Soil conditioner as well as preparation method and application thereof

Abstract

The invention relates to the field of agricultural planting, and provides a soil conditioner as well as a preparation method and application thereof. The soil conditioner is prepared from the following raw materials in parts by mass: 30 to 80 parts of guano phosphorite, 10 to 20 parts of zeolite, 10 to 20 parts of shell, 10 to 20 parts of volcanic ash, 10 to 20 parts of activated carbon, 5 to 10 parts of silicon fertilizer, 5 to 10 parts of humic acid and 10 to 20 parts of rice husk. The soil conditioner provided by the invention not only can remarkably reduce the content of heavy metals such as cadmium, lead, chromium, mercury and the like in crops, but also can effectively increase the content of selenium and strontium in the crops, meanwhile, the soil conditioner has the effects of promoting crop growth and increasing crop yield, and double improvement of soil improvement and crop quality and yield is realized.

Description

Technical Field

[0001] The present invention relates to the field of agricultural planting, and in particular to a soil conditioner, a preparation method thereof and an application thereof. Background Art

[0002] Selenium, an essential trace element for humans and animals, is not only a key component in maintaining enzyme activity but is also deeply involved in key physiological processes such as immune regulation and anti-cancer. Studies have shown that many human diseases, such as anemia, cancer, and hepatitis, are closely related to selenium deficiency. Therefore, adequate selenium intake is crucial for maintaining human health. Furthermore, although selenium is not essential for plant growth, it can affect plant growth and development, participate in photosynthesis and respiration, and enhance plant resistance to stress.

[0003] Geological surveys show that selenium often coexists with heavy metals such as cadmium, leading to widespread risk of heavy metal contamination in selenium-rich areas. Immobilizing free cadmium through the application of soil conditioners is an important way to inhibit the accumulation of heavy metals in crops. However, existing soil conditioners, while adsorbing and passivating harmful heavy metals like cadmium, also tend to simultaneously adsorb and immobilize beneficial elements such as selenium in the soil, resulting in a decrease in selenium content in crops. This contradiction is particularly prominent in the development of selenium-rich agricultural products in selenium-rich soil areas. Summary of the Invention

[0004] Therefore, the technical problem to be solved by the present invention is to overcome the defect in the prior art that soil conditioners reduce the content of harmful heavy metals such as cadmium while also reducing the selenium content, making it difficult to simultaneously achieve selenium enrichment and cadmium reduction, thereby providing a soil conditioner and its preparation method and application.

[0005] To this end, the present invention provides the following technical solutions:

[0006] The present invention provides a soil conditioner comprising the following raw materials in parts by weight:

[0007] 30-80 parts of guano phosphate rock, 10-20 parts of zeolite, 10-20 parts of shells, 10-20 parts of volcanic ash, 10-20 parts of activated carbon, 5-10 parts of silicon fertilizer, 5-10 parts of humic acid, and 10-20 parts of rice husk.

[0008] In an optional embodiment, guano phosphate rock is formed by the deposition, transformation and mineralization of guano over hundreds of millions of years.

[0009] In an optional embodiment, the guano phosphate rock is derived from a natural guano deposit in Kazakhstan; the guano phosphate rock is obtained by mining the natural guano deposit using conventional techniques in the art, followed by crushing, jigging, beneficiation and classification.

[0010] In an optional embodiment, the mass fraction of SiO2 in the guano phosphate rock is ≥35%, the mass fraction of CaO is ≥28%, the mass fraction of P2O5 is ≥18%, the mass fraction of organic matter is 6%-7%, the mass fraction of Al2O3 is 2%-2.5%, the mass fraction of Fe2O3 is 1.5%-2%, the mass fraction of K2O is 0.5%-1%, and the mass fraction of SrO is 0.1%-0.3%.

[0011] In an optional embodiment, the effective silicon content in the guano phosphate rock is ≥300 mg / kg, and the mass fraction of effective P2O5 is ≥11%.

[0012] Available silicon and available P2O5 refer to silicon and P2O5 that can be directly absorbed and utilized by plants.

