A method for underground drip irrigation of puccinellia distans in soda saline soil

Abstract

The application belongs to the technical field of planting and soil improvement method of Leymus chinensis, and relates to a method for underground drip irrigation of Leymus chinensis in soda saline-alkali soil, and specifically comprises the following steps: step one, drip irrigation of humic acid-citric acid complex and potassium dihydrogen phosphate solution in the early stage; drip irrigation of gypsum-sulfur activated suspension and potassium silicate solution in the middle stage; drip irrigation of bacteria-algae complex and zinc sulfate-ammonium molybdate mixed solution in the late stage; drip irrigation of humic-like polymer in the intermittent stage; and after each time of drip irrigation, the dripper is flushed with a sugar lipid solution; through the time-sequencing targeted drip irrigation system, the method realizes the trinity of "soil improvement, growth promotion and soil nurturing" of Leymus chinensis planting in soda saline-alkali soil, solves three technical problems of salt recirculation, loss of biological activity and system maintenance difficulty, and provides a closed-loop solution for ecological restoration of saline-alkali soil.

Description

Technical Field

[0001] This invention belongs to the technical field of sheepgrass planting and soil improvement, and relates to a method for underground drip irrigation of sheepgrass in soda saline-alkali land. Background Technology

[0002] Currently, the cultivation of Leymus chinensis in saline-alkali land mainly relies on conventional drip irrigation combined with chemical amendments (such as gypsum and humic acid), or single microbial preparations. For example, leaching drip irrigation reduces surface salinity through large-volume leaching, but consumes a lot of water and only temporarily alleviates salinization, failing to prevent the upward movement of deeper salts. The gypsum amendment method, which involves applying gypsum powder followed by drip irrigation, requires a long time to show results, and the calcium content is high. 2+ It is easily fixed by soil colloids, resulting in insufficient sodium ion replacement rate. Single-agent application, with only Bacillus subtilis inoculated, leads to insufficient viable cell survival at high pH, ​​causing failure to build a biological barrier. Drip irrigation systems in saline-alkali land have a high clogging rate; conventional hydrochloric acid flushing accelerates equipment corrosion and shortens service life. Summary of the Invention

[0003] To address the aforementioned problems, this invention provides a method for underground drip irrigation of sheep pastures in soda-saline-alkali land, specifically comprising the following steps:

[0004] Step 1: Mix humic acid powder (humic acid content ≥85%), citric acid crystals (food grade) and water at 45-50℃, stir at 150-350rpm for 25-35min, let stand and mature for 2-2.5h, then add polyepoxysuccinic acid (PESA) with a molecular weight of 800-1000Da to obtain humic acid-citric acid complex (HLC).

[0005] Preferably, the mass ratio of the humic acid powder, citric acid crystals, polyepoxysuccinic acid and water is (0.1-0.15):(0.05-0.1):(0.02-0.04):(100-120).

[0006] Step 2: Mix CaSO4·2H2O (purity ≥95%) and sulfur powder (S content ≥99%) and ball mill until the particle size is ≤80μm. Then mix with water and stir at 150-250rpm for 25-35min. During stirring, add dispersant and urea phosphate (urea phosphate, N:P2O5=17:44). After stirring, a gypsum-sulfur activated suspension is obtained.

[0007] Preferably, the mass ratio of CaSO4·2H2O, sulfur powder, dispersant, urea phosphate, and water is (0.1-0.3):(0.02-0.03):(0.01-0.02):(0.2-0.3):(100-120). Most preferably, the dispersant is xanthan gum.

[0008] Step 3: Mix brown algae extract (fucoidan ≥30%) with Bacillus subtilis bacterial solution, let stand in a dark environment at 20-25℃ for 23-25 ​​hours, add water and film-forming agent, stir at 90-120 rpm for 10-15 minutes to obtain bacterial-algae complex.

[0009] Preferably, the brown algae extract, Bacillus subtilis bacterial solution, film-forming agent, and water are in a mass ratio of (0.5-0.7):(0.1-0.3):(0.1-0.3):(100-120). Most preferably, the Bacillus subtilis bacterial solution is prepared by mixing Bacillus subtilis powder and water to achieve a viable count ≥10⁻⁶. 9 CFU / mL yields Bacillus subtilis bacterial suspension. Most preferably, the film-forming agent is sodium lignosulfonate with a molecular weight of 5000-10000 Da.

