Ecological restoration method for saline-alkali soil

Abstract

The invention relates to the technical field of soil remediation, in particular to a saline-alkali soil ecological remediation method. The ecological restoration method for the saline-alkali soil comprises the following steps: (1) adding a saline-alkali soil modifier into the saline-alkali soil; (2) applying a microbial fertilizer to the saline-alkali soil; (3) applying a mixed microalgae solution to the saline-alkali soil; and (4) carrying out rotation planting on saline-alkali tolerant plants in the treated saline-alkali soil. According to the comprehensive and systematic ecological restoration method for the saline-alkali soil, the saline-alkali soil modifier, the microbial fertilizer and microalgae treatment are organically combined, saline-alkali tolerant crops are planted in the saline-alkali soil in a rotation mode, the restoration effect of the saline-alkali soil can be effectively improved, and a solution is provided for an actual engineering project.

Description

Technical Field

[0001] The present invention relates to the technical field of soil restoration, and in particular to a method for ecological restoration of saline-alkali land. Background Art

[0002] In recent years, the area of ​​salinized soil has been gradually expanding globally, and the degree of salinization has become increasingly serious. At the same time, the area of ​​secondary salinized soil caused by human activities has increased faster, especially in arid and semi-arid areas. Some areas are affected by secondary salinization, resulting in the area of ​​cultivated land becoming salinized soil at a faster rate each year. Soil salinization will inhibit the growth of crops and herbaceous plants and lead to reduced production, becoming a key factor restricting the development of agriculture and animal husbandry.

[0003] At present, the restoration of saline-alkali land often adopts a single method, such as using chemical modifiers to reduce or eliminate soil alkalinity, improve soil physical and chemical properties, or continuously leaching and removing salt from the soil through irrigation, flood diversion and silt release, etc. The single saline-alkali land restoration method is not ideal for the saline-alkali land restoration effect. Therefore, it is of great significance to provide a systematic saline-alkali land restoration method to effectively improve the saline-alkali land restoration effect and maintain the effect for a long time. Summary of the invention

[0004] In order to overcome the shortcomings and deficiencies in the prior art, the purpose of the present invention is to provide a systematic saline-alkali land restoration method, which can effectively improve the saline-alkali land restoration effect and maintain the effect for a long time.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solution: a method for ecological restoration of saline-alkali land, comprising the following steps:

[0006] (1) Adding saline-alkali land improvers to saline-alkali land;

[0007] (2) Applying microbial fertilizer to saline-alkali land;

[0008] (3) Applying mixed microalgae liquid to saline-alkali land;

[0009] (4) Rotate salt-alkali tolerant plants in treated saline-alkali land.

[0010] Furthermore, in step (1), the saline-alkali land improver comprises the following raw materials in percentage by mass: 30-50% phosphogypsum, 10-30% calcium-magnesium modified biochar, 10-20% humic acid, 10-20% attapulgite, 10-20% bentonite, and 5-10% polyacrylamide.

[0011] Furthermore, the preparation method of the calcium-magnesium modified biochar comprises the following steps:

[0012] (A1) Remove impurities from rice and corn stalks, wash and dry them, and grind them through a 10-mesh sieve. Dry them in an oven at 100-110°C until the mass is constant. Then, place them in a muffle furnace and pass a flow rate of 90-110 mL min -1 After 25-35 minutes of nitrogen, the temperature was 8-12℃·min -1 The temperature was raised to 280-320℃ at a rate of 1.5-2.5h, then maintained at 8-12℃·min -1 The temperature was raised to 480-520℃ at a rate of 8-12℃·min and maintained for 3.5-4.5h. -1 The temperature is raised to 680-720°C at a rate and maintained for 3.5-4.5 hours, and then cooled. After cooling, the obtained biochar is taken out, and the obtained biochar is ground and passed through a 100-mesh sieve, and then dried and stored away from light;

[0013] (A2) Soaking the biochar obtained in step (A1) in a mixed solution of magnesium chloride and calcium chloride at a concentration of 20-50 g / L for 20-28 h, wherein the concentration of magnesium chloride is 0.8-1.2 mol / L, and the concentration of calcium chloride is 0.8-1.2 mol / L; then adding 0.8-1.2 g urea, 0.8-1.2 g ammonium sulfate, 0.4-0.6 g potassium dihydrogen phosphate, 0.4-0.6 g ammonium dihydrogen phosphate and 0.8-1.2 g potassium nitrate, adjusting the pH to 7.5-8.5, soaking for 20-28 h, and drying in an oven at 100-110° C. for 6-8 h to prepare calcium-magnesium modified biochar.

[0014] Furthermore, in step (2), the microbial fertilizer comprises the following raw materials in percentage by mass: 40-45% cow dung fertilizer, 40-45% sheep dung fertilizer, 2-4% Bacillus subtilis, 2-4% Trichoderma aculeatus, 2-4% Trichoderma viride, and 2-4% white rot fungi.

