Phosphogypsum-based milk thistle planting soil and preparation method thereof

Abstract

The invention relates to the technical field of milk thistle planting soil preparation, in particular to a method for preparing planting soil by taking ardealite, bamboo mud (or organic matter sludge mainly comprising other short fibers), chitosan, sludge product nutrient soil and plant ash as main additive components and application of the planting soil. The invention relates to planting soil, in particular to ardealite-based milk thistle planting soil and a preparation method thereof. Comprising the following raw materials: hydrated granulated ardealite, a filler, unhydrated ardealite, bamboo mud, chitosan, saline-alkali soil, sludge product nutrient soil and plant ash. The planting soil is suitable for planting milk thistle in farmlands, hillsides and desolate beaches. The method has better advantages in areas with heavy soil texture, low fertility and high salinity and alkalinity, and high-yield planting of milk thistle is ensured. Meanwhile, the method is particularly suitable for large-scale mechanical planting of milk thistle.

Description

Technical Field

[0001] The present invention relates to the technical field of preparing soil for planting milk thistle, and in particular to a method and application of preparing soil for planting using phosphogypsum, bamboo mud (or other short-fiber-based organic sludge), chitosan, sludge product nutrient soil and plant ash as main additives. More specifically, it relates to phosphogypsum-based soil for planting milk thistle and a preparation method thereof. Background Art

[0002] Milk thistle, a member of the genus Silybum in the Asteraceae family, is an annual or biennial herb.

[0003] Milk thistle can be used to extract silymarin, a strong antioxidant flavonoid that can activate liver protein regeneration, restore liver cell activity damaged by alcohol and viruses, remove free radicals, maintain liver cell membrane permeability, reduce liver damage caused by toxins, and protect people who suffer from long-term alcohol consumption and acute and chronic hepatitis, fatty liver, cirrhosis, and toxic liver damage.

[0004] At the same time, milk thistle has very beautiful spherical flowers, bright leaves and white veins. It is a green ornamental crop. Its flower language is silent love and caution.

[0005] Milk thistle is best cultivated and planted in acidic, fertile, high-permeability loam and sandy loam. Milk thistle planted in neutral and alkaline soils is not easy to absorb nutrients, has many diseases and pests, grows slowly, has a short plant height, poor seed plumpness, and low oil yield; planting milk thistle in soils with low permeability and easy compaction has a low survival rate of microorganisms in the soil, frequent soil diseases, inhibited root growth, slow development, and in severe cases, root rot.

[0006] The prior art provides a method for preparing soil for planting milk thistle, comprising the following steps:

[0007] 1. Site selection and land preparation

[0008] Choose high, dry, well-drained sandy soil; you can also choose fertile, deep soil sloping plateau land; low-lying, waterlogged or poorly drained land is not suitable. After the previous crop is harvested, apply 2500kg of decomposed fertilizer or 10kg of diammonium phosphate, 2kg of potash fertilizer per mu; or 13kg of full-element compound fertilizer, add 0.06kg of carbofuran per mu and mix it with the fertilizer and plant it in between seeds. Deeply plow 25-30cm, plow finely and harrow flat.

[0009] 2. Plant fertilizer

[0010] Apply 2-3 kg of diammonium phosphate per mu of barren land to ensure uniform emergence of seedlings.

[0011] 3. Topdressing

[0012] For fertile land, to prevent milk thistle from growing too tall and affecting yield, apply an appropriate amount of dwarfing agent.

[0013] The existing methods have high requirements for the planting environment and planting soil; the amount of fertilizer applied in the land preparation process is large and the requirements for topdressing are high; after a round of milk thistle planting, the soil fertility decreases rapidly and the land is easily compacted, requiring fallow or other crop rotation before milk thistle can be planted again.

[0014] Therefore, the present application proposes a method for preparing phosphogypsum-based milk thistle planting soil. Summary of the invention

[0015] The object of the present invention is to provide a phosphogypsum-based milk thistle planting soil and a preparation method thereof. The planting soil of the present invention is not only suitable for planting milk thistle in farmland, hillsides, and wastelands, but also can play a greater role in areas with heavy soil, low fertility, and high salinity, ensuring high-yield planting of milk thistle. At the same time, the present invention is particularly suitable for large-scale mechanized planting of milk thistle.