[0013] In an alternative embodiment, guano phosphate rock is used to treat Cd 2+ The adsorption capacity is 2.1mg / g-6.7mg / g.

[0014] Guano phosphate rock to Cd 2+ The adsorption capacity refers to the maximum mass (in milligrams) of cadmium ions that can be adsorbed by a unit mass of guano phosphate rock (in grams).

[0015] In an optional embodiment, the specific surface area of ​​the guano phosphate rock is 62m 2 / g-195m 2 / g.

[0016] In an optional embodiment, the mass fraction of SiO2 in the zeolite is ≥50%, the content of effective silicon is ≥150 mg / kg, the mass fraction of Al2O3 is ≥8%, and the zeolite has a Cd 2+ The adsorption capacity is 1.5mg / g-3.6mg / g.

[0017] Zeolite to Cd 2+ The adsorption capacity refers to the maximum mass (in milligrams) of cadmium ions that can be adsorbed by a unit mass of zeolite (in grams).

[0018] Guano phosphate rock to Cd 2+ The adsorption capacity of zeolite for Cd 2+ The adsorption capacity test method is based on the method of "Wang Cheng et al., Study on the hydrothermal conversion of natural clinoptilolite to Na-P zeolite and its cadmium adsorption performance, Mineral Protection and Utilization. 2021, 41(06): 96-102)".

[0019] In an alternative embodiment, the specific surface area of ​​the zeolite is 21 m 2 / g-72m 2 / g.

[0020] In an optional embodiment, the mass fraction of CaCO3 in the shell is ≥90%, and the mass fraction of SrO is ≥0.3%.

[0021] In an alternative embodiment, the shell has a specific surface area of ​​110 m 2 / g-320m 2 / g.

[0022] In an optional embodiment, the shells include one or more of oyster shells, clam shells, and conch shells.

[0023] In an optional embodiment, the mass fraction of SiO2 in the volcanic ash is ≥50%, the mass fraction of Al2O3 is ≥30%, and the mass fraction of FeO is ≥2%.

[0024] In an alternative embodiment, the specific surface area of ​​the volcanic ash is 240 m 2 / g-470m 2 / g.

[0025] In an optional embodiment, the mass fraction of C in the activated carbon is ≥70%, and the mass fraction of O is 18%-25%.

[0026] In an optional embodiment, the specific surface area of ​​the activated carbon is ≥1000m 2 / g.

[0027] In an optional embodiment, the activated carbon includes one or more of bamboo charcoal activated carbon, wood activated carbon, and rice husk activated carbon.

[0028] The preparation method of activated carbon is completed by conventional technical means in this field.

[0029] In an optional embodiment, the preparation method of bamboo charcoal activated carbon comprises the following steps:

[0030] The moso bamboo is collected, dried, crushed and sieved, and the sieved material is carbonized under a protective atmosphere to obtain bamboo charcoal activated carbon.

[0031] In an optional embodiment, the mesh size of the sieve is 60-100 mesh; the protective atmosphere includes nitrogen; the temperature of the carbonization treatment is 450° C.-550° C., and the time of the carbonization treatment is 50 min-70 min.

[0032] In an optional embodiment, the mass fraction of Na4SiO4 (sodium silicate) in the silicon fertilizer is 55-65%, the mass fraction of K2SiO3 (potassium silicate) is 30-40%, the mass fraction of Na2Si2O5 (sodium persilicate) is 3-7%, and the mass fraction of Na2SiO3 (sodium metasilicate) is 1-3%.

[0033] In an optional embodiment, the mass fraction of C in humic acid is 40-50%, and the mass fraction of O is 45-55%.

[0034] The present invention also provides a method for preparing the soil conditioner, comprising the following steps:

[0035] S1. calcining the zeolite and shells;

[0036] S2. The material obtained by roasting S1 is mixed with guano phosphate rock, volcanic ash, activated carbon, silicon fertilizer, humic acid, and rice husk to obtain the soil conditioner.