[0015] Furthermore, the preparation method of Bacillus subtilis comprises the following steps:

[0016] (B1) inoculating Bacillus subtilis into a seed culture medium, culturing in an incubator at a temperature of 25-40° C. for 18-30 hours with shaking to obtain a primary seed solution, and controlling the rotation speed at 150-200 rpm; the seed culture medium is LB culture medium;

[0017] (B2) inoculating the seed solution obtained in step (B1) into a primary seed tank at an inoculum volume fraction of 10-20%, wherein the culture conditions of the primary seed tank are as follows: temperature 25-40° C., rotation speed 150-200 rpm, pH 6.5-7.5, dissolved oxygen 20-50%, and culturing for 18-30 hours to obtain a secondary seed solution;

[0018] (B3) inoculating the secondary seed solution obtained in step (B2) into a fermentation tank at an inoculum volume fraction of 10-20%, and culturing the fermentation tank at a temperature of 25-40° C., a rotation speed of 150-200 rpm, a pH of 6.5-7.5, and culturing for 18-30 hours to obtain a Bacillus subtilis fermentation liquid;

[0019] (B4) centrifuging the Bacillus subtilis fermentation liquid obtained in step (B3), adjusting the solid content of the bacterial liquid to 50-80%, and adding a drying protective agent in an amount of 0.5-15% by weight of the bacterial liquid to the adjusted bacterial liquid to obtain a bacterial slurry; the drying protective agent is at least one of galactose, trehalose, sucrose, lactose, raffinose, glycerol, dimethyl sulfoxide, and gelatin;

[0020] (B5) mixing the bacterial slurry obtained in step (4) with auxiliary materials in a mass ratio of 1:0.5-3 to obtain solid particles; the auxiliary material component is at least one of wood ash, vermiculite powder, kaolin, diatomaceous earth, clay, and magnesium stearate;

[0021] (B6) vacuum drying the solid particles at a drying temperature of 30-50° C. for a drying time of 0.5-10 h to obtain a Bacillus subtilis product.

[0022] Further, in steps (B2) and (B3), the culture medium used includes raw materials of the following concentrations: glucose 1-5 g / L, NaAC 1-5 g / L, potassium nitrate 0.1-1 g / L, ammonium nitrate 0.1-1 g / L, potassium dihydrogen phosphate 0.05-2 g / L, ammonium dihydrogen phosphate 0.05-2 g / L, sodium chloride 5-15 g / L, magnesium sulfate heptahydrate 0.08-0.3 g / L, trace elements 0.01-1%. Wherein, the trace elements include raw materials of the following concentrations: ferrous sulfate heptahydrate 0.1-0.5 g / L, cobalt chloride 0.01-0.2 g / L, manganese chloride 0.5-3 g / L, anhydrous copper sulfate 0.02-0.1 g / L, sodium molybdate 0.2-0.5 g / L, hydrochloric acid 0.01-0.05 g / L.

[0023] Furthermore, the preparation method of Trichoderma acanthosporum comprises the following steps:

[0024] (C1) inoculating Trichoderma aculeatus into a seed solution containing a culture medium, and culturing the solution in an incubator at a temperature of 25-37° C. for 48-60 hours to obtain a seed solution, wherein the seed culture medium is a potato-glucose culture medium;

[0025] (C2) Inoculate the seed liquid into a solid culture medium at a rate of 20-100 mL / kg, control the water content to be 60-80%, culture at 25-37° C. for 3-6 days, dry at room temperature for 3-5 days, grind, and pass through a 200-mesh sieve to obtain Trichoderma spinulosa powder.

[0026] Furthermore, the preparation method of the green Trichoderma comprises the following steps:

[0027] (D1) inoculating Trichoderma viride into seed solution containing culture medium, and culturing in an incubator at a temperature of 25-37° C. for 48-60 hours to obtain seed solution, wherein the seed culture medium is potato-glucose culture medium;

[0028] (D2) The seed liquid is inoculated into a solid culture medium at a rate of 20-100 mL / kg, the water content is controlled to be 60-80%, and the culture is carried out at 25-37° C. for 3-6 days, followed by drying at room temperature for 3-5 days. The mixture is crushed and passed through a 200-mesh sieve to obtain green Trichoderma powder.

[0029] Furthermore, in steps (C2) and (D2), the solid culture medium comprises the following raw materials in percentage by mass: 40-70% straw, 30-50% wheat bran, 0.5-3% cornmeal, 0.5-2% ammonium nitrate, 0.05-0.5% manganese sulfate, and 0.01-0.03% magnesium sulfate.

[0030] Furthermore, the preparation method of the white rot fungus comprises the following steps:

[0031] (F1) inoculating white rot fungi into a liquid seed culture medium at an inoculum rate of 10-20%, and culturing the liquid in an incubator at a temperature of 28-35° C. for 18-30 hours to obtain a seed solution, wherein the seed culture medium is a PDA culture medium;

[0032] (F2) The seed liquid is inoculated into a solid culture medium at an inoculum rate of 10-20%, stirred evenly after inoculation, the culture medium is turned over every day, and cultured at 28-35° C. for 5-7 days to obtain white rot fungi.

[0033] Furthermore, in step (3), the mixed microalgae liquid includes Chlorella, Nostoc, Anabaena and Unipedia, and the weight ratio of Chlorella, Nostoc, Anabaena and Unipedia is 0.5-2:0.5-2:0.5-2:0.5-2.

[0034] Furthermore, the culture method of the mixed microalgae liquid includes the following steps: inoculating Chlorella, Nostoc, Anabaena, and Monochamus species into an algae culture device at a volume ratio of 1-10% for culture, controlling the pH to 6.5-6.8, and setting the chlorophyll a to 1.5 mg / L to complete the culture.