[0016] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0017] A phosphogypsum-based milk thistle planting soil comprises the following raw materials: hydrated granulated phosphogypsum, filler, unhydrated phosphogypsum, bamboo mud, chitosan, saline-alkali soil, sludge product nutrient soil and plant ash.

[0018] Furthermore, the invention comprises the following raw materials in parts by weight: 10-20 parts of hydrated granulated phosphogypsum, 5-10 parts of fillers, 15-20 parts of unhydrated phosphogypsum, 10-20 parts of bamboo mud, 3-8 parts of chitosan, 30-60 parts of saline-alkali soil, 1 part of nutrient soil of sludge product, and 0.5 part of wood ash.

[0019] Furthermore, the filler may be one of clay, kaolin and bentonite.

[0020] A method for preparing phosphogypsum-based milk thistle planting soil comprises the following steps:

[0021] 1) Steaming and dehydrating part of the phosphogypsum to form α-hemihydrate gypsum;

[0022] 2) α-type hemihydrate gypsum and fillers are hydrated and granulated into phosphogypsum beads after adding water;

[0023] 3) The bamboo mud is decomposed;

[0024] 4) The hydrated and granulated phosphogypsum beads, initial phosphogypsum, decomposed bamboo mud, chitosan, sludge product nutrient soil, plant ash and saline-alkali soil are fully mixed to obtain planting soil.

[0025] Further, the diameter of the phosphogypsum beads is 3 to 5 mm.

[0026] The prepared phosphogypsum planting soil is used for the cultivation of milk thistle.

[0027] The present invention has at least one of the following beneficial effects:

[0028] The phosphogypsum used in the present invention is the phosphogypsum specified in GB / T 23456-2018 "Phosphogypsum", which is acidic and its main components are calcium sulfate (CaSO4), attached water (H2O), water-soluble phosphorus pentoxide (P2O5), etc.

[0029] When phosphogypsum is mixed into the soil (especially salinized and barren topsoil), calcium ions can replace sodium ions in the soil and improve the soil ion structure; calcium ions react with bicarbonate in the soil to form calcium carbonate, reducing soil alkalinity; phosphogypsum can promote the dissolution of citrate-soluble phosphorus in the soil and activate trace elements in the soil to facilitate absorption by milk thistle.

[0030] After applying phosphogypsum to salinized fluvo-aquic soil, the soil bulk density can be reduced, the permeability coefficient can be increased, the capillary voids can be reduced, and the ventilation voids can be increased. The looseness and air permeability and water permeability of the soil can be improved.

[0031] The bamboo mud used in the present invention is waste after bamboo pulp papermaking, is alkaline, and its main components are short fibers, other wood fibers and organic matter, and does not contain heavy metals. The bamboo mud can be oxidized and decomposed into humus that is easily absorbed by plants after microbial fermentation. The bamboo mud contains a large amount of nitrogen, phosphorus and potassium elements after being decomposed, which can be directly absorbed and utilized by milk thistle.

[0032] After targeted treatment, phosphogypsum and bamboo mud play a positive role in the breeding and cultivation of milk thistle.

[0033] The chitosan used in the present invention is also called deacetylated chitosan, which has good antibacterial activity. The polycations of chitosan are easy to interact with the negatively charged groups on the surface of fungal cells, thereby changing the fluidity and permeability of the cell membrane of pathogens, interfering with the replication and transcription of pathogen DNA, and blocking the metabolism of pathogens. The addition of chitosan can inhibit the reproduction and growth of harmful insect eggs and pathogens in bamboo mud humus and soil, and become an isolation barrier for planting soil.

[0034] Chitosan is also a natural plant nutrition and growth promoter. It can not only kill insects and resist diseases for plants, but also decompose animal and plant residues and trace metal elements in the soil, thereby converting them into nutrients needed by plants, enhancing plant immunity and promoting plant health.

[0035] Chitosan has numerous amino and hydroxyl groups on its molecular chain, and has excellent chemical adsorption or chelation ion capabilities. It has good chelation capabilities for the excess water-soluble fluoride ions in phosphogypsum, making them lose their ionic capacity and thus not being excessively absorbed by plants.

[0036] The phosphogypsum produced by the wet phosphoric acid process is calcium sulfate dihydrate (CaSO4.·2H2O).

