline soil, especially in the inland cotton-growing areas of Northwest China (such as the cotton-growing areas of southern and northern Xinjiang Uygur Autonomous Region). The high proportion of saline cotton fields exacerbates the accumulation of surface salts in the soil due to the arid climate with low rainfall and high evaporation rates, severely restricting cotton production. Cotton seedlings are extremely sensitive to soil microenvironments, and saline cotton fields generally suffer from three core problems: First, excessively high soil salinity creates high osmotic pressure, making it difficult for cotton seeds to absorb water, damaging the radicle, and even causing seed rot; second, uneven soil moisture distribution, with improper drip irrigation easily leading to localized waterlogging and compaction or drought, further exacerbating salt stress; and third, an imbalance in the soil microbial community, with low activity of beneficial microorganisms and the proliferation of pathogens, and soil compaction resulting in poor aeration, affecting seed germination and seedling root growth.

[0003] Existing techniques for regulating seedling emergence in saline cotton fields primarily rely on single measures, such as simple drip irrigation to suppress salt, application of chemical amendments, or single microbial agents. These methods suffer from drawbacks including limited effectiveness, lack of specificity, susceptibility to secondary pollution, and high costs. For example, conventional drip irrigation can lead to deep salt migration and significant salt return later in the season; while single chemical amendments can reduce salt levels in the short term, they can disrupt the soil microbial community; and single microbial agents have a slow onset of action and are insufficient to quickly alleviate acute salt stress during the seedling stage. Furthermore, current technologies fail to achieve synergistic regulation of "salt-water-microorganisms-cultivation," making it impossible to construct a stable and suitable soil microenvironment for cotton seedling emergence. This results in large fluctuations in emergence rate and low seedling vigor, hindering cotton yield increases. Therefore, developing a synergistic regulation method that integrates salt reduction, water retention, microbial regulation, and growth promotion to precisely optimize the soil microenvironment during the seedling stage in saline cotton fields has significant practical implications and application value. Summary of the Invention

[0004] In view of this, the purpose of this invention is to provide a method for regulating soil microenvironment that is beneficial to seedling emergence in saline cotton fields.

[0005] To achieve the above-mentioned objectives, the present invention provides the following technical solution: This invention provides a method for regulating soil microenvironment to facilitate seedling emergence in saline cotton fields, comprising the following steps: (1) After the land is prepared, a simple strip electrode system is laid at the predetermined sowing row position. The anode is placed in the center of the sowing row, and the cathode is placed 10-20cm on each side of the sowing row. A DC electric field is applied to perform electrodialysis. (2) Apply the carbonaceous algae-bacterial compound buffer agent in furrows 2-4 cm deep in the sowing row, cover with soil and then sow; (3) Lay underground and above-ground drip irrigation tapes, cover with biodegradable biological mulch, and use micro-nano bubble water filling drip irrigation.

[0006] Preferably, the voltage gradient of the DC electric field in step (1) is 1~2V / cm, and the electrodialysis time is 2~4h.

[0007] Preferably, the application rate of the charcoal-algae-bacterial composite buffer in step (2) is 3000~4000 kg / hm. 2 The charcoal-algae-bacterial composite buffer comprises modified biochar and a composite algae-bacterial agent, wherein the mass ratio of the modified biochar to the composite algae-bacterial agent is 4~6:1.

[0008] Preferably, the method for preparing the modified biochar includes the following steps: pyrolyzing cotton stalks to prepare biochar, and using a ball milling process to load polyaluminum ferric sulfate and bamboo vinegar onto the surface of the biochar to obtain modified biochar; Preferably, the pyrolysis temperature is 400~500℃, and the pyrolysis time is 1~2h; The mass ratio of biochar, polyaluminum ferric sulfate, and bamboo vinegar is 8~12:1:1~3.

[0009] Preferably, the compound algae and bacteria agent includes desert algae, green algae, Brazilian nitrogen-fixing spirochete and Bacillus subtilis, and the mass ratio of desert algae, green algae, Brazilian nitrogen-fixing spirochete and Bacillus subtilis is 3~5:1~3:1:1~3.

