Alginic acid type multifunctional long-acting soil conditioner and preparation method and application thereof

Abstract

The application relates to the technical field of land improvement, in particular to a seaweed acid type multifunctional long-acting soil conditioner as well as a preparation method and application thereof. The soil conditioner comprises a core particle layer and a slow-release layer coated on the surface of the core particle layer. The core particle layer comprises organic materials, nano silicon, calcium magnesium polyphosphate, magnesium hydride, ammonium borate, rhamnose and a binder. The slow-release layer comprises clay minerals and seaweed acid salt. The mass ratio of the clay minerals, the seaweed acid salt, the organic materials, the calcium magnesium polyphosphate, the nano silicon, the magnesium hydride, the ammonium borate, the rhamnose and the binder is controlled within a certain range. The soil conditioner provided by the application has good slow-release performance, can slowly and durably release effective components, has multiple functions such as improving soil quality, providing nutrition, promoting crop growth and improving resistance, and the components can synergistically act to effectively solve the problems of soil acidification, heavy metal pollution, micro-plastic pollution, pesticide pollution and antibiotic pollution in agricultural production.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of land improvement, in particular to a seaweed acid type multifunctional long-acting soil conditioner and a preparation method and application thereof. BACKGROUND

[0002] The quality of arable land is related to national food security and people's livelihood. In recent years, with the acceleration of industrialization, the intensification of agricultural production and the advancement of urbanization, a large amount of agricultural chemical inputs are used, and various harmful substances are continuously input, which has caused a series of problems such as soil quality degradation and ecological system dysfunction, seriously restricting the comprehensive production capacity of arable land, and further affecting food safety and human health. Soil degradation and pollution have become an important global environmental issue, and soil ecological restoration and sustainable utilization are of great significance to the green and sustainable development of agriculture in China. Soil conditioner can effectively improve the physical and chemical properties of soil, supplement organic matter and mineral nutrients, and improve soil biological function. However, the soil obstacle factors are complex and interrelated, and the current soil conditioner on the market has the problems of single function, short duration and poor ecological restoration effect. Therefore, it is urgent to develop a new type of multifunctional long-acting soil conditioner, which is of great significance to the restoration of degraded and polluted soil, the improvement of arable land quality, and the maintenance of food security and sustainable development of agriculture. SUMMARY

[0003] One of the purposes of the present application is to provide a seaweed acid type multifunctional long-acting soil conditioner, which has good slow-release performance and can release effective components slowly and persistently, and has multiple functions such as improving soil quality, providing nutrition, promoting crop growth and improving resistance.

[0004] In order to achieve the above-mentioned purposes, the following technical solutions are adopted in the present application:

[0005] A seaweed acid type multifunctional long-acting soil conditioner, comprising a core particle layer and a slow-release layer coated on the surface of the core particle layer, wherein the core particle layer comprises organic material, nano-silicon, calcium magnesium polyphosphate, magnesium hydride, ammonium borate, rhamnose and adhesive, and the slow-release layer comprises clay mineral and seaweed acid salt; wherein the mass ratio of clay mineral, seaweed acid salt, organic material, calcium magnesium polyphosphate, nano-silicon, magnesium hydride, ammonium borate, rhamnose and adhesive is (50.0-50.9):(1.0-1.9):(100.0-100.9):(20.0-29.9):(2.0-2.9):(3.0-3.9):(2.0-2.9):(1.0-1.9):(6.0-6.9).

[0006] Preferably, the particle size of the soil conditioner is 4-5mm, and the core particle size of the core particle layer is 1-2mm.

[0007] Preferably, the clay mineral comprises at least one of kaolinite, montmorillonite, attapulgite, sepiolite, rectorite, diatomite, illite, quartz, sericite, dickite, bentonite, chlorite, zeolite; the alginate comprises at least one of sodium alginate, potassium alginate, calcium alginate.

[0008] Preferably, the pH value of the clay mineral is 7.0-8.5, the main clay mineral in the clay mineral is ≥70wt%, Hg≤5mg / kg, As≤50mg / kg, Pb≤50mg / kg, Cd≤10mg / kg, Cr≤50mg / kg; the uronic acid content in the alginate is ≥85%.

[0009] Preferably, the pH value of the clay mineral is 8.2-8.5, the main clay mineral in the clay mineral is ≥72wt%, Ca≥0.2wt%, Mg≥0.05mg / kg, N≥0.1wt%, P2O5≥0.15wt%, Hg≤0.15mg / kg, As≤10mg / kg, Pb≤25mg / kg, Cd≤0.1mg / kg, Cr≤20mg / kg; the uronic acid content in the alginate is ≥90%, the uronic acid comprises a-L-mannuronic acid and b-D-guluronate in a mass ratio of (6-8):(2-4).

[0010] Preferably, the organic material comprises at least one of organic fertilizer, manure, compost, fermented fertilizer, green manure, vinasse, vinegar dregs, cassava residue, oil residue, sugar residue, furfural residue, mushroom residue, kelp residue, protein mud, amino acid, humic acid, plant straw, wood ash, cake fertilizer, soybean meal, cottonseed meal, peanut shell powder, biogas fertilizer, kitchen garbage, urban sludge; the binder comprises at least one of lignin sulfonate, lignin phenolic resin, carboxyethyl cellulose, carboxymethyl cellulose, biomass tar, carboxymethyl chitosan salt, polyglutamate salt, humic acid salt, acrylamide, starch, dextrin, polyvinyl alcohol, locust bean gum, gum guaiac, xanthan gum, gum arabic, guar gum, broad bean gum, west yellow ox gall, coca gum, Irish moss gum, agar, egg white protein, tyrosine, fish pulp, bacterial protein, wheat germ protein, gluten, gelatin, polyvinyl alcohol, sodium polyacrylate, acryloyl glycol, carboxymethyl starch, phosphate cross-linked starch, urea-formaldehyde condensate, vegetable oil, mineral oil.

[0011] The second object of the present application is to provide a preparation method of the alginate type multifunctional long-acting soil conditioner.

[0012] S1, dry-mix the organic material, nano-silicon, calcium magnesium polyphosphate, magnesium hydride, ammonium borate and rhamnose in a mass ratio of 1:0.1-0.5:0.1-0.5:0.1-0.5:0.1-0.5:0.1-0.5, then add the binder and mix, and then transfer to the first granulation to obtain core particles;

[0013] S2, mixing the clay mineral and the alginate with the core particles obtained in step S1 according to a mass ratio, and then transferring to a second granulation to obtain the soil conditioner comprising a core particle layer and a slow-release layer.

[0014] Preferably, the first granulation is steam granulation, the granulation time is 3-10 min, and the obtained particle size is 1-2 mm; the second granulation is steam granulation, the granulation time is 4-12 min, and the obtained particle size is 4-5 mm.

[0015] Preferably, in step S2, the clay mineral is pretreated before being mixed with the alginate and the core particles; the pretreatment step is: first, sorting by using the autoclaving-steam curing hydrothermal reaction method, and then removing harmful elements, so that the clay mineral in the clay mineral is ≥ 70wt%, Hg≤5mg / kg, As≤50mg / kg, Pb≤50mg / kg, Cd≤10mg / kg, Cr≤50mg / kg.

