Microbial remediation method for improving desert steppe soil quality

Abstract

The invention discloses a microbial remediation method for improving desert steppe soil quality, which comprises the following steps: sowing grass seeds and applying microbial fertilizer to a pretreated land parcel, sowing 1-5kg of grass seeds per mu, applying 15-45kg of fertilizer per mu, sowing line spacing of 35cm and sowing depth of 2-3cm, and the grass seeds comprise 40-60 parts by weight of Aconitum carmichaeli, 5-15 parts by weight of Astragalus adsurgens and 30-50 parts by weight of Mongolian wheatgrass; the microbial fertilizer comprises nitrogen-fixing bacteria, phosphate solubilizing bacteria and growth-promoting bacteria, the content of organic matters is greater than or equal to 40%, and the pH value is 6.5-7.5; wherein nitrogen-fixing bacteria in the microbial fertilizer are alfalfa rhizobium or soybean rhizobium; the phosphate solubilizing bacteria are pseudomonas fluorescens or pseudomonas putida; the growth promoting bacteria are bacillus subtilis or bacillus licheniformis; the weight ratio of the nitrogen-fixing bacteria to the phosphate solubilizing bacteria to the growth-promoting bacteria is 2: (1-1.5): (1-1.5). By applying the microbial fertilizer and sowing the grass seeds, the physical properties, chemical properties and microbial properties of the soil are effectively improved.

Description

Technical Field

[0001] The present invention relates to the technical field of soil remediation, and more specifically, to a microbial remediation method for improving desert steppe soil quality. Background Art

[0002] As one of the most important terrestrial ecosystems, grassland ecosystems have extremely important production and ecological functions. In recent years, as humans continue to demand the service value that grassland ecosystems can provide, grassland ecosystems have degraded to varying degrees around the world. Frequent ecological disasters induced by large-scale grassland degradation have greatly affected ecological security and social stability. Therefore, curbing grassland degradation, strengthening degraded grassland management and ecological restoration have become major problems that need to be solved globally. Under the general background of emphasizing ecological priority and green development, the implementation of a series of ecological restoration measures, including fencing and fertilization, has provided a theoretical reference for the ecological restoration of degraded grasslands. Enclosure is a restoration measure for the natural recovery of grasslands, but it takes a long time. Therefore, artificial restoration measures have become an indispensable means to accelerate grassland recovery. Among them, reseeding is an important measure commonly used in the ecological restoration of degraded grasslands. It is a technical means of directly reseeding suitable and excellent grass species on the premise of minimizing or disturbing the original vegetation and soil of the grassland. Fertilization is an ecological restoration measure that directly improves the nutrient status of degraded grassland soil, rapidly promotes vegetation growth, and changes the interspecific relationship of soil microorganisms and the overall quality of the soil. The restoration effect and negative effect of fertilization vary depending on the type of fertilizer, the amount of fertilizer, the duration of fertilization and the habitat conditions. The concentrated addition of fertilizers in traditional agriculture will lead to low fertilizer utilization and high costs. The loss of plant diversity caused by long-term excessive fertilization will cause irreversible and far-reaching effects in the short term. However, sowing grass seeds alone cannot achieve a good soil restoration effect. Summary of the invention

[0003] An object of the present invention is to solve at least the above problems and to provide at least the advantages which will be described hereinafter.

[0004] Another object of the present invention is to provide a method for effectively improving the physical, chemical and microbial properties of the soil by applying microbial fertilizers and sowing grass seeds.

[0005] In order to achieve these purposes and other advantages according to the present invention, a microbial remediation method for improving desert steppe soil quality is provided, comprising the following steps:

[0006] Sowing grass seeds and applying microbial fertilizer to the pretreated plots, sowing 1-5 kg ​​of grass seeds per mu, applying 15-45 kg of fertilizer per mu, sowing row spacing of 35 cm, sowing depth of 2-3 cm, wherein the grass seeds include 40-60 parts of Rhizoma Cynanchum, 5-15 parts of Astragalus membranaceus, and 30-50 parts of Mongolian wheatgrass by weight;

[0007] Microbial fertilizers include nitrogen-fixing bacteria, phosphate-solubilizing bacteria and growth-promoting bacteria, with an organic matter content of ≥40% and a pH value of 6.5-7.5;

[0008] Among them, the nitrogen-fixing bacteria in the microbial fertilizer are meliloti root nodules or soybean root nodules; the phosphate-solubilizing bacteria are Pseudomonas fluorescens or Pseudomonas putida; the growth-promoting bacteria are Bacillus subtilis or Bacillus licheniformis; and the weight ratio of the nitrogen-fixing bacteria, the phosphate-solubilizing bacteria and the growth-promoting bacteria is 2:1-1.5:1-1.5.

[0009] Preferably, the sowing amount of the grass seeds and the application amount of the microbial fertilizer are dynamically adjusted according to the soil barrenness and climatic conditions, specifically including:

[0010] For slightly poor soil with an organic matter content of ≥1.5%, the sowing rate of grass seeds is 1-2 kg per mu, and the application rate of microbial fertilizer is 15-25 kg per mu;

[0011] For moderately poor soil with an organic matter content of 1.0% to 1.5%, the sowing rate of grass seeds is 2 to 3 kg per mu, and the application rate of microbial fertilizer is 25 to 35 kg per mu;

[0012] For severely poor soil with organic matter content ≤1.0%, the grass seed sowing rate is 3-5 kg ​​per mu, and the microbial fertilizer application rate is 35-45 kg per mu.

[0013] Preferably,

[0014] For mildly barren soil, the weight ratio of grass seeds is 40 parts of Rhizoma Cyperi, 10 parts of Astragalus membranaceus, and 50 parts of Mongolian wheatgrass;

[0015] For moderately poor soil, the weight ratio of grass seeds is 50 parts of Rhizoma Cyperi, 10 parts of Astragalus membranaceus, and 40 parts of Mongolian wheatgrass;

[0016] For severely barren soil, the weight ratio of grass seeds is 60 parts of Rhizoma Cyperi, 10 parts of Astragalus membranaceus, and 30 parts of Mongolica scoparia.