[0010] Preferably, in step (3), underground drip irrigation tape is buried in the narrow rows of cotton plants at a depth of 10-20cm underground, and above-ground drip irrigation tape is buried in the wide rows of cotton plants. The underground drip irrigation tape is used for watering when seedlings emerge, and the surface drip irrigation tape is used for watering during the growing season.

[0011] Preferably, the covering method in step (3) is double-film covering, and the biodegradable biofilm includes the following components: 60-80 parts of polybutylene terephthalate, 20-40 parts of polylactic acid, 5-15 parts of humic acid, 3-8 parts of carnauba wax and 1-3 parts of talc.

[0012] Preferably, the dissolved oxygen content of the micro-nano bubble water-filled drip irrigation in step (3) is 5~15 mg / L, the particle size of the micro-nano bubbles is 200 nm~4 μm, the bubble content is 84~90%, the average bubble rising rate is 4~8 mm / s, and the bubble generation is 1~3 m³ / s. 3 / h.

[0013] Preferably, the irrigation volume of the seedling emergence water is 675~1125m³. 3 / hm 2 The irrigation amount during the growth period is 375~450m³. 3 / hm2 .

[0014] Compared with the prior art, the present invention has the following beneficial effects: This invention solves the core problems of saline cotton fields, such as severe surface salt accumulation, poor soil structure, rhizosphere hypoxia, and insufficient nutrients during the seedling stage, resulting in low emergence rate, seed rot, seedling rot, and weak and uneven seedlings. It can gradually improve the physical and chemical properties of saline soil and significantly increase the emergence rate and yield of cotton in saline cotton fields.

[0015] This invention employs a strip electrode system to apply a 1-2 V / cm DC electric field to the sowing rows for 2-4 hours. Through electrodialysis, salt in the center of the sowing rows is directionally migrated to the non-sowing areas on both sides, creating a localized low-salt microenvironment for cotton seed germination in a short time. This significantly reduces salt osmotic stress and ion toxicity to the seeds. The desalination is highly targeted and fast-acting, effectively solving germination obstacles caused by salt accumulation in saline soils.

[0016] The carbon-algae-bacterial composite buffer of this invention is a scientific compound of cotton straw-based modified biochar and salt-tolerant composite algae-bacterial agent. The modified biochar further fixes free salts in the soil through adsorption, while improving soil aggregate structure and enhancing water and fertilizer retention capacity. The polyaluminum ferric sulfate and bamboo vinegar loaded on it can synergistically regulate soil pH and inhibit soil-borne harmful microorganisms. The salt-tolerant composite algae-bacterial agent (desert algae, green algae, Brazilian nitrogen-fixing spirochete, Bacillus subtilis) can secrete extracellular polysaccharides to bind soil particles, improve rhizosphere microstructure, and simultaneously achieve biological nitrogen fixation, phosphorus and potassium solubilization, replenish seedling nutrients, and enhance soil microbial activity.

[0017] This invention employs a dual-drip irrigation system, combining underground and above-ground drip irrigation for zoned water supply. Underground drip irrigation during the seedling stage avoids secondary salt accumulation due to surface soil compaction and evaporation, precisely meeting the water requirements for seed germination. During the growing season, surface drip irrigation is switched to match the later water needs of cotton. Combined with micro-nano bubble-filled drip irrigation technology, it significantly increases dissolved oxygen content in the rhizosphere, promoting aerobic respiration and root growth, while inhibiting the proliferation of anaerobic harmful bacteria, improving nutrient absorption and utilization, and further enhancing the cotton seedlings' resistance and uniformity.

[0018] This invention uses a biodegradable biofilm for double-layer covering, which can effectively increase soil temperature, maintain soil moisture, inhibit soil evaporation and reduce salt accumulation, providing suitable temperature and humidity conditions for seed germination and seedling growth. The humic acid added to the film can simultaneously improve soil fertility, while carnauba wax and talc powder optimize the mechanical properties and degradability of the film, completely avoiding the white pollution problem caused by traditional plastic films and realizing eco-friendly agricultural production. Detailed Implementation

[0019] This invention provides a method for regulating soil microenvironment to facilitate seedling emergence in saline cotton fields, comprising the following steps: (1) After the land is prepared, a simple strip electrode system is laid at the predetermined sowing row position. The anode is placed in the center of the sowing row, and the cathode is placed 10-20cm on each side of the sowing row. A DC electric field is applied to perform electrodialysis. (2) Apply carbonaceous algae-bacterial compound buffer agent in furrows 2-4 cm deep in the sowing row, cover with soil and then sow cotton; (3) Lay underground and above-ground drip irrigation tapes, cover with biodegradable biological mulch, and use micro-nano bubble water filling drip irrigation.