[0016] The third object of the present application is to provide the alginate type multifunctional long-acting soil conditioner and the application of the soil conditioner prepared by the above-mentioned preparation method in soil improvement.

[0017] The soil conditioner provided by the present application uses clay mineral and alginate as coating materials, which can isolate organic materials, calcium magnesium polyphosphate and other substances in the core particle layer, has good slow-release performance, can release the effective components in the core particle layer for a long time, and can improve soil quality, provide organic matter and mineral nutrients, and enhance crop resistance; on the other hand, the clay mineral also has the advantages of adjusting the pH value, physical structure, nutrient status of the soil and accelerating the degradation of organic pollutants, and the alginate also has the effects of promoting growth, resisting stress and accelerating the decomposition of organic pollutants, both of which are involved in soil improvement, and through the synergistic effect of the components, the problems of soil acidification, heavy metal pollution, microplastic pollution, pesticide pollution and antibiotic pollution in agricultural production can be effectively solved. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 It is the electrospray ionization mass spectrum of sodium alginate in Example 1 of the present application. DETAILED DESCRIPTION

[0019] The soil conditioner is widely used in soil ecological restoration of soil acidification, heavy metal pollution, microplastic pollution, pesticide pollution and antibiotic pollution, but due to the problems of single function, short duration and poor ecological restoration effect of the current soil conditioner, the improved soil quality is often poor, and the fruit rate of crops planted in the soil is not significantly improved.

[0020] The alginate-based multifunctional long-lasting soil conditioner provided by this invention can improve the soil, making it suitable for cash crops, food crops, vegetables, fruit trees, economic forest trees, flowers, Chinese medicinal herbs, or lawns. Among them, the flower and fruit retention rate of flowering and fruiting plants can reach 50% to 99%, and the synthesis of various enzymes and secondary metabolites related to crop resistance also increases by 10% to 90%.

[0021] Applicable cash crops include tobacco, cotton, camellia oleifera, rapeseed, sugar beets, sugarcane, soybeans, tea trees, and peanuts. Applicable grain crops include wheat, rice, corn, and sorghum. Applicable vegetables include cabbage, bitter melon, loofah, celery, eggplant, tomato, winter melon, spinach, garlic, scallions, chili peppers, cucumber, spinach, turnip, potato, sweet potato, radish, carrot, pea, green bean, string bean, and edamame. Applicable fruits include mango, watermelon, apple, pear, banana, papaya, citrus, orange, grape, cherry, lychee, peach, plum, apricot, strawberry, pineapple, blueberry, kiwi, jujube, persimmon, and cantaloupe. Suitable economic trees include rubber, coconut, walnut, chestnut, hazelnut, etc.; suitable flowers include annual and biennial herbaceous flowers such as carnation, marigold, calendula, impatiens, four o'clock flower, poppy, California poppy, salvia splendens, violet, morning glory, mimosa, cockscomb, etc.; perennial herbaceous flowers such as asparagus fern, impatiens, spider plant, clivia, vanilla, violet, bird of paradise, crinum, amaryllis, etc.; and deciduous perennial and bulbous herbaceous flowers such as lily, daylily, peony, chrysanthemum, etc. Aquatic flowers such as lotus and water lilies; ferns such as kidney fern and maidenhair fern; orchids such as Cymbidium goeringii, Cymbidium faberi, and Cymbidium ensifolium; evergreen shrubs such as Milan, gardenia, and Michelia figo; deciduous shrubs such as rose, rosehip, and rosehip; evergreen trees such as cycad, mountain palm, fan palm, and banyan; deciduous trees such as peach blossom, plum blossom, cherry blossom, and magnolia; evergreen vines such as clematis, monstera, and bougainvillea; deciduous vines such as trumpet creeper, vines, and climbing rose; and cacti and succulents such as epiphyllum, aloe vera, and sedum. Applicable Chinese medicinal herbs include ginseng, Panax notoginseng, rhubarb, Ligusticum chuanxiong, Gastrodia elata, Auricularia auricula-judae, Aucklandia lappa, Ophiopogon japonicus, Bupleurum chinense, Codonopsis pilosula, Astragalus membranaceus, Coptis chinensis, Areca catechu, Mentha haplocalyx, Strychnos nux-vomica, Schisandra chinensis, Galla chinensis, Arctium lappa, Cordyceps sinensis, Myristica fragrans, Benzoin, Corydalis yanhusuo, Zanthoxylum bungeanum, Polygonum multiflorum, Isatis indigotica, Acanthopanax senticosus, and Siraitia grosvenorii. Suitable turfgrasses include: *Agropyron cristatum*, *Agropyron velutina*, *Agropyron simsii*, *Branca*, *Festuca tenuifolia*, *Festuca pubescens*, *Festuca spp.*, *Festuca spp.*, and *Festuca spp.*; *Poa przewalskii*, *Poa przewalskii*, *Poa przewalskii*, and *Poa przewalskii*; perennial ryegrass, *Setaria viridis*, *Tetracentron sinense*, *Zoysia japonica*, *Zoysia japonica*, *Zoysia sinensis*, *Zoysia japonica*, *Zoysia japonica*, *Zoysia japonica*, *Carex spp.*, *Carex spp.*, *Carex spp.*, and *Carex spp.*; white clover, red clover, *Coronado variegata*, creeping *Dioscorea opposita*, *Ophiopogon japonicus*, thyme, and creeping *Potentilla chinensis*.

[0022] The alginic acid type multifunctional long-acting soil conditioner comprises a core particle layer and a slow-release layer coated on the surface of the core particle layer, the core particle layer comprises organic material, nano silicon, calcium magnesium polyphosphate, magnesium hydride, ammonium borate, rhamnose and a binder, and the slow-release layer comprises clay minerals and alginates; wherein the mass ratio of the clay minerals, the alginates, the organic material, the calcium magnesium polyphosphate, the nano silicon, the magnesium hydride, the ammonium borate, the rhamnose, the binder is (50.0-50.9):(1.0-1.9):(100.0-100.9):(20.0-29.9):(2.0-2.9):(3.0-3.9):(2.0-2.9):(1.0-1.9):(6.0-6.9).

[0023] The selected clay minerals in the slow-release layer comprise at least one of kaolinite, montmorillonite, attapulgite, sepiolite, rectorite, diatomite, illite, quartz, sericite, dickite, bentonite, chlorite and zeolite; the pH value of the clay minerals is 7.0-8.5, the content of the main material of the clay minerals is greater than or equal to 70 wt%, the clay minerals contain other beneficial nutrient elements, and the content of harmful elements is very small after removal, Hg is less than or equal to 5 mg / kg, As is less than or equal to 50 mg / kg, Pb is less than or equal to 50 mg / kg, Cd is less than or equal to 10 mg / kg and Cr is less than or equal to 50 mg / kg, so that the selected clay minerals are not only a cheap coating material, but also can better adjust the pH, physical structure and nutrient status of the disturbed soil and accelerate the degradation of organic pollutants. The pH value of the clay minerals after activation and magnetic separation is 8.2-8.5, the content of the main material of the clay minerals in the clay minerals is greater than or equal to 72 wt%, Ca is greater than or equal to 0.2 wt%, Mg is greater than or equal to 0.05 mg / kg, N is greater than or equal to 0.1 wt%, P2O5 is greater than or equal to 0.15 wt%, Hg is less than or equal to 0.15 mg / kg, As is less than or equal to 10 mg / kg, Pb is less than or equal to 25 mg / kg, Cd is less than or equal to 0.1 mg / kg and Cr is less than or equal to 20 mg / kg.