[0017] Preferably, the microbial fertilizer is applied by embedding the fertilizer with a composite carrier material, which specifically includes the following steps:

[0018] Bacterial fertilizer embedding treatment: nitrogen-fixing bacteria, phosphate-solubilizing bacteria and growth-promoting bacteria are mixed with a composite carrier material respectively, and the composite carrier material is composed of humic acid, sodium alginate and biochar in a weight ratio of 3:1:2.

[0019] Preferably, the microbial fertilizer is applied in stages, specifically comprising the following steps:

[0020] The first stage: 7 to 10 days before sowing, evenly spread 50% of the total amount of microbial fertilizer on the surface of the pre-treated plot, and shallowly till the soil to a depth of 10 to 15 cm. Immediately cover the soil with a degradable water-retaining film with a light transmittance of 60% to 70% and a covering time of 20 to 30 days;

[0021] The second stage: when sowing, 30% of the total amount of microbial fertilizer is mixed with grass seeds and then applied to the sowing furrow simultaneously, and a mixed isolation layer consisting of straw debris and fertilizer particles is laid in the furrow with a thickness of 2 to 3 cm, and the proportion of fertilizer particles in the isolation layer is 20% to 30%;

[0022] The third stage: 30 days after the grass seeds emerge, mix the remaining 20% ​​of the microbial fertilizer with nanoclay with a particle size of ≤100nm in a weight ratio of 1:0.5, and spray it on the soil around the roots of the plants through high-pressure atomization with a spraying pressure of 0.3-0.5MPa.

[0023] Preferably, the embedded microbial fertilizer is synergistically coated with natural polymer materials and nanoclay, and specifically comprises the following steps:

[0024] During the embedding process, nano-clay particles with a particle size of ≤100nm are added, and the amount of the added particles is 5% to 10% of the total mass of the embedding material.

[0025] Preferably, both sowing and fertilizing are carried out using a fertilizing device:

[0026] The fertilizing device comprises a movable frame and two pairs of discharge mechanisms arranged on the movable frame, the two pairs of discharge mechanisms are used to hold fertilizers and grass seeds, the discharge mechanisms comprise: a holding barrel, the lower end of which is connected to a transfer cylinder with a circular vertical cross-section, the lower end of the transfer cylinder is connected to a discharge pipe, a rotatable material distribution plate is arranged in the transfer cylinder, a driving cylinder is coaxially arranged in the material distribution plate, the driving cylinder rotates through the transfer cylinder, the driving cylinder has a thread, a matching threaded rod is arranged in the driving cylinder, a driving rod is arranged at the end of the threaded rod, the diameter of the driving rod is smaller than the diameter of the threaded rod, and a fixed rod is arranged at the end of the driving rod. The fixing disk is slidably connected with the driving cylinder, the outer edges of the material distribution disk are all recessed to form a plurality of accommodating grooves, the accommodating grooves include an inclined transition portion and a cylindrical portion connected with the transition portion, the center axis of the cylindrical portion is arranged along the radial direction of the material distribution disk, the bottom of the cylindrical portion is connected with the driving cylinder through a threading hole, a first spring is provided at the bottom of the cylindrical portion, an adjusting disk is provided at the end of the first spring, the adjusting disk is slidably connected with the cylindrical portion, a driving rope is provided on the adjusting disk, the driving rope passes through the threading hole and is connected with the fixing disk to adjust the position of the adjusting plate through the fixing disk;

[0027] The lower ends of the four discharge pipes in the two pairs of discharge mechanisms are connected to a guide pipe, a furrow opener is provided at the lower end of the guide pipe, and the two distribution plates in each pair of discharge mechanisms are arranged in parallel;

[0028] The driving assembly is used to drive the four material distribution plates to rotate.

[0029] Preferably, a first gear is provided at the moving wheel of the movable bracket;

[0030] The driving assembly includes two connecting shafts rotatably connected to the movable bracket, and the two connecting shafts are arranged in a one-to-one correspondence with the two pairs of discharging mechanisms. The two ends of the connecting shaft are respectively connected to the distribution plate to drive the distribution plate to rotate, wherein a second gear is provided on the connecting shaft, and the second gear is connected to the first gear through a first chain to drive the connecting shaft to rotate, and a third gear is provided on each connecting shaft, and the two third gears are connected through a second chain to enable the two connecting shafts to rotate simultaneously.

[0031] Preferably, the material distribution trays are multiple groups, and the sizes and numbers of the containing slots in any two groups of material distribution trays are different;

[0032] The connecting shaft is a hollow structure, and a connecting rod is provided on the material distribution plate. The connecting rod rotates through the transfer cylinder and extends into the connecting shaft, and the connecting shaft and the connecting rod are connected by a latch;

[0033] The side wall of the transfer cylinder located on the outside is detachably connected to facilitate replacement of the material distribution tray.

[0034] Preferably, a second spring is provided on the adjusting disk, a driving disk is provided at the end of the second spring, and the driving disk is slidably connected to the cylindrical portion, wherein when the notch of the accommodating groove faces upward, the second spring is in a compressed state under the gravity of the driving disk;

[0035] A stirring assembly is arranged in the material holding barrel to facilitate the discharge of grass seeds or fertilizers.

[0036] The present invention has at least the following beneficial effects:

[0037] First, the present invention effectively improves the physical, chemical and microbial properties of the soil by applying microbial fertilizer and sowing grass seeds, reduces bulk density, increases porosity, and optimizes soil structure. The available phosphorus content and alkaline nitrogen are significantly increased, the nutrient release intensity is enhanced, the colonization efficiency of the bacterial community is improved, and the activity of β-1,4 glucosidase is increased to improve the activity of microorganisms.

[0038] Second, the present invention significantly improves the organic matter content, nutrient effectiveness and microbial activity of desert steppe soil through bacterial fertilizer encapsulation, phased application and grass seed-nanomaterial synergy, which is particularly suitable for extremely arid environments and provides an efficient and stable technical solution for desertification control.

[0039] Third, the present invention uses natural polymer materials and nano-clay particles for synergistic coating. The coating layer locks the internal moisture of the bacterial fertilizer through the adsorption effect of nano-clay under drought conditions, and slowly releases live bacteria through the gel micropores, so that the effective live bacteria preservation rate of the bacterial fertilizer is ≥85% under the conditions of 40°C and soil humidity ≤10%, and the survival time is extended to more than 30 days; in the third stage, the synergistic effect of nano-clay and the embedded bacterial fertilizer forms a soil-fertilizer-nanoclay composite protective layer, which increases the colonization efficiency of the bacterial community in the soil around the roots of the plants by 20% to 30%.