[0010] Step 4: Mix gallic acid, glucose and water in a mass ratio of (2-4):(0.5-1.5):(8-12) and incubate in a water bath at 50-60℃ for 2-2.5 hours to obtain a humic polymer.

[0011] Step 5: After sowing sheepgrass, start drip irrigation and cycle through the irrigation in the following sequence:

[0012] From day 1 to day 30 after sowing, irrigate with humic acid-citric acid complex (HLC) at a flow rate of (4-5) L / h / dripper, for 3-4 hours each time, with an interval of 4-5 days between each irrigation. Then, irrigate with a 0.1-0.2% potassium dihydrogen phosphate solution at a flow rate of (2-3) L / h / dripper, for 1.5-2 hours each time, once a day. Stop irrigating after the seeds germinate.

[0013] Mechanism of action: Organic acids in HLC can dissociate to produce H+. + -COOH is converted to -COO - In a saline-alkali environment, H + and OH - Combined with lowering pH, -COO - It combines with Na+ adsorbed in soil colloids to form water-soluble sodium humate complexes. PESA disrupts the double electric layer structure of soil clay particles, releases closed sodium ions, improves the saline-alkali environment, and promotes seed germination.

[0014] From day 31 to day 60, gypsum-sulfur activated suspension is drip-irrigated at a flow rate of (3-4) L / h / dripper, for 3-4 hours each time, with an interval of 7-8 days between each irrigation. Potassium silicate solution with a mass fraction of 0.1-0.2% is drip-irrigated at a flow rate of (1-2) L / h / dripper, for 2-3 hours each time, with an interval of 3-4 days between each irrigation.

[0015] Mechanism of action: Sulfur particles are oxidized into H2SO4 by aerobic sulfur-oxidizing bacteria in the soil (such as sulfur-oxidizing bacteria). The H2SO4 dissociates into H+. + On the one hand and OH - This is combined with lowering pH, and on the other hand, with soil CO3. 2- Combined with the release of CO2, the calcium in the gypsum dissociates. 2+ and the remaining CO3 2- The combination of CaCO3 precipitate and urea phosphate inhibits urease activity, preventing NH4+ precipitate formation. 4+ An increase in pH leads to a rebound, and potassium silicate enhances cell wall resistance.

[0016] From day 61 to day 120, the bacterial-algae complex is drip-irrigated at a flow rate of (1.5-2.5) L / h / drip head for 1.5-2.5 hours each time, with an interval of 9-10 days between each irrigation. A zinc sulfate-ammonium molybdate mixture is drip-irrigated at a flow rate of (2-3) L / h / drip head for 3-4 hours each time, with an interval of 6-7 days between each irrigation. The zinc sulfate-ammonium molybdate mixture, based on water, comprises 0.01-0.02% ammonium molybdate and 0.02-0.03% zinc sulfate by mass.

[0017] Mechanism of action: The bacterial-algae complex colonizes in soil micropores and secretes β-glucan to bind and disperse soil particles. Sodium lignin sulfonate promotes the formation of bacterial biofilms and builds a salt-alkali resistant biological barrier. Bacillus subtilis metabolizes to produce iron phosphate, which alleviates the stress of soil iron ions on crops. Trace elements prevent yellowing of Leymus chinensis.

[0018] During drip irrigation intervals and after Leymus chinensis harvest, the humic polymer is diluted with water to a mass fraction of 0.1-0.2% and dripped into the soil through the underground drip irrigation tape at a flow rate of (1-1.5) L / h / drip head. Each drip irrigation lasts 10-12 hours, and drip irrigation is performed 1-2 times during each drip irrigation interval. After Leymus chinensis harvest, drip irrigation is performed once every 10-15 days to promote the accumulation of soil organic matter and improve soil water holding capacity.

[0019] Step six: After each drip irrigation in step five, rinse with a glycolipid solution at a flow rate of (20-25) L / h / drip head for 10-12 minutes. The glycolipid solution is based on water and includes 300-500 mg / L of sophorolipid and 300-500 mg / L of rhamnolipid.

[0020] Mechanism of action: Rhamnolipids have a critical micelle concentration of 50 mg / L. They can reduce the surface tension of water, and through the embedding of hydrophobic groups into the salt crystal lattice (such as CaCO3) and the binding of hydrophilic groups with water, they achieve nanoscale disintegration of the crystals. Furthermore, both sophorolipids and rhamnolipids are biodegradable.