[0024] The alginate contained in the slow-release layer is a green, safe and environmentally friendly coating material, which is a natural polysaccharide carbohydrate extracted from kelp. The selected uronic acid content is greater than or equal to 85%. It is a copolymer composed of a-L-mannuronic acid (M) and b-D-guluronic acid (G) connected by 1,4-glycosidic bond and composed of different GGGMMM fragments. The alginate also has the effects of regulating plant growth, inducing plant stress resistance, accelerating the decomposition of organic pollutants and directly acting on plant pathogens. Together with clay minerals as the slow-release layer, the soil can be preferentially conditioned, the soil environment is improved, and the effective components in the subsequent core particle layer can better play a role. At the same time, as a coating material, the organic material, calcium and magnesium polyphosphate and other substances can be well isolated in the core particle layer, ensuring that the effective components in the core particle layer are released slowly and durably, and play a long-acting role in improving soil quality, providing organic matter and mineral nutrients, and enhancing crop resistance. Preferably, the selected alginate has a uronic acid content of greater than or equal to 90%. The uronic acid includes a-L-mannuronic acid (M) and b-D-guluronic acid (G) in a mass ratio of 6-8:2-4. The alginate can be at least one of sodium alginate, potassium alginate and calcium alginate, and is preferably sodium alginate. The molecular formula is (C6H7O6Na)n, the polymerization degree is 2-20, the uronic acid composition is M / G=7:3, and the uronic acid content is greater than 90%.

[0025] Compared with using only alginate or clay minerals as the slow-release layer, the above two substances selected together as the slow-release layer have good synergistic effect and better long-acting effect.

[0026] The organic material in the core particle layer can be at least one of organic fertilizer, manure, compost, fermented fertilizer, green manure, vinasse, vinegar dregs, cassava residue, oil residue, sugar residue, furfural residue, mushroom residue, kelp residue, protein mud, amino acid, humic acid, plant straw, wood ash, cake fertilizer, soybean meal, cottonseed meal, peanut shell powder, biogas fertilizer, kitchen garbage and urban sludge. The organic material not only improves the soil physical structure, increases the soil organic matter and promotes the reproduction of soil microorganisms, but also adjusts the soil pH, reduces the activity of heavy metals and promotes crop growth. The preferred organic material in the present application is kelp organic fertilizer, which is made of natural kelp as raw material through physical and biochemical processes. The organic matter content is greater than or equal to 40%, and contains alginate, mineral matter, amino acid, polysaccharide, betaine, plant growth hormone and other active substances. It has the characteristics of promoting growth, increasing yield, resisting stress, improving soil and accelerating the decomposition of organic pollutants.

[0027] The selected nano-silicon has the characteristics of large surface area, good biocompatibility, high stability, good adsorption performance and the like. As a slow-release fertilizer, the nano-silicon can not only provide nutrition support for crop growth, but also enhance the resistance of crops, control the absorption of heavy metals by crops, thereby improving the quality of agricultural products and assisting the safe production of crops in obstacle soil.

[0028] The selected calcium magnesium polyphosphate is a new type of slow-release fertilizer. The calcium magnesium polyphosphate applied to the soil can control the release rate of phosphorus, calcium and magnesium, and is wrapped by a slow-release layer, so that the orthophosphate, calcium ions and magnesium ions are slowly released, thereby slowing down the fixation of phosphorus and the loss of calcium and magnesium ions, better meeting the needs of crop growth, and improving the nutrient utilization efficiency and promoting crop yield. The preferred calcium magnesium polyphosphate of the application has a porous amorphous structure, and the effective phosphorus, calcium and magnesium nutrient content is more than 85%.

[0029] The selected magnesium hydride has the characteristics of high hydrogen storage capacity, low cost and convenient use. Hydrolysis generates hydrogen and magnesium hydroxide at room temperature, wherein the hydrogen can promote plant root development, improve the tolerance to abiotic stress such as acidification and heavy metals, and accelerate the decomposition of organic pollutants. The generated magnesium hydroxide can not only provide magnesium nutrition, but also adjust the soil acidity and alkalinity and passivate soil heavy metals.

[0030] The selected ammonium borate can not only provide boron nutrition and available nitrogen for crop growth, but also regulate soil pH, reduce heavy metal activity, sterilize and disinfect, and enhance the resistance of crops.

[0031] The selected rhamnose can not only enhance the immunity of crops by activating the internal immune response mechanism of crops, so that the crops have stronger resistance and adaptability to adverse environments, but also improve the soil environment, increase the soil organic matter content, promote the reproduction of soil microorganisms, and improve the soil fertility, thereby promoting the nutrient absorption and storage of crops.

[0032] The above-mentioned several substances are used together as the effective components of the core particles. The components not only can exert their own effects to improve the content of the required nutrient elements in the soil, but also can synergistically improve the soil environment. For example, the nano-silicon can control the absorption of heavy metals by crops, and the organic matter, magnesium hydroxide and ammonium borate can also inhibit the activity of heavy metals, so as to effectively control the influence of soil heavy metals on crops.

[0033] The selected binder includes at least one of lignosulfonate, lignophenol formaldehyde resin, carboxyethyl cellulose, carboxymethyl cellulose, biomass tar, carboxymethyl chitosan salt, polyglutamate salt, humic acid salt, acrylamide, starch, dextrin, polyvinyl alcohol, locust bean gum, guaiacum gum, xanthan gum, gum arabic, guar gum, broad bean gum, Chinese yellowwood gum, coca gum, Irish moss gum, agar, egg white protein, tyrosine, fish paste, bacterial protein, wheat germ protein, gluten, gelatin, polyvinyl alcohol, sodium polyacrylate, acryl glycol, carboxymethyl starch, phosphate cross-linked starch, urea-formaldehyde condensate, vegetable oil, and mineral oil.

[0034] The inventors have verified through multiple experiments that, when the contents of the clay mineral, alginate, organic material, calcium magnesium polyphosphate, nano silicon, magnesium hydride, ammonium borate, and rhamnose are controlled within the above ranges, the matching degree is high, which not only ensures that the thickness of the slow-release layer composed of the clay mineral and alginate is appropriate, but also ensures that the core particle layer has a sufficient amount of effective ingredients. Specifically, the mass ratio of the clay mineral, alginate, organic material, calcium magnesium polyphosphate, nano silicon, magnesium hydride, ammonium borate, rhamnose, and binder includes but is not limited to 50:1:100:20:2:3:2:1:6, 50.3:1.3:100.3:20.3:2.3:3.3:2.3:1.3:6.3, 50.5:1.5:100.4:20.6:2.5:3.5:2.5:1.5:6.5, or 50.9:1.9:100.9:20.9:2.9:3.9:2.9:1.9:6.9.

