Composite modifier suitable for South China coastal viscous saline-alkali soil and three-dimensional rapid-effect improvement method

Abstract

The invention relates to the technical field of soil improvement, in particular to a composite modifier suitable for sticky saline-alkali soil in coastal areas in South China and a three-dimensional quick-effect improvement method.The composite modifier is prepared from, by weight, 30-50 parts of sugar refinery filter mud, 20-40 parts of decomposed cassava residues, 10-20 parts of vinegar residues, 3-5 parts of urea phosphate and 0.1-0.5 part of fungicide. Compared with the prior art, the invention provides a new scheme for improving the sticky saline-alkali soil in the coastal area of south China by preferably selecting the components of the composite modifier and the components of the microbial agent with the best phosphorus and potassium dissolving capacity and combining a three-dimensional quick-effect improvement method, the pH value of the improved sticky saline-alkali soil is about 7.5, the total salt content is reduced to about 0.25%, and the soil quality is improved. The total porosity of the soil is remarkably improved by 60% or above, the content of rapidly available potassium and rapidly available phosphorus is improved, the emergence rate of sea rice planted on the land is 85% or above, and the growth condition is good.

Description

Technical Field

[0001] This invention relates to the field of soil improvement technology, specifically to a composite soil conditioner and a three-dimensional rapid soil improvement method suitable for clayey saline-alkali land in coastal South China. Background Technology

[0002] In the coastal areas of southern my country, such as the Beibu Gulf coast of Guangxi Zhuang Autonomous Region and the Leizhou Peninsula of Guangdong Province, factors such as seawater intrusion, aquaculture wastewater discharge, seasonal drought, and inappropriate irrigation have led to severe surface alkalinity and high soil salinity, resulting in large areas of saline-alkali land. This region's saline-alkali land has the following significant characteristics: I. Salt composition: Mainly sodium chloride (NaCl); II. Soil texture: Mostly clay soil, with poor permeability, poor drainage, and difficulty in leaching salts; 3. pH: Due to the parent material and long-term leaching by rainfall, the bottom soil is often acidic or weakly acidic, but the surface layer is alkaline due to salt accumulation, and there are fewer bacteria and fungi that are adapted to its growth.

[0003] IV. Lack of organic matter: The soil is infertile, with poor structure, weak water and fertilizer retention capacity, high total phosphorus and total potassium content, but low available phosphorus and available potassium content.

[0004] Current saline-alkali land improvement technologies are mostly designed for alkali soils or sulfate-type saline soils in arid and semi-arid regions of northern China. Directly applying them to South China has the following shortcomings: First, using gypsum (CaSO4) to improve saline-alkali soil will increase the calcium ion concentration. Calcium ions combine with clay soil, which will lead to a worsening of the heavy and compacted soil in saline-alkali soil. Secondly, while using sand as an exogenous material can improve permeability, it is costly and has weak water and fertilizer retention capacity. Furthermore, the compound soil conditioner was not very effective, and there was a lack of microbial agents that could adapt to clayey coastal saline soils with a pH value greater than 8 and a total salt content greater than 0.6%. Finally, there is a lack of resource utilization solutions for the region's abundant agricultural waste.

[0005] Therefore, there is an urgent need for a comprehensive improvement technology that is low-cost, environmentally friendly, can quickly improve soil structure, effectively reduce salinity, and enhance soil fertility. Summary of the Invention

[0006] The purpose of this invention is to provide a composite conditioner and a three-dimensional rapid-acting conditioner method suitable for clayey saline-alkali land along the coast of South China, in order to solve the above-mentioned technical problems.

[0007] To address the aforementioned technical problems, this invention provides a composite soil conditioner suitable for clayey saline-alkali soils along the South China coast. The composite soil conditioner comprises, by weight, 30-50 parts sugar mill filter mud, 20-40 parts decomposed cassava residue, 10-20 parts vinegar residue, 3-5 parts urea phosphate, and 0.1-0.5 parts microbial agent.

[0008] Preferably, in the above technical solution, the microbial agent is composed of Aspergillus niger, Pseudomonas cepacia, Bacillus mucilaginosus, and Bacillus circulatoryus in a mass ratio of 1-2:1:2-1:1.

[0009] Preferably, in the above technical solution, the composite improver further includes: 20-30 parts rice husk, 10-20 parts mushroom residue, and 10-20 parts sawdust and wood chips mixture.

[0010] Preferably, in the above technical solution, the preparation method of the composite modifier is as follows: (1) The raw material of sugar factory filter mud is processed to a moisture content of 30%-35%, and the sugar factory filter mud is physically crushed to a particle size of ≤8mm to obtain sugar factory filter mud for use. (2) The vinegar residue raw material is processed to a moisture content of 25%-30%, and the vinegar residue raw material is crushed to a particle size ≤3mm to obtain vinegar residue for later use; (3) The urea phosphate raw material is crushed into powder to obtain urea phosphate for later use; (4) Mix the culture medium of Pseudomonas cereus, Bacillus mucilaginosus, and Bacillus circulans at a volume ratio of 1:1-2:1 to obtain a bacterial solution for later use. Mix Aspergillus niger with 5-8 parts of decomposed cassava residue evenly and let it stand at room temperature for 1-2 days. Then take the bacterial solution and add it to the decomposed cassava residue. The mass ratio of Aspergillus niger to bacterial solution is 0.5-1:2. (5) Mix 5-8 parts of fermented cassava residue containing microbial agent, 25-42 parts of fermented cassava residue, 20-40 parts of sugar factory filter mud, 10-20 parts of vinegar residue and 3-5 parts of urea phosphate evenly to obtain a composite improver.

[0011] Preferably, in the above technical solution, the preparation method of the composite modifier is as follows: (1) The raw material of sugar factory filter mud is processed to a moisture content of 30%-35%, and the sugar factory filter mud is physically crushed to a particle size of ≤8mm to obtain sugar factory filter mud for use. (2) The vinegar residue raw material is processed to a moisture content of 25%-30%, and the vinegar residue raw material is crushed to a particle size ≤3mm to obtain vinegar residue for later use; (3) The urea phosphate raw material is crushed into powder to obtain urea phosphate for later use; (4) Crush the mushroom residue raw material to a particle size ≤10mm, and then process it to make its moisture content 15%-20% to obtain mushroom residue for later use; (5) Mix the culture medium of Pseudomonas cereus, Bacillus mucilaginosus, and Bacillus circulans at a volume ratio of 1:1-2:1 to obtain a bacterial solution for later use. Mix Aspergillus niger with 5-8 parts of decomposed cassava residue evenly and let it stand at room temperature for 1-2 days. Then take the bacterial solution and add it to the decomposed cassava residue. The mass ratio of Aspergillus niger to bacterial solution is 0.5-1:2. (6) Mix 5-8 parts of fermented cassava residue containing microbial agent, 25-42 parts of fermented cassava residue, 20-40 parts of sugar factory filter mud, 10-20 parts of vinegar residue, 3-5 parts of urea phosphate, 10-30 parts of rice husk, 10-20 parts of mushroom residue, and 10-20 parts of sawdust evenly to obtain a composite improver.