[0021] The present invention has the following advantages:

[0022] (1) This invention improves the saline-alkali environment through a three-level salt control method of "chemical-biological-physical" to avoid the phenomenon of salt reversion. In the early stage, PESA in the humic acid-citric acid complex destroys the double layer of the clay particles and releases the closed-state N. + H + With OH - Combining direct pH reduction to improve salinity and alkalinity improvement; in the mid-term, sulfur is oxidized to H2SO4 by sulfur-oxidizing bacteria, continuously dissociating H+. + Remove CO3 2- Urea phosphate blocks the urease pathway, preventing NH4+. + The increase leads to a pH rebound; in the later stage, the bacterial-algal complex secretes β-glucan to cement and disperse soil particles, forming a salt-resistant biological barrier and improving soil aggregates. This solves the problem that traditional leaching methods only remove surface salts. This invention achieves the whole-chain removal of salt ions through "desorption-conversion-fixation".

[0023] 2) This invention constructs a long-lasting biological barrier. The bacterial-algae complex (Bacillus subtilis + brown algae polysaccharide) forms a three-dimensional biofilm in soil micropores with the assistance of sodium lignosulfonate film-forming agent. Brown algae polysaccharide enhances the salt tolerance of the bacterial community, and Bacillus subtilis continuously secretes heparin to alleviate iron stress. The biofilm encapsulates and isolates free salt crystals, reduces salt contact with the roots, and improves the root vigor of Leymus chinensis. This invention solves the problem of easy inactivation of existing single bacterial agents due to lack of polysaccharide protection and film-forming medium.

[0024] (3) When rinsing with glycolipid solution (sophorolipid + rhamnolipin), rhamnolipin is embedded in the CaCO3 lattice and disintegrates into nanoparticles, reducing the dripper clogging rate. Zinc sulfate-ammonium molybdate is delivered directly to the root zone through underground drip irrigation, improving the zinc and molybdenum absorption rate and reducing the yellowing rate.

[0025] (4) This invention uses a humus-like polymer to simulate the structure of natural humus. After drip irrigation, it promotes the annual accumulation of soil organic matter, improves water retention capacity, and increases carbon sequestration by bacteria and algae and humus accumulation, thereby increasing the carbon storage of saline-alkali land. Detailed Implementation

[0026] The technical solutions in the embodiments of the invention are described clearly and completely below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0027] The raw materials in the following examples were prepared by the following methods:

[0028] Humic acid powder with a humic acid content ≥85%, food-grade citric acid crystals, and water at 50°C were mixed, stirred at 250 rpm for 30 min, and allowed to stand for 2 h for aging. Then, PESA with a molecular weight of 1000 Da was added to obtain HLC. The mass ratio of humic acid powder, citric acid crystals, polyepoxysuccinic acid, and water was 0.12:0.08:0.03:100.

[0029] CaSO4·2H2O with a purity ≥95% and sulfur powder with a sulfur content ≥99% were mixed and ball-milled until the particle size was ≤80μm. Then, they were mixed with water and stirred at 200rpm for 30min. During stirring, xanthan gum and urea phosphate with an N:P2O5 ratio of 17:44 were added. After stirring, a gypsum-sulfur activated suspension was obtained. The mass ratio of CaSO4·2H2O, sulfur powder, xanthan gum, urea phosphate, and water was 0.2:0.025:0.015:0.25:100.

[0030] A brown algae extract with ≥30% fucoidan (purchased from Xi'an An'ao Biotechnology Co., Ltd.) and ≥10 live bacteria counts were used. 9 CFU / mL Bacillus subtilis bacterial suspension (a mixture of bacterial powder and water, the bacterial powder being purchased from Jinan Qianqi Chemical Co., Ltd.) was mixed and allowed to stand at 23°C in the dark for 24 hours. Water and 10000 Da sodium lignosulfonate were then added, and the mixture was stirred at 100 rpm for 12 minutes to obtain the bacterial-algae complex. The brown algae extract, Bacillus subtilis bacterial suspension, sodium lignosulfonate, and water were mixed in a mass ratio of 0.6:0.2:0.2:100.

[0031] Gallic acid, glucose and water were mixed in a mass ratio of 3:1:10 and heated in a water bath at 55°C for 2 hours to obtain a humic polymer.

[0032] The zinc sulfate-ammonium molybdate mixture, based on water, comprises 0.015% ammonium molybdate and 0.025% zinc sulfate by mass.

