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CN-121986617-A - Chemical improvement and ecological restoration method for saline-alkali soil

CN121986617ACN 121986617 ACN121986617 ACN 121986617ACN-121986617-A

Abstract

The invention provides a chemical improvement and ecological restoration method for saline-alkali soil, which comprises the following steps of S1, carrying out rotary tillage on soil before planting, digging holes in narrow rows according to a layout of wide and narrow rows, applying a composite modifier, S2, coating alfalfa seeds with a suspension liquid containing rhizobium inoculant, ammonium molybdate and a water-retaining agent, sowing, S3, carrying out cutting in the early flowering stage of alfalfa, leaving stubbles for 5-7cm, crushing fresh grass to cover the wide rows of ground surfaces, S5, carrying out scattering of a composite microbial inoculant containing arbuscular mycorrhizal fungi and cellulose degrading bacteria before rain after cutting, and carrying out turning stubble pressing rotation on the alfalfa crops after soil indexes reach standards. The invention combines chemical improvement and ecological restoration, improves the water and fertilizer retaining capacity of soil, relieves heavy metal pollution and promotes plant growth.

Inventors

  • WEI XI
  • XU ZHIBO
  • ZHANG LINLIN
  • YANG HAISHENG
  • PAN WENBO
  • ZHANG HUATAO
  • GAO XINGANG
  • SUN XUETAO

Assignees

  • 东盛生态科技股份有限公司

Dates

Publication Date
20260508
Application Date
20251231

Claims (10)