[0012] Preferably, in the above technical solution, the bacterial concentration of the *Pseudomonas cepacia* culture medium is 1×10⁻⁶. 8 -1×10 9 CFU / mL, the bacterial concentration of the Bacillus mucilaginosus culture medium is 1×10⁻⁶. 8 -1×10 9 CFU / mL, the bacterial concentration of the Bacillus circulans culture medium is 1×10⁻⁶. 8 -1×10 9 CFU / mL.

[0013] A three-dimensional rapid improvement method for clayey saline-alkali land suitable for coastal areas of South China, the three-dimensional rapid improvement method comprising: S1. Construct a drainage system on the plot to be improved. After the drainage system is completed, irrigate and rinse the soil in small amounts for 2-4 consecutive days. The amount of irrigation should be such that the soil moisture content reaches 60%-70% of the field capacity. S2, External application of compound soil conditioner: When the plot to be improved is relatively dry, it is deep-plowed to a depth of 30-40cm. The compound soil conditioner is spread on the surface at a rate of 2-5 tons / acre, and then rotary tilled to fully mix the compound soil conditioner with the 0-40cm soil. The plot is left to stand for 45-60 days. During the standing period, shallow tilling is carried out once every 15 days to a depth of 10-15cm. S3, Cultivated crops: High ridges are made according to the habits of salt-tolerant crops. The height of the high ridges is 25-30cm, the width is 50-65cm, and the ridge spacing is 30-40cm. The high ridges are covered with biodegradable black mulch film. Holes are punched in the black mulch film and salt-tolerant crops are sown in holes on the ridges. S4, Planting Management: Irrigate multiple times during the initial sowing period, with each irrigation amount being 15-20 m³ / mu. During the seed germination period and crop growth period, pay attention to irrigation to maintain the soil moisture content at 55%-75% of field capacity, and avoid drought leading to salt return and leaching of soil nutrients. During the crop growth period, apply 5-8 kg / mu of humic acid-based water-soluble fertilizer once a month, and apply 0.5-1 ton / mu of well-rotted organic fertilizer.

[0014] Preferably, in the above technical solution, the composite improver comprises, by weight parts, 30-50 parts sugar mill filter mud, 20-40 parts decomposed cassava residue, 10-20 parts vinegar residue, 3-5 parts urea phosphate, and 0.1-0.5 parts microbial agent, wherein the microbial agent is composed of Aspergillus niger, Pseudomonas cepacia, Bacillus mucilaginosus, and Bacillus circinus in a mass ratio of 1-2:1:2-1:1.

[0015] Preferably, in the above technical solution, the construction of a drainage system on the land to be improved specifically involves: opening a drainage ditch on the land to be improved, laying 10-15cm high sand and gravel at the bottom of the drainage ditch, filling it with sugarcane bagasse or straw, and then laying 4-7cm of sand and gravel on the sugarcane bagasse or straw to complete the construction of the drainage system.

[0016] Preferably, in the above technical solution, the salt-tolerant crop is one or more of seawater rice, sweet sorghum, and Suaeda salsa.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) This invention provides a three-dimensional rapid improvement method for clayey saline-alkali land in coastal South China, providing a new solution for the improvement of clayey saline-alkali land in coastal South China. After improvement, the soil pH value of clayey saline-alkali land is about 7.5, the total salt content is reduced to about 0.25%, the total porosity of the soil is significantly increased by more than 60%, and the content of available potassium and available phosphorus is increased. The emergence rate of seawater rice planted on this land is more than 85%, and the growth is good.

[0018] (2) By selecting the best composite amendment components, the best composite amendment components for reducing soil pH and total salt content, increasing organic matter content and total soil porosity in clayey coastal saline soil were selected. Then, the best phosphorus and potassium solubilizing agent components were selected to solve the problem that clayey coastal saline soil has high total phosphorus and total potassium content and low available potassium and available phosphorus due to long-term and frequent seawater intrusion. The composite amendment improves the physical and chemical properties of clayey coastal saline soil and enhances its water and fertilizer retention capacity, thereby increasing the survival rate of planted crops.

[0019] (3) The exogenous material components of the composite soil conditioner are all abundant agricultural wastes in the Guangxi Zhuang Autonomous Region, which is conducive to the reuse of agricultural waste resources. At the same time, the agricultural wastes are all biodegradable materials, avoiding the secondary damage to saline-alkali land caused by improper application of traditional chemical soil conditioners. Detailed Implementation

[0020] The technical solutions in the embodiments of this invention are clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0021] Example 1: Screening experiment for exogenous substances suitable for improving clayey saline-alkali land along the coast of South China The clayey saline-alkali soil used in this experiment was taken from the coastal saline-alkali land of Hepu County, Beihai City, Guangxi Zhuang Autonomous Region. This land is clayey coastal saline soil with a pH value of 8.2, a total salt content of 0.6%, and an organic matter content of 0.8%. The exogenous materials were corn stalks, decomposed pig manure, sugar factory filter mud, decomposed cassava residue, rice husks, a mixture of sawdust and wood chips, mushroom residue, and tea cake residue. The physicochemical properties of the clayey coastal salt and exogenous materials are shown in Table 1 below.