[0040] Fourth, the present invention realizes adjustment of the depth of the containing groove by providing a driving cylinder, a threaded rod, and an adjusting disk, so as to adjust the capacity based on the required amount of grass seeds or fertilizers, thereby effectively improving the use range of the fertilizing device; the driving adjustment disk is driven to move by providing a driving rope, and the positions of multiple driving disks can be adjusted simultaneously by providing a driving cylinder, which is convenient and quick; the present invention realizes easy replacement of the dividing disks according to needs by providing the connecting rods and the connecting rods with detachable connections, the side walls of the transfer cylinder located on the outside being detachably connected, and multiple pairs of dividing disks; the present invention promotes the grass seeds or fertilizers in the containing groove by providing a second spring and a driving disk, which is beneficial to the discharge of the grass seeds or fertilizers.

[0041] Other advantages, objectives and features of the present invention will be embodied in part through the following description, and in part will be understood by those skilled in the art through study and practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 It is a structural schematic diagram of a fertilization device according to one of the technical solutions of the present invention;

[0043] Figure 2 This is a schematic structural diagram of a material holding barrel according to one of the technical solutions of the present invention;

[0044] Figure 3 for Figure 2 A is an enlarged view of the middle image. DETAILED DESCRIPTION

[0045] The present invention is further described in detail below in conjunction with embodiments so that those skilled in the art can implement the invention with reference to the description.

[0046] <Example 1>

[0047] A microbial remediation method for improving desert steppe soil quality comprises the following steps:

[0048] For slightly poor soil with an organic matter content of ≥1.5%, grass seeds and microbial fertilizers were sown on the pre-treated plots. The sowing rate of grass seeds was 1 kg per mu, and the application rate of microbial fertilizers was 15 kg per mu. The sowing row spacing was 35 cm and the sowing depth was 2 to 3 cm.

[0049] Microbial fertilizer includes nitrogen-fixing bacteria, phosphate-solubilizing bacteria, growth-promoting bacteria, calcium, and magnesium. The organic matter content is ≥40% and the pH value is 6.5;

[0050] The nitrogen-fixing bacteria in the microbial fertilizer are meliloti root nodule bacteria, and the effective viable bacteria count thereof is ≥1×108CFU / g; the phosphate-solubilizing bacteria are fluorescing Pseudomonas, and the effective viable bacteria count thereof is ≥5×107CFU / g; the growth-promoting bacteria are Bacillus subtilis, and the effective viable bacteria count thereof is ≥5×107CFU / g; and the weight ratio of the nitrogen-fixing bacteria, the phosphate-solubilizing bacteria and the growth-promoting bacteria is 2:1:1.

[0051] The weight proportion of the grass seeds is 40 parts of Rhizoma Cynanchum, 10 parts of Astragalus membranaceus, and 50 parts of Icegrass Mongolia;

[0052] The application method of the microbial fertilizer is to embed the fertilizer with a composite carrier material, which specifically includes the following steps:

[0053] Bacterial fertilizer embedding treatment: nitrogen-fixing bacteria, phosphate-solubilizing bacteria and growth-promoting bacteria are mixed with composite carrier materials respectively. The composite carrier material is composed of humic acid, sodium alginate and biochar in a weight ratio of 3:1:2. The diameter of the bacterial fertilizer particles after embedding is 0.5 mm, and the embedding rate is ≥90%.

[0054] The microbial fertilizer is applied in stages, specifically comprising the following steps:

[0055] Phase 1: 7 days before sowing, evenly spread 50% of the total amount of microbial fertilizer on the surface of the pre-treated plot, and shallowly till the soil to a depth of 10 to 15 cm. Immediately cover the soil with a degradable water-retaining film with a light transmittance of 60% for 20 days.

[0056] The second stage: when sowing, 30% of the total amount of microbial fertilizer is mixed with grass seeds and then applied to the sowing furrow simultaneously, and a mixed isolation layer consisting of straw debris and fertilizer particles is laid in the furrow with a thickness of 2 to 3 cm, and the fertilizer particles in the isolation layer account for 20%;

[0057] The third stage: 30 days after the grass seeds emerge, mix the remaining 20% ​​of the microbial fertilizer with nano-clay with a particle size of ≤100nm at a weight ratio of 1:0.5, and spray it on the soil around the roots of the plants through high-pressure atomization at a spraying pressure of 0.3-0.5MPa;

[0058] The effective live bacteria count preservation rate of the microbial fertilizer after embedding treatment is ≥85%, and the survival time is extended to more than 30 days under drought conditions of 40°C and soil moisture ≤10%.

[0059] The embedded microbial fertilizer is synergistically coated with natural polymer materials and nano-clay, and specifically comprises the following steps:

[0060] Nanoclay particles with a particle size of ≤100 nm were added during the embedding process, and the amount added was 5% of the total mass of the embedding material;

[0061] The coating layer locks the moisture inside the bacterial fertilizer through the adsorption of nano-clay under drought conditions, and slowly releases live bacteria through the gel micropores, so that the effective live bacteria count preservation rate of the bacterial fertilizer is ≥85% under the conditions of 40°C and soil humidity ≤10%, and the survival time is extended to more than 30 days;

[0062] In the third stage, the synergistic effect of nanoclay and embedded bacterial fertilizer forms a soil-bacterial fertilizer-nanoclay composite protective layer, which increases the colonization efficiency of the bacterial community in the soil around the roots of the plants by 20%.

[0063] <Example 2>

[0064] A microbial remediation method for improving desert steppe soil quality comprises the following steps:

[0065] For slightly poor soil with an organic matter content of ≥1.5%, grass seeds and microbial fertilizers were sown on the pre-treated plots. The sowing rate of grass seeds was 2 kg per mu, the application rate of microbial fertilizers was 25 kg per mu, the sowing row spacing was 35 cm, and the sowing depth was 2 to 3 cm.