[0037] The phosphogypsum in the present invention is partially original calcium sulfate dihydrate, and partially calcium sulfate dihydrate obtained by hydrating the original calcium sulfate dihydrate to calcium sulfate hemihydrate.

[0038] The present invention adopts a steaming and dehydration method under supersaturated steam conditions of 0.13MPa and 124°C to firstly prepare calcium sulfate dihydrate into α-type calcium sulfate hemihydrate (CaSO4.·0.5H2O).

[0039] Then, during the hydration process of α-type calcium sulfate hemihydrate, the present invention adds a filler. The filler can be one of clay, kaolin, and bentonite. The calcium sulfate hemihydrate and the filler are uniformly mixed and granulated by a granulator during the hydration process. After the hydration is completed, spherical calcium sulfate dihydrate beads with a diameter of 3 to 5 mm are molded. The calcium sulfate dihydrate beads have a certain strength, are not easy to break, reduce the bulk density of the planting soil, and increase the permeability coefficient of the planting soil.

[0040] The sludge product nutrient soil in the present invention is obtained by anaerobic fermentation of activated sludge. During the anaerobic fermentation process, microorganisms biologically decompose organic matter in the activated sludge, and the mineralized organic matter and nutrients have high availability.

[0041] Since the planting soil contains phosphogypsum, bamboo mud, chitosan, sludge product nutrient soil and plant ash, the pH value of the planting soil is acidic and rich in the effective ingredients of organic fertilizer, phosphate fertilizer, nitrogen fertilizer and potash fertilizer required for the growth of milk thistle. The escape of the effective ingredients in phosphogypsum and bamboo mud is a slow release process. Under normal circumstances, the planting soil of the present invention does not need topdressing within three years. In addition to providing nutrients for plant growth, the sludge product nutrient soil is also a superior culture matrix for beneficial bacteria such as photosynthetic bacteria, yeast, and Bacillus colloidus. The participation of beneficial bacteria can continuously fertilize the planting soil, improve the structure of the planting soil, and prevent the planting soil from becoming compacted.

[0042] The planting soil of the present invention is not only suitable for planting milk thistle in farmland, hillside and wasteland, but also can play a greater role in areas with heavy soil, low fertility and high salinity, ensuring high-yield planting of milk thistle. At the same time, the present invention is particularly suitable for large-scale mechanized planting of milk thistle. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 The present invention is a flow chart for preparing the planting soil. DETAILED DESCRIPTION

[0044] The technical solutions in the present invention will be described clearly and completely below in combination with the specific implementation of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0045] The methods described in the embodiments of the present invention are conventional methods unless otherwise specified. The materials, reagents, etc. used can be obtained from commercial sources unless otherwise specified.

[0046] Example 1

[0047] A phosphogypsum-based milk thistle planting soil is composed of the following raw materials in parts by weight: 25 parts of phosphogypsum, 5 parts of fillers, 15 parts of bamboo mud, 5 parts of chitosan, 1 part of sludge product nutrient soil, 0.5 parts of plant ash, and 50 parts of saline-alkali soil.

[0048] A method for preparing phosphogypsum-based milk thistle planting soil specifically comprises the following steps:

[0049] 1) 15 parts of phosphogypsum are steamed and dehydrated to α-type hemihydrate gypsum by supersaturated steam at 0.13MPa and 124℃;

[0050] 2) α-type hemihydrate gypsum and 5 parts of filler are hydrated by adding water, and granulated into phosphogypsum beads with a diameter of 3 to 5 mm by a granulator;

[0051] 3) 15 portions of bamboo mud after decomposition were sterilized by microwave;

[0052] 4) The hydrated and granulated phosphogypsum beads, 10 parts of phosphogypsum, 15 parts of decomposed bamboo mud, 5 parts of chitosan, 1 part of sludge product nutrient soil, 0.5 parts of wood ash, and 50 parts of saline-alkali soil were fully mixed, and the pH value of the planting soil was measured to be 6.2.

[0053] A method for growing milk thistle:

[0054] 1) Spread the planting soil to the planting site with a thickness of 30 cm. Sprinkle water evenly to a moisture content of 20-25%;

[0055] 2) Plant seeds 3-5 cm apart and bury them 3-4 cm deep;

[0056] 3) After the seedlings emerge, ditches are cleared between the rows of milk thistle, with a depth of 20 cm and a width of 30 cm. Drip irrigation belts are laid in the ditches;

[0057] 4) Field management until harvest.