[0022] Table 1. Physicochemical properties of various exogenous substances and clayey coastal saline soils name pH value Total salt content (%) Organic matter content (%) Total porosity (%) clayey coastal saline soil 8.2 0.60 0.8 43.32 corn stalks 6.3 —— 41.3 59.54 Well-rotted pig manure 7.4 —— 43.5 52.28 Sugar factory filter mud 6.3 —— 37.1 47.71 rotten cassava residue 6.6 —— 51.8 69.52 Vinegar lees 5.7 —— 56.2 73.12 rice husk 6.6 —— 33.6 61.48 Sawdust and wood chip mixture 6.7 —— 56.2 83.31 Mushroom residue 7.6 —— 43.8 67.48 Tea cake residue 6.1 —— 41.6 59.76 The exogenous materials were corn stalks, decomposed pig manure, sugar factory filter mud, decomposed cassava residue, rice husks, a mixture of sawdust and wood chips, mushroom residue, tea cake residue, etc., in a pulverized state. The exogenous materials were used at 2% of the amount of clayey coastal saline soil. The exogenous materials were mixed with the clayey coastal saline soil and left to stand for 45 days. The effects of the exogenous materials on the physicochemical properties of the clayey coastal saline soil were tested, as shown in Table 2 below. The blank control was clayey coastal saline soil that had been left to stand for 45 days.

[0023] Table 2. Effects of different exogenous substances on the physicochemical properties of clayey coastal saline soil name pH value Total salt content (%) Organic matter content (%) Total porosity (%) Blank control 8.2 0.60 0.80 43.32 corn stalks 8.2 0.54 0.93 44.65 Well-rotted pig manure 8.1 0.56 1.14 44.01 Sugar factory filter mud 8.0 0.53 1.16 44.95 rotten cassava residue 8.0 0.50 1.07 46.63 Vinegar lees 7.9 0.54 1.26 47.21 rice husk 8.2 0.52 0.94 46.38 Sawdust and wood chip mixture 8.1 0.53 1.04 47.89 Mushroom residue 8.1 0.54 1.09 44.98 Tea cake residue 8.1 0.53 0.97 44.72 Table 2 shows that among the exogenous materials mentioned above, sugar mill filter mud, decomposed cassava residue, and vinegar residue had the best alkalinity reduction effect, while decomposed cassava residue and rice husk had the best salinity reduction effect. Decomposed pig manure, sugar mill filter mud, and vinegar residue showed the best organic matter improvement effect, and sawdust-wood chip mixture, vinegar residue, and decomposed cassava residue showed the most significant improvement in porosity. Considering the possibility that decomposed pig manure may contain excessive levels of heavy metals, using decomposed pig manure containing excessive heavy metals to improve clayey coastal saline soil could lead to soil and seawater pollution. Furthermore, testing the heavy metal content of decomposed pig manure before use would increase the improvement cost and be unfriendly to improvement units without testing capabilities. Therefore, decomposed pig manure was not considered as an exogenous material.

[0024] Example 2: Screening the optimal combination of exogenous materials for improving clayey saline-alkali land along the coast of South China The soil used in this screening test was taken from the coastal saline-alkali land of Hepu County, Beihai City, Guangxi Zhuang Autonomous Region. Its physicochemical properties were consistent with those of Example 1. The exogenous substances mentioned were all from the same batch as those in Example 1, so no secondary testing was performed.

[0025] Combination A: The mass ratio of sugar factory filter mud, decomposed cassava residue, and vinegar residue is 2:1:1; Combination B: The mass ratio of rice husks, sawdust and wood chips mixture, and mushroom residue is 2:1:1; Combination C: The mass ratio of sugar factory filter mud, rice husks, and mushroom residue is 2:1:1; Combination D: The mass ratio of decomposed cassava residue, vinegar residue, and rice husks is 2:1:1; Combination E: The mass ratio of sugar factory filter mud, decomposed cassava residue, and mushroom residue is 2:1:1; Combination F: The mass ratio of the mixture of sugar mill filter mud, rice husks, and sawdust is 2:1:1; Combination G: The mass ratio of vinegar residue, sawdust and wood chips mixture, and rice husks is 2:1:1; Combination H: The mass ratio of mushroom residue, decomposed cassava residue, and vinegar residue is 2:1:1.

[0026] The above-mentioned exogenous material groups were mixed with clayey coastal saline soil and left to stand for 45 days. The amount of the exogenous material group accounted for 2% of the weight of the clayey coastal saline soil. The physicochemical properties of the treated clayey coastal saline soil are shown in Table 3 below.

[0027] Table 3. Effects of different exogenous material groups on the physicochemical properties of clayey coastal saline soil. Exogenous material group pH value Total salt content (%) Organic matter content (%) Total porosity (%) Blank control 8.2 0.60 0.80 43.32 Combination A 7.9 0.33 1.56 53.71 Combination B 7.9 0.49 1.17 57.44 Combination C 7.9 0.45 1.39 57.83 Combination D 7.8 0.43 1.31 54.67 Combination E 7.8 0.37 1.45 52.49 Combination F 8.1 0.43 1.24 56.28 Combination G 8.0 0.49 1.28 59.36 Combination H 7.9 0.48 1.36 56.75 The table shows that applying sugar factory filter mud, decomposed cassava residue, and vinegar residue in a mass ratio of 2:1:1 to clayey coastal saline soil has the best comprehensive improvement effect on clayey coastal saline soil, followed by a mass ratio of sugar factory filter mud, decomposed cassava residue, and mushroom residue of 2:1:1.

[0028] Example 3: Investigating the effects of different bacteria on reducing total phosphorus and total potassium in clayey coastal saline soils The soil used in this experiment was taken from the coastal saline-alkali land of Hepu County, Beihai City, Guangxi Zhuang Autonomous Region. 2% of the weight of the exogenous material group of clayey coastal saline soil was added to the clayey coastal saline soil and mixed evenly. The mass ratio of sugar factory filter mud, decomposed cassava residue and vinegar residue of the exogenous material group was 2:1:1. The contents of total phosphorus, total potassium, available phosphorus and available potassium in the above mixture were detected.

[0029] Table 4. Content of total phosphorus, total potassium, available phosphorus, and available potassium in the above mixtures. Testing items Total phosphorus (mg / g) Available phosphorus (mg / g) Total potassium (mg / g) Available potassium (mg / g) mixture 2.73 0.16 41.52 0.27 This may be due to the long-term and frequent intrusion of seawater into the soil, and the fact that seawater itself carries a high concentration of phosphorus and potassium ions, resulting in high total phosphorus and total potassium content in the clayey coastal saline soil.