[0037] In an optional embodiment, each raw material is crushed and sieved respectively, and then the undersized material of each raw material is subjected to S1 and S2 in sequence; the mesh number of the sieve is 60-100 mesh.

[0038] In an optional embodiment, in S1, the zeolite and the shell are mixed and calcined, and after the calcination, they are naturally cooled to room temperature.

[0039] In an optional embodiment, the calcination temperature in S1 is 400° C.-500° C., and the calcination time is 2 h-3 h.

[0040] In an optional embodiment, S2 further comprises granulation after mixing;

[0041] Optionally, the diameter of the particles obtained by granulation is 2 mm to 4 mm.

[0042] The invention also provides application of the soil conditioner in crop planting.

[0043] In an optional embodiment, the application method includes the following steps:

[0044] (1) Applying soil conditioners to the soil surface and then planting crops;

[0045] (2) Apply soil conditioner again before crops mature.

[0046] In an optional embodiment, the process of applying the soil conditioner to the soil surface in step (1) includes: applying the soil conditioner evenly to the soil surface 13 to 17 days before planting crops, and then plowing and first irrigation are performed in sequence, and the water is allowed to drain naturally after the first irrigation is completed.

[0047] In an optional embodiment, the application amount of the soil conditioner in step (1) is 50 kg / mu to 150 kg / mu.

[0048] In an optional embodiment, the water layer height of the first irrigation is 3 cm-5 cm.

[0049] In an optional embodiment, in step (1), when the crops are paddy field crops, a second irrigation is further performed 3 to 7 days before planting. After the second irrigation, the fields are harrowed and then the crops are planted.

[0050] In an optional embodiment, the paddy field crops include rice, and the water layer height of the second irrigation is 3 cm-5 cm.

[0051] In an optional embodiment, in step (1), when the crops are dryland crops, the land is directly cultivated after the water has naturally dried up, and then the crops are planted.

[0052] In an optional embodiment, the dryland crops include corn and vegetables.

[0053] In an optional embodiment, in step (2), before the crops mature, the soil conditioner is applied again and evenly spread on the soil surface or the roots of the crops.

[0054] Before crops mature, for grain or fruit crops, it refers to the heading and flowering period; for leaf or rhizome crops, it refers to 28-32 days before harvest.

[0055] In an optional embodiment, the application amount of the soil conditioner applied again in step (2) is 20kg / mu to 80kg / mu.

[0056] In an optional embodiment, when the crops are paddy field crops, after applying the soil conditioner again, a third irrigation is performed and the water is allowed to drain naturally; the water layer height of the third irrigation is 3 cm-5 cm.

[0057] In an optional embodiment, when the crops are dryland crops, after applying the soil conditioner again, a fourth irrigation is carried out in the furrows between the furrows to keep water in the furrows to ensure that the soil remains moist for 2-3 days.

[0058] The technical solution of the present invention has the following advantages:

[0059] 1. The present invention provides a soil conditioner comprising the following raw materials in parts by weight:

[0060] 30-80 parts of guano phosphate rock, 10-20 parts of zeolite, 10-20 parts of shells, 10-20 parts of volcanic ash, 10-20 parts of activated carbon, 5-10 parts of silicon fertilizer, 5-10 parts of humic acid, and 10-20 parts of rice husk.

[0061] The soil conditioner provided by the present invention is rich in various elements and organic matter such as silicon, calcium, aluminum, phosphorus, etc., and has a rich and diverse porous crystal structure, which enables it to effectively adsorb harmful heavy metal elements such as cadmium, lead, chromium, and mercury. At the same time, the conditioner releases effective silicon in the soil, thereby promoting the formation and absorption of effective selenium; the rich nutrients such as phosphorus it contains can help crop growth. Through the synergistic effect of each component, the soil conditioner can not only significantly reduce the content of heavy metals such as cadmium, lead, chromium, and mercury in crops, but also effectively increase the content of selenium and strontium in crops, while also promoting crop growth and increasing crop yield, achieving a dual improvement in soil improvement and crop quality and yield.