[0058] Example 2

[0059] A phosphogypsum-based milk thistle planting soil is composed of the following raw materials in parts by weight: 28 parts of phosphogypsum, 5 parts of fillers, 20 parts of bamboo mud, 5 parts of chitosan, 1 part of sludge product nutrient soil, 0.5 parts of plant ash, and 42 parts of saline-alkali soil.

[0060] A method for preparing phosphogypsum-based milk thistle planting soil specifically comprises the following steps:

[0061] 1) 10 parts of phosphogypsum are steamed and dehydrated to α-type hemihydrate gypsum by supersaturated steam at 0.13MPa and 124℃;

[0062] 2) α-type hemihydrate gypsum and 5 parts of filler are hydrated by adding water, and granulated into phosphogypsum beads with a diameter of 3 to 5 mm by a granulator;

[0063] 3) 20 portions of bamboo mud after decomposition were sterilized by microwave;

[0064] 4) The hydrated and granulated phosphogypsum beads, 18 parts of phosphogypsum, 20 parts of decomposed bamboo mud, 5 parts of chitosan, 1 part of sludge product nutrient soil, 0.5 parts of wood ash, and 42 parts of saline-alkali soil were fully mixed, and the pH value of the planting soil was measured to be 6.0.

[0065] A method for growing milk thistle:

[0066] 1) Spread the planting soil to the planting site with a thickness of 30 cm. Sprinkle water evenly to a moisture content of 20-25%;

[0067] 2) Plant seeds 3-5 cm apart and bury them 3-4 cm deep;

[0068] 3) After the seedlings emerge, ditches are cleared between the rows of milk thistle, with a depth of 20 cm and a width of 30 cm. Drip irrigation tapes are laid in the ditches;

[0069] 4) Field management until harvest.

[0070] Example 3

[0071] A phosphogypsum-based milk thistle planting soil is composed of the following raw materials in parts by weight: 30 parts of phosphogypsum, 5 parts of fillers, 20 parts of bamboo mud, 5 parts of chitosan, 1 part of sludge product nutrient soil, 0.5 parts of plant ash, and 40 parts of saline-alkali soil.

[0072] A method for preparing phosphogypsum-based milk thistle planting soil specifically comprises the following steps:

[0073] 1) 15 parts of phosphogypsum are steamed and dehydrated to α-type hemihydrate gypsum by supersaturated steam at 0.13MPa and 124℃;

[0074] 2) α-type hemihydrate gypsum and 5 parts of filler are hydrated by adding water, and granulated into phosphogypsum beads with a diameter of 3 to 5 mm by a granulator;

[0075] 3) 20 portions of bamboo mud after decomposition were sterilized by microwave;

[0076] 4) The hydrated and granulated phosphogypsum beads, 15 parts of phosphogypsum, 20 parts of decomposed bamboo mud, 5 parts of chitosan, 1 part of sludge product nutrient soil, 0.5 parts of wood ash, and 40 parts of saline-alkali soil were fully mixed, and the pH value of the planting soil was measured to be 5.9.

[0077] A method for growing milk thistle:

[0078] 1) Spread the planting soil to the planting site with a thickness of 30 cm. Sprinkle water evenly to a moisture content of 20-25%;

[0079] 2) Plant seeds 3-5 cm apart and bury them 3-4 cm deep;

[0080] 3) After the seedlings emerge, ditches are cleared between the rows of milk thistle, with a depth of 20 cm and a width of 30 cm. Drip irrigation belts are laid in the ditches;

[0081] 4) Field management until harvest.

[0082] Example 4

[0083] A phosphogypsum-based milk thistle planting soil is composed of the following raw materials in parts by weight: 33 parts of phosphogypsum, 8 parts of fillers, 22 parts of bamboo mud, 6 parts of chitosan, 1 part of sludge product nutrient soil, 0.5 parts of plant ash, and 31 parts of saline-alkali soil.