[0020] In this invention, after land preparation, a simple strip electrode system is laid at the predetermined planting row positions. The anode is placed in the center of the planting row, and the cathode is placed 10-20 cm on each side of the planting row. A direct current electric field is applied for electrodialysis. The voltage gradient of the direct current electric field is 1-2 V / cm, preferably 1.5 V / cm; the electrodialysis time is 2-4 hours, preferably 3 hours. The electric field drives Na... + Cl - Harmful ions migrate to the cathodes on both sides, forming a low-salt zone in the seed row. The ions from electrodialysis migrate in a directional manner, achieving rapid and precise salt reduction in the micro-domain of the seed row.

[0021] In this invention, a carbonaceous-algae-bacterial composite buffer agent is applied by making furrows 2-4 cm deep in the sowing row, and then sown after covering with soil. The application rate of the carbonaceous-algae-bacterial composite buffer agent is 3000-4000 kg / hm². 2 The preferred value is 3750 kg / hm 2 The charcoal-algae-bacterial composite buffer comprises modified biochar and a composite algae-bacterial agent, wherein the mass ratio of the modified biochar to the composite algae-bacterial agent is 4-6:1, preferably 5:1. The preparation method of the modified biochar includes the following steps: pyrolyzing cotton stalks to obtain biochar; using a ball milling process to load polyaluminum ferric sulfate and bamboo vinegar onto the surface of the biochar to obtain modified biochar; the pyrolysis temperature is 400-500℃, preferably 450℃; the pyrolysis time is 1-2 hours, preferably 1.5 hours; the mass ratio of the biochar, polyaluminum ferric sulfate, and bamboo vinegar is 8-12:1:1-3, preferably 10:1:2. The composite algae-bacterial agent comprises desert algae, *Agrocystis jirovecii*, *Azotobacter brasiliensis*, and *Bacillus subtilis*, wherein the mass ratio of the desert algae, *Agrocystis jirovecii*, *Azotobacter brasiliensis*, and *Bacillus subtilis* is 3-5:1-3:1:1-3, preferably 4:2:1:2. Modified biochar possesses a well-developed porous structure and abundant metal-hydroxyl complexes, enabling it to efficiently adsorb Na. + Cl - Ions and bamboo vinegar regulate soil pH, biochar provides a habitat for microorganisms, significantly improving their survival rate and colonization efficiency, and functional microorganisms alleviate salt damage and promote seed germination.

[0022] In this invention, underground and above-ground drip irrigation tapes are laid, covered with a biodegradable biofilm, and micro-nano bubble-filled drip irrigation is used. Underground drip irrigation tapes are buried in narrow rows of cotton plants at a depth of 10-20 cm, preferably 15 cm; above-ground drip irrigation tapes are buried in wider rows of cotton plants. Watering during seedling emergence is done using the underground drip irrigation tapes, while watering during the growing season is done using the surface drip irrigation tapes. The covering method is double-film covering. The biodegradable biofilm comprises the following components: 60-80 parts polybutylene terephthalate (PET), 20-40 parts polylactic acid (PLA), 5-15 parts humic acid, 3-8 parts carnauba wax, and 1-3 parts talc. The preferred amount of PET is 70 parts; the preferred amount of PLA is 30 parts; the preferred amount of humic acid is 10 parts; the preferred amount of carnauba wax is 5 parts; and the preferred amount of talc is 2 parts. Brazilian carnauba wax enhances the barrier properties of mulch film, reduces surface water evaporation, and inhibits salt rise with capillary water. Humic acid is slowly released into the soil during degradation, regulating pH and improving soil fertility. The biodegradable material avoids white pollution, and its degradation products can serve as a carbon source to promote soil microbial activity. The dissolved oxygen content of the micro-nano bubble-filled drip irrigation system is 5-15 mg / L, preferably 10 mg / L; the micro-nano bubbles have a particle size of 200 nm-4 μm, a bubble content of 84-90%, an average bubble rise rate of 4-8 mm / s, and a bubble generation rate of 1-3 m³ / s. 3 / h. Micro-nano bubbles improve soil pore structure and permeability through cavitation, promoting root respiration. They also oxidize the surface of salt crystals, increasing salt decomposition efficiency and accelerating salt leaching. The irrigation volume for seedling emergence is 675~1125m³. 3 / hm 2 The irrigation amount during the growing season is 375~450 m³. 3 / hm 2 .