[0062] 2. The soil conditioner of the present invention uses guano phosphate as its main component. It is rich in silicon (SiO2 mass fraction ≥35%, effective silicon content ≥300mg / kg), calcium (CaO mass fraction ≥28%), phosphorus (P2O5 mass fraction ≥18%, effective P2O5 mass fraction ≥11%), and contains organic matter (organic matter mass fraction of 6%-7%) and trace elements such as aluminum (Al2O3 mass fraction of 2%-2.5%), iron (Fe2O3 mass fraction of 1.5%-2%), potassium (K2O mass fraction of 0.5%-1%), and strontium (SrO mass fraction of 0.1%-0.3%). These components together form a porous crystal structure with strong adsorption properties. This unique porous crystal structure not only efficiently absorbs heavy metals in the soil, but also directly promotes crop growth through the nutrients such as phosphorus and potassium it contains. In particular, the active strontium element therein can be directly absorbed by crops, thereby significantly increasing the strontium content of the crops.

[0063] 3. The raw materials for preparing the soil conditioner of the present invention also include zeolite, shells, and volcanic ash. Among them, zeolite is a porous aluminosilicate crystal with a water-containing framework structure (the mass fraction of SiO2 is ≥50%, the content of effective silicon is ≥150mg / kg, and the mass fraction of Al2O3 is ≥8%), shells are minerals with a porous fibrous double helix structure (the mass fraction of CaCO3 is ≥90%, and the mass fraction of SrO is ≥0.3%), and volcanic ash is a porous lightweight mineral formed by the cooling of volcanic lava (the mass fraction of SiO2 is ≥50%, the mass fraction of Al2O3 is ≥30%, and the mass fraction of FeO is ≥2%). By calcining the zeolite and shells, while removing the adsorbed water, interlayer water, and organic impurities, the silicon, calcium and other elements therein are activated; and by precisely controlling the calcination temperature (400℃-500℃), the three-dimensional pore structure inside the mineral is not destroyed, the specific surface area is increased, and its adsorption performance for heavy metal ions is significantly improved. Naturally formed volcanic ash minerals themselves have a good adsorption effect on heavy metals in the soil.

[0064] 4. The soil conditioner of the present invention is added with activated carbon, whose specific surface area is ≥1000m 2 / g, it has super strong heavy metal adsorption capacity, and the mass fraction of C in activated carbon is ≥70%. It can also improve soil structure after being applied to the soil.

[0065] 5. The silicon fertilizer (main component of which is water-soluble silicate) added to the soil conditioner of the present invention can directly form free silicate in the soil. Silicate and selenite have similar chemical structures and can compete with the adsorption sites of selenite in the soil (in the soil, selenite is the main form of selenium that plants can absorb and utilize), releasing more free selenite, thereby increasing the biological effectiveness of selenium in the soil; at the same time, silicate can also promote the expression of channel genes related to selenite and selenate absorption in the roots of crops (such as the rice OsNIP2 gene), further enhancing the crop's ability to absorb selenium. In addition, the guano phosphate rock, zeolite, volcanic ash and other ingredients contained in the soil conditioner are all rich in silicon. These minerals will gradually release free silicate in the soil, and by replacing selenite in the insoluble selenium, promote its conversion to effective selenium, and ultimately enhance the selenium-enriching ability of the crop.

[0066] 6. The soil conditioner of the present invention also contains humic acid and rice husks, which primarily regulate organic matter content and improve soil structure. Once applied to the soil, the soil conditioner blends more easily with the soil, and the organic matter helps improve soil permeability, thereby enhancing the soil conditioner's selenium-enriching and cadmium-reducing properties. DETAILED DESCRIPTION

[0067] The following examples are provided for a better understanding of the present invention and are not intended to limit the best mode of implementation. They do not limit the content and scope of protection of the present invention. Any product identical or similar to the present invention obtained by anyone under the guidance of the present invention or by combining the features of the present invention with other prior arts shall fall within the scope of protection of the present invention.