[0035] In some embodiments, the particle size of the soil conditioner is 4-5 mm, wherein the core particle size of the core particle layer is 1-2 mm.

[0036] The application also provides a preparation method of the soil conditioner, including the following steps:

[0037] S1, dry-mixing the organic material, nano silicon, calcium magnesium polyphosphate, magnesium hydride, ammonium borate, and rhamnose according to a mass ratio of 50:1:100:20:2:3:2:1:6, and then adding a binder to mix and transfer to first granulation to obtain a core particle;

[0038] S2, mixing the clay mineral and alginate according to a mass ratio of 50:1 with the core particle obtained in step S1, and then transferring to second granulation to obtain a soil conditioner containing a core particle layer and a slow-release layer.

[0039] The preparation method provided by the application adopts a double-layer granulation technology to prepare the soil conditioner. The core particle is prepared first, and then mixed with the clay mineral and alginate. The slow-release layer formed by the clay mineral and alginate can well wrap the core particle, thereby forming a double-layer structure of the core particle layer and the slow-release layer, and ensuring the long-acting release of the effective ingredients. In addition, the preparation method also has the advantages of low energy consumption, low cost, and environmental protection.

[0040] Compared with the preparation method of mixing all components directly, the soil conditioner prepared by the method of the application has a double-layer structure, small and uniform particles, and allows clay minerals and alginate to be mixed as the outer slow-release layer, thereby ensuring the long-acting effect of soil improvement.

[0041] In some embodiments, the first granulation is steam granulation, the granulation time is 3-10 min, and the particle size of the obtained particles is 1-2 mm; the second granulation is steam granulation, the granulation time is 4-12 min, and the particle size of the obtained particles is 4-5 mm. The particle size of the steam granulation is small and uniform, the thickness of the slow-release layer is appropriate, which avoids the problem that the slow-release layer is too thick to affect the release of the effective components of the inner core particles, and also avoids the problem that the thickness is too small to cause poor long-acting effect.

[0042] In some embodiments, in step S2, the clay minerals are pretreated before being mixed with the alginate and the core particles; the pretreatment step is: first, sorting by using the autoclaving-steam curing hydrothermal reaction method, and then removing harmful elements, so that the content of the clay minerals in the clay minerals is ≥70wt%, Hg≤5mg / kg, As≤50mg / kg, Pb≤50mg / kg, Cd≤10mg / kg, and Cr≤50mg / kg. The application also innovatively uses the autoclaving-steam curing hydrothermal reaction activation technology to treat the clay minerals, removes many harmful elements in the clay minerals after the activation treatment, and improves the content of effective calcium, magnesium, silicon and other clay minerals by more than 30% compared with the traditional process, and then mixes the clay minerals with the alginate as the slow-release layer, thereby further ensuring the long-acting effect of soil improvement.

[0043] In order to make the technical solutions and advantages of the application clearer, the application and its beneficial effects will be further described in detail below with reference to the specific embodiments and the accompanying drawings, but the embodiments of the application are not limited thereto.

[0044] Example 1

[0045] A kind of alginate type multifunctional long-acting soil conditioner, including core particle layer and slow-release layer coated on the surface of core particle layer, the core particle layer includes organic material, nano silicon, calcium magnesium polyphosphate, magnesium hydride, ammonium borate, rhamnose and binder, slow-release layer includes clay minerals and alginate;Wherein, the mass ratio of clay minerals, alginate, organic material, calcium magnesium polyphosphate, nano silicon, magnesium hydride, ammonium borate, rhamnose, binder is 50:1:100:20:2:3:2:1:6.

[0046] The preparation method of the alginate type multifunctional long-acting soil conditioner is as follows:

[0047] 1) The organic material kelp residue is dried, crushed, sieved, calcium magnesium polyphosphate (total phosphorus 50%, polyphosphorus ≥40%, polymerization rate ≥80%) is finely ground and homogenized in a ball mill to make the particle size less than 30 μm; the organic material, nano-silicon, calcium magnesium polyphosphate, magnesium hydride, ammonium borate, rhamnose are weighed according to 100:2:20:3:2:1 and dry mixed; then mixed with the binder carboxymethyl chitosan salt and added to the drum granulator, steam granulation is carried out for 5 min, and core granules with an average particle size of 1-2 mm are prepared;

[0048] 2) The clay mineral (kaolinite and chlorite) is finely ground in a ball mill, and the effective calcium, magnesium and silicon clay minerals are separated by steam pressure-steam curing hydrothermal reaction process, and harmful elements are removed by magnetic separation method, so that the content of the main material of the clay mineral is ≥80wt%, Ca≥0.2wt%, Mg≥0.05mg / kg, N≥0.1wt%, P2O5≥0.15wt%, Hg≤5mg / kg, As≤10mg / kg, Pb≤15mg / kg, Cd≤8mg / kg, Cr≤25mg / kg; then the activated and magnetically separated kaolinite, chlorite and sodium alginate are weighed according to the ratio of 25:25:1, and mixed with the above prepared core granules, then added to the drum granulator again, steam granulation is carried out for 8 min, the particle size of the granules is 4-5 mm, then the hot air is blown into the dryer to dry the granules, and the soil conditioner containing core granule layer and slow release layer is obtained after screening, cooling, the pH value is 8.5.

[0049] The test method of the soil conditioner after the test includes: (1) for pH value, the potential method is used for determination, which is carried out according to the provisions of HJ962-2018; (2) the determination of organic matter is carried out according to the provisions of GB9834-88; (3) the determination of phosphorus is carried out according to the provisions of national standard GB20412-2006; (4) the determination of calcium, magnesium and silicon content is carried out according to the provisions of NY / T2272-2012; (5) the polymerization degree of sodium alginate is determined by liquid chromatography-mass spectrometry with electrospray ion source (ESI); (6) the chromatographic determination conditions are: mass spectrometry mode is positive ion mode, electrospray ion source (ESI), spray voltage 4.5kV, transmission capillary temperature 350℃, sheath gas (N2) pressure 30au (1au is about 1psi), auxiliary gas (N2) pressure 5au, ion purge gas (N2) pressure 0au, scanning range: 150-2000, and the electrospray ionization mass spectrum is as shown in Figure 1 ; (7) the content of each component is determined by colorimetry.

[0050] The soil conditioner obtained above is tested.

[0051] Test 1: Application of the seaweed acid type multifunctional long-acting soil conditioner for acid reduction and yield increase test

[0052] The test was completed in Wuyang from October 2020 to October 2022. The test plot was flat, neat, uniform in fertility, and the pH value was 4.53, and the acidification was obvious. The test wheat variety was Zhengmai 7698, and the corn variety was Zhengdan 1002. The test set 3 treatments, respectively, treatment 1: control, no application of the soil conditioner treatment; treatment 2, 100 kg / mu of quicklime; treatment 3, 100 kg / mu of the seaweed acid type multifunctional long-acting soil conditioner prepared in the embodiment 1 of the application. The quicklime and the seaweed acid type multifunctional long-acting soil conditioner prepared in the embodiment 1 of the application were all applied before the first season of wheat planting, and were sowed after rotary ploughing for 15 days, and the soil acidification index and crop yield were determined after the harvest of each season of crops, and the specific results are shown in Table 1 and Table 2.