[0030] Inoculum A: A mixture of *Bacillus megaterium*, *Pseudomonas fluorescens*, *Bacillus mucilaginosus*, and *Bacillus circulans* in a volume ratio of 2:1:2:1, with each bacterium having a concentration of 1×10⁻⁶. 8 CFU / mL culture medium; Inoculum agent B: A bacterial solution was prepared by mixing *Bacillus megaterium*, *Bacillus mucilaginosus*, and *Bacillus circulans* at a volume ratio of 2:1:1. The mass ratio of *Aspergillus niger* to the bacterial solution was 1:2. All the above-mentioned bacilli were present at a bacterial solution concentration of 1×10⁻⁶. 8 CFU / mL culture medium; Inoculant C: Bacillus subtilis, Bacillus mucilaginosus, Pseudomonas fluorescens, and Bacillus circinus are mixed in a volume ratio of 2:1:2:1, with all bacteria having a concentration of 1×10⁻⁶. 8 CFU / mL culture medium; Inoculum D: A bacterial solution was obtained by mixing *Pseudomonas cepacia*, *Bacillus mucilaginosus*, and *Bacillus circulans* at a volume ratio of 2:1:1. The mass ratio of *Aspergillus niger* to the bacterial solution was 1:2. The concentration of the *Pseudomonas cepacia*, *Bacillus mucilaginosus*, and *Bacillus circulans* in the bacterial solution was 1×10⁻⁶. 8 CFU / mL culture medium; Inoculum E: A bacterial solution was prepared by mixing *Pseudomonas fluorescens*, *Bacillus mucilaginosus*, and *Bacillus circulans* at a volume ratio of 2:1:1. The mass ratio of *Aspergillus niger* to the bacterial solution was 1:2. The concentrations of the *Pseudomonas fluorescens*, *Bacillus mucilaginosus*, and *Bacillus circulans* in the bacterial solution were all 1×10⁻⁶. 8 CFU / mL culture medium; Bacterial agent F: Bacillus megaterium, Pseudomonas cepacia, Bacillus mucilaginosus, Bacillus circulans.

[0031] The above-mentioned bacterial agent was mixed into the above-mentioned exogenous substance group and clayey coastal saline soil mixture in several batches, and left to stand for 45 days. The phosphorus and potassium content of the clayey coastal saline soil in each group was tested, and the results are shown in Table 5 below.

[0032] Table 5. Available potassium and available phosphorus content in clayey coastal saline soil after treatment with various microbial agents. Bacteria name Available potassium (mg / g) Available phosphorus (mg / g) Pretreatment of saline soil 0.27 0.16 Inoculant A 1.24 0.32 Bacterial agent B 1.53 0.45 Inoculant C 0.94 0.28 Bacterial agent D 2.81 0.64 Bacterial agent E 1.77 0.39 Bacterial agent F 1.63 0.25 The table above shows that the combined use of *Aspergillus niger*, *Pseudomonas cepacia*, *Bacillus mucilaginosus*, and *Bacillus circulatory* has the best effect on phosphorus and potassium solubilization in clayey coastal saline soils. *Aspergillus niger*, *Pseudomonas cepacia*, *Bacillus mucilaginosus*, and *Bacillus circulatory* show better adaptability to the soil conditions of clayey coastal saline soils. *Aspergillus niger* secretes phosphatase to decompose organic phosphorus, *Pseudomonas cepacia* secretes alkaline phosphatase and organic acids to decompose organic phosphorus and promote the dissolution of inorganic phosphorus, and *Bacillus mucilaginosus* and *Bacillus circulatory* release H+ through metabolism. +Isocations, H + The reaction of ions with potassium ions adsorbed on the surface of silicate minerals: mineral-K + +H + =Mineral-H + +K + The replaced K + Increasing the content of readily available potassium, Bacillus mucilaginosus and Bacillus circulans release potassium ions by destroying the Si-O and Al-O framework and disrupting the mineral crystal structure. Example 1

[0033] A composite soil conditioner suitable for clayey saline-alkali soils along the coast of South China, the composite soil conditioner is made from the following raw materials in parts by weight: 40 parts sugar factory filter mud, 30 parts decomposed cassava residue, 15 parts vinegar residue, 4 parts urea phosphate, and 0.3 parts microbial agent, wherein the microbial agent is composed of Aspergillus niger, Pseudomonas cepacia, Bacillus mucilaginosus, and Bacillus circinus in a mass ratio of 2:1:2:1.

[0034] The preparation method of the composite modifier is as follows: (1) The raw material of sugar factory filter mud is processed to a moisture content of 30%-35%, and the sugar factory filter mud is physically crushed to a particle size of ≤8mm to obtain sugar factory filter mud for use. (2) The vinegar residue raw material is processed to a moisture content of 25%-30%, and the vinegar residue raw material is crushed to a particle size ≤3mm to obtain vinegar residue for later use; (3) The urea phosphate raw material is crushed into powder to obtain urea phosphate for later use; (4) The concentration is 1×10 8 CFU / mL of *Pseudomonas cereus* culture medium, bacterial concentration 1×10⁻⁶ 8 CFU / mL Bacillus mucilaginosus culture medium, bacterial concentration 1×10 8 The bacterial culture medium of Bacillus circulatory system with CFU / mL was mixed at a volume ratio of 1:2:1 to obtain a bacterial solution for later use. Aspergillus niger was mixed evenly with 5 parts of decomposed cassava residue and allowed to stand at room temperature for 1-2 days. Then, the bacterial solution was added to the decomposed cassava residue. The mass ratio of Aspergillus niger to bacterial solution was 1:2. (5) Mix 5 parts of fermented cassava residue containing microbial agent, 25 parts of fermented cassava residue, 40 parts of sugar factory filter mud, 30 parts of vinegar residue and 4 parts of urea phosphate evenly to obtain a composite improver.

[0035] Comparative Example 1 A composite soil conditioner suitable for clayey saline-alkali soils along the coast of South China, the composite soil conditioner is made from the following raw materials in parts by weight: 40 parts sugar factory filter mud, 30 parts decomposed cassava residue, 15 parts vinegar residue, 4 parts urea phosphate, and 0.3 parts microbial agent, wherein the microbial agent is composed of Aspergillus niger, Pseudomonas cepacia, Bacillus mucilaginosus, and Bacillus circinus in a mass ratio of 2:1:2:1.