[0068] If no specific experimental steps or conditions are specified in the examples, the conventional experimental steps or conditions described in the literature in this field can be used. If the manufacturer of the reagents or instruments is not specified, they are all commercially available conventional reagents.

[0069] In the following embodiments and comparative examples of the present invention, (1) the raw material of guano phosphate ore is collected from a natural guano deposit in Kazakhstan. After mining on the deposit, the guano phosphate ore is crushed, jigged and graded to obtain the guano phosphate ore. The mass fraction of SiO2 in the guano phosphate ore is 35.97% (of which the effective silicon content is 312.26 mg / kg), the mass fraction of CaO is 28.82%, the mass fraction of P2O5 is 18.28% (of which the mass fraction of effective P2O5 is 11.65%), the mass fraction of organic matter is 6.43%, the mass fraction of Al2O3 is 2.28%, the mass fraction of Fe2O3 is 1.75%, the mass fraction of K2O is 0.81%, the mass fraction of SrO is 0.16%, and the specific surface area of ​​the guano phosphate ore is 128 m 2 / g, for Cd 2+ The adsorption capacity is 3.4 mg / g; (2) the zeolite is clinoptilolite, which comes from the zeolite mine in Faku County, Liaoning Province. The mass fraction of SiO2 in the zeolite is 50.78% (of which the effective silicon content is 188.45 mg / kg), the mass fraction of Al2O3 is 8.61%, and the specific surface area of ​​the zeolite is 43 m 2 / g, for Cd 2+ The adsorption capacity is 2.1 mg / g; (3) The oyster shell comes from the Pacific oyster in Zhangpu County, Fujian Province. The mass fraction of CaCO3 in the oyster shell is 94.37%, the mass fraction of SrO is 0.34%, and the specific surface area of ​​the oyster shell is 212 m 2 / g; (4) The volcanic ash comes from Tengchong City, Yunnan Province. The mass fraction of SiO2 in the volcanic ash is 58.28%, the mass fraction of Al2O3 is 32.18%, the mass fraction of FeO is 2.32%, and the specific surface area of ​​the volcanic ash is 359m 2 / g; (5) The preparation method of bamboo charcoal activated carbon includes the following steps: collecting bamboo from Yifeng County, Yichun City, Jiangxi Province, drying and crushing it, passing it through an 80-mesh sieve, placing the sieve-undergrowth into a tubular furnace, continuously introducing nitrogen, and carbonizing it at 500°C for 60 minutes to obtain bamboo charcoal activated carbon. The mass fraction of C in the bamboo charcoal activated carbon is 74.16%, the mass fraction of O is 21.81%, and the specific surface area of ​​the bamboo charcoal activated carbon is 1291m 2 / g; (6) Silicon fertilizer was purchased from Shanxi Fubang Fertilizer Co., Ltd., and the mass fraction of Na4SiO4, K2SiO3, Na2Si2O5 and Na2SiO3 in the silicon fertilizer was 58.1%, 34.2%, 4.7% and 2.2% respectively; (7) Humic acid was purchased from Shanxi Jiayou Humic Acid Technology Co., Ltd., and the mass fraction of C and O in the humic acid was 44.35% and 48.94% respectively; (8) Rice husks were the by-products of rice milling in Nanchang, Jiangxi Province.

[0070] In the following embodiments and comparative examples of the present invention, the planting base was selected from Gao'an City, Jiangxi Province, and the total area of ​​the planting base of the embodiments and comparative examples was 8.6 mu (the planting base was divided equally according to the area to serve as the planting base of each embodiment and comparative example).

[0071] Example 1

[0072] This embodiment provides a soil conditioner, comprising the following raw materials in parts by weight:

[0073] 50 parts of guano phosphate rock, 15 parts of zeolite, 20 parts of oyster shells, 20 parts of volcanic ash, 15 parts of bamboo charcoal activated carbon, 10 parts of silicon fertilizer, 8 parts of humic acid, and 10 parts of rice husks.