[0066] Microbial fertilizer includes nitrogen-fixing bacteria, phosphate-solubilizing bacteria, growth-promoting bacteria, calcium, and magnesium. The organic matter content is ≥40% and the pH value is 7.5;

[0067] The nitrogen-fixing bacteria in the microbial fertilizer are soybean rhizobia, and the effective live bacteria count is ≥1×108CFU / g; the phosphate-solubilizing bacteria are Pseudomonas putida, and the effective live bacteria count is ≥5×107CFU / g; the growth-promoting bacteria are Bacillus licheniformis, and the effective live bacteria count is ≥5×107CFU / g; the weight ratio of the nitrogen-fixing bacteria, the phosphate-solubilizing bacteria and the growth-promoting bacteria is 2:1.5:1.5.

[0068] The weight proportion of the grass seeds is 40 parts of Rhizoma Cynanchum, 10 parts of Astragalus membranaceus, and 50 parts of Icegrass Mongolia;

[0069] The application method of the microbial fertilizer is to embed the fertilizer with a composite carrier material, which specifically includes the following steps:

[0070] Bacterial fertilizer embedding treatment: nitrogen-fixing bacteria, phosphate-solubilizing bacteria and growth-promoting bacteria are mixed with composite carrier materials respectively. The composite carrier material is composed of humic acid, sodium alginate and biochar in a weight ratio of 3:1:2. The diameter of the bacterial fertilizer particles after embedding is 1.0 mm, and the embedding rate is ≥90%.

[0071] The microbial fertilizer is applied in stages, specifically comprising the following steps:

[0072] Phase 1: 10 days before sowing, evenly spread 50% of the total amount of microbial fertilizer on the surface of the pre-treated plot, and shallowly till the soil to a depth of 10 to 15 cm. Immediately cover the soil with a degradable water-retaining film with a light transmittance of 70% for 30 days.

[0073] The second stage: when sowing, 30% of the total amount of microbial fertilizer is mixed with grass seeds and then applied to the sowing furrow simultaneously, and a mixed isolation layer consisting of straw debris and fertilizer particles is laid in the furrow with a thickness of 2 to 3 cm, and the proportion of fertilizer particles in the isolation layer is 30%;

[0074] The third stage: 30 days after the grass seeds emerge, mix the remaining 20% ​​of the microbial fertilizer with nanoclay with a particle size of ≤100nm at a weight ratio of 1:0.5, and spray it on the soil around the roots of the plants through high-pressure atomization at a spraying pressure of 0.5MPa;

[0075] The effective live bacteria count preservation rate of the microbial fertilizer after embedding treatment is ≥85%, and the survival time is extended to more than 30 days under drought conditions of 40°C and soil moisture ≤10%.

[0076] The embedded microbial fertilizer is synergistically coated with natural polymer materials and nano-clay, and specifically comprises the following steps:

[0077] Nanoclay particles with a particle size of ≤100 nm were added during the embedding process, and the amount added was 10% of the total mass of the embedding material;

[0078] The coating layer locks the moisture inside the bacterial fertilizer through the adsorption of nano-clay under drought conditions, and slowly releases live bacteria through the gel micropores, so that the effective live bacteria count preservation rate of the bacterial fertilizer is ≥85% under the conditions of 40°C and soil humidity ≤10%, and the survival time is extended to more than 30 days;

[0079] In the third stage, the synergistic effect of nanoclay and embedded bacterial fertilizer forms a soil-bacterial fertilizer-nanoclay composite protective layer, which increases the colonization efficiency of the bacterial community in the soil around the roots of the plants by 30%.

[0080] <Example 3>

[0081] A microbial remediation method for improving desert steppe soil quality comprises the following steps:

[0082] For slightly poor soil with an organic matter content of ≥1.5%, grass seeds and microbial fertilizers were sown on the pre-treated plots. The sowing rate of grass seeds was 1.5 kg per mu, the application rate of microbial fertilizers was 20 kg per mu, the sowing row spacing was 35 cm, and the sowing depth was 2 to 3 cm.

[0083] Microbial fertilizer includes nitrogen-fixing bacteria, phosphate-solubilizing bacteria, growth-promoting bacteria, calcium, and magnesium. The organic matter content is ≥40% and the pH value is 7.

[0084] The nitrogen-fixing bacteria in the microbial fertilizer are meliloti root nodule bacteria, and the effective live bacteria count thereof is ≥1×108CFU / g; the phosphate-solubilizing bacteria are Pseudomonas putida, and the effective live bacteria count thereof is ≥5×107CFU / g; the growth-promoting bacteria are Bacillus licheniformis, and the effective live bacteria count thereof is ≥5×107CFU / g; and the weight ratio of the nitrogen-fixing bacteria, the phosphate-solubilizing bacteria and the growth-promoting bacteria is 2:1.2:1.2.

[0085] The weight proportion of the grass seeds is 40 parts of Rhizoma Cynanchum, 10 parts of Astragalus membranaceus, and 50 parts of Icegrass Mongolia;

[0086] The application method of the microbial fertilizer is to embed the fertilizer with a composite carrier material, which specifically includes the following steps:

[0087] Bacterial fertilizer embedding treatment: nitrogen-fixing bacteria, phosphate-solubilizing bacteria and growth-promoting bacteria are mixed with composite carrier materials respectively. The composite carrier material is composed of humic acid, sodium alginate and biochar in a weight ratio of 3:1:2. The diameter of the bacterial fertilizer particles after embedding is 0.7 mm, and the embedding rate is ≥90%.

[0088] The microbial fertilizer is applied in stages, specifically comprising the following steps:

[0089] Phase 1: 8 days before sowing, evenly spread 50% of the total amount of microbial fertilizer on the surface of the pre-treated plot, and shallowly till the soil to a depth of 10-15 cm. Immediately cover the soil with a degradable water-retaining film with a light transmittance of 65% for 25 days.

[0090] The second stage: when sowing, 30% of the total amount of microbial fertilizer is mixed with grass seeds and then applied to the sowing furrow simultaneously, and a mixed isolation layer consisting of straw debris and fertilizer particles is laid in the furrow with a thickness of 2 to 3 cm, and the proportion of fertilizer particles in the isolation layer is 25%;

[0091] The third stage: 30 days after the grass seeds emerge, mix the remaining 20% ​​of the microbial fertilizer with nano-clay with a particle size of ≤100nm at a weight ratio of 1:0.5, and spray it on the soil around the roots of the plants through high-pressure atomization at a spraying pressure of 0.4MPa;

[0092] The effective live bacteria count preservation rate of the microbial fertilizer after embedding treatment is ≥85%, and the survival time is extended to more than 30 days under drought conditions of 40°C and soil moisture ≤10%.