[0035] Furthermore, the nutrient solution of the mixed microalgae liquid includes the following raw materials at the following concentrations: NaNO 3 1.0-2.0g / L, KNO 3 1.0-2.0g / L, KH 2 PO 4 0.02-0.06g / L, MgSO4 7H 2 O 0.04-0.08g / L, CaCl 2 ·2H 2 O 0.02-0.06g / L, Na 2 CO 3 0.01-0.03g / L, K 2 CO 3 0.01-0.03g / L, EDTANa 2 0.001-0.005g / L, ferric citrate 0.005-0.01g / L, trace elements 0.5-2mL / L.

[0036] Further, the trace elements include raw materials with the following concentrations: H 3 BO 3 1-3g / L, MnSO 2 ·4H 2 O 0.5-3g / L, ZnSO 4 7H 2 O 0.1-0.5g / L, FeSO 4 7H 2 O 0.1-0.5g / L, NaMoO 4 ·2H 2 O 0.1-0.5g / L, CuSO 4 ·5H 2 O0.05-0.1g / L, Co(NO 3 ) 2 6H 2 O 0.02-0.06g / L.

[0037] Furthermore, in step (4), the salt-alkali tolerant plants are Suaeda salsa and alfalfa, and indole-3-acetic acid is applied during the planting process, with an application amount of 1-5 kg / mu.

[0038] Furthermore, in step (1), the dosage of the saline-alkali land improver is 2-4 t / mu; in step (2), the dosage of the microbial fertilizer is 1-2 t / mu; and in step (3), the dosage of the mixed microalgae liquid is 10-20 L / mu.

[0039] The Medicago sativa and alfalfa used in the present invention are both salt-tolerant plants, and play an important role in improving saline-alkali land. Suaeda sativa is a plant of the genus Suaeda of the Chenopodiaceae family, and is a typical true halophyte. The total population of salt-tolerant bacteria and halophilic bacteria in the rhizosphere and tissue of Suaeda sativa is rich, which can improve soil fertility, reduce salt-alkali stress damage and improve saline-alkali soil. Alfalfa (Medicago sativa) is known as the "king of forage grass" and is the leguminous forage grass with the largest cultivation area and the widest range in the world. It has the characteristics of strong adaptability and stress resistance, high yield, high nutritional value and easy harvesting. The present invention adopts Suaeda sativa and alfalfa for crop rotation, and the growth-promoting bacteria in the Suaeda sativa plant and its rhizosphere soil can effectively promote the germination of alfalfa seeds and the growth of seedlings, and further improve saline-alkali soil.

[0040] The saline-alkali land ecological restoration method of the present invention comprises the following steps: firstly, a saline-alkali land improver is added, and then applied to the soil in combination with deep loosening and shallow turning combined with land preparation, and then the application is made to the tillage layer by deep turning to break the plow bottom layer, and then microbial fertilizer is applied, and then mixed microalgae are applied, and after the mixed microalgae grows on the saline-alkali land for 20-40 days, Suaeda salsa and alfalfa are rotated and planted, which can effectively improve the saline-alkali land restoration effect and can maintain the effect for a long time.

[0041] The beneficial effects of the present invention are:

[0042] (1) The present invention provides a comprehensive and systematic method for ecological restoration of saline-alkali land, organically combines saline-alkali land improvers, microbial fertilizers and microalgae treatment, and rotates salt-alkali-tolerant crops in saline-alkali land, which can effectively improve the saline-alkali land restoration effect and provide solutions for actual engineering projects.

[0043] (2) The saline-alkali land conditioner of the present invention contains calcium-magnesium modified biochar, which is prepared from corn and rice straw, and can fully utilize the straw as a resource. The biochar is modified to contain calcium, magnesium and other nutrients, and can provide nutrition for the subsequent growth of microalgae and salt-alkali tolerant plants.

[0044] (3) The microalgae of the present invention can assimilate carbon dioxide in the atmosphere into biomass through photosynthesis, and can fix nitrogen in the atmosphere, which helps to increase the nitrogen content in the soil; the microalgae can secrete extracellular polysaccharides to provide organic carbon for the growth of microorganisms and form bioflocs and biofilms in the rhizosphere of plants. The extracellular polysaccharides have adhesion, which helps to aggregate soil particles, improve soil structure, and enhance the stability of aggregates.

[0045] (4) The invention adopts Suaeda salsa and alfalfa as rotational plants to plant salt-alkali tolerant plants, which plays an important role in improving saline-alkali land. Suaeda salsa is a plant of the genus Suaeda of the Chenopodiaceae family. Suaeda salsa and alfalfa are rotated, and the growth-promoting bacteria in the Suaeda salsa plants and their rhizosphere soil can effectively promote the germination of alfalfa seeds and the growth of seedlings, further improving saline-alkali soil. DETAILED DESCRIPTION

[0046] In order to facilitate the understanding of those skilled in the art, the present invention is further described below in conjunction with embodiments, and the contents mentioned in the implementation modes are not intended to limit the present invention.