  1. 1. The method for chemically improving and ecologically repairing the saline-alkali soil is characterized by comprising the following steps of: S1, soil preparation before planting: rotary tillage is carried out on soil, wide and narrow rows are adopted, holes are dug at equal intervals on the narrow rows, and a composite modifier is applied to each hole and mixed with soil in the hole; s2, seed pretreatment and sowing: Coating alfalfa seeds with a suspension containing rhizobia agent, ammonium molybdate and water-retaining agent, and sowing the coated seeds in the center of each hole; S3, earthing, irrigation and water and fertilizer management: Covering seeds with fine soil, and dripping the seeds in a tank once, keeping the soil moist until alfalfa is planted, and spraying a molybdenum and boron trace element fertilizer on leaf surfaces in the alfalfa branching period; S4, mowing and coverage management: When the alfalfa is in the early flowering stage, the first mowing is carried out, the stubble remaining height is 5-7cm, the mowed fresh alfalfa part is crushed by a crusher and is directly covered on the wide-row bare ground surface, and the covering thickness is 3-5cm; s5, inoculating a microbial inoculum: after the first mowing, applying a composite microbial agent into soil by broadcasting before rain, wherein the composite microbial agent comprises a arbuscular mycorrhizal fungi inoculant and cellulose degrading bacteria; S6, rotation: After alfalfa is planted, soil key indexes are monitored regularly, and after soil conditions reach a preset target, alfalfa stubble is turned over and pressed, one-season grain crops are planted in turns.
  2. 2. The method for chemically modifying and ecologically restoring the saline-alkali soil according to claim 1, wherein in the step S1, the depth of rotary tillage is 10-15cm, the spacing between wide rows is 60-70cm, the width between narrow rows is 20-25cm, and/or the hole digging is performed at the spacing of 15-20cm according to the plant spacing, the hole depth is 8-10cm, and the dosage of the composite modifier per hole is 15-20g.
  3. 3. The method for chemically modifying and ecologically restoring the saline-alkali soil according to claim 1, wherein in the step S1, the preparation method of the compound modifier comprises the following steps: 1. Mixing and stirring attapulgite and deionized water, adding dilute hydrochloric acid to remove impurities, washing with water, drying, grinding to obtain preactivated attapulgite powder, mixing the preactivated attapulgite powder with deionized water, ball milling, performing ultrasonic treatment on the ball-milled slurry, standing the suspension obtained by ultrasonic treatment, collecting the supernatant, and centrifuging to obtain a nano attapulgite filter cake; 2. Dissolving citric acid in deionized water to obtain a citric acid solution with the concentration of 4-6wt%, mixing a nano attapulgite filter cake with the citric acid solution, controlling the mass ratio of the nano attapulgite filter cake to the citric acid to be (15-20) (4-6), stirring and heating to 75-80 ℃ at the rotating speed of 300-400rpm for reacting for 2-3 hours, cooling to room temperature after the reaction is finished, filtering the reaction solution, washing the precipitate with absolute ethyl alcohol and deionized water in sequence, and then carrying out vacuum freeze drying, wherein the cold trap temperature during drying is-50 ℃, the vacuum degree is less than 10 Pa, and drying is carried out for 24-36 hours to obtain the citric acid modified nano attapulgite; 3. Dispersing sodium carboxymethyl cellulose and chitosan in deionized water, adding a lithium bromide solution, heating, stirring and dissolving, and then cooling to obtain a solution A for later use; mixing silk fibroin and lithium bromide solution, heating, stirring and dissolving to obtain silk fibroin solution, slowly adding the silk fibroin solution into the solution A, and continuously stirring and mixing to obtain polymer solution; 4. Uniformly mixing potassium dihydrogen phosphate, potassium humate, citric acid modified attapulgite and diatomite to obtain a nutrient compound, adding the nutrient compound into the polymer solution, stirring, cooling, adding an initiator and a cross-linking agent, and reacting under the protection of nitrogen to obtain primary gel; 5. cutting the primary gel, mixing with excessive methanol, standing at room temperature for 20-30h, washing with deionized water, granulating by an extrusion granulator, pre-treating gel particles with average particle size of 2-4mm at-20 ℃ for 10-12h, and freezing at-30 to-40 ℃ for 40-50h to obtain a regulating component; 6. Mixing CaSO 4 ·2H 2 O、MgSO 4 ·7H 2 O、Fe 2 (SO 4 ) 3 , adding deionized water, continuously stirring and mixing, finally extruding and granulating, drying to obtain metal composite particles, mixing and granulating the metal composite particles with citric acid modified attapulgite and deionized water, and finally drying to obtain a repairing component; 7. Mixing the repairing component and the regulating component to obtain mixed particles, placing the mixed particles into a fluidized bed coating machine, taking a mixed solution of polyvinyl alcohol, glycerol and water in a mass ratio of (4-5)/(2-3)/(92-94) as a coating solution for film coating, and drying to obtain the composite modifier.
  4. 4. A method for chemically modifying and ecologically restoring soil in saline-alkali soil according to claim 3, characterized in that in the first step, the stirring speed is 500-800rpm, the temperature is 45-50 ℃ and the time is 1-2h, and/or the concentration of dilute hydrochloric acid is 1M, and/or when dilute hydrochloric acid is adopted for removing impurities, the pH of the system is adjusted to 3.5-4.0, and then the mixture is stirred for 2-3h at 55-60 ℃, and/or the mass ratio of the preactivated attapulgite powder to deionized water is 1 (15-20), and/or the mixture is ground by adopting zirconia balls, the mass ratio of zirconia balls to materials is 20:1, the ball grinding speed is 350-400rpm and the ball grinding time is 5-6h, and/or the ultrasonic power is 900W, the total ultrasonic time is 20-30min after 5s of ultrasonic treatment, and/or the time of standing treatment is 0.5-1h and/or the rotation speed of centrifugation is 20-12000 min and/or the ball grinding speed is 20-30min.