[0093] The embedded microbial fertilizer is synergistically coated with natural polymer materials and nano-clay, and specifically comprises the following steps:

[0094] Nanoclay particles with a particle size of ≤100 nm were added during the embedding process, and the amount added was 7% of the total mass of the embedding material;

[0095] The coating layer locks the moisture inside the bacterial fertilizer through the adsorption of nano-clay under drought conditions, and slowly releases live bacteria through the gel micropores, so that the effective live bacteria count preservation rate of the bacterial fertilizer is ≥85% under the conditions of 40°C and soil humidity ≤10%, and the survival time is extended to more than 30 days;

[0096] In the third stage, the synergistic effect of nanoclay and embedded bacterial fertilizer forms a soil-bacterial fertilizer-nanoclay composite protective layer, which increases the colonization efficiency of the bacterial community in the soil around the roots of the plants by 25%.

[0097] <Example 4>

[0098] Microbial remediation was carried out using the method of Example 3, with the following differences: the soil to be remediated was moderately poor soil with an organic matter content of 1.0% to 1.5%, the grass seed sowing rate was 2 kg per mu, the microbial fertilizer application rate was 25 kg per mu, the weight ratio of the grass seeds was 50 parts of Rhizoma Cnidium, 10 parts of Astragalus membranaceus, and 40 parts of Mongolica mongoliae, and the remaining steps were the same as in Example 3.

[0099] <Example 5>

[0100] Microbial remediation was carried out using the method of Example 3, with the following differences: the soil to be remediated was moderately poor soil with an organic matter content of 1.0% to 1.5%, the grass seed sowing rate was 3 kg per mu, the microbial fertilizer application rate was 35 kg per mu, the weight ratio of the grass seeds was 50 parts of Rhizoma Cnidium, 10 parts of Astragalus membranaceus, and 40 parts of Mongolica mongoliae, and the remaining steps were the same as in Example 3.

[0101] <Example 6>

[0102] Microbial remediation was carried out using the method of Example 3, with the following differences: the soil to be remediated was moderately poor soil with an organic matter content of 1.0% to 1.5%, the grass seed sowing rate was 2.5 kg per mu, the microbial fertilizer application rate was 30 kg per mu, the weight ratio of the grass seeds was 50 parts of Rhizoma Cnidium, 10 parts of Astragalus membranaceus, and 40 parts of Mongolica mongoliae, and the remaining steps were the same as in Example 3.

[0103] <Example 7>

[0104] The method of Example 3 was used for microbial remediation, with the difference that the soil to be remediated was severely barren soil with an organic matter content of ≤1.0%, the grass seed sowing rate was 3 kg per mu, the microbial fertilizer application rate was 35 kg per mu, the weight ratio of the grass seeds was 60 parts of Rhizoma Coptidis, 10 parts of Astragalus membranaceus, and 30 parts of Mongolica mongoliae, and the remaining steps were the same as in Example 3.

[0105] <Example 8>

[0106] The method of Example 3 was used for microbial remediation, except that the soil to be remediated was severely barren soil with an organic matter content of ≤1.0%, the grass seed sowing rate was 5 kg per mu, the microbial fertilizer application rate was 45 kg per mu, the weight ratio of the grass seeds was 60 parts of Rhizoma Coptidis, 10 parts of Astragalus membranaceus, and 30 parts of Mongolica mongoliae, and the remaining steps were the same as in Example 3.

[0107] <Example 9>

[0108] The method of Example 3 was used for microbial remediation, except that the soil to be remediated was severely barren soil with an organic matter content of ≤1.0%, the grass seed sowing rate was 4 kg per mu, the microbial fertilizer application rate was 40 kg per mu, the weight ratio of the grass seeds was 60 parts of Rhizoma Coptidis, 10 parts of Astragalus membranaceus, and 30 parts of Mongolica mongoliae, and the remaining steps were the same as in Example 3.

[0109] <Comparative Example 1>

[0110] For slightly poor soil with an organic matter content ≥1.5%, grass seeds are sown in the pretreated plots, with 1.5 kg of grass seeds per mu, a sowing row spacing of 35 cm, and 20 kg of bio-fertilizer applied per mu, with a sowing depth of 2 to 3 cm. The grass seeds include 50% Rhizoma Cnidium, 10% Astragalus membranaceus, and 50% Mongolian ice grass. The microbial fertilizer is not buried or coated, and the microbial fertilizer and grass seeds are sown at the same time (the microbial fertilizer is applied once and not in stages).

[0111] <Comparative Example 2>

[0112] For moderately poor soil with an organic matter content of 1.0% to 1.5%, grass seeds are sown in the pretreated plots, 2.5 kg of grass seeds are sown per mu, 30 kg of biological fertilizer is applied per mu, the sowing row spacing is 35 cm, and the sowing depth is 2 to 3 cm. The grass seeds include 50% Rhizoma Cnidium, 10% Astragalus membranaceus, and 40% Mongolian ice grass. The microbial fertilizer is not buried or coated, and the microbial fertilizer and grass seeds are sown at the same time (the microbial fertilizer is applied once and not in stages).

[0113] <Comparative Example 3>

[0114] For moderately poor soil with an organic matter content of 1.0% to 1.5%, grass seeds are sown in the pretreated plots, with 4 kg of grass seeds per mu, 40 kg of biological fertilizer applied per mu, 35 cm in row spacing, and 2 to 3 cm in depth. The grass seeds include 60 parts of Rhizoma Coptidis, 10 parts of Astragalus membranaceus, and 30 parts of Mongolica mongoliaensis. The microbial fertilizer is not buried or coated, and the microbial fertilizer and grass seeds are sown at the same time (the microbial fertilizer is applied once and not in stages).