[0033] Glycolipid solution: based on water, comprising 500 mg / L sophorolipid and 500 mg / L rhamnolipid.

[0034] Example 1

[0035] After sowing sheepgrass, start drip irrigation and cycle it according to the following drip irrigation sequence:

[0036] From day 1 to day 30 after sowing, irrigate HLC with a flow rate of 4.5 L / h / dripper for 3.5 hours each time, with an interval of 4 days between each irrigation. Then, irrigate with a 0.15% potassium dihydrogen phosphate solution at a flow rate of 2.5 L / h / dripper for 1.75 hours each time, once a day. Stop irrigating after the seeds germinate.

[0037] From day 31 to day 60, gypsum-sulfur activated suspension was drip-irrigated at a flow rate of 3.5 L / h / dripper for 3.8 hours each time, with an interval of 7 days between each irrigation. 0.15% potassium silicate solution was drip-irrigated at a flow rate of 1.5 L / h / dripper for 2 hours each time, with an interval of 3 days between each irrigation.

[0038] From day 61 to day 120, the bacterial-algae complex was drip-irrigated at a flow rate of 2 L / h / dripper for 2 hours each time, with an interval of 10 days between each irrigation. The zinc sulfate-ammonium molybdate mixture was drip-irrigated at a flow rate of 2.5 L / h / dripper for 3 hours each time, with an interval of 7 days between each irrigation.

[0039] During drip irrigation intervals and after Leymus chinensis harvest, the humic polymer is diluted with water to a mass fraction of 0.15% and dripped into the soil through the underground drip irrigation tape at a flow rate of 1.5 L / h / drip head, with each drip irrigation lasting 10 hours. Drip irrigation is performed twice during each drip irrigation interval and once every 12 days after Leymus chinensis harvest.

[0040] After each drip irrigation, rinse with a glycolipid solution at a flow rate of 23 L / h / drip head for 10 minutes.

[0041] Experimental Example 1

[0042] Experimental location: Soda saline-alkali land in Baicheng, Jilin Province (initial soil pH 9.8, EC 8.2mS / cm).

[0043] The test crop was sheepgrass (seeding rate 20 kg / ha).

[0044] Drip irrigation system: underground drip irrigation tape (30cm spacing between drippers, 20cm burial depth).

[0045] Drip irrigation method: Example 1: Drip irrigation method.

[0046] Testing indicators: pH, EC, organic matter, sodium adsorption ratio, sheepgrass plant height, fresh weight, root activity, yellowing rate, and dripper clogging rate.

[0047] Table 1 Changes in soil properties

[0048]

[0049]

[0050] Table 2. Growth Indicators of Leymus chinensis (Harvest Period)

[0051] index data Plant height (cm) 62±3.1 <![CDATA[Density (plants / m 2 )]]> 310±15 <![CDATA[Fresh weight (g / m 2 )]]> 680±25 Root activity (μg / g·h) 35.2±2.1 Yellowing rate (%) ＜5 Drip head clogging rate (%) ≤3

[0052] Table 1-2 shows that the soil pH decreased from 9.8 to 7.5, and the EC decreased from 8.2 to 2.1 mS / cm, indicating that salt and alkali ions were efficiently removed, organic matter increased to 1.8%, and water-holding capacity was enhanced. The biomass of Leymus chinensis (fresh weight 680 g / m²) was also measured. 2 Significant improvement, enhanced root vitality, and due to the direct supply of zinc and molybdenum to the root zone, the yellowing rate of Leymus chinensis is less than 5%, and the sugar and lipid flushing reduces the dripper clogging rate to ≤3%, ensuring long-term operation.