[0047] In some embodiments of the present invention, a method for ecological restoration of saline-alkali land comprises the following steps:

[0048] (1) Adding saline-alkali land improver to saline-alkali land, the dosage of saline-alkali land improver is 2-4t / mu;

[0049] (2) Apply microbial fertilizer to saline-alkali land at a dosage of 1-2t / mu;

[0050] (3) Applying mixed microalgae liquid to the saline-alkali land; the amount of mixed microalgae liquid added is 10-20L / mu;

[0051] (4) After the mixed algae have grown on saline-alkali land for 20-40 days, Suaeda salsa and alfalfa are planted in rotation;

[0052] In some embodiments of the present invention, in step (1), the saline-alkali land improver includes the following raw materials in percentage by mass: 30-50% phosphogypsum, 10-30% calcium-magnesium modified biochar, 10-20% humic acid, 10-20% attapulgite, 10-20% bentonite, and 5-10% polyacrylamide.

[0053] In some embodiments of the present invention, the method for preparing calcium-magnesium modified biochar comprises the following steps:

[0054] (A1) Remove impurities from rice and corn stalks, wash and dry them, and grind them through a 10-mesh sieve. Dry them in an oven at 100-110°C until the mass is constant. Then, place them in a muffle furnace and pass a flow rate of 90-110 mL min -1 After 25-35 minutes of nitrogen, the temperature was 8-12℃·min -1 The temperature was raised to 280-320℃ at a rate of 1.5-2.5h, then maintained at 8-12℃·min -1 The temperature was raised to 480-520℃ at a rate of 8-12℃·min and maintained for 3.5-4.5h. -1 The temperature is raised to 680-720°C at a rate and maintained for 3.5-4.5 hours, then cooled. After cooling, the obtained biochar is taken out, ground and sieved through a 100-mesh sieve, and stored in a dry and dark place.

[0055] (A2) The biochar obtained in step (A1) is soaked in a mixed solution of magnesium chloride and calcium chloride at a concentration of 20-50 g / L for 20-28 h, the concentration of magnesium chloride is 0.8-1.2 mol / L, and the concentration of calcium chloride is 0.8-1.2 mol / L; then 0.8-1.2 g urea, 0.8-1.2 g ammonium sulfate, 0.4-0.6 g potassium dihydrogen phosphate, 0.4-0.6 g ammonium dihydrogen phosphate and 0.8-1.2 g potassium nitrate are added and mixed, and the pH is adjusted to 7.5-8.5 with sulfuric acid solution. After soaking for 20-28 h, it is dried in an oven at 100-110° C. for 6-8 h to prepare calcium-magnesium modified biochar.

[0056] In some embodiments of the present invention, in step (2), the microbial fertilizer comprises the following raw materials in percentage by mass: 40-45% cow dung fertilizer, 40-45% sheep dung fertilizer, 2-4% Bacillus subtilis, 2-4% Trichoderma aculeatus, 2-4% Trichoderma viride, and 2-4% white rot fungi.

[0057] In some embodiments of the present invention, the method for preparing Bacillus subtilis comprises the following steps:

[0058] (B1) inoculating Bacillus subtilis into a seed culture medium, culturing in an incubator at a temperature of 25-40° C. for 18-30 hours with shaking to obtain a primary seed solution, and controlling the rotation speed at 150-200 rpm; the seed culture medium is LB culture medium;

[0059] (B2) inoculating the seed solution obtained in step (B1) into a primary seed tank at an inoculum volume fraction of 10-20%, wherein the culture conditions of the primary seed tank are as follows: temperature 25-40° C., rotation speed 150-200 rpm, pH 6.5-7.5, dissolved oxygen 20-50%, and culturing for 18-30 hours to obtain a secondary seed solution;

[0060] (B3) inoculating the secondary seed solution obtained in step (B2) into a fermentation tank at an inoculum volume fraction of 10-20%, and culturing the fermentation tank at a temperature of 25-40° C., a rotation speed of 150-200 rpm, a pH of 6.5-7.5, and culturing for 18-30 hours to obtain a Bacillus subtilis fermentation liquid;

[0061] (B4) centrifuging the Bacillus subtilis fermentation broth obtained in step (B3), adjusting the solid content of the bacterial broth to 50-80%, adding a drying protective agent to the adjusted bacterial broth, wherein the mass percentage of the drying protective agent added is 0.5-15%, to obtain a bacterial slurry; the drying protective agent is at least one of galactose, trehalose, sucrose, lactose, raffinose, glycerol, dimethyl sulfoxide, and gelatin;

[0062] (B5) mixing the bacterial slurry obtained in step (4) with auxiliary materials in a mass ratio of 1:0.5-3 to obtain solid particles; the auxiliary material component is at least one of wood ash, vermiculite powder, kaolin, diatomaceous earth, clay, and magnesium stearate;

[0063] (B6) vacuum drying the solid particles at a drying temperature of 30-50° C. for a drying time of 0.5-10 h to obtain a Bacillus subtilis product.