[0115] In Example 1-9 and Comparative Example 1-3, when the microbial fertilizer is mixed with grass seeds for sowing, a fertilizing device is used for both sowing and fertilizing:

[0116] like Figure 1-3As shown, the fertilizing device includes a movable frame (the movable frame includes a frame body and movable wheels), two pairs of discharge mechanisms arranged on the movable frame (in actual use, if more grass seeds need to be sown at the same time, the number of pairs of discharge mechanisms can be increased to meet the needs of sowing multiple grass seeds at the same time), the two pairs of discharge mechanisms are used to hold fertilizers and grass seeds, and the discharge mechanisms include: a holding barrel 2, the lower end of which is connected to a transfer cylinder 3 with a circular vertical section, the lower end of the transfer cylinder 3 is connected to a discharge pipe 10 (the discharge pipe 10 is arranged obliquely), and the transfer cylinder A rotatable material distribution plate 9 is provided in the transfer cylinder 3 (the thickness of the material distribution plate 9 is slightly smaller than the thickness of the material holding barrel 2), a driving cylinder 18 is coaxially provided in the material distribution plate 9 (the driving cylinder 18 is horizontally arranged), the driving cylinder 18 rotates through the transfer cylinder 3 and extends out of the transfer cylinder 3 (specifically, a through hole 5 can be provided on the transfer cylinder 3, and the diameter of the through hole 5 is larger than the diameter of the driving cylinder 18), the driving cylinder 18 has a thread, a matching threaded rod 4 is provided in the driving cylinder 18, a driving rod 20 is provided at the end of the threaded rod 4, and the diameter of the driving rod 20 is The driving rod 20 is smaller than the diameter of the threaded rod 4. A fixed disk 21 is provided at the end of the driving rod 20. The fixed disk 21 is slidably connected to the driving cylinder 18 (the inner wall of the driving cylinder 18 is provided with a first slide rail, and the first slide rail is provided with a first slider, and the first slider is connected to the fixed disk 21). The outer edges of the distribution plate 9 are all recessed (recessed toward the central axis of the distribution plate 9) to form a plurality of accommodating grooves 17 (a plurality of accommodating grooves 17 are arranged at equal intervals). The accommodating grooves 17 include an inclined transition portion and a cylindrical portion connected to the transition portion. The cylindrical The central axis of the cylindrical part is arranged along the radial direction of the distributing plate 9, the bottom of the cylindrical part is connected with the driving cylinder 18 through a threading hole, a first spring 23 is arranged at the bottom of the cylindrical part, an adjusting disk 22 is arranged at the end of the first spring 23, the adjusting disk 22 is slidably connected with the cylindrical part, a driving rope 24 is arranged on the adjusting disk 22, the driving rope 24 passes through the threading hole and is connected with the fixed disk 21 so as to adjust the position of the adjusting plate through the fixed disk 21 (the fertilizer and grass seeds entering the grass trough will not push the adjusting disk 22 to move);

[0117] The lower ends of the four discharge pipes 10 in the two pairs of discharge mechanisms are connected to a guide pipe 6, and a furrow opener is provided at the lower end of the guide pipe 6. The two material distribution plates 9 and the two transfer cylinders 3 in each pair of discharge mechanisms are arranged in parallel.

[0118] The driving assembly is used to drive the two material distribution plates 9 to rotate. During use, based on the amount of seeds and fertilizer required for each hole, the threaded rod 4 is twisted, the threaded rod 4 moves, and the driving rope 24 moves to adjust the depth of the receiving groove 17, and the fertilizer is placed in one of the material storage barrels 2, and the grass seeds (beef twigs, astragalus, Mongolian ice grass) are placed in the remaining material storage barrels 2, and the movable frame 1 moves to drive the two material distribution plates 9 to rotate, so as to complete simultaneous sowing and fertilization. By adopting this technical solution, the present invention adjusts the depth of the containing groove 17 by setting a driving cylinder 18, a threaded rod 4, and an adjusting disk 22, so as to adjust the capacity based on the required amount of grass seeds or fertilizers, thereby effectively improving the use range of the fertilization device; the driving adjustment disk 22 is driven to move by setting a driving rope 24, and the positions of multiple driving disks 26 can be adjusted simultaneously by setting a driving cylinder 18, which is convenient and quick; the present invention sets two pairs of discharge mechanisms to achieve the simultaneous sowing and fertilization of three kinds of grass seeds and fertilizers, thereby ensuring that each grass seed in each acupoint can be sown as much as possible in proportion, which can not only improve the fertilization and sowing efficiency, but also effectively improve the quality of desert grassland soil.

[0119] In another technical solution, a first gear 8 is provided at the moving wheel of the movable bracket 1 (the first gear 8 rotates with the rotation of the moving wheel);

[0120] The driving assembly includes two connecting shafts 12 rotatably connected to the movable bracket 1, and the two connecting shafts 12 are arranged in one-to-one correspondence with the two pairs of discharging mechanisms. The two ends of the connecting shaft 12 are respectively connected to the material distribution plate 9 to drive the material distribution plate 9 to rotate. The connecting shaft 12 is provided with a second gear 14, and the second gear 14 is connected to the first gear 8 through a chain 7 to drive the connecting shaft 12 to rotate. Each connecting shaft 12 is provided with a third gear, and the two third gears are connected through a second chain to make the two connecting shafts 12 rotate simultaneously. With this technical solution, the present invention realizes the rotation of the material distribution plate 9 driven by the rotation of the moving wheel by setting the first gear 8, the second gear 14, and the chain 7.

[0121] In another technical solution, the material distribution trays 9 are multiple groups (the number of material distribution trays 9 in each group is consistent with the number of material barrels), the size and number of the receiving slots 17 in any two groups of material trays 9 are different, and the number of receiving slots 17 in each group of material trays 9 is equal to facilitate the simultaneous addition of fertilizers and grass seeds;

[0122] The connecting shaft 12 is a hollow structure, and a connecting rod 13 is provided on the distributing plate 9. The connecting rod 13 rotates through the transfer cylinder 3 and extends into the connecting shaft 12 (the transfer cylinder 3 is provided with a through hole 5, and the diameter of the connecting rod 13 is slightly smaller than the diameter of the through hole 5). The connecting shaft 12 is connected to the connecting rod 13 by a latch 15 (the connecting rod 13 and the connecting shaft 12 are both provided with positioning holes, and the latch 15 is inserted into the positioning hole to fix the connecting rod 13);

[0123] The side wall of the transfer cylinder 3 located on the outside is detachably connected to facilitate replacement of the material distribution tray 9. By adopting this technical solution, the present invention realizes that the material distribution tray 9 can be easily replaced according to needs by arranging the connecting rod 13 to be detachably connected to the connecting rod 13, the side wall of the transfer cylinder 3 located on the outside is detachably connected, and multiple pairs of material distribution trays 9.