[0084] A method for preparing phosphogypsum-based milk thistle planting soil specifically comprises the following steps:

[0085] 1) 20 parts of phosphogypsum are steamed and dehydrated to α-type hemihydrate gypsum by supersaturated steam at 0.13MPa and 124℃;

[0086] 2) α-type hemihydrate gypsum and 8 parts of filler are hydrated by adding water, and granulated into phosphogypsum beads with a diameter of 3 to 5 mm by a granulator;

[0087] 3) 20 portions of bamboo mud after decomposition were sterilized by microwave;

[0088] 4) The hydrated and granulated phosphogypsum beads, 13 parts of phosphogypsum, 22 parts of decomposed bamboo mud, 6 parts of chitosan, 1 part of sludge product nutrient soil, 0.5 parts of wood ash, and 31 parts of saline-alkali soil were fully mixed, and the pH value of the planting soil was measured to be 6.5.

[0089] A method for growing milk thistle:

[0090] 1) Spread the planting soil to the planting site with a thickness of 30 cm. Sprinkle water evenly to a moisture content of 20-25%;

[0091] 2) Plant seeds 3-5 cm apart and bury them 3-4 cm deep;

[0092] 3) After the seedlings emerge, ditches are cleared between the rows of milk thistle, with a depth of 20 cm and a width of 30 cm. Drip irrigation belts are laid in the ditches;

[0093] 4) Field management until harvest.

[0094] Example 5

[0095] A phosphogypsum-based milk thistle planting soil is composed of the following raw materials in parts by weight: 35 parts of phosphogypsum, 8 parts of fillers, 20 parts of bamboo mud, 6 parts of chitosan, 1 part of sludge product nutrient soil, 0.5 parts of plant ash, and 31 parts of saline-alkali soil.

[0096] A method for preparing phosphogypsum-based milk thistle planting soil specifically comprises the following steps:

[0097] 1) 20 parts of phosphogypsum are steamed and dehydrated to α-type hemihydrate gypsum by supersaturated steam at 0.13MPa and 124℃;

[0098] 2) α-type hemihydrate gypsum and 8 parts of filler are hydrated by adding water, and granulated into phosphogypsum beads with a diameter of 3 to 5 mm by a granulator;

[0099] 3) 20 portions of bamboo mud after decomposition were sterilized by microwave;

[0100] 4) The hydrated and granulated phosphogypsum beads, 15 parts of phosphogypsum, 20 parts of decomposed bamboo mud, 6 parts of chitosan, 1 part of sludge product nutrient soil, 0.5 parts of wood ash, and 31 parts of saline-alkali soil were fully mixed, and the pH value of the planting soil was measured to be 6.2.

[0101] A method for growing milk thistle:

[0102] 1) Spread the planting soil to the planting site with a thickness of 30 cm. Sprinkle water evenly to a moisture content of 20-25%;

[0103] 2) Plant seeds 3-5 cm apart and bury them 3-4 cm deep;

[0104] 3) After the seedlings emerge, ditches are cleared between the rows of milk thistle, with a depth of 20 cm and a width of 30 cm. Drip irrigation belts are laid in the ditches;

[0105] 4) Field management until harvest.

[0106] Comparative Example 1

[0107] A phosphogypsum-based milk thistle planting soil is composed of the following raw materials in parts by weight: 30 parts of decomposed sheep manure, 3 parts of diammonium phosphate, 3 parts of urea and 100 parts of saline-alkali soil.

[0108] A method for preparing phosphogypsum-based milk thistle planting soil specifically comprises the following steps:

[0109] 1) 100 parts of saline-alkali soil were plowed to a depth of 30 cm, and the soil was crushed and raked flat;

[0110] 2) Sprinkle 30 parts of decomposed sheep manure, 3 parts of diammonium phosphate and 3 parts of urea evenly into the soil, and measure the pH value of the planting soil to 8.3.

[0111] A method for growing milk thistle:

[0112] 1) Sprinkle water evenly, the moisture content of the planting soil is 20-25%;

[0113] 2) Plant seeds 3-5 cm apart and bury them 3-4 cm deep;

[0114] 3) After the seedlings emerge, ditches are cleared between the rows of milk thistle, with a depth of 20 cm and a width of 30 cm. Drip irrigation tapes are laid in the ditches;

[0115] 4) Field management until harvest.

[0116] Comparative Example 2

[0117] A phosphogypsum-based milk thistle planting soil is composed of the following raw materials in parts by weight: 28 parts of phosphogypsum, 20 parts of bamboo mud, 5 parts of chitosan, 1 part of sludge product nutrient soil, 0.5 parts of plant ash, and 47 parts of saline-alkali soil.