[0023] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0024] Azotobacter brasiliensis ATCC 29145 was purchased from the American Center for Type Culture Collection, Desert Algae was purchased from Xinjiang Desert Gurun Biotechnology Co., Ltd., Green Lysate was purchased from the Algal Germplasm Bank of the Institute of Oceanology, Chinese Academy of Sciences, and Bacillus subtilis HFN04 was purchased from Beijing Aerospace Hengfeng Technology Co., Ltd.

[0025] Example 1

[0026] A method for regulating soil microenvironment to promote seedling emergence in saline cotton fields is as follows: Level the land and lay a simple strip electrode system at the predetermined sowing row position. The anode is placed in the center of the sowing row and the cathode is placed 15cm on each side of the sowing row. Apply a DC electric field to perform electrodialysis. The voltage gradient of the DC electric field is 1.5V / cm and the electrodialysis time is 3h.

[0027] Apply 3750 kg / hm² evenly in furrows 3 cm deep in the sowing rows. 2 The compound buffering agent consists of charcoal, algae, and bacteria (modified biochar with a mass ratio of 5:1, prepared by pyrolyzing cotton stalks at 450℃ for 1.5 h, and then loading polyaluminum ferric sulfate and bamboo vinegar onto the surface of the biochar using a ball milling process, wherein the mass ratio of biochar, polyaluminum ferric sulfate, and bamboo vinegar is 10:1:2) and a compound algae and bacteria agent (desert algae, green algae, *Azotobacter brasiliensis*, and *Bacillus subtilis* in a mass ratio of 4:2:1:2, with a total algal cell count of 2.0 × 10⁻⁶). 9 cells / g, effective viable count is 2.0 × 10⁻⁶ 9 After covering with soil, cotton is sown at a depth of 2.5 cm.

[0028] Underground drip irrigation tape is laid in narrow rows of cotton plants at a depth of 15cm. Aboveground drip irrigation tape is laid in wide rows of cotton plants, using a 1-film-3-pipe-6-row pattern (one unit of film covers 6 rows of cotton, with 3 drip irrigation tapes laid). Mechanical double-film mulching is performed. The film is a biodegradable biofilm (composed of 70 parts polybutylene terephthalate-adipate, 30 parts polylactic acid, 10 parts humic acid, 5 parts carnauba wax, and 2 parts talc), 2.05m wide. The distances between wide and narrow rows and between films are 66cm, 10cm, and 46cm, respectively, with a plant spacing of 10cm. Micro-nano bubble-filled drip irrigation is used. An ultra-micron aerator is connected to the drip irrigation tape to aerate the incoming water, achieving a dissolved oxygen content of 10mg / L. The micro-nano bubble particle size is 2μm, the bubble content is 88%, the average bubble rise rate is 6mm / s, and the bubble generation rate is 2m³. 3 / h. Irrigation for seedling emergence is done using underground drip irrigation tape, three times a day, with irrigation quotas of 675, 300, and 150 m³ / h. 3 / hm 2 During the growing season, irrigation is carried out using surface drip irrigation tape, with an irrigation volume of 400 m³. 3 / hm 2 .

[0029] Example 2

[0030] A method for regulating soil microenvironment to promote seedling emergence in saline cotton fields is as follows: Level the land and lay a simple strip electrode system at the predetermined sowing row position. The anode is placed in the center of the sowing row and the cathode is placed 10cm on each side of the sowing row. Apply a DC electric field to perform electrodialysis. The voltage gradient of the DC electric field is 1V / cm and the electrodialysis time is 2h.