  5. 5. The method for chemically improving and ecologically repairing the soil in the saline-alkali soil according to claim 3, wherein in the step three, when the solution A is prepared, the mass ratio of sodium carboxymethyl cellulose to chitosan is (2-3) (1-2), the concentration of the lithium bromide solution is 8M, the addition amount of the lithium bromide solution is 10-15 times of the mass of the chitosan, the heating stirring dissolution is performed under 120 ℃ oil bath, the dissolution time is 2-3h, and/or when the solution A is prepared, the concentration of the lithium bromide solution is 9.0-9.5mol/L, the mass ratio of the silk fibroin to the lithium bromide solution is 1 (9-10), the mass ratio of the silk fibroin to the chitosan is 1 (1.5-2), the temperature during the heating stirring dissolution is 55-60 ℃ and the time is 3-4h, the temperature during the continuous stirring dissolution is 65-70 ℃ and the time is 1-2h.
  6. 6. The method for chemically improving and ecologically restoring soil in saline-alkali soil according to claim 3, wherein in the fourth step, when the primary gel is prepared, the mass ratio of potassium dihydrogen phosphate, potassium humate, citric acid modified attapulgite and diatomite is (10-15): 6-9): 10-20): 5, and/or the addition amount of the nutrient compound is 1 (0.8-1.2) in terms of potassium dihydrogen phosphate, the mass ratio of potassium dihydrogen phosphate and chitosan is/are 1 (0.8-1.2), and/or the temperature of the stirring treatment is 65-70 ℃ for 20-30min, and/or the initiator is APS, the cross-linking agent is MBA, and/or the addition amount of the initiator and the cross-linking agent is 4-5wt% in terms of silk fibroin protein, 1-2wt% and/or the addition temperature of the initiator and the cross-linking agent is 60 ℃, the reaction temperature under nitrogen protection is 60 ℃ and the time is 3-4h.
  7. 7. The method for chemically improving and ecologically repairing the saline-alkali soil according to claim 3, wherein in the sixth step, the mass ratio of CaSO 4 ·2H 2 O、MgSO 4 ·7H 2 O、Fe 2 (SO 4 ) 3 is (6-7): 2-3): 1-1.5, the addition amount of deionized water is 8-10wt% of the total mass of CaSO 4 ·2H 2 O、MgSO 4 ·7H 2 O、Fe 2 (SO 4 ) 3 , the average particle size of the metal composite particles is 1-2mm, and/or the mass ratio of the metal composite particles to the citric acid modified attapulgite is 10 (2.5-3), and the addition amount of deionized water is 4-5wt% of the total mass of solids when the metal composite particles, the citric acid modified attapulgite and the deionized water are mixed and granulated.
  8. 8. The method for chemical improvement and ecological restoration of saline-alkali soil according to claim 1, wherein in the step S3, the process of coating treatment comprises the following steps: (1) Placing 2-3kg of rhizobia agent into a sterile container, adding 4L of sterile water, stirring to obtain a uniform paste, adding 8-10g of yeast extract powder, standing and activating at 25-28 ℃ for 24h under a dark condition, and stirring for 2-3 times to obtain a microbial agent suspension; (2) Dissolving 100-110g of ammonium molybdate powder in 2L of deionized water at 40-50 ℃, and cooling to room temperature to obtain an ammonium molybdate solution; (3) Mixing 1.0-1.5kg of sodium carboxymethylcellulose and 30L of water, stirring and dissolving, adding 100g of xanthan gum, and continuing stirring for 20-30min to obtain colloid base solution; (4) Premixing 1.0-1.2kg of a potassium polyacrylate water-retaining agent and 3-5kg of kaolin, adding into the colloid base solution, stirring and mixing for 10-20min, adding an ammonium molybdate solution, continuously stirring for 10-20min, adding 0.5-0.6g of potassium humate powder, stirring for 5-10min, finally reducing the rotating speed, adding the microbial inoculum suspension, and stirring for 5-10min to obtain a coating solution; (5) Adding 100kg of selected alfalfa seeds into a rotary coating pot, spraying liquid for 10-15 seconds each time, stopping for 30 seconds, enabling the alfalfa seeds to roll and disperse, aligning the spray gun angle with the center of the seed flow when spraying liquid, and controlling the spraying liquid pressure to be 0.15-0.25 MPa cm away from the surface of the seed; (6) Spraying 20-30wt% of the total coating amount, drying at 30deg.C for 5min, spraying the rest coating solution, drying at 30-35deg.C until the surface of the seed is not sticky, turning off heating, and naturally cooling to room temperature to obtain coated seed.
  9. 9. The method for chemically improving and ecologically repairing the soil in the saline-alkali soil according to claim 1, wherein in the step S3, 5-8 coated seeds are sown in the center of each hole, the sowing depth is 1.5-2.5cm, and/or the water application amount is 10-12m 3 water per mu when the pot is dropped once, and/or the thickness of the covering soil is 2.0-3.0cm when the seeds are covered with fine soil, and/or when the molybdenum and boron trace element fertilizer is sprayed on the leaf surface, the molybdenum trace element fertilizer is ammonium molybdate, the boron trace element fertilizer is boric acid, and when the method is specifically used, the ammonium molybdate, the boric acid and the water are mixed, the concentration of the ammonium molybdate is controlled to be 0.05-0.07%, the concentration of the boric acid is 0.1-0.15%, the application amount is 30-45 kg/mu, and/or the soil moisture is kept to the alfalfa planting by adopting an insufficient irrigation strategy to keep the water content of the soil at 60-70% of the water holding capacity in the field.
  10. 10. The compound microbial inoculant for soil chemical improvement and ecological restoration of saline-alkali soil according to claim 1, wherein in the step S5, the mass ratio of arbuscular mycorrhizal fungi inoculant to cellulose degrading bacteria is (60-75) (25-40), the application amount of the compound microbial inoculant is 4-8 kg/mu, and/or in the step S6, the soil key index comprises pH, EC, ESP and organic matters, the preset target comprises pH <8.5, ESP <15%, EC <0.8 dS/m and organic matters >2.0%.