[0036] The preparation method of the composite modifier is as follows: (1) The raw material of sugar factory filter mud is processed to a moisture content of 30%-35%, and the sugar factory filter mud is physically crushed to a particle size of ≤8mm to obtain sugar factory filter mud for use. (2) The vinegar residue raw material is processed to a moisture content of 25%-30%, and the vinegar residue raw material is crushed to a particle size ≤3mm to obtain vinegar residue for later use; (3) The urea phosphate raw material is crushed into powder to obtain urea phosphate for later use; (4) Set the bacterial concentration to 1×10 8 CFU / mL of *Pseudomonas cereus* culture medium, bacterial concentration 1×10⁻⁶ 8 CFU / mL Bacillus mucilaginosus culture medium, bacterial concentration 1×10 8 The bacterial culture medium of Bacillus circulatory system with CFU / mL was mixed at a volume ratio of 1:2:1 to obtain a bacterial solution for later use. Aspergillus niger was mixed evenly with 5 parts of sugar factory filter mud and allowed to stand at room temperature for 1-2 days. Then, the bacterial solution was added to the decomposed cassava residue. The mass ratio of Aspergillus niger to bacterial solution was 1:2. (5) Mix 5 parts of sugar factory filter mud containing microbial agent, 35 parts of sugar factory filter mud, 30 parts of decomposed cassava residue, 30 parts of vinegar residue and 4 parts of urea phosphate evenly to obtain a composite improver.

[0037] Comparative Example 2 A composite soil conditioner suitable for clayey saline-alkali soils along the coast of South China, the composite soil conditioner is made from the following raw materials in parts by weight: 40 parts sugar factory filter mud, 30 parts decomposed cassava residue, 15 parts vinegar residue, 4 parts urea phosphate, and 0.3 parts microbial agent, wherein the microbial agent is composed of Aspergillus niger, Pseudomonas cepacia, Bacillus mucilaginosus, and Bacillus circinus in a mass ratio of 2:1:2:1.

[0038] The preparation method of the composite modifier is as follows: (1) The raw material of sugar factory filter mud is processed to a moisture content of 30%-35%, and the sugar factory filter mud is physically crushed to a particle size of ≤8mm to obtain sugar factory filter mud for use. (2) The vinegar residue raw material is processed to a moisture content of 25%-30%, and the vinegar residue raw material is crushed to a particle size ≤3mm to obtain vinegar residue for later use; (3) The urea phosphate raw material is crushed into powder to obtain urea phosphate for later use; (4) Mix the powders of Pseudomonas cereus, Bacillus mucilaginosus, Bacillus circulans, and Aspergillus niger in a mass ratio of 1:2:1:2 to obtain a microbial agent for later use. Mix the microbial agent with 5 parts of decomposed cassava residue and let it stand at room temperature for 1-2 days. (5) Mix 5 parts of fermented cassava residue containing microbial agent, 25 parts of fermented cassava residue, 40 parts of sugar factory filter mud, 30 parts of vinegar residue and 4 parts of urea phosphate evenly to obtain a composite improver. Example 2

[0039] The composite improver is made from the following raw materials in parts by weight: 40 parts sugar factory filter mud, 30 parts decomposed cassava residue, 15 parts vinegar residue, 4 parts urea phosphate, and 0.3 parts microbial agent. The microbial agent is composed of Aspergillus niger, Pseudomonas cepacia, Bacillus mucilaginosus, and Bacillus circinus in a mass ratio of 2:1:2:1.

[0040] The preparation method of the composite modifier is as follows: (1) The raw material of sugar factory filter mud is processed to a moisture content of 30%-35%, and the sugar factory filter mud is physically crushed to a particle size of ≤8mm to obtain sugar factory filter mud for use. (2) The vinegar residue raw material is processed to a moisture content of 25%-30%, and the vinegar residue raw material is crushed to a particle size ≤3mm to obtain vinegar residue for later use; (3) The urea phosphate raw material is crushed into powder to obtain urea phosphate for later use; (4) Crush the mushroom residue raw material to a particle size ≤10mm, and then process it to make its moisture content 15%-20% to obtain mushroom residue for later use; (5) Mix the culture medium of Pseudomonas cereus, Bacillus mucilaginosus, and Bacillus circulatoryus at a volume ratio of 1:2:1 to obtain a bacterial solution for later use. Mix Aspergillus niger with 5 parts of decomposed cassava residue evenly and let it stand at room temperature for 1-2 days. Then take the bacterial solution and add it to the decomposed cassava residue. The mass ratio of Aspergillus niger to bacterial solution is 1:2. (6) Mix 5 parts of fermented cassava residue containing microbial agent, 25 parts of fermented cassava residue, 20 parts of sugar factory filter mud, 10 parts of vinegar residue, 4 parts of urea phosphate, 15 parts of rice husk, 10 parts of mushroom residue, and 10 parts of sawdust evenly to obtain a composite improver.

[0041] The composite amendments of Example 4, Comparative Example 1, Comparative Example 2 and Example 5 were added to the soil to be improved and mixed evenly. The amount of composite amendment added was 5% of the weight of the soil to be improved. The soil to be improved was taken from the clayey coastal saline soil of the coastal saline-alkali land in Hepu County, Beihai City, Guangxi Zhuang Autonomous Region. The clayey coastal saline soil was treated with the composite amendments prepared in Example 4, Comparative Example 1, Comparative Example 2 and Example 5 for 3 months. The physicochemical properties of the clayey coastal saline soil are shown in Table 6 below.

[0042] Table 6. Physicochemical properties of clayey coastal saline soils treated with composite modifiers in each embodiment. Improved compound pH value Total salt content (%) Organic matter content (%) Total porosity (%) Available potassium (mg / g) Available phosphorus (mg / g) Improved saline soil 8.1 0.50 0.83 45.62 0.31 0.19 Example 4 7.8 0.31 1.73 60.68 3.27 0.79 Comparative Example 1 7.8 0.29 1.69 56.39 3.16 0.73 Comparative Example 2 7.8 0.30 1.70 55.76 2.87 0.64 Example 5 7.7 0.28 1.95 63.49 3.53 0.81 Table 6 shows that using decomposed cassava residue as a carrier for the microbial agent resulted in better phosphorus and potassium solubilization than using sugar mill filter residue. This is likely because decomposed cassava residue has better pH, organic matter content, and porosity than sugar mill filter residue, which is more conducive to the growth of *Aspergillus niger* and the growth and reproduction of activated bacteria, thus promoting their respective effects. Using activated *Pseudomonas cereus*, *Bacillus mucilaginosus*, and *Bacillus circulans* cultures is better than directly mixing with the microbial powder, possibly to ensure the activity of the microbial cells in the agent.