[0031] Apply 3000 kg / hm² evenly in furrows 2 cm deep in the sowing rows. 2 The compound buffering agent consists of charcoal, algae, and bacteria (modified biochar with a mass ratio of 4:1, prepared by pyrolyzing cotton stalks at 400℃ for 1 hour, and then loading polyaluminum ferric sulfate and bamboo vinegar onto the surface of the biochar using a ball milling process, wherein the mass ratio of biochar, polyaluminum ferric sulfate, and bamboo vinegar is 8:1:1) and a compound algae and bacteria agent (desert algae, green algae, *Azotobacter brasiliensis*, and *Bacillus subtilis* in a mass ratio of 3:1:1:1, with a total algal cell count of 1.0 × 10⁻⁶). 9 cells / g, effective viable count is 1.0 × 10⁻⁶ 9 After covering with soil, cotton is sown at a depth of 2.5 cm.

[0032] Underground drip irrigation tape is laid in narrow rows of cotton plants at a depth of 10 cm. Aboveground drip irrigation tape is laid in wide rows of cotton plants, using a 1-film-3-pipe-6-row pattern (one unit of mulch film covers 6 rows of cotton, with 3 drip irrigation tapes laid). Mechanical double-film mulching is performed. The mulch film is biodegradable (composed of 60 parts polybutylene terephthalate, 20 parts polylactic acid, 5 parts humic acid, 3 parts carnauba wax, and 1 part talc), with a width of 2.05 m. The distances between wide and narrow rows and between the films are 66 cm, 10 cm, and 46 cm, respectively, with a plant spacing of 10 cm. Micro-nano bubble-filled drip irrigation is used. An ultra-micron aerator is connected to the drip irrigation tape to aerate the incoming water, achieving a dissolved oxygen content of 5 mg / L. The micro-nano bubble particle size is 200 nm, the bubble content is 84%, the average bubble rise rate is 4 mm / s, and the bubble generation rate is 1 m³. 3 / h. Irrigation for seedling emergence is done using underground drip irrigation tape, once, with an irrigation quota of 1125m³. 3 / hm 2 During the growing season, surface drip irrigation tape is used for irrigation, and the irrigation volume during the growing season is 375 m³. 3 / hm 2 .

[0033] Example 3

[0034] A method for regulating soil microenvironment to promote seedling emergence in saline cotton fields is as follows: Level the land and lay a simple strip electrode system at the predetermined sowing row position. The anode is placed in the center of the sowing row and the cathode is placed 20cm on each side of the sowing row. Apply a DC electric field to perform electrodialysis. The voltage gradient of the DC electric field is 2V / cm and the electrodialysis time is 4h.

[0035] Apply 4000 kg / hm² evenly in furrows 4 cm deep in the sowing rows. 2 The compound buffering agent consists of charcoal, algae, and bacteria (modified biochar with a mass ratio of 6:1, prepared by pyrolyzing cotton stalks at 500℃ for 2 hours, and then loading polyaluminum ferric sulfate and bamboo vinegar onto the surface of the biochar using a ball milling process, wherein the mass ratio of biochar, polyaluminum ferric sulfate, and bamboo vinegar is 12:1:3) and a compound algae and bacteria agent (desert algae, green algae, *Azotobacter brasiliensis*, and *Bacillus subtilis* in a mass ratio of 5:3:1:3, with a total algal cell count of 3.0 × 10⁻⁶). 9 The effective viable count is 3.0 × 10⁻⁶ cells / g. 9 After covering with soil, cotton is sown at a depth of 2.5 cm.