[0053] Table 1 Effect of the soil conditioner of the application on soil acidification index

[0054]

[0055] As shown in Table 1 above, in 2020-2021, the soil pH of the wheat harvest season of the application of the seaweed acid type multifunctional long-acting soil conditioner increased by 0.48 compared with the control, but was 0.16 lower than the lime treatment; in the corn harvest season, it was significantly increased by 0.44 and 0.21 compared with the control and the lime treatment, respectively. In 2021-2022, the soil pH of the wheat harvest season of the application of the seaweed acid type multifunctional long-acting soil conditioner increased by 0.46 and 0.27 compared with the control and the lime treatment, respectively; in the corn season, it increased by 0.48 and 0.31, respectively. Table 1 also shows that in 2020-2021, the soil exchangeable total acid content of the wheat harvest season of the application of the seaweed acid type multifunctional long-acting soil conditioner was significantly reduced by 34.4% compared with the control, but was significantly higher than the lime treatment by 37.4%; in the corn harvest season, it was significantly increased by 66.2% and 3.7% compared with the control and the lime treatment, respectively. In 2021-2022, the soil exchangeable total acid content of the wheat season and the corn season of the application of the seaweed acid type multifunctional long-acting soil conditioner was significantly reduced by 34.5% and 33.9% compared with the control, respectively, but there was no significant difference with the lime treatment. The results show that compared with lime, the application of the seaweed acid type multifunctional long-acting soil conditioner of the application on acidified soil has a more lasting effect on acid reduction.

[0056] Table 2 Effect of the soil conditioner of the application on crop yield and grain cadmium content

[0057]

[0058] As can be seen from Table 2, in 2020-2021, the yield of wheat and corn treated with the alginic acid type multifunctional long-acting soil conditioner of the application was 14.2% and 8.8% higher than that of the control respectively, but there was no significant difference with lime treatment. In 2021-2022, the yield of wheat treated with the alginic acid type multifunctional long-acting soil conditioner of the application was 14.0% and 3.0% higher than that of the control and lime treatment respectively, and the yield of corn was 11.3% higher than that of the control, but there was no significant difference with lime treatment. Table 2 also shows that in 2020-2021, the cadmium content in wheat grains treated with the alginic acid type multifunctional long-acting soil conditioner of the application was 39.6% lower than that of the control, but 11.5% higher than that of lime treatment; the cadmium content in corn grains was 31.7% and 10.4% lower than that of the control and lime treatment respectively. In 2021-2022, the cadmium content in wheat grains treated with the alginic acid type multifunctional long-acting soil conditioner of the application was 45.5% and 13.3% lower than that of the control and lime treatment respectively; the cadmium content in corn grains was 34.8% and 22.8% lower than that of the control and lime treatment respectively. The results show that the application of the alginic acid type multifunctional long-acting soil conditioner of the application on acidified soil can increase crop yield and reduce cadmium content in grains, and has better persistence than lime.

[0059] Test 2: Application of the alginic acid type multifunctional long-acting soil conditioner of the application for acidified soil improvement test

[0060] The test was completed in Zhengyang from October 2020 to June 2021. The pH of the test plot was 3.83, which was obviously acidified, and the planted crop was Zhengmai 139. Three treatments were set, namely treatment 1, control; treatment 2, biochar 150 kg / mu; treatment 3, alginic acid type multifunctional long-acting soil conditioner prepared by the application example 1 150 kg / mu. After the wheat was harvested, the soil available phosphorus content was determined by molybdenum-antimony anti-colorimetric method; the soil available potassium content was determined by flame photometry. The soil organic matter content was determined by oil bath heating-potassium dichromate method. The soil exchangeable calcium and magnesium content was determined by ammonium acetate exchange atomic absorption spectrophotometry. The soil pH was determined by PHSJ-3FX type pH meter; the soil available copper and cadmium content was determined by DTPA extraction-atomic absorption spectrometry flame method and graphite furnace method. The specific results are shown in Table 3.

[0061] Table 3 Effect of the soil conditioner of the application on wheat yield and soil physical and chemical properties

[0062]

[0063] As can be seen from Table 3 above, the yield of wheat treated with the alginic acid type multifunctional long-acting soil conditioner of the application is significantly higher than that of the control and the biochar treatment, with an increase of 25.0% and 8.1% respectively; the soil pH value is increased by 0.73 and 0.50 respectively compared with the control and the biochar treatment; the soil organic matter content is increased by 42.8% and 12.8% respectively compared with the control and the biochar treatment; the soil exchangeable magnesium content is increased by 60.0% and 54.3% respectively compared with the control and the biochar treatment; the soil exchangeable calcium content is increased by 177.8% and 174.7% respectively compared with the control and the biochar treatment. The soil available potassium content is increased by 59.0% and 31.3% respectively compared with the control and the biochar treatment; the soil available phosphorus content is increased by 78.2% and 67.0% respectively compared with the control and the biochar treatment; the soil available copper content is decreased by 30.9% and 20.0% respectively compared with the control and the biochar content; the soil available cadmium content is decreased by 32.3% and 17.9% respectively compared with the control and the biochar content. The results show that the application of the alginic acid type multifunctional long-acting soil conditioner of the application can increase the soil pH and the content of available nutrients, reduce the activity of heavy metals, and thus promote the yield increase of wheat.

[0064] Test 3: Application of the alginic acid type multifunctional long-acting soil conditioner of the application for heavy metal contaminated soil improvement test

[0065] The test was completed in Daku Town, Fengquan District, Xinxiang City from October 2020 to June 2021. The soil cadmium content was 28.35 mg / kg, and Xinmai 26 was used as the material. Four treatments were set up, i.e. treatment 1, control; treatment 2, biochar 140 kg / mu; treatment 3, calcium magnesium phosphate fertilizer 40 kg / mu; treatment 4, alginic acid type multifunctional long-acting soil conditioner prepared in Example 1 of the application 140 kg / mu. The yield of wheat, cadmium absorption, soil pH at maturity and soil heavy metal cadmium forms, including exchangeable state (EXC-Cd), carbonate bound state (CAR-Cd), iron and manganese oxide bound state (OX-Cd), organic bound state (OM-Cd) and residual state (RES-Cd), were determined, and the results are shown in Tables 4 and 5.

[0066] Table 4 Effect of the soil conditioner of the application on soil pH and cadmium forms

[0067]

[0068] As can be seen from the above Table 4, after the wheat is harvested, the soil pH of the soil to which the seaweed acid type multifunctional long-acting soil conditioner of the present application is applied is increased by 0.35, 0.09 and 0.07 respectively compared with the control, the biochar and the calcium magnesium phosphate fertilizer treatment. The EXC-Cd proportion of the soil to which the seaweed acid type multifunctional long-acting soil conditioner of the present application is applied is significantly lower than that of the control, the biochar and the calcium magnesium phosphate fertilizer treatment, but the CAR-Cd, OX-Cd and OM-Cd proportions are significantly increased, and the RES-Cd proportion is also significantly higher than that of the control. The results show that the seaweed acid type multifunctional long-acting soil conditioner of the present application can increase the soil pH and promote the transformation of the exchangeable Cd into the residual Cd.