[0064] In some embodiments of the present invention, in steps (B2) and (B3), the culture medium used includes raw materials of the following concentrations: glucose 1-5 g / L, NaAC 1-5 g / L, potassium nitrate 0.1-1 g / L, ammonium nitrate 0.1-1 g / L, potassium dihydrogen phosphate 0.05-2 g / L, ammonium dihydrogen phosphate 0.05-2 g / L, sodium chloride 5-15 g / L, magnesium sulfate heptahydrate 0.08-0.3 g / L, trace elements 0.01-1%. The trace elements include raw materials of the following concentrations: ferrous sulfate heptahydrate 0.1-0.5 g / L, cobalt chloride 0.01-0.2 g / L, manganese chloride 0.5-3 g / L, anhydrous copper sulfate 0.02-0.1 g / L, sodium molybdate 0.2-0.5 g / L, and hydrochloric acid 0.01-0.05 g / L.

[0065] In some embodiments of the present invention, the preparation method of Trichoderma aspergillus comprises the following steps:

[0066] (C1) inoculating Trichoderma aculeatus into a seed solution containing a culture medium, and culturing the solution in an incubator at a temperature of 25-37° C. for 48-60 hours to obtain a seed solution, wherein the seed culture medium is a potato-glucose culture medium;

[0067] (C2) inoculating the seed liquid into a solid culture medium at a rate of 20-100 mL / kg, controlling the water content to be 60-80%, culturing at 25-37° C. for 3-6 days, drying at room temperature for 3-5 days, crushing and passing through a 200-mesh sieve to obtain Trichoderma spinulosa powder;

[0068] In some embodiments of the present invention, the method for preparing Trichoderma viride comprises the following steps:

[0069] (D1) inoculating Trichoderma viride into seed solution containing culture medium, and culturing in an incubator at a temperature of 25-37° C. for 48-60 hours to obtain seed solution, wherein the seed culture medium is potato-glucose culture medium;

[0070] (D2) The seed liquid is inoculated into a solid culture medium at a rate of 20-100 mL / kg, the water content is controlled to be 60-80%, and the culture is carried out at 25-37° C. for 3-6 days, followed by drying at room temperature for 3-5 days. The powder is then crushed and passed through a 200-mesh sieve to obtain green Trichoderma powder.

[0071] Furthermore, in steps (C2) and (D2), the solid culture medium comprises the following raw materials in percentage by mass: 40-70% straw, 30-50% wheat bran, 0.5-3% cornmeal, 0.5-2% ammonium nitrate, 0.05-0.5% manganese sulfate, and 0.01-0.03% magnesium sulfate.

[0072] In some embodiments of the present invention, the method for preparing the white rot fungus comprises the following steps:

[0073] (F1) inoculating white rot fungi in a liquid seed culture medium at an inoculum volume fraction of 10-20%, culturing in an incubator at a temperature of 28-35° C. for 18-30 hours to obtain a seed solution, wherein the seed culture medium is a PDA culture medium;

[0074] (F2) The seed liquid is inoculated into a solid culture medium at an inoculum volume fraction of 10-20%, stirred evenly after inoculation, the culture medium is turned over every day, and cultured at 28-35° C. for 5-7 days to obtain white rot fungi.

[0075] In some embodiments of the present invention, in step (3), the mixed microalgae liquid includes Chlorella, Nostoc, Anabaena and Unipedia, and the weight ratio of Chlorella, Nostoc, Anabaena and Unipedia is 0.5-2:0.5-2:0.5-2:0.5-2.

[0076] Furthermore, the culture method of the mixed microalgae liquid includes the following steps: inoculating Chlorella, Nostoc, Anabaena, and Monochamus species into an algae culture device at a volume ratio of 1-10% for culture, controlling the pH to 6.5-6.8, and setting the chlorophyll a to 1.5 mg / L to complete the culture.

[0077] Furthermore, the nutrient solution of the mixed microalgae liquid includes the following raw materials at the following concentrations: NaNO 3 1.0-2.0g / L, KNO 3 1.0-2.0g / L, KH 2 PO 4 0.02-0.06g / L, MgSO 4 7H 2 O 0.04-0.08g / L, CaCl 2 ·2H 2 O 0.02-0.06g / L, Na 2 CO 3 0.01-0.03g / L, K 2 CO 3 0.01-0.03g / L, EDTANa 20.001-0.005g / L, ferric citrate 0.005-0.01g / L, trace elements 0.5-2mL / L. The trace elements include the following raw materials: H 3 BO 3 1-3g / L, MnSO 2 ·4H 2 O0.5-3g / L, ZnSO 4 7H 2 O 0.1-0.5g / L, FeSO 4 7H 2 O 0.1-0.5g / L, NaMoO 4 ·2H 2 O0.1-0.5g / L, CuSO 4 ·5H 2 O 0.05-0.1g / L, Co(NO 3 ) 2 6H 2 O 0.02-0.06g / L.

[0078] In some embodiments of the present invention, in step (4), the salt-alkali tolerant plants are Suaeda salsa and alfalfa, and indole-3-acetic acid is applied during the planting process, with an application amount of 1-5 kg / mu.

[0079] Example 1

[0080] In this embodiment, a saline-alkali land improver includes the following raw materials in percentage by weight: 35% phosphogypsum, 12% calcium-magnesium modified biochar, 18% humic acid, 16% attapulgite, 14% bentonite, and 5% polyacrylamide.