[0043] Example 6 A three-dimensional, rapid-acting method for improving clayey saline-alkali land suitable for coastal areas of South China, the method comprising the following steps: S1. Drainage ditches are dug on the plot to be improved. A 10-15cm high layer of sand and gravel is laid at the bottom of the drainage ditch, and then sugarcane bagasse or straw is filled in. A 4-7cm layer of sand and gravel is laid on top of the sugarcane bagasse or straw to complete the construction of the drainage system. The drainage ditch is 60-70cm deep and 30-40cm wide. After the drainage system is constructed, irrigation should be carried out in small amounts and multiple times for 2-4 consecutive days. The amount of irrigation each time should be such that the soil moisture content reaches 60%-70% of the field capacity. S2, External application of compound soil conditioner: When the plot to be improved is relatively dry, it is deep-plowed to a depth of 30-40cm. The compound soil conditioner prepared in Example 1 is spread on the surface at a rate of 2-5 tons / acre. Then, the soil is rotary-tilled to fully mix the compound soil conditioner with the 0-40cm soil. The soil is left to stand for 45-60 days. During the standing period, the soil is shallow-tilled once every 15 days to a depth of 10-15cm. S3, Cultivated crop: According to the salt-tolerant crop's habits, raise high ridges with a height of 25-30cm, a width of 50-65cm, and a ridge spacing of 30-40cm. Cover the high ridges with biodegradable black mulch film, punch holes in the black mulch film, and sow seawater rice seedlings in holes on the ridges. S4, Planting Management: Irrigate once every 10 days during the initial transplanting period, with an irrigation volume of 15-20 m³ / mu, ensuring water penetration into the raised beds. During the seed germination period and crop growth period, pay attention to irrigation to maintain the soil moisture content at 55%-75% of field capacity, avoiding drought that leads to salt return and leaching of soil nutrients. During the crop growth period, apply 5-8 kg / mu of humic acid-based water-soluble fertilizer and 0.5-1 ton / mu of well-rotted organic fertilizer once a month.

[0044] Example 7 A three-dimensional, rapid soil improvement method suitable for clayey saline-alkali land along the coast of South China was implemented in Hepu County, Beihai City, Guangxi Zhuang Autonomous Region. The steps of the improvement method are as follows: S1. Drainage ditch 70cm deep and 40cm wide is dug in the plot to be improved. A 15cm high layer of sand and gravel is laid at the bottom of the drainage ditch, and then sugarcane bagasse is filled in. A 5cm layer of sand and gravel is laid on top of the sugarcane bagasse to complete the construction of the drainage system. After the drainage system is constructed, irrigation and leaching will be carried out in small amounts and multiple times for three consecutive days. Each irrigation should be carried out when the soil moisture content reaches 60%-70% of the field capacity. S2, External application of compound soil conditioner: When the plot to be improved is relatively dry, it is deep plowed to a depth of 40cm. The compound soil conditioner prepared in Example 1 is spread on the surface at a rate of 3 tons / acre. Then, the soil is rotary tilled to mix the compound soil conditioner with the 40cm soil. The soil is left to stand for 45 days. During the standing period, the soil is shallowly tilled once every 15 days to a depth of 15cm. The preparation method of the composite modifier is as follows: (1) The raw material of sugar factory filter mud is processed to a moisture content of 30%-35%, and the sugar factory filter mud is physically crushed to a particle size of ≤8mm to obtain sugar factory filter mud for use. (2) The vinegar residue raw material is processed to a moisture content of 25%-30%, and the vinegar residue raw material is crushed to a particle size ≤3mm to obtain vinegar residue for later use; (3) The urea phosphate raw material is crushed into powder to obtain urea phosphate for later use; (4) The concentration is 1×10 8 CFU / mL of *Pseudomonas cereus* culture medium, concentration 1×10⁻⁶ 8 CFU / mL Bacillus mucilaginosus culture medium, concentration 1×10 8 The bacterial culture medium of Bacillus circulatory system with CFU / mL was mixed at a volume ratio of 1:2:1 to obtain a bacterial solution for later use. Aspergillus niger was mixed evenly with 5 parts of decomposed cassava residue and allowed to stand at room temperature for 1-2 days. Then, the bacterial solution was added to the decomposed cassava residue. The mass ratio of Aspergillus niger to bacterial solution was 1:2. (5) Mix 5 parts of fermented cassava residue containing microbial agent, 25 parts of fermented cassava residue, 40 parts of sugar factory filter mud, 30 parts of vinegar residue and 4 parts of urea phosphate evenly to obtain a composite improver.

[0045] S3, Cultivated crops: High ridges are made according to the habits of seawater rice. The height of the high ridges is 30cm, the width is 55cm, and the ridge spacing is 40cm. Degradable black mulch film is covered on the high ridges. Holes are punched in the black mulch film and salt-tolerant crops are sown in holes on the ridges. S4, Planting Management: In the early stage of sowing, irrigate once every 10 days with an irrigation amount of 20m³ / mu to ensure water penetration into the raised beds. During the seed germination period and crop growth period, pay attention to irrigation to maintain the soil moisture content at 55%-75% of field capacity to avoid drought leading to salt return and leaching of soil nutrients. During the crop growth period, apply 8kg / mu of humic acid-based water-soluble fertilizer and 1 ton / mu of well-rotted organic fertilizer once a month.

[0046] Example 8 A three-dimensional, rapid soil improvement method suitable for clayey saline-alkali land along the coast of South China was implemented in Hepu County, Beihai City, Guangxi Zhuang Autonomous Region. The steps of the improvement method are as follows: S1. Drainage ditch 70cm deep and 40cm wide is dug in the plot to be improved. A 15cm high layer of sand and gravel is laid at the bottom of the drainage ditch, and then sugarcane bagasse is filled in. A 5cm layer of sand and gravel is laid on top of the sugarcane bagasse to complete the construction of the drainage system. After the drainage system is constructed, irrigation and leaching will be carried out in small amounts and multiple times for three consecutive days. Each irrigation should be carried out when the soil moisture content reaches 60%-70% of the field capacity. S2, External application of compound soil conditioner: When the plot to be improved is relatively dry, it is deep plowed to a depth of 40cm. The compound soil conditioner prepared in Example 1 is spread on the surface at a rate of 3 tons / acre. Then, the soil is rotary tilled to mix the compound soil conditioner with the 40cm soil. The soil is left to stand for 45 days. During the standing period, the soil is shallowly tilled once every 15 days to a depth of 15cm. The preparation method of the composite modifier is as follows: (1) The raw material of sugar factory filter mud is processed to a moisture content of 30%-35%, and the sugar factory filter mud is physically crushed to a particle size of ≤8mm to obtain sugar factory filter mud for use. (2) The vinegar residue raw material is processed to a moisture content of 25%-30%, and the vinegar residue raw material is crushed to a particle size ≤3mm to obtain vinegar residue for later use; (3) The urea phosphate raw material is crushed into powder to obtain urea phosphate for later use; (4) Crush the mushroom residue raw material to a particle size ≤10mm, and then process it to make its moisture content 15%-20% to obtain mushroom residue for later use; (5) Mix the culture medium of Pseudomonas cereus, Bacillus mucilaginosus, and Bacillus circulatoryus at a volume ratio of 1:2:1 to obtain a bacterial solution for later use. Mix Aspergillus niger with 5 parts of decomposed cassava residue evenly and let it stand at room temperature for 1-2 days. Then take the bacterial solution and add it to the decomposed cassava residue. The mass ratio of Aspergillus niger to bacterial solution is 1:2. (6) Mix 5 parts of fermented cassava residue containing microbial agent, 25 parts of fermented cassava residue, 20 parts of sugar factory filter mud, 10 parts of vinegar residue, 4 parts of urea phosphate, 15 parts of rice husk, 10 parts of mushroom residue, and 10 parts of sawdust evenly to obtain a composite improver.