[0036] Underground drip irrigation tape is laid in narrow rows of cotton plants at a depth of 20cm. Aboveground drip irrigation tape is laid in wide rows of cotton plants, using a 1-film-3-pipe-6-row pattern (one unit of film covers 6 rows of cotton, with 3 drip irrigation tapes laid). Mechanical double-film mulching is performed. The film is a biodegradable biofilm (composed of 80 parts polybutylene terephthalate-adipate, 40 parts polylactic acid, 15 parts humic acid, 8 parts carnauba wax, and 3 parts talc), 2.05m wide. The distances between wide and narrow rows and between the films are 66cm, 10cm, and 46cm, respectively, with a plant spacing of 10cm. Micro-nano bubble-filled drip irrigation is used. An ultra-micron aerator is connected to the drip irrigation tape to aerate the incoming water, achieving a dissolved oxygen content of 15mg / L. The micro-nano bubble particle size is 4μm, the bubble content is 90%, the average bubble rise rate is 8mm / s, and the bubble generation rate is 3m³. 3 / h. Irrigation for seedling emergence is done using underground drip irrigation tape, twice a day, with irrigation quotas of 675 and 450 m³ / h. 3 / hm 2 During the growing season, surface drip irrigation tape is used for irrigation, and the irrigation volume during the growing season is 450 m³. 3 / hm 2 .

[0037] Comparative Example 1

[0038] The difference from Example 1 is that electrodialysis is not performed.

[0039] Comparative Example 2

[0040] The difference from Example 1 is that the "carbon-algae-bacterial composite buffer" is replaced with "saline-alkali soil conditioner, purchased from Shandong Chint New Materials Co., Ltd."

[0041] Comparative Example 3

[0042] The difference from Example 1 is that the biodegradable mulch film is composed of 80 parts of polybutylene terephthalate and 40 parts of polylactic acid.

[0043] Comparative Example 4

[0044] The difference from Example 1 is that the drip irrigation tape is not connected to an ultra-micron aerator, and the water coming from the pipeline is not aerated.

[0045] Experimental Example 1

[0046] An experiment was conducted in Gulebag Village, Shaya County, Aksu City, Xinjiang Uygur Autonomous Region, on moderately saline soil, sandy loam soil. The cotton variety was Xinluzhong 54. The methods described in Examples 1-3 and Comparative Examples 1-4 were used to regulate soil salinity, pH, emergence rate, plant height, stem diameter, and yield. Soil salinity was measured at depths of 0-20 cm, following the method described in "Soil Testing Part 16: Determination of Total Water-Soluble Salts and Salt Isolates in Soil" (NY / T 1121.16). Soil pH was measured using the potentiometric method (using a pH meter). Emergence rate was measured 30 days after sowing. Plant height (cm) and stem diameter (mm) were measured 45 days after sowing using a ruler and vernier calipers (accuracy 0.01 mm). Yield was measured at the boll opening stage.

[0047] Experimental Results: After the method in Example 1 was improved, the total soil salinity decreased from 8.39 g / kg to 4.06 g / kg, the pH value decreased from 8.73 to 7.37, the seedling emergence rate was 95.31%, the plant height was 34.8 cm, the stem diameter was 32.4 mm, and the cotton yield reached 7637 kg / hm². 2 .

[0048] After the method improvement in Example 2, the total soil salinity decreased from 8.21 g / kg to 4.16 g / kg, the pH value decreased from 8.66 to 7.49, the seedling emergence rate was 93.57%, the plant height was 33.4 cm, the stem diameter was 31.6 mm, and the cotton yield reached 7416 kg / hm². 2 .

[0049] After the method improvement in Example 3, the total soil salinity decreased from 8.24 g / kg to 4.38 g / kg, the pH value decreased from 8.63 to 7.34, the seedling emergence rate was 94.12%, the plant height was 32.1 cm, the stem diameter was 30.4 mm, and the cotton yield reached 7528 kg / hm². 2 .

[0050] After the improvement method in Comparative Example 1, the total soil salinity decreased from 8.32 g / kg to 7.98 g / kg, the pH value decreased from 8.93 to 8.21, the emergence rate was 58.84%, the plant height was 21.3 cm, the stem diameter was 22.4 mm, and the cotton yield reached 4817 kg / hm². 2 .

[0051] After the method in Comparative Example 2 was improved, the total soil salinity decreased from 8.27 g / kg to 7.66 g / kg, the pH value decreased from 8.86 to 7.98, the emergence rate was 62.54%, the plant height was 24.4 cm, the stem diameter was 23.6 mm, and the cotton yield reached 5374 kg / hm². 2 .

[0052] After the improvement method in Comparative Example 3, the total soil salinity decreased from 8.15 g / kg to 6.88 g / kg, the pH value decreased from 8.78 to 7.85, the emergence rate was 69.67%, the plant height was 25.6 cm, the stem diameter was 26.1 mm, and the cotton yield reached 6017 kg / hm². 2 .