[0081] Furthermore, the preparation method of the calcium-magnesium modified biochar comprises the following steps:

[0082] (A1) Remove impurities from rice and corn stalks, wash and dry them, grind them through a 10-mesh sieve, dry them in an oven at 105°C until the mass is constant, and then place them in a muffle furnace and pass them through a flow rate of 100 mL min -1 After 30 min of nitrogen, the -1 The temperature was raised to 300℃, 500℃ and 700℃ at a rate of 10℃·min and maintained for 4h respectively. -1 The temperature was raised to 300°C at a rate of 10 min and maintained for 4 h. -1 The temperature was raised to 500°C at a rate of 10°C min-1 and maintained for 4 h. -1 The temperature was raised to 720°C at a rate of 100°C and maintained for 4 hours, then cooled. After cooling, the biochar was taken out to obtain the biochar, which was ground and passed through a 100-mesh sieve and stored in a dry and dark place.

[0083] (A2) The biochar obtained in step (1) was soaked in a mixed solution of magnesium chloride (1 mol / L) and calcium chloride (1 mol / L) at a concentration of 30 g / L for 24 hours, and then 1 g of urea, 1 g of ammonium sulfate, 0.5 g of potassium dihydrogen phosphate, 0.5 g of ammonium dihydrogen phosphate and 1 g of potassium nitrate were added and mixed, and the pH was adjusted to 7.8 with sulfuric acid solution. After soaking for 24 hours, the mixture was dried in an oven at 105°C for 7 hours to prepare calcium-magnesium modified biochar.

[0084] Example 2

[0085] In this embodiment, a microbial fertilizer includes the following raw materials in percentage by mass: 42% cow dung fertilizer, 42% sheep dung fertilizer, 4% Bacillus subtilis, 4% Trichoderma aculeatus, 4% Trichoderma viride, and 4% white rot fungi. The cow dung fertilizer and sheep dung fertilizer are commercially available.

[0086] Furthermore, the preparation method of Bacillus subtilis comprises the following steps:

[0087] (B1) inoculating Bacillus subtilis into a seed culture medium, and incubating the culture medium in an incubator at 30° C. with shaking for 22 h to obtain a primary seed solution, while controlling the rotation speed at 180 rpm;

[0088] (B2) inoculating the seed solution obtained in step (B1) into a primary seed tank at an inoculum volume fraction of 10%, the culture conditions of the primary seed tank being 30° C., 180 rpm, pH 5.8, and 40% dissolved oxygen, and culturing for 22 h to obtain a secondary seed solution;

[0089] (B3) inoculating the secondary seed solution obtained in step (B2) into a fermentation tank at an inoculum volume fraction of 15%, and culturing the fermentation tank at a temperature of 30° C., a rotation speed of 180 rpm, a pH of 6.8, and culturing for 24 hours to obtain a Bacillus subtilis fermentation liquid;

[0090] (B4) centrifuging the Bacillus subtilis fermentation broth obtained in step (B3), adjusting the solid content of the bacterial broth to 70%, and adding a drying protective agent in an amount of 8% by weight of the bacterial broth to the adjusted bacterial broth to obtain a bacterial slurry; the drying protective agent comprises galactose, trehalose, glycerol and dimethyl sulfoxide, and the mass ratio of galactose, trehalose, glycerol and dimethyl sulfoxide is 1:1:1:1;

[0091] (B5) mixing the bacterial slurry obtained in step (B4) with auxiliary materials in a mass ratio of 1:2 to obtain solid particles; the auxiliary materials include wood ash, vermiculite powder, diatomaceous earth and clay, and the mass ratio of wood ash, vermiculite powder, diatomaceous earth and clay is 1:1:1:1.

[0092] (B5) The solid particles are vacuum dried at a drying temperature of 40° C. for a drying time of 2 h to obtain a Bacillus subtilis product.

[0093] Furthermore, the culture medium in step (B1) is LB culture medium,

[0094] Further, the culture medium in steps (B2) and B3) includes raw materials of the following concentrations: glucose 2g / L, NaAc 2g / L, potassium nitrate 0.5g / L, ammonium nitrate 0.3g / L, potassium dihydrogen phosphate 1g / L, ammonium dihydrogen phosphate 0.8g / L, sodium chloride 8g / L, magnesium sulfate heptahydrate 0.1g / L, and trace elements 0.03%; wherein the trace elements include raw materials of breast cancer concentration: ferrous sulfate heptahydrate 0.2g / L, cobalt chloride 0.08g / L, manganese chloride 0.8g / L, anhydrous copper sulfate 0.05g / L, sodium molybdate 0.3g / L, and hydrochloric acid 0.03g / L.

[0095] Furthermore, the preparation method of Trichoderma acanthosporum comprises the following steps:

[0096] (C1) inoculating Trichoderma aculeatus into a seed solution containing a culture medium, and culturing the solution in an incubator at 28° C. for 48 hours to obtain a seed solution, wherein the seed culture medium is a potato-glucose culture medium;

[0097] (C2) Inoculating the seed liquid at 50 mL / kg into a solid culture medium, controlling the water content to 70%, culturing at 28° C. for 5 days, drying at room temperature for 3 days, crushing and passing through a 200-mesh sieve to obtain Trichoderma spinulosa powder; the solid culture medium comprises the following raw materials in percentage by weight: 60% straw, 36% wheat bran, 2.5% cornmeal, 1.4% ammonium nitrate, 0.08% manganese sulfate, and 0.02% magnesium sulfate.