[0047] S3, Cultivated crop: Make high ridges with a height of 30cm, a width of 55cm, and a ridge spacing of 40cm, cover the high ridges with biodegradable black mulch film, punch holes in the black mulch film and sow seawater rice seedlings in holes on the ridges; S4, Planting Management: Irrigate once every 10 days during the initial transplanting period, with an irrigation volume of 20 m³ / mu, ensuring water penetration into the raised beds. During the seed germination period and crop growth period, pay attention to irrigation to maintain the soil moisture content at 55%-75% of field capacity, avoiding drought that leads to salt return and leaching of soil nutrients. During the crop growth period, apply 8 kg / mu of humic acid-based water-soluble fertilizer and 1 ton / mu of well-rotted organic fertilizer once a month.

[0048] Blank control A three-dimensional, rapid soil improvement method suitable for clayey saline-alkali land along the coast of South China was implemented in Hepu County, Beihai City, Guangxi Zhuang Autonomous Region. The steps of the improvement method are as follows: S1. Drainage ditch 70cm deep and 40cm wide is dug in the plot to be improved. A 15cm high layer of sand and gravel is laid at the bottom of the drainage ditch, and then sugarcane bagasse is filled in. A 5cm layer of sand and gravel is laid on top of the sugarcane bagasse to complete the construction of the drainage system. After the drainage system is constructed, irrigation and leaching will be carried out in small amounts and multiple times for three consecutive days. Each irrigation should be carried out when the soil moisture content reaches 60%-70% of the field capacity. S2, Cultivated crop: Make high ridges with a height of 30cm, a width of 55cm, and a ridge spacing of 40cm, and sow seawater rice seedlings in holes on the ridges; S4, Planting Management: Irrigate once every 10 days during the initial transplanting period, with an irrigation volume of 20 m³ / mu, ensuring water penetration into the raised beds. During the seed germination period and crop growth period, pay attention to irrigation to maintain the soil moisture content at 55%-75% of field capacity, avoiding drought that leads to salt return and leaching of soil nutrients. During the crop growth period, apply 8 kg / mu of humic acid-based water-soluble fertilizer and 1 ton / mu of well-rotted organic fertilizer once a month.

[0049] The physicochemical properties of the topsoil layer (0-20cm) were tested after 3 months of planting and management. The results are shown in Table 7 below.

[0050] Table 7 Physicochemical properties of the topsoil layer of clayey coastal saline soil before and after treatment in Examples 7 and 8 name pH value Total salt content (%) Organic matter content (%) Total porosity (%) Available potassium (mg / g) Available phosphorus (mg / g) Before blank control processing 8.1 0.50 0.83 45.62 0.31 0.19 After blank control processing 7.8 0.38 0.56 49.84 0.23 0.12 Example 7 Before treatment 8.2 0.60 0.80 43.32 0.27 0.16 After treatment in Example 7 7.6 0.25 33.01 64.73 2.83 0.65 Example 8 Before treatment 8.3 0.60 0.76 40.87 0.19 0.11 After treatment in Example 8 7.5 0.23 35.47 68.31 2.67 0.71 As can be seen from Tables 7 and 6, the composite soil conditioner combined with the three-dimensional rapid soil improvement method can more effectively reduce soil pH and total salt content, and has a more significant effect on improving organic matter content and total soil porosity, especially organic matter content. This may be because organic fertilizer was applied during the three-dimensional rapid soil improvement process, and the improved clayey coastal saline soil has a good effect on organic matter preservation, resulting in a significant increase in organic matter content in the clayey coastal saline soil. However, the available potassium and available phosphorus contents in Table 7 are lower than those in Table 6, which may be because seawater rice needs to absorb available potassium and available phosphorus for growth, leading to a decrease in the available potassium and available phosphorus contents in the clayey coastal saline soil.

[0051] Three months after planting and management, the emergence and growth of the seawater rice were monitored, as shown in Table 8 below.

[0052] Table 8. Emergence and growth of seawater rice in each embodiment. name Emergence rate / % fresh weight of underground roots / g Fresh weight of aerial parts / g Blank control 41.67 2.03 15.44 Example 7 86.33 3.29 23.71 Example 8 89.67 3.42 23.89 The emergence rate, underground root fresh weight, and aboveground part fresh weight of seawater rice using the improved method of this invention are significantly better than those of seawater rice in the blank control treatment.

[0053] This invention can be implemented in various ways and is not limited to the embodiments described. Those skilled in the art will understand that the invention can be implemented in other specific ways without changing the technical concept or essential features. Therefore, it should be understood that the embodiments described above are exemplary and not intended to limit the invention.

Claims

1. A composite soil conditioner suitable for clayey saline-alkali soils along the South China coast, characterized in that, The composite improver comprises, by weight, 30-50 parts sugar mill filter mud, 20-40 parts decomposed cassava residue, 10-20 parts vinegar residue, 3-5 parts urea phosphate, and 0.1-0.5 parts microbial agent.

2. The composite soil conditioner for clayey saline-alkali land in coastal South China as described in claim 1, characterized in that, The bacterial agent is composed of Aspergillus niger, Pseudomonas cepacia, Bacillus mucilaginosus, and Bacillus circulatoryus in a mass ratio of 1-2:1:2-1:

1.