[0053] After the improvement method in Comparative Example 4, the total soil salinity decreased from 8.10 g / kg to 7.58 g / kg, the pH value decreased from 8.84 to 7.97, the seedling emergence rate was 64.37%, the plant height was 25.0 cm, the stem diameter was 24.3 mm, and the cotton yield reached 5768 kg / hm². 2 .

[0054] As can be seen from the above embodiments and experimental examples, the method of the present invention can significantly improve the physical and chemical properties of saline soil and increase the emergence rate and yield of cotton in saline cotton fields.

[0055] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for regulating soil microenvironment to facilitate seedling emergence in saline cotton fields, characterized in that, Includes the following steps: (1) After the land is prepared, a simple strip electrode system is laid at the predetermined sowing row position. The anode is placed in the center of the sowing row, and the cathode is placed 10-20cm on each side of the sowing row. A DC electric field is applied to perform electrodialysis. (2) Apply carbonaceous algae-bacterial compound buffer agent in furrows 2-4 cm deep in the sowing row, cover with soil and then sow cotton; (3) Lay underground and above-ground drip irrigation tapes, cover with biodegradable biological mulch, and use micro-nano bubble water filling drip irrigation.

2. The method for regulating soil microhabitats according to claim 1, characterized in that, The voltage gradient of the DC electric field in step (1) is 1~2V / cm, and the electrodialysis time is 2~4h.

3. The method for regulating soil microhabitats according to claim 1, characterized in that, The application rate of the carbon-algae-bacterial composite buffer in step (2) is 3000~4000 kg / hm. 2 The charcoal-algae-bacterial composite buffer comprises modified biochar and a composite algae-bacterial agent, wherein the mass ratio of the modified biochar to the composite algae-bacterial agent is 4~6:

1.

4. The method for regulating soil microhabitats according to claim 3, characterized in that, The method for preparing the modified biochar includes the following steps: pyrolyzing cotton stalks to prepare biochar, and using a ball milling process to load polyaluminum ferric sulfate and bamboo vinegar onto the surface of the biochar to obtain modified biochar.

5. The method for regulating soil microhabitats according to claim 4, characterized in that, The pyrolysis temperature is 400~500℃, and the pyrolysis time is 1~2h; The mass ratio of biochar, polyaluminum ferric sulfate, and bamboo vinegar is 8~12:1:1~3.

6. The method for regulating soil microhabitats according to claim 3, characterized in that, The compound algae and bacteria agent includes desert algae, green algae, Brazilian nitrogen-fixing spirochete and Bacillus subtilis, and the mass ratio of the desert algae, green algae, Brazilian nitrogen-fixing spirochete and Bacillus subtilis is 3~5:1~3:1:1~3.

7. The method for regulating soil microhabitats according to claim 1, characterized in that, Step (3) Bury underground drip irrigation tape in the narrow rows of cotton plants at a depth of 10-20cm underground. Bury above-ground drip irrigation tape in the wide rows of cotton plants. Use underground drip irrigation tape for seedling watering and surface drip irrigation tape for watering during the growing season.

8. The method for regulating soil microhabitats according to claim 1, characterized in that, The covering method in step (3) is double-film covering, and the biodegradable biofilm includes the following components: 60-80 parts of polybutylene terephthalate-adipate, 20-40 parts of polylactic acid, 5-15 parts of humic acid, 3-8 parts of carnauba wax and 1-3 parts of talc.

9. The method for regulating soil microhabitats according to claim 1, characterized in that, The dissolved oxygen content of the micro-nano bubble water-filled drip irrigation in step (3) is 5~15 mg / L, the particle size of the micro-nano bubbles is 200 nm~4 μm, the bubble content is 84~90%, the average bubble rising speed is 4~8 mm / s, and the bubble generation is 1~3 m³ / s. 3 / h.

10. The method for regulating soil microhabitats according to claim 7, characterized in that, The irrigation volume for seedling emergence is 675~1125m³. 3 / hm 2 The irrigation amount during the growing season is 375~450 m³. 3 / hm 2 .