[0053] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for underground drip irrigation of Puccinellia tenuiflora in soda-saline soils, characterized by that, The method comprises the following steps: Step one, after the seeding of Leymus chinensis, start the drip irrigation, and follow the drip irrigation sequence to carry out the cycle drip irrigation: On the first day to the 30th day after the seeding, drip irrigate the humic acid-citric acid complex at a flow rate of (4-5) L / h / dripper, drip irrigate for 3-4 hours each time, and the interval between each drip irrigation is 4-5 days, drip irrigate the potassium dihydrogen phosphate solution at a flow rate of (2-3) L / h / dripper, drip irrigate for 1.5-2 hours each time, drip irrigate once a day, and do not drip irrigate after the seed germination; On the 31st day to the 60th day, drip irrigate the gypsum-sulfur activated suspension at a flow rate of (3-4) L / h / dripper, drip irrigate for 3-4 hours each time, the interval between each drip irrigation is 7-8 days, drip irrigate the potassium silicate solution at a flow rate of (1-2) L / h / dripper, drip irrigate for 2-3 hours each time, and the interval between each drip irrigation is 3-4 days; On the 61st day to the 120th day, drip irrigate the bacteria-algae complex at a flow rate of (1.5-2.5) L / h / dripper, drip irrigate for 1.5-2.5 hours each time, the interval between each drip irrigation is 9-10 days, drip irrigate the zinc sulfate-ammonium molybdate mixed solution at a flow rate of (2-3) L / h / dripper, drip irrigate for 3-4 hours each time, and the interval between each drip irrigation is 6-7 days; During the drip irrigation interval and after the harvesting of Leymus chinensis, drip irrigate the humus-like polymer with a mass fraction of 0.1-0.2% at a flow rate of (1-1.5) L / h / dripper, drip irrigate for 10-12 hours each time, drip irrigate 1-2 times during each drip irrigation interval, and drip irrigate once every 10-15 days after the harvesting of Leymus chinensis; Step two, after each drip irrigation in step one, flush with the glycolipid solution at a flow rate of 20-25 L / h / dripper for 10-12 minutes.

2. The underground drip irrigation method for Puccinellia peisoni in soda saline soil according to claim 1, characterized in that, The preparation method of the humic acid-citric acid complex is as follows: humic acid powder, citric acid crystals and water are mixed and stirred, and then polyepoxysuccinic acid is added after standing and aging, to obtain the humic acid-citric acid complex, and the mass ratio of the humic acid powder, the citric acid crystals, the polyepoxysuccinic acid and the water is (0.1-0.15):(0.05-0.1):(0.02-0.04):(100-120).

3. The underground drip irrigation method for Puccinellia peisoni in soda saline land according to claim 1, characterized in that, The preparation method of the gypsum-sulfur activated suspension is as follows: CaSO4·2H2O and sulfur powder are mixed and ball milled to a particle size of ≤80 μm, and then mixed and stirred with water, and a dispersing agent and urea phosphate are added during the stirring process, to obtain the gypsum-sulfur activated suspension, and the mass ratio of the CaSO4·2H2O, the sulfur powder, the dispersing agent, the urea phosphate and the water is (0.1-0.3):(0.02-0.03):(0.01-0.02):(0.2-0.3):(100-120).

4. The underground drip irrigation method for Puccinellia peisoni in soda saline land according to claim 3, characterized in that, The N:P2O5 in the urea phosphate is 17:

44.

5. The underground drip irrigation method for Puccinellia peisoni in soda saline land according to claim 3, characterized in that, The dispersing agent is xanthan gum.

6. The underground drip irrigation method for Puccinellia peisoni in soda saline land according to claim 1, characterized in that, The preparation method of the bacteria-algae complex is as follows: brown algae extract and bacillus subtilis bacteria solution are mixed, and then placed in a dark environment, and then water and a film forming agent are added and stirred, to obtain the bacteria-algae complex, and the mass ratio of the brown algae extract, the bacillus subtilis bacteria solution, the film forming agent and the water is (0.5-0.7):(0.1-0.3):(0.1-0.3):(100-120).

7. The underground drip irrigation method for Puccinellia peisoni in soda saline land according to claim 6, characterized in that, The preparation method of the Bacillus subtilis bacterial liquid is to mix Bacillus subtilis bacterial powder and water to make the number of living bacteria ≥10 9 CFU / mL, and obtain the Bacillus subtilis bacterial liquid.

8. The underground drip irrigation method for Puccinellia peisoni in soda saline land according to claim 6, characterized in that, The film forming agent is sodium lignosulfonate.

9. The underground drip irrigation method for Puccinellia peisoni in soda saline land according to claim 1, characterized in that, The preparation method of the humus-like polymer is mixing gallic acid, glucose and water according to the mass ratio (2-4):(0.5-1.5):(8-12), water-bathing at 50-60 DEG C for 2-2.5 h to obtain the humus-like polymer.

10. The underground drip irrigation method for Puccinellia peisoni in soda saline land according to claim 1, characterized in that, The glycolipid solution comprises 300-500 mg / L sophorolipid and 300-500 mg / L rhamnolipid based on water.

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