[0118] A method for preparing phosphogypsum-based milk thistle planting soil specifically comprises the following steps:

[0119] 1) 28 parts of phosphogypsum are dispersed evenly;

[0120] 2) 20 portions of bamboo mud after decomposition were sterilized by microwave;

[0121] 3) 28 parts of phosphogypsum, 15 parts of decomposed bamboo mud, 5 parts of chitosan, 1 part of sludge product nutrient soil, 0.5 parts of wood ash, and 47 parts of saline-alkali soil were fully mixed, and the pH value of the planting soil was measured to be 6.1.

[0122] A method for growing milk thistle:

[0123] 1) Spread the planting soil to the planting site with a thickness of 30 cm. Sprinkle water evenly to a moisture content of 20-25%;

[0124] 2) Plant seeds 3-5 cm apart and bury them 3-4 cm deep;

[0125] 3) After the seedlings emerge, ditches are cleared between the rows of milk thistle, with a depth of 20 cm and a width of 30 cm. Drip irrigation tapes are laid in the ditches;

[0126] 4) Field management until harvest.

[0127] Comparative Example 3

[0128] A phosphogypsum-based milk thistle planting soil is composed of the following raw materials in parts by weight: 30 parts of phosphogypsum, 5 parts of fillers, 20 parts of bamboo mud, 1 part of sludge product nutrient soil, 0.5 parts of plant ash, and 45 parts of saline-alkali soil.

[0129] A method for preparing phosphogypsum-based milk thistle planting soil specifically comprises the following steps:

[0130] 1) 15 parts of phosphogypsum are steamed and dehydrated to α-type hemihydrate gypsum by supersaturated steam at 0.13MPa and 124℃;

[0131] 2) α-type hemihydrate gypsum and 5 parts of filler are hydrated by adding water, and granulated into phosphogypsum beads with a diameter of 3 to 5 mm by a granulator;

[0132] 3) 20 portions of bamboo mud after decomposition were sterilized by microwave;

[0133] 4) The hydrated and granulated phosphogypsum beads, 20 parts of phosphogypsum, 20 parts of decomposed bamboo mud, 1 part of sludge product nutrient soil, 0.5 parts of wood ash, and 40 parts of saline-alkali soil were fully mixed, and the pH value of the planting soil was measured to be 5.9.

[0134] A method for growing milk thistle:

[0135] 1) Spread the planting soil to the planting site with a thickness of 30 cm. Sprinkle water evenly to a moisture content of 20-25%;

[0136] 2) Plant seeds 3-5 cm apart and bury them 3-4 cm deep;

[0137] 3) After the seedlings emerge, ditches are cleared between the rows of milk thistle, with a depth of 20 cm and a width of 30 cm. Drip irrigation tapes are laid in the ditches;

[0138] 4) Field management until harvest.

[0139] Comparative Example 4

[0140] A phosphogypsum-based milk thistle planting soil is composed of the following raw materials in parts by weight: 33 parts of phosphogypsum, 8 parts of fillers, 22 parts of bamboo mud, 3 parts of chitosan, 1 part of sludge product nutrient soil, 0.5 parts of plant ash, and 34 parts of saline-alkali soil.

[0141] A method for preparing phosphogypsum-based milk thistle planting soil specifically comprises the following steps:

[0142] 1) 20 parts of phosphogypsum are steamed and dehydrated to α-type hemihydrate gypsum by supersaturated steam at 0.13MPa and 124℃;

[0143] 2) α-type hemihydrate gypsum and 8 parts of filler are hydrated by adding water, and granulated into phosphogypsum beads with a diameter of 3 to 5 mm by a granulator;

[0144] 3) 20 portions of bamboo mud after decomposition were sterilized by microwave;

[0145] 4) The hydrated and granulated phosphogypsum beads, 13 parts of phosphogypsum, 22 parts of decomposed bamboo mud, 3 parts of chitosan, 1 part of sludge product nutrient soil, 0.5 parts of wood ash, and 34 parts of saline-alkali soil were fully mixed, and the pH value of the planting soil was measured to be 6.4.