[0069] Table 5 Effect of the soil conditioner of the present application on the yield and cadmium absorption of wheat

[0070]

[0071] As can be seen from the above Table 5, the yield of the wheat to which the seaweed acid type multifunctional long-acting soil conditioner of the present application is applied is increased by 23.5%, 2.5% and 4.2% respectively compared with the control, the biochar and the calcium magnesium phosphate fertilizer treatment. The root cadmium content is reduced by 48.8%, 42.9% and 17.0% respectively compared with the control, the biochar and the calcium magnesium phosphate fertilizer treatment; the straw cadmium content is significantly reduced by 36.5%, 29.0% and 12.9% respectively compared with the control, the biochar and the calcium magnesium phosphate fertilizer treatment; and the grain cadmium content is significantly reduced by 57.1%, 33.3% and 20.0% respectively compared with the control, the biochar and the calcium magnesium phosphate fertilizer treatment. The results show that the seaweed acid type multifunctional long-acting soil conditioner of the present application can reduce the absorption of heavy metal Cd by the wheat and increase the yield of the wheat.

[0072] Test 4: Application of the seaweed acid type multifunctional long-acting soil conditioner of the present application for the improvement of heavy metal compound contaminated soil

[0073] The test was completed in a sewage irrigation farmland near a battery factory in Xinxiang County, Henan Province from October 2022 to June 2023. The planted crop was radish, and the soil type was moist soil. Due to long-term sewage irrigation, the soil accumulated heavy metals, among which the cadmium content was 31.53 mg / kg, the arsenic content was 18.56 mg / kg, and the lead content was 25.48 mg / kg, which was a cadmium, arsenic and lead compound contaminated soil. Four treatments were set, namely treatment 1, control; treatment 2, biochar 150 kg / mu; treatment 3, seaweed acid type multifunctional long-acting soil conditioner prepared by the seaweed acid type multifunctional long-acting soil conditioner of the present application 150 kg / mu. The yield of radish and the heavy metal content thereof were determined and are shown in Table 6.

[0074] Table 6 Effect of the soil conditioner of the present application on the yield of radish and the heavy metal content thereof

[0075] Treatment Yield (t / hm 2 )]]> Cadmium content (mg / kg) Arsenic content (mg / kg) Lead content (mg / kg) Control 18.57 15.65 0.55 3.18 Biochar 23.45 13.23 0.48 2.84 Soil conditioner 25.59 9.45 0.32 2.56

[0076] As can be seen from Table 6 above, the yield of radish planted by applying the bauxite type acidic nutrient soil of the application is significantly higher than that of the control and biochar, with an increase of 37.8% and 9.1% respectively. The cadmium content in radish is significantly reduced by 39.6% and 28.6% respectively compared with the control and biochar. The arsenic content in radish is significantly reduced by 41.8% and 33.3% respectively compared with the control and biochar; the lead content in radish is significantly reduced by 19.5% and 9.9% respectively compared with the control and biochar. The results show that the application of the alginic acid type multifunctional long-acting soil conditioner of the application can increase the yield of radish and reduce the content of heavy metals.

[0077] Test 5: Application of the alginic acid type multifunctional long-acting soil conditioner of the application for soil cadmium, microplastic single and composite pollution soil improvement test

[0078] The test was completed in the light culture room of Henan Agricultural Academy of Sciences from October 2020 to June 2021. Indoor pot experiment was adopted, Zhengmai 139 was used as the material, and the improvement effect of single and composite pollution of soil heavy metal cadmium (4 mg / kg) and polyethylene microplastic (PP-MPs, 5%) was studied. Two treatments were set, namely control and application of the alginic acid type multifunctional long-acting soil conditioner prepared by the application example 1, the addition amount was 10 g / kg. The photosynthetic characteristics of functional leaf of wheat were determined at jointing stage, and part of the samples were harvested to determine the antioxidant enzyme activity of leaf, and the soil available cadmium content and microplastic occurrence characteristics were determined after the wheat was harvested. The results are shown in Tables 7 and 8.

[0079] Table 7 Effect of the soil conditioner of the application on photosynthetic characteristics and antioxidant enzyme activity of wheat

[0080]

[0081] As can be seen from the above Table 7, under the condition of cadmium single pollution, the SPAD value, net photosynthetic rate, SOD, POD and CAT activity of functional leaf of wheat applied with the seaweed acid type multifunctional long-acting soil conditioner of the application are increased by 26.5%, 29.3%, 9.5%, 78.3% and 42.1% respectively compared with the control. Under the condition of microplastic single pollution, the SPAD value, net photosynthetic rate, SOD, POD and CAT activity of functional leaf of wheat applied with the seaweed acid type multifunctional long-acting soil conditioner of the application are increased by 11.7%, 9.0%, 5.1%, 93.3% and 40.7% respectively compared with the control. Under the condition of cadmium and microplastic composite pollution, the SPAD value, net photosynthetic rate, SOD, POD and CAT activity of functional leaf of wheat applied with the seaweed acid type multifunctional long-acting soil conditioner of the application are increased by 28.1%, 26.5%, 7.0%, 76.5% and 32.1% respectively compared with the control. The results show that the seaweed acid type multifunctional long-acting soil conditioner of the application can increase the photosynthetic pigment content of wheat, promote photosynthesis, and can alleviate the damage of soil cadmium, microplastic single and composite pollution to the growth of wheat seedlings by increasing the activity of antioxidant enzymes.

[0082] Table 8 Effect of the soil conditioner of the application on the content of cadmium in soil and the occurrence characteristics of microplastics

[0083]

[0084]

[0085] As can be seen from the above Table 8, under the condition of cadmium single pollution soil, the effective cadmium content of soil applied with the seaweed acid type multifunctional long-acting soil conditioner of the application is significantly reduced by 34.2%; under the condition of cadmium and microplastic composite pollution, the effective cadmium content of soil applied with the seaweed acid type multifunctional long-acting soil conditioner of the application is significantly reduced by 37.8%. Under the condition of microplastic single pollution, the microplastic abundance of soil is significantly reduced by 18.4%; under the condition of cadmium and microplastic composite pollution, the microplastic abundance of soil applied with the seaweed acid type multifunctional long-acting soil conditioner of the application is significantly reduced by 19.4%. Under the condition of microplastic single pollution or composite pollution with cadmium, the seaweed acid type multifunctional long-acting soil conditioner of the application can increase the proportion of microplastics with particle size of <0.5mm and 0.5-1mm, and reduce the proportion of microplastics with particle size of 1-2mm and 2-5mm. The results show that the seaweed acid type multifunctional long-acting soil conditioner can reduce the effective cadmium content of soil and accelerate the degradation of microplastics, thereby reducing the abundance of microplastics.