[0124] In another technical solution, a second spring 25 is provided on the adjusting disk 22, and a driving disk 26 is provided at the end of the second spring 25, and the driving disk 26 is slidably connected to the cylindrical portion, wherein when the notch of the receiving groove 17 faces upward, the second spring 25 is in a compressed state under the gravity of the driving disk 26, and when the notch of the receiving groove 17 faces downward, the second spring 25 is extended under the gravity of the driving disk 26 and drives the grass seeds or fertilizers in the receiving groove 17 to be discharged. With this technical solution, the present invention promotes the grass seeds or fertilizers in the receiving groove 17 by providing the second spring 25 and the driving disk 26, which is conducive to the discharge of the grass seeds or fertilizers.

[0125] In another technical solution, a stirring assembly is provided in the material storage barrel 2 to facilitate the discharge of grass seeds or fertilizers. With this technical solution, the present invention can stir the materials in the material storage barrel 2 by providing a stirring assembly to avoid the problem that the fertilizers or grass seeds are compacted and difficult to discharge during use.

[0126] <Experimental Results>

[0127] The soil was repaired by the methods of Example 3, Example 6, Example 9, and Comparative Examples 1-3. Three years after the repair, soil testing was performed, and a plot that was not artificially repaired was set as a control group. The control groups were divided into control 1, control 2, and control 3. Control group 1 was a slightly poor soil with an organic matter content of ≥1.5%, control group 2 was a moderately poor soil with an organic matter content of 1.0% to 1.5%, and control group 3 was a moderately poor soil with an organic matter content of 1.0% to 1.5%. The detection method was as follows: the soil bulk density was determined by the ring knife method; the soil moisture content was determined by the drying method; and the soil moisture content was determined by the drying method. The volume percentage of soil clay particles was determined by laser particle size analyzer; soil pH was determined by potentiometric method; soil organic carbon was determined by potassium dichromate volumetric method; soil total nitrogen was determined by fully automatic Kjeldahl method; soil total phosphorus and available phosphorus were determined by molybdenum antimony colorimetric method; soil alkaline nitrogen was determined by alkaline diffusion absorption method; the total number of soil microorganisms was determined by plate coating method; soil microbial biomass carbon and nitrogen content were treated with chloroform fumigation-extraction method, and then soil microbial biomass carbon was determined by potassium dichromate volumetric method; soil microbial biomass nitrogen was determined by fully automatic Kjeldahl method; and two enzyme activities were determined by microplate reader.

[0128] 1. Changes in physical properties of soil after restoration

[0129] The changes in the physical properties of the soil in the control groups 1-3, comparative examples 1-3, examples 3, 6 and 9 were detected, as shown in Table 1;

[0130] Table 1 shows the changes in soil physical properties

[0131]

[0132] It can be seen from Table 1 that sowing grass seeds and applying microbial fertilizers effectively improved the physical properties of the soil, reduced the soil bulk density and pH, and increased the soil moisture content and clay volume percentage.

[0133] 2. Changes in soil chemical properties after restoration

[0134] The changes in the chemical properties of the soil in the control groups 1-3, comparative examples 1-3, examples 3, 6 and 9 were detected, as shown in Table 2;

[0135] Table 2 shows the changes in soil physical properties

[0136]

[0137]

[0138] It can be seen from Table 2 that the soil nutrient content was increased by sowing grass seeds and applying microbial fertilizers, specifically the soil organic matter, total nitrogen, total phosphorus, alkaline nitrogen and available phosphorus contents were increased.

[0139] 3. Changes in soil microbial properties after restoration

[0140] The changes in the microbial properties of the soil in the control group, comparative example 1, and examples 1-3 were detected, as shown in Table 3;

[0141] Table 3 shows the changes in soil microbial properties

[0142]

[0143] Table 3 shows that sowing grass seeds and applying microbial fertilizers increased the number of soil microorganisms, soil microbial biomass and the activity of extracellular enzymes representing carbon- and nitrogen-acquisition.

[0144] To sum up, 3kg / mu of grass seeds and 30kg / mu of fertilizer can significantly improve the quality of desert steppe soil.

[0145] Although the embodiments of the present invention have been disclosed as above, they are not limited to the applications listed in the specification and the implementation modes, and they can be fully applied to various fields suitable for the present invention. For those familiar with the art, additional modifications can be easily implemented. Therefore, without departing from the general concept defined by the claims and the scope of equivalents, the present invention is not limited to the specific details and the illustrations shown and described herein.

Claims

1. A microbial remediation method for improving desert steppe soil quality, characterized in that: The following steps are involved: Sowing grass seeds and applying microbial fertilizer to the pretreated plots, sowing 1-5 kg ​​of grass seeds per mu, applying 15-45 kg of fertilizer per mu, sowing row spacing of 35 cm, sowing depth of 2-3 cm, wherein the grass seeds include 40-60 parts of Rhizoma Cynanchum, 5-15 parts of Astragalus membranaceus, and 30-50 parts of Mongolian wheatgrass by weight; Microbial fertilizers include nitrogen-fixing bacteria, phosphate-solubilizing bacteria and growth-promoting bacteria, with an organic matter content of ≥40% and a pH value of 6.5-7.5; Among them, the nitrogen-fixing bacteria in the microbial fertilizer are meliloti root nodules or soybean root nodules; the phosphate-solubilizing bacteria are Pseudomonas fluorescens or Pseudomonas putida; the growth-promoting bacteria are Bacillus subtilis or Bacillus licheniformis; and the weight ratio of the nitrogen-fixing bacteria, the phosphate-solubilizing bacteria and the growth-promoting bacteria is 2:1-1.5:1-1.

5.

2. The microbial remediation method for improving desert steppe soil quality according to claim 1, characterized in that: The sowing amount of the grass seeds and the application amount of the microbial fertilizer are dynamically adjusted according to the soil barrenness and climatic conditions, specifically including: For slightly poor soil with an organic matter content of ≥1.5%, the sowing rate of grass seeds is 1-2 kg per mu, and the application rate of microbial fertilizer is 15-25 kg per mu; For moderately poor soil with an organic matter content of 1.0% to 1.5%, the sowing rate of grass seeds is 2 to 3 kg per mu, and the application rate of microbial fertilizer is 25 to 35 kg per mu; For severely poor soil with organic matter content ≤1.0%, the grass seed sowing rate is 3-5 kg ​​per mu, and the microbial fertilizer application rate is 35-45 kg per mu.