[0146] A method for growing milk thistle:

[0147] 1) Spread the planting soil to the planting site with a thickness of 30 cm. Sprinkle water evenly to a moisture content of 20-25%;

[0148] 2) Plant seeds 3-5 cm apart and bury them 3-4 cm deep;

[0149] 3) After the seedlings emerge, ditches are cleared between the rows of milk thistle, with a depth of 20 cm and a width of 30 cm. Drip irrigation tapes are laid in the ditches;

[0150] 4) Field management until harvest.

[0151] Comparative Example 5

[0152] A phosphogypsum-based milk thistle planting soil is composed of the following raw materials in parts by weight: 35 parts of phosphogypsum, 4 parts of filler, 20 parts of bamboo mud, 6 parts of chitosan, 1 part of sludge product nutrient soil, 0.5 parts of plant ash, and 35 parts of saline-alkali soil.

[0153] A method for preparing planting soil specifically comprises the following steps:

[0154] 1) 20 parts of phosphogypsum are steamed and dehydrated to α-type hemihydrate gypsum by supersaturated steam at 0.13MPa and 124℃;

[0155] 2) α-type hemihydrate gypsum and 4 parts of filler are hydrated by adding water, and granulated into 3 to 5 mm diameter phosphogypsum beads by a granulator;

[0156] 3) 20 portions of bamboo mud after decomposition were sterilized by microwave;

[0157] 4) The hydrated and granulated phosphogypsum beads, 15 parts of phosphogypsum, 20 parts of decomposed bamboo mud, 6 parts of chitosan, 1 part of sludge product nutrient soil, 0.5 parts of wood ash, and 35 parts of saline-alkali soil were fully mixed, and the pH value of the planting soil was measured to be 6.3.

[0158] A method for growing milk thistle:

[0159] 1) Spread the planting soil to the planting site with a thickness of 30 cm. Sprinkle water evenly to a moisture content of 20-25%;

[0160] 2) Plant seeds 3-5 cm apart and bury them 3-4 cm deep;

[0161] 3) After the seedlings emerge, ditches are cleared between the rows of milk thistle, with a depth of 20 cm and a width of 30 cm. Drip irrigation belts are laid in the ditches;

[0162] 4) Field management until harvest.

[0163] Experimental analysis:

[0164] The planting soil of Examples 1-5 and Comparative Examples 1-5 was tested (the results are shown in Table 1 below), and the conditions of the milk thistle plants planted in Examples 1-5 and Comparative Examples 1-5 were counted (the results are shown in Table 2 below).

[0165] Table 1 Soil test values ​​of planting soil in different embodiments and comparative examples

[0166]

[0167]

[0168] Table 2 Planting conditions of milk thistle plants in different embodiments and comparative examples

[0169]

[0170] From Table 1 and Table 2 above, we can see that

[0171] Example 1 and Comparative Example 1:

[0172] Example 1 is configured with phosphogypsum, chitosan, decomposed bamboo mud, sludge product nutrient soil, wood ash, soil, pH 6.2, which is suitable for milk thistle breeding and growth; Example 1 adds granulated phosphogypsum, which effectively reduces the soil bulk density and greatly improves the cation exchange capacity to a medium level; Example 1's effective phosphorus, slow-release potassium and organic matter content reach the third level; after the harvest period, the indicators of milk thistle such as plant height and grass seed yield are close to the average level.

[0173] Comparative Example 1 did not use phosphogypsum, and the soil was saline and poor, with a pH of 8.3. Milk thistle prefers acidic soil and grows slowly in alkaline soil; the soil in Comparative Example 1 has a high specific gravity and poor cation exchange capacity; after applying inorganic and organic fertilizers, the content of available phosphorus, slow-release potassium and organic matter is still low. The plant height and seed yield of milk thistle are low after the harvest period.

[0174] Example 2 and Comparative Example 2:

[0175] The proportions of phosphogypsum, chitosan and decomposed bamboo mud in Example 2 and Comparative Example 2 are similar, and the difference is that Comparative Example 2 does not granulate part of the phosphogypsum. The soil permeability of Comparative Example 2 is lower than that of Example 2, and the cation exchange capacity of Comparative Example 2 is lower than that of Example 2; the plant height and grass seed yield of milk thistle after harvest are better than those of Comparative Example 2.