3. The composite soil conditioner for clayey saline-alkali land in coastal South China as described in claim 2, characterized in that, The composite improver also includes: 20-30 parts rice husk, 10-20 parts mushroom residue, and 10-20 parts sawdust and wood chips mixture.

4. The composite soil conditioner for clayey saline-alkali land in coastal South China as described in claim 2, characterized in that, The preparation method of the composite modifier is as follows: (1) The raw material of sugar factory filter mud is processed to a moisture content of 30%-35%, and the sugar factory filter mud is physically crushed to a particle size of ≤8mm to obtain sugar factory filter mud for use. (2) The vinegar residue raw material is processed to a moisture content of 25%-30%, and the vinegar residue raw material is crushed to a particle size ≤3mm to obtain vinegar residue for later use; (3) The urea phosphate raw material is crushed into powder to obtain urea phosphate for later use; (4) Mix the culture medium of Pseudomonas cereus, Bacillus mucilaginosus, and Bacillus circulans at a volume ratio of 1:1-2:1 to obtain a bacterial solution for later use. Mix Aspergillus niger with 5-8 parts of decomposed cassava residue evenly and let it stand at room temperature for 1-2 days. Then take the bacterial solution and add it to the decomposed cassava residue. The mass ratio of Aspergillus niger to bacterial solution is 0.5-1:

2. (5) Mix 5-8 parts of fermented cassava residue containing microbial agent, 25-42 parts of fermented cassava residue, 20-40 parts of sugar factory filter mud, 10-20 parts of vinegar residue and 3-5 parts of urea phosphate evenly to obtain a composite improver.

5. The composite soil conditioner for clayey saline-alkali land in coastal South China as described in claim 3, characterized in that, The preparation method of the composite modifier is as follows: (1) The raw material of sugar factory filter mud is processed to a moisture content of 30%-35%, and the sugar factory filter mud is physically crushed to a particle size of ≤8mm to obtain sugar factory filter mud for use. (2) The vinegar residue raw material is processed to a moisture content of 25%-30%, and the vinegar residue raw material is crushed to a particle size ≤3mm to obtain vinegar residue for later use; (3) The urea phosphate raw material is crushed into powder to obtain urea phosphate for later use; (4) Crush the mushroom residue raw material to a particle size ≤10mm, and then process it to make its moisture content 15%-20% to obtain mushroom residue for later use; (5) Mix the culture medium of Pseudomonas cereus, Bacillus mucilaginosus, and Bacillus circulans at a volume ratio of 1:1-2:1 to obtain a bacterial solution for later use. Mix Aspergillus niger with 5-8 parts of decomposed cassava residue evenly and let it stand at room temperature for 1-2 days. Then take the bacterial solution and add it to the decomposed cassava residue. The mass ratio of Aspergillus niger to bacterial solution is 0.5-1:

2. (6) Mix 5-8 parts of fermented cassava residue containing microbial agent, 25-42 parts of fermented cassava residue, 20-40 parts of sugar factory filter mud, 10-20 parts of vinegar residue, 3-5 parts of urea phosphate, 10-30 parts of rice husk, 10-20 parts of mushroom residue, and 10-20 parts of sawdust evenly to obtain a composite improver.

6. The composite soil conditioner for clayey saline-alkali land along the South China coast as described in claim 4 or 5, characterized in that, The bacterial concentration of the *Pseudomonas cepacia* culture broth was 1 × 10⁻⁶. 8 -1×10 9 CFU / mL, the bacterial concentration of the Bacillus mucilaginosus culture medium is 1×10⁻⁶. 8 -1×10 9 CFU / mL, the bacterial concentration of the Bacillus circulans culture medium is 1×10⁻⁶. 8 -1×10 9 CFU / mL.

7. A three-dimensional, rapid-acting method for improving clayey saline-alkali land suitable for coastal areas of South China, characterized in that, The three-dimensional rapid improvement method includes: S1. Construct a drainage system on the plot to be improved. After the drainage system is completed, irrigate and rinse the soil in small amounts for 2-4 consecutive days. The amount of irrigation should be such that the soil moisture content reaches 60%-70% of the field capacity. S2, External application of compound soil conditioner: When the plot to be improved is relatively dry, it is deep-plowed to a depth of 30-40cm. The compound soil conditioner is spread on the surface at a rate of 2-5 tons / acre, and then rotary tilled to fully mix the compound soil conditioner with the 0-40cm soil. The plot is left to stand for 45-60 days. During the standing period, shallow tilling is carried out once every 15 days to a depth of 10-15cm. S3, Cultivated crops: High ridges are made according to the habits of salt-tolerant crops. The height of the high ridges is 25-30cm, the width is 50-65cm, and the ridge spacing is 30-40cm. The high ridges are covered with biodegradable black mulch film. Holes are punched in the black mulch film and salt-tolerant crops are sown in holes on the ridges. S4, Planting Management: Irrigate multiple times during the initial sowing period, with each irrigation amount being 15-20 m³ / mu. During the seed germination period and crop growth period, pay attention to irrigation to maintain the soil moisture content at 55%-75% of field capacity, and avoid drought leading to salt return and leaching of soil nutrients. During the crop growth period, apply 5-8 kg / mu of humic acid-based water-soluble fertilizer once a month, and apply 0.5-1 ton / mu of well-rotted organic fertilizer.

8. The composite soil conditioner for clayey saline-alkali land along the South China coast as described in claim 7, characterized in that, The composite improver comprises, by weight, 30-50 parts sugar mill filter mud, 20-40 parts decomposed cassava residue, 10-20 parts vinegar residue, 3-5 parts urea phosphate, and 0.1-0.5 parts microbial agent, wherein the microbial agent is composed of Aspergillus niger, Pseudomonas cepacia, Bacillus mucilaginosus, and Bacillus circinus in a mass ratio of 1-2:1:2-1:

1.

9. The composite soil conditioner for clayey saline-alkali land in coastal South China as described in claim 7, characterized in that, The construction of a drainage system on the land to be improved specifically involves: opening a drainage ditch on the land to be improved, laying a 10-15cm high layer of sand and gravel at the bottom of the drainage ditch, filling it with sugarcane bagasse or straw, and then laying a 4-7cm layer of sand and gravel on top of the sugarcane bagasse or straw to complete the construction of the drainage system.

10. The composite soil conditioner for clayey saline-alkali land along the South China coast as described in claim 7, characterized in that, The salt-tolerant crops mentioned are one or more of the following: seawater rice, sweet sorghum, and Suaeda salsa.