3. The microbial remediation method for improving desert steppe soil quality according to claim 2, characterized in that: For mildly poor soil, the weight ratio of grass seeds is 40 parts of Rhizoma Cyperi, 10 parts of Astragalus membranaceus, and 50 parts of Mongolian wheatgrass; For moderately poor soil, the weight ratio of grass seeds is 50 parts of Rhizoma Cyperi, 10 parts of Astragalus membranaceus, and 40 parts of Mongolian wheatgrass; For severely barren soil, the weight ratio of grass seeds is 60 parts of Rhizoma Cyperi, 10 parts of Astragalus membranaceus, and 30 parts of Mongolica scoparia.

4. The microbial remediation method for improving desert steppe soil quality according to claim 3, characterized in that: The application method of the microbial fertilizer is to embed the fertilizer with a composite carrier material, which specifically includes the following steps: Bacterial fertilizer embedding treatment: nitrogen-fixing bacteria, phosphate-solubilizing bacteria and growth-promoting bacteria are mixed with a composite carrier material respectively, and the composite carrier material is composed of humic acid, sodium alginate and biochar in a weight ratio of 3:1:

2.

5. The microbial remediation method for improving desert steppe soil quality according to claim 4, characterized in that: The microbial fertilizer is applied in stages, specifically comprising the following steps: The first stage: 7 to 10 days before sowing, evenly spread 50% of the total amount of microbial fertilizer on the surface of the pre-treated plot, and shallowly till the soil to a depth of 10 to 15 cm. Immediately cover the soil with a degradable water-retaining film with a light transmittance of 60% to 70% and a covering time of 20 to 30 days; The second stage: when sowing, 30% of the total amount of microbial fertilizer is mixed with grass seeds and then applied to the sowing furrow simultaneously, and a mixed isolation layer consisting of straw debris and fertilizer particles is laid in the furrow with a thickness of 2 to 3 cm, and the proportion of fertilizer particles in the isolation layer is 20% to 30%; The third stage: 30 days after the grass seeds emerge, mix the remaining 20% ​​of the microbial fertilizer with nanoclay with a particle size of ≤100nm in a weight ratio of 1:0.5, and spray it on the soil around the roots of the plants through high-pressure atomization with a spraying pressure of 0.3-0.5MPa.

6. The microbial remediation method for improving desert steppe soil quality according to claim 4, characterized in that: The embedded microbial fertilizer is synergistically coated with natural polymer materials and nano-clay, and specifically comprises the following steps: During the embedding process, nano-clay particles with a particle size of ≤100nm are added, and the amount of the added particles is 5% to 10% of the total mass of the embedding material.

7. The microbial remediation method for improving desert steppe soil quality according to claim 1, characterized in that: Fertilizer devices are used for both sowing and fertilization: The fertilizing device comprises a movable frame and two pairs of discharge mechanisms arranged on the movable frame, the two pairs of discharge mechanisms are used to hold fertilizers and grass seeds, the discharge mechanisms comprise: a holding barrel, the lower end of which is connected to a transfer cylinder with a circular vertical cross-section, the lower end of the transfer cylinder is connected to a discharge pipe, a rotatable material distribution plate is arranged in the transfer cylinder, a driving cylinder is coaxially arranged in the material distribution plate, the driving cylinder rotates through the transfer cylinder, the driving cylinder has a thread, a matching threaded rod is arranged in the driving cylinder, a driving rod is arranged at the end of the threaded rod, the diameter of the driving rod is smaller than the diameter of the threaded rod, and a fixed rod is arranged at the end of the driving rod. The fixing disk is slidably connected with the driving cylinder, the outer edges of the material distribution disk are all recessed to form a plurality of accommodating grooves, the accommodating grooves include an inclined transition portion and a cylindrical portion connected with the transition portion, the center axis of the cylindrical portion is arranged along the radial direction of the material distribution disk, the bottom of the cylindrical portion is connected with the driving cylinder through a threading hole, a first spring is provided at the bottom of the cylindrical portion, an adjusting disk is provided at the end of the first spring, the adjusting disk is slidably connected with the cylindrical portion, a driving rope is provided on the adjusting disk, the driving rope passes through the threading hole and is connected with the fixing disk to adjust the position of the adjusting plate through the fixing disk; The lower ends of the four discharge pipes in the two pairs of discharge mechanisms are connected to a guide pipe, a furrow opener is provided at the lower end of the guide pipe, and the two distribution plates in each pair of discharge mechanisms are arranged in parallel; The driving assembly is used to drive the four material distribution plates to rotate.

8. The microbial remediation method for improving desert steppe soil quality according to claim 7, characterized in that: The movable wheel of the movable bracket is provided with a first gear; The driving assembly includes two connecting shafts rotatably connected to the movable bracket, and the two connecting shafts are arranged in a one-to-one correspondence with the two pairs of discharging mechanisms. The two ends of the connecting shaft are respectively connected to the distribution plate to drive the distribution plate to rotate, wherein a second gear is provided on the connecting shaft, and the second gear is connected to the first gear through a first chain to drive the connecting shaft to rotate, and a third gear is provided on each connecting shaft, and the two third gears are connected through a second chain to enable the two connecting shafts to rotate simultaneously.

9. The microbial remediation method for improving desert steppe soil quality according to claim 7, characterized in that: The material distribution trays are multiple groups, and the sizes and quantities of the containing slots in any two groups of material distribution trays are different; The connecting shaft is a hollow structure, and a connecting rod is provided on the material distribution plate. The connecting rod rotates through the transfer cylinder and extends into the connecting shaft, and the connecting shaft and the connecting rod are connected by a latch; The side wall of the transfer cylinder located on the outside is detachably connected to facilitate replacement of the material distribution tray.

10. The microbial remediation method for improving desert steppe soil quality according to claim 7, characterized in that: The adjusting disk is provided with a second spring, the end of the second spring is provided with a driving disk, and the driving disk is slidably connected with the cylindrical portion, wherein when the notch of the accommodating groove faces upward, the second spring is in a compressed state under the gravity of the driving disk; A stirring assembly is arranged in the material holding barrel to facilitate the discharge of grass seeds or fertilizers.

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