[0176] Example 3 and Comparative Example 3:

[0177] The proportions of phosphogypsum and decomposed bamboo mud in Example 3 and Comparative Example 3 are similar, the difference is that chitosan is not applied in Comparative Example 3. The slow-release potassium of Comparative Example 3 is lower than that of Example 3, and the cation exchange capacity of Comparative Example 3 is lower than that of Example 3; during field management, it was found that the pests and diseases in Example 3 were significantly less than those in Example 3; in terms of plant height and grass seed yield of milk thistle after harvest, Example 3 was superior to Comparative Example 3.

[0178] Example 4 and Comparative Example 4:

[0179] The proportions of phosphogypsum and decomposed bamboo mud in Example 4 and Comparative Example 4 are similar, the difference is that the amount of chitosan applied in Comparative Example 4 is less than that in Comparative Example 4.

[0180] The available phosphorus, slow-release potassium and organic matter of Comparative Example 4 are lower than those of Example 4, and the cation exchange capacity of Comparative Example 4 is slightly lower than that of Example 4. In terms of indicators such as plant height and grass seed yield of milk thistle after harvest, Example 4 is better than Comparative Example 4.

[0181] Example 5 and Comparative Example 5:

[0182] The proportions of phosphogypsum, decomposed bamboo mud and chitosan in Example 5 and Comparative Example 5 are similar, the difference is that the amount of phosphogypsum granulation in Comparative Example 5 is less than that in Comparative Example 5. The cation exchange capacity of Comparative Example 5 is slightly lower than that of Example 5; the plant height and grass seed yield of milk thistle after harvest are better than those of Comparative Example 5.

[0183] From the data comparison of Examples 1-5, the examples with high addition ratios of phosphogypsum, decomposed bamboo mud and chitosan have better indicators such as plant height and grass seed yield after harvest of milk thistle; the examples with higher phosphogypsum granulation have stronger soil cation exchange capacity.

[0184] The phosphogypsum-based milk thistle planting soil prepared by the present invention plays a good role in the cultivation and high yield of milk thistle, while reducing the labor intensity of field management, and is suitable for small-scale planting by farmers, and is more suitable for large-scale mechanized farming production.

[0185] Although the present invention is described herein with reference to a number of illustrative embodiments, it will be appreciated that those skilled in the art may devise many other modifications and implementations that fall within the scope and spirit of the principles disclosed herein. More specifically, within the scope of the present disclosure, drawings, and claims, a variety of variations and improvements may be made to the components and / or layout of the subject combination layout. In addition to variations and improvements made to the components and / or layout, other uses will also be apparent to those skilled in the art.

Claims

1. A phosphogypsum-based milk thistle planting soil, characterized in that: The raw materials include: hydrated granulated phosphogypsum, filler, unhydrated phosphogypsum, bamboo mud, chitosan, saline-alkali soil, nutrient soil from sludge products, and wood ash.

2. The phosphogypsum-based milk thistle planting soil according to claim 1, characterized in that: The method comprises the following raw materials in parts by weight: 10-20 parts of hydrated granulated phosphogypsum, 5-10 parts of fillers, 15-20 parts of unhydrated phosphogypsum, 10-20 parts of bamboo mud, 3-8 parts of chitosan, 30-60 parts of saline-alkali soil, 1 part of sludge product nutrient soil, and 0.5 part of plant ash.

3. The phosphogypsum-based milk thistle planting soil according to claim 1 or 2, characterized in that: The filler can be one of clay, kaolin and bentonite.

4. The method for preparing a phosphogypsum-based milk thistle planting soil according to any one of claims 1 to 3, characterized in that: The steps include: 1) Steaming and dehydrating part of the phosphogypsum to form α-hemihydrate gypsum; 2) α-type hemihydrate gypsum and fillers are hydrated and granulated into phosphogypsum beads after adding water; 3) The bamboo mud is decomposed; 4) The hydrated and granulated phosphogypsum beads, initial phosphogypsum, decomposed bamboo mud, chitosan, sludge product nutrient soil, plant ash and saline-alkali soil are fully mixed to obtain planting soil.

5. The method for preparing a phosphogypsum-based milk thistle planting soil according to claim 4, characterized in that: The diameter of the phosphogypsum beads is 3 to 5 mm.

6. A phosphogypsum planting soil made according to any one of claims 4 to 5 for planting milk thistle.

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