Description

Chemical improvement and ecological restoration method for saline-alkali soil Technical Field The invention relates to the technical field of soil improvement, in particular to a chemical improvement and ecological restoration method for saline-alkali soil. Background Saline-alkali soil refers to soil with excessive content of soluble salt and sodium ions, which results in deterioration of soil structure, reduced fertility and limited plant growth. The global saline-alkali soil is wide, and the agricultural production and ecological safety are seriously restricted. The current saline-alkali soil improvement method mainly comprises physical improvement such as drainage and salt washing, chemical improvement such as gypsum application and humic acid application, and biological improvement such as planting of salt-tolerant plants and microorganism inoculation. The existing method for improving the saline-alkali soil mainly has the following problems that firstly, the improvement effect is single, a plurality of improvers only aim at a certain problem, such as salt reduction, pH adjustment, fertilizer increase and the like, and lack comprehensive and synergistic comprehensive improvement effects, secondly, the improvement persistence is poor, part of chemical improvers are easy to run off or convert, the long-term effect is unstable, thirdly, the ecological compatibility is poor, certain chemical improvers possibly inhibit soil microbial communities and influence the ecological restoration process, fourthly, the improvement cost is high, the operation is complex, and measures such as deep soil replacement, large-scale irrigation and drainage and the like are large in investment and difficult to popularize. Based on the above problems, it is necessary to provide a new saline-alkali soil improvement method. Disclosure of Invention Aiming at the defects of the prior art, the invention provides the chemical improvement and ecological restoration method for the saline-alkali soil, which can not only effectively improve the water and fertilizer retention capacity of the soil, but also effectively improve the heavy metal pollution of the soil and better promote the growth of plants by combining the chemical improvement and the ecological restoration. In order to solve the technical problems, the technical scheme of the invention is as follows: a method for chemically improving and ecologically restoring saline-alkali soil comprises the following steps: S1, soil preparation before planting: rotary tillage is carried out on soil, wide and narrow rows are adopted, holes are dug at equal intervals on the narrow rows, and a composite modifier is applied to each hole and mixed with soil in the hole; s2, seed pretreatment and sowing: Coating alfalfa seeds with a suspension containing rhizobia agent, ammonium molybdate and water-retaining agent, and sowing the coated seeds in the center of each hole; S3, earthing, irrigation and water and fertilizer management: Covering seeds with fine soil, and dripping the seeds in a tank once, keeping the soil moist until alfalfa is planted, and spraying a molybdenum and boron trace element fertilizer on leaf surfaces in the alfalfa branching period; S4, mowing and coverage management: When the alfalfa is in the early flowering stage, the first mowing is carried out, the stubble remaining height is 5-7cm, the mowed fresh alfalfa part is crushed by a crusher and is directly covered on the wide-row bare ground surface, and the covering thickness is 3-5cm; s5, inoculating a microbial inoculum: after the first mowing, applying a composite microbial agent into soil by broadcasting before rain, wherein the composite microbial agent comprises a arbuscular mycorrhizal fungi inoculant and cellulose degrading bacteria; S6, rotation: After alfalfa is planted, soil key indexes are monitored regularly, and after soil conditions reach a preset target, alfalfa stubble is turned over and pressed, one-season grain crops are planted in turns. Preferably, in the step S1, the depth of rotary tillage is 10-15cm, the spacing between wide rows is 60-70cm, and the width of narrow rows is 20-25cm. Preferably, in the step S1, the hole digging is carried out according to the spacing of 15-20cm, the hole depth is 8-10cm, and the dosage of the composite modifier in each hole is 15-20g. Preferably, in step S1, the preparation method of the composite modifier includes the following steps: 1. Mixing and stirring attapulgite and deionized water, adding dilute hydrochloric acid to remove impurities, washing with water, drying, grinding to obtain preactivated attapulgite powder, mixing the preactivated attapulgite powder with deionized water, ball milling, performing ultrasonic treatment on the ball-milled slurry, standing the suspension obtained by ultrasonic treatment, collecting the supernatant, and centrifuging to obtain a nano attapulgite filter cake; 2. Dissolving citric acid in deionized water to obtain a citric acid