[0086] Test 6: Application of the seaweed acid type multifunctional long-acting soil conditioner of the application for soil improvement test of pesticide pollution

[0087] The experiment was completed in a vegetable greenhouse in Lankao in 2022-2024. Two treatments were set, control and application of the seaweed acid type multifunctional long-acting soil conditioner prepared in Example 1 of the application 100 kg / mu, applied once a year. After 2 years, the plough layer soil was collected, and the residues of thiamethoxam, carbendazim, abamectin and carbofuran were determined by ultra-high performance liquid chromatography tandem mass spectrometry. The specific results are shown in Table 9.

[0088] Table 9 Effect of seaweed acid type multifunctional long-acting soil conditioner of the application on the content of pesticides in soil

[0089] Treatment Thiamethoxam (mg / kg) Imidacloprid (mg / kg) Abamectin (mg / kg) Carbofuran (mg / kg) Control 0.885 0.265 0.225 0.065 Soil conditioner 0.645 0.132 0.137 0.037

[0090] As can be seen from the above Table 9, compared with the control, the content of thiamethoxam, imidacloprid, abamectin and carbofuran in the soil applied with the seaweed acid type multifunctional long-acting soil conditioner of the application decreased significantly by 27.1%, 50.2%, 39.1% and 43.1% respectively. The results show that the application of the seaweed acid type multifunctional long-acting soil conditioner of the application can accelerate the degradation of pesticides in the soil, reduce pesticide pollution, and thus be beneficial to safe production of vegetables.

[0091] Experiment 7: Application of seaweed acid type multifunctional long-acting soil conditioner for antibiotic contaminated soil improvement test

[0092] The experiment was completed in a vegetable greenhouse in Lankao in 2021-2022. The greenhouse has been applying livestock manure as organic fertilizer (about 250 kg / mu) for a long time, and a certain amount of chemical fertilizer is also applied. Two treatments were set, control and application of the seaweed acid type multifunctional long-acting soil conditioner prepared in Example 1 of the application 100 kg / mu, applied once a year. After 2 years, the plough layer soil was collected, and the content of 4 tetracycline compounds (tetracycline, oxytetracycline, chlortetracycline and doxycycline) was determined by LC-MS. See Table 10 for details.

[0093] Table 10 Effect of soil conditioner of the application on the content of tetracycline compounds in soil

[0094] Treatment Oxytetracycline (μg / kg) Tetracycline (μg / kg) Chlortetracycline (μg / kg) Doxycycline (μg / kg) Control 11.12 4.65 4.25 6.58 Soil conditioner 6.45 3.23 2.37 3.74

[0095] As can be seen from the above Table 10, compared with the control, the content of oxytetracycline, tetracycline, chlortetracycline and doxycycline in the soil applied with the seaweed acid type multifunctional long-acting soil conditioner of the application decreased significantly by 42.0%, 30.5%, 44.2% and 43.2% respectively. The results show that the application of the seaweed acid type multifunctional long-acting soil conditioner of the application can reduce the content of tetracycline compounds in the soil and reduce antibiotic pollution.

[0096] Example 2

[0097] The application discloses a long-acting soil conditioner of alginate type, which comprises a core particle layer and a slow-release layer coated on the surface of the core particle layer, wherein the core particle layer comprises organic material, nano-silicon, calcium magnesium polyphosphate, magnesium hydride, ammonium borate, rhamnose and a binder, and the slow-release layer comprises clay minerals and alginate; the mass ratio of the clay minerals, the alginate, the organic material, the calcium magnesium polyphosphate, the nano-silicon, the magnesium hydride, the ammonium borate, the rhamnose and the binder is 50.5:1.5:100.4:20.6:2.5:3.5:2.5:1.5:6.3.

[0098] The preparation method of the long-acting soil conditioner of alginate type is as follows:

[0099] 1) The organic material is dried, crushed, sieved, the calcium magnesium polyphosphate (total phosphorus 55%, polyphosphorus ≥42%, polymerization rate ≥81%) is finely ground and homogenized in a ball mill so as to have a particle size less than 25 μm; the organic material, the nano-silicon, the calcium magnesium polyphosphate, the magnesium hydride, the ammonium borate and the rhamnose are weighed according to the mass ratio of 100.4:20.6:2.5:3.5:2.5:1.5 and dry-mixed; then the binder carboxymethyl starch is mixed and added into a drum granulator, steam granulation is carried out for 3 min, and the core particles with an average particle size of 1-2 mm are prepared.

[0100] 2) The clay minerals (sepiolite) are finely ground in a ball mill, the effective calcium, magnesium and silicon clay minerals are sorted by adopting a steam pressure-steam curing hydrothermal reaction process, and harmful elements are removed by adopting a magnetic separation method, so that the main content of the clay minerals is ≥75 wt%, Ca is ≥0.2 wt%, Mg is ≥0.05 mg / kg, N is ≥0.1 wt%, P2O5 is ≥0.15 wt%, Hg is ≤4 mg / kg, As is ≤35 mg / kg, Pb is ≤45 mg / kg, Cd is ≤9 mg / kg and Cr is ≤40 mg / kg; then the activated and magnetically separated sepiolite and potassium alginate are weighed according to the ratio of 50.5:1.5, and mixed with the core particles prepared in the above step and then added into the drum granulator again, steam granulation is carried out for 5 min, the particle size of the particles is 4-5 mm, the particles are dried by blowing hot air into a drying machine, and the soil conditioner containing the core particle layer and the slow-release layer is obtained after screening and cooling, and the pH value is 8.8.

[0101] Example 3

[0102] The alginic acid type multifunctional long-acting soil conditioner comprises a core particle layer and a slow-release layer coated on the surface of the core particle layer, the core particle layer comprises organic material, nano silicon, calcium magnesium polyphosphate, magnesium hydride, ammonium borate, rhamnose and a binder, and the slow-release layer comprises clay minerals and alginic acid salt; wherein the mass ratio of the clay minerals, the alginic acid salt, the organic material, the calcium magnesium polyphosphate, the nano silicon, the magnesium hydride, the ammonium borate, the rhamnose and the binder is 50.9:1.9:100.9:20.9:2.9:3.9:2.9:1.9:6.9.

[0103] The preparation method of the alginic acid type multifunctional long-acting soil conditioner is as follows:

[0104] 1) The organic material, kitchen garbage, is dried, crushed, sieved, the calcium magnesium polyphosphate (total phosphorus 45%, polyphosphorus ≥38%, polymerization rate ≥75%) is finely ground and homogenized in a ball mill so that the particle size is less than 28 μm; the organic material, nano silicon, calcium magnesium polyphosphate, magnesium hydride, ammonium borate and rhamnose are weighed according to 100.9:20.9:2.9:3.9:2.9:1.9 and dry mixed; then mixed with the binder locust bean gum and added into a rotary drum granulator, steam granulation is carried out for 9 minutes to prepare the core particles with an average particle size of 1-2 mm;

[0105] 2) The clay minerals (diatomite) are finely ground in a ball mill, the effective calcium, magnesium and silicon clay minerals are sorted by adopting the steam pressure-steam curing hydrothermal reaction process, and harmful elements are removed by adopting the magnetic separation method, so that the main content of the clay minerals is ≥73wt%, Ca≥0.2wt%, Mg≥0.05mg / kg, N≥0.1wt%, P2O5≥0.15wt%, Hg≤0.15mg / kg, As≤10mg / kg, Pb≤25mg / kg, Cd≤0.1mg / kg and Cr≤20mg / kg; then the activated and magnetically separated diatomite and calcium alginate are weighed according to the ratio of 50.9:1.9, mixed with the core particles prepared above and added into the rotary drum granulator again, steam granulation is carried out for 12 minutes, the particle size is 4-5 mm, then the hot air is blown into the dryer to dry the particles, and the soil conditioner containing the core particle layer and the slow-release layer is obtained after screening and cooling, and the pH value is 8.6.