[0098] Furthermore, the preparation method of the green Trichoderma comprises the following steps:

[0099] (D1) inoculating Trichoderma viride into seed solution containing culture medium, and culturing in an incubator at 28° C. for 48 h to obtain seed solution, wherein the seed culture medium is potato-glucose culture medium;

[0100] (D2) Inoculate the seed liquid at 50 mL / kg into a solid culture medium, control the water content to 70%, culture at 28° C. for 5 days, dry at room temperature for 3 days, grind and sieve through a 200-mesh sieve to obtain green Trichoderma powder; the solid culture medium comprises the following raw materials in percentage by weight: 60% straw, 36% wheat bran, 2.5% cornmeal, 1.4% ammonium nitrate, 0.08% manganese sulfate, and 0.02% magnesium sulfate.

[0101] Furthermore, the preparation method of the white rot fungus comprises the following steps:

[0102] (F1) White rot fungi were inoculated into a liquid seed culture medium at an inoculum volume fraction of 20%, and cultured in an incubator at a temperature of 30° C. for 24 hours to obtain a seed solution; the seed culture medium was a PDA culture medium.

[0103] (F2) The seed liquid is inoculated into a solid culture medium at an inoculum volume fraction of 20%, stirred evenly after inoculation, and the culture medium is turned over every day. The culture medium is cultured at 30° C. for 5 days to obtain white rot fungi.

[0104] Example 3

[0105] In this embodiment, a mixed microalgae liquid includes Chlorella, Nostoc, Anabaena and Unipedia, and the weight ratio of Chlorella, Nostoc, Anabaena and Unipedia is 1:1:1:1.

[0106] Furthermore, the culturing method of the mixed algae liquid comprises the following steps: inoculating Chlorella, Nostoc, Anabaena, and Monochamus species into an algae culturing device at a volume ratio of 2%, controlling the pH to 6.5-6.8, and setting the chlorophyll a to 1.5 mg / L when the culturing is completed; the algae culturing device adopts the algae culturing device disclosed in the patent with authorization announcement number CN 218778953 U.

[0107] Furthermore, the nutrient solution of the mixed algae liquid includes the following raw materials at the following concentrations: NaNO 3 1.0g / L, KNO 3 1.0g / L, KH 2 PO 4 0.03g / L, MgSO 4 7H 2 O 0.05g / L, CaCl 2 ·2H 2 O0.05g / L, Na 2 CO 3 0.01g / L, K 2 CO 3

[0108] 0.01g / L, EDTANa 2 0.002g / L, ferric citrate 0.006g / L, trace elements 1mL / L. Trace elements include the following raw materials: H 3 BO 3 1g / L, MnSO 2 ·4H 2 O 1g / L, ZnSO 4 7H 2 O 0.2g / L, FeSO 4 7H 2O 0.2g / L, NaMoO 4 ·2H 2 O 0.1g / L, CuSO 4 ·5H 2 O 0.08g / L, Co(NO 3 ) 2 6H 2 O 0.04g / L.

[0109] Example 4

[0110] In this embodiment, a saline-alkali land ecological restoration method comprises the following steps:

[0111] (1) adding the saline-alkali land improver prepared in Example 1 to the saline-alkali land, the addition amount of the saline-alkali land improver is 3 t / mu, and applying it to the soil in combination with deep loosening and shallow turning combined with land preparation, deep turning and applying it to the tillage layer to break the plow bottom layer;

[0112] (2) Then, the microbial fertilizer prepared in Example 2 was applied to the saline-alkali land, and the amount of the microbial fertilizer added was 2 t / mu;

[0113] (3) applying the mixed microalgae solution prepared in Example 3 to the saline-alkali land; the amount of the mixed microalgae solution added is 15 L / mu;

[0114] (4) After the mixed microalgae grew on the saline-alkali land for 30 days, Suaeda salsa and alfalfa were planted in rotation; Suaeda salsa was planted in the first year, and alfalfa was planted in the second year. Indole-3-acetic acid was applied during the planting of Suaeda salsa and alfalfa, and the application amount was 2 kg / mu. The changes in the saline-alkali land indicators after each step of treatment are shown in Table 1 below:

[0115] Table 1 Changes in indicators of saline-alkali land in each step

[0116]

[0117] The present invention provides a comprehensive and systematic method for ecological restoration of saline-alkali land, organically combines saline-alkali land improvers, microbial fertilizers and microalgae treatment, and rotates the planting of salt-alkali tolerant crops, which can effectively improve the saline-alkali land restoration effect and provide solutions for actual engineering projects.

[0118] The above specific embodiments are further explanations of the technical solutions and beneficial effects of the present invention, and are not limitations of the implementation methods. For those skilled in the art, any obvious replacements that do not depart from the concept of the present invention are within the protection scope of the present invention.

Claims

1. A method for ecological restoration of saline-alkali land, characterized in that: The steps include: (1) Adding saline-alkali land improvers to saline-alkali land; (2) Applying microbial fertilizer to saline-alkali land; (3) Applying mixed microalgae liquid to saline-alkali land; (4) Rotate and plant salt-tolerant plants in treated saline-alkali land.

2. The saline-alkali land ecological restoration method according to claim 1, characterized in that: In step (1), the saline-alkali land improver comprises the following raw materials in percentage by weight: 30-50% phosphogypsum, 10-30% calcium-magnesium modified biochar, 10-20% humic acid, 10-20% attapulgite, 10-20% bentonite, and 5-10% polyacrylamide.

3. The saline-alkali land ecological restoration method according to claim 2, characterized in that: The preparation method of the calcium-magnesium modified biochar comprises the following steps: (A1) removing impurities from rice and corn stalks, washing, drying, crushing and sieving, placing in an oven to dry, and then placing in a muffle furnace to introduce nitrogen and heating to obtain biochar; after cooling, taking out the obtained biochar, grinding and sieving the obtained biochar; (A2) The biochar obtained in step (A1) is immersed in a mixed solution of magnesium chloride and calcium chloride, and then urea, ammonium sulfate, potassium dihydrogen phosphate, ammonium dihydrogen phosphate and potassium nitrate are added and mixed, and the pH is adjusted to 7.5-8.

5. After immersion, the mixture is dried to obtain calcium-magnesium modified biochar.

4. The saline-alkali land ecological restoration method according to claim 1, characterized in that: In step (2), the microbial fertilizer comprises the following raw materials in percentage by weight: 40-45% cow dung fertilizer, 40-45% sheep dung fertilizer, 2-4% Bacillus subtilis, 2-4% Trichoderma acanthosporum, 2-4% Trichoderma viride, and 2-4% white rot fungi.

5. The method for ecological restoration of saline-alkali land according to claim 4, characterized in that: The preparation method of the Bacillus subtilis comprises the following steps: (B1) Inoculate Bacillus subtilis into a seed culture medium, and culture in an incubator at a temperature of 25-40° C. with shaking for 18-30 hours to obtain a primary seed solution; (B2) inoculating the seed solution obtained in step (B1) into a primary seed tank at an inoculum volume fraction of 10-20%, wherein the culture conditions of the primary seed tank are a temperature of 25-40° C., a pH of 6.5-7.5, and a dissolved oxygen of 20-50%, and culturing for 18-30 hours to obtain a secondary seed solution; (B3) inoculating the secondary seed solution obtained in step (B2) into a fermentation tank at an inoculum amount of 10-20% by volume, and culturing the fermentation tank under the conditions of a temperature of 25-40° C. and a pH of 6.5-7.5 for 18-30 hours to obtain a Bacillus subtilis fermentation solution; (B4) centrifuging the Bacillus subtilis fermentation liquid obtained in step (B3), adjusting the solid content of the bacterial liquid to 50-80%, and adding a drying protective agent in an amount of 0.5-15% by weight of the bacterial liquid to the adjusted bacterial liquid to obtain a bacterial slurry; (B5) mixing the bacterial slurry obtained in step (4) with auxiliary materials in a mass ratio of 1:0.5-3 to obtain solid particles; (B6) Drying the solid particles to obtain a Bacillus subtilis product.

6. The method for ecological restoration of saline-alkali land according to claim 4, characterized in that: The preparation method of Trichoderma acanthosporum comprises the following steps: (C1) inoculating Trichoderma spinulosa into a seed solution containing a culture medium, and culturing the solution in an incubator at a temperature of 25-37° C. for 48-60 hours to obtain a seed solution; (C2) inoculating the seed liquid into a solid culture medium at a rate of 20-100 mL / kg, controlling the water content to be 60-80%, culturing at 25-37° C. for 3-6 days, drying at room temperature, crushing, and sieving to obtain Trichoderma spinulosa powder; The preparation method of the green Trichoderma comprises the following steps: (D1) inoculating Trichoderma viride into a seed solution containing a culture medium, and culturing the solution in an incubator at a temperature of 25-37° C. for 48-60 hours to obtain a seed solution; (D2) Inoculate the seed liquid into a solid culture medium at a rate of 20-100 mL / kg, control the water content to 60-80%, culture at 25-37°C for 3-6 days, dry at room temperature, crush and sieve to obtain green Trichoderma powder.

7. The saline-alkali land ecological restoration method according to claim 4, characterized in that: The preparation method of the white rot fungus comprises the following steps: (F1) inoculating white rot fungi in a liquid seed culture medium at an inoculum volume fraction of 10-20%, and culturing the culture medium in an incubator at a temperature of 28-35° C. for 18-30 hours to obtain a seed solution; (F2) The seed liquid is inoculated into a solid culture medium at an inoculum volume fraction of 10-20%, and the culture medium is stirred evenly after inoculation. The culture medium is turned over during the culture process and cultured at 28-35°C for 5-7 days to obtain white rot fungi.

8. The method for ecological restoration of saline-alkali land according to claim 2, characterized in that: In step (3), the mixed microalgae liquid includes Chlorella, Nostoc, Anabaena and Unipedia, and the weight ratio of Chlorella, Nostoc, Anabaena and Unipedia is 0.5-2:0.5-2:0.5-2:0.5-2.

9. The method for ecological restoration of saline-alkali land according to claim 2, characterized in that: In step (4), the salt-alkali tolerant plants are Suaeda salsa and alfalfa.

10. The method for ecological restoration of saline-alkali land according to claim 1, characterized in that: In step (1), the dosage of saline-alkali land improver is 2-4 t / mu; in step (2), the dosage of microbial fertilizer is 1-2 t / mu; in step (3), the dosage of mixed microalgae liquid is 10-20 L / mu.

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