[0106] As can be seen from the above, the soil conditioner provided by the present application can be applied in soil ecological restoration of soil acidification, heavy metal pollution, micro-plastic pollution, pesticide pollution and antibiotic pollution, etc., can not only provide nutrition, adjust soil acidity and alkalinity, enhance resistance and accelerate the decomposition of organic pollutants, has good slow-release property, can long-acting improve soil quality, effectively solves the problems of soil acidification, heavy metal pollution, micro-plastic pollution, pesticide pollution and antibiotic pollution in agricultural production, and has the advantages of green, environmental protection, no public hazard and no pollution.

[0107] Those skilled in the art can make various modifications and alterations to the above embodiments on the basis of the disclosure and teachings of this specification. Therefore, the present application should not be limited to the above embodiments, and any and all modifications, equivalents or substitutes should be considered within the scope of the present application. In addition, although some specific terms are used in this specification, these terms are only for the convenience of explanation and should not be considered as limiting the present application.

Claims

1. A seaweed acid type multifunctional long-acting soil conditioner, characterized by, The granule includes a core particle layer and a slow-release layer coated on the surface of the core particle layer, the core particle layer includes organic material, nano-silicon, calcium magnesium polyphosphate, magnesium hydride, ammonium borate, rhamnose and adhesive, and the slow-release layer includes clay mineral and alginate; wherein the mass ratio of the clay mineral, the alginate, the organic material, the calcium magnesium polyphosphate, the nano-silicon, the magnesium hydride, the ammonium borate, the rhamnose and the adhesive is (50.0-50.9):(1.0-1.9):(100.0-100.9):(20.0-29.9):(2.0-2.9):(3.0-3.9):(2.0-2.9):(1.0-1.9):(6.0-6.9).

2. The alginate type multifunctional long-acting soil conditioner according to claim 1, characterized by, The particle size of the soil conditioner is 4-5 mm, and the core particle size of the core particle layer is 1-2 mm.

3. The alginate type multifunctional long-acting soil conditioner according to claim 1, characterized by, The clay mineral includes at least one of kaolinite, montmorillonite, attapulgite, sepiolite, rectorite, diatomite, illite, quartz, sericite, dickite, bentonite, chlorite and zeolite; and the alginate includes at least one of sodium alginate, potassium alginate and calcium alginate.

4. The alginate-based multifunctional long-acting soil conditioner according to claim 3, characterized by, The pH value of the clay mineral is 7.0-8.5, the main material of the clay mineral in the clay mineral is ≥70 wt%, Hg ≤5 mg / kg, As ≤50 mg / kg, Pb ≤50 mg / kg, Cd ≤10 mg / kg and Cr ≤50 mg / kg; and the uronic acid content of the alginate is ≥85%.

5. The alginate-based multifunctional long-acting soil conditioner according to claim 4, characterized in that, The pH value of the clay mineral is 8.2-8.5, the main material of the clay mineral in the clay mineral is ≥72 wt%, Ca ≥0.2 wt%, Mg ≥0.05 mg / kg, N ≥0.1 wt%, P2O5 ≥0.15 wt%, Hg ≤0.15 mg / kg, As ≤10 mg / kg, Pb ≤25 mg / kg, Cd ≤0.1 mg / kg and Cr ≤20 mg / kg; and the uronic acid content of the alginate is ≥90%, and the uronic acid includes a-L-mannuronic acid and b-D-guluronic acid in a mass ratio of (6-8):(2-4).

6. The alginate-based multifunctional long-acting soil conditioner according to claim 1, characterized by, The organic material includes at least one of organic fertilizer, manure, compost, fermented fertilizer, green manure, vinasse, vinegar dregs, cassava dregs, oil dregs, sugar dregs, furfural dregs, mushroom dregs, kelp dregs, protein mud, amino acid, humic acid, plant straw, wood ash, cake fertilizer, soybean meal, cottonseed meal, peanut shell powder, biogas fertilizer, kitchen garbage and urban sludge; and the adhesive includes at least one of lignin sulfonate, lignin phenol formaldehyde resin, carboxyethyl cellulose, carboxymethyl cellulose, biomass tar, carboxymethyl chitosan salt, polyglutamic acid salt, humic acid salt, acrylamide, starch, dextrin, polyvinyl alcohol, locust bean gum, gum guaiac, xanthan gum, gum arabic, guar gum, broad bean gum, west yellow ox gall, coca gum, Irish moss gum, agar, egg white protein, tyrosine, fish pulp, bacterial protein, wheat germ protein, gluten, gelatin, polyvinyl alcohol, sodium polyacrylate, acryloyl glycol, carboxymethyl starch, phosphate cross-linked starch, urea-formaldehyde condensate, vegetable oil and mineral oil.

7. A method for preparing the alginate-type multifunctional long-acting soil conditioner according to any one of claims 1 to 6, characterized by, The method includes the following steps: S1, dry-mixing the machine material, nano-silicon, calcium magnesium polyphosphate, magnesium hydride, ammonium borate and rhamnose according to a mass ratio of 1:1:1:1:1:1, then adding a binder, mixing and transferring to first granulation to obtain core granules; S2, mixing clay minerals and alginate with the core granules obtained in step S1 according to a mass ratio of 1:1, then transferring to second granulation to obtain the soil conditioner comprising a core granule layer and a slow-release layer.

8. The preparation method of the alginate-based multifunctional long-lasting soil conditioner according to claim 7, characterized in that, The first granulation is steam granulation, the granulation time is 3-10 min, and the obtained granule particle size is 1-2 mm; the second granulation is steam granulation, the granulation time is 4-12 min, and the obtained granule particle size is 4-5 mm.

9. The preparation method of the alginate-based multifunctional long-lasting soil conditioner according to claim 7, characterized in that, In step S2, the clay minerals are pretreated before being mixed with alginate and core granules; the pretreatment step is: first, sorting by using steam pressure-steam curing hydrothermal reaction, then removing harmful elements, so that the clay minerals in the clay minerals are ≥ 70wt%, Hg≤5mg / kg, As≤50mg / kg, Pb≤50mg / kg, Cd≤10mg / kg, Cr≤50mg / kg.

10. Application of the alginate type multifunctional long-acting soil conditioner according to any one of claims 1-6 or the soil conditioner prepared by the preparation method according to any one of claims 7-9 in soil improvement.

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