[0074] This embodiment also provides a method for preparing the soil conditioner, comprising the following steps:

[0075] The raw materials were crushed separately and passed through an 80-mesh sieve to obtain the undersize materials of the raw materials; the undersize materials of the zeolite and the undersize materials of the oyster shell were mixed in proportion, calcined at 500°C for 3 hours, and naturally cooled to room temperature. Then, the undersize materials of the remaining raw materials were added, mixed evenly, and formed into particles with a diameter of 3 mm by a granulator, which was a soil conditioner.

[0076] This embodiment also provides an application method of the above-mentioned soil conditioner (the crop is single-season rice), comprising the following steps:

[0077] Fifteen days before rice planting, evenly apply soil conditioner to the soil surface (at a rate of 100 kg / mu), then plow and irrigate the soil (to a water layer height of 3 cm), allowing the water to drain naturally. Irrigate again five days before planting (to a water layer height of 3 cm), harrow the field, and plant. During the rice heading and flowering period, apply soil conditioner again, evenly apply it to the soil surface (at a rate of 50 kg / mu), irrigate (to a water layer height of 3 cm), and allow the water to drain naturally.

[0078] Example 2

[0079] This embodiment provides a soil conditioner, comprising the following raw materials in parts by weight:

[0080] 70 parts of guano phosphate rock, 11 parts of zeolite, 16 parts of oyster shells, 12 parts of volcanic ash, 12 parts of bamboo charcoal activated carbon, 7 parts of silicon fertilizer, 10 parts of humic acid, and 17 parts of rice husks.

[0081] This embodiment also provides a preparation method of the soil conditioner, which is the same as that of Example 1.

[0082] This embodiment also provides an application method of the soil conditioner, which is the same as that of Example 1.

[0083] Example 3

[0084] This embodiment provides a soil conditioner, comprising the following raw materials in parts by weight:

[0085] 30 parts of guano phosphate rock, 17 parts of zeolite, 12 parts of oyster shells, 19 parts of volcanic ash, 13 parts of bamboo charcoal activated carbon, 9 parts of silicon fertilizer, 7 parts of humic acid, and 13 parts of rice husks.

[0086] This embodiment also provides a preparation method of the soil conditioner, which is the same as that of Example 1.

[0087] This embodiment also provides an application method of the soil conditioner, which is the same as that of Example 1.

[0088] Example 4

[0089] This embodiment provides a soil conditioner, which is the same as that of Example 1.

[0090] This embodiment also provides a preparation method of the soil conditioner, which is the same as that of Example 1.

[0091] This embodiment also provides an application method of the soil conditioner (the crop is corn), comprising the following steps:

[0092] Fifteen days before corn planting, evenly apply soil conditioner to the soil surface (at a rate of 100 kg / mu). Then, plow and irrigate the soil (to a depth of 3 cm). After irrigating, let the water drain naturally; then proceed directly to ploughing and planting. During the corn earing and flowering period, apply soil conditioner again, evenly applying it to the corn roots (at a rate of 50 kg / mu). Irrigate the furrows between the beds, keeping them constantly filled with water to ensure the soil remains moist for two days.

[0093] Comparative Example 1

[0094] This comparative example provides a soil conditioner that is substantially the same as Example 1, except that guano phosphate rock is not included.

[0095] This comparative example also provides a preparation method of the soil conditioner, which is substantially the same as that of Example 1, except that the addition of guano phosphate rock is not included.

[0096] This comparative example also provides an application method of the soil conditioner, which is the same as that of Example 1.

[0097] Comparative Example 2

[0098] This comparative example provides a soil conditioner that is substantially the same as Example 1, except that zeolite is not included.

[0099] This comparative example also provides a preparation method of the soil conditioner, which is substantially the same as that of Example 1, except that zeolite is not included.

[0100] This comparative example also provides an application method of the soil conditioner, which is the same as that of Example 1.

[0101] Comparative Example 3

[0102] This comparative example provides a soil conditioner that is substantially the same as Example 1, except that oyster shells are not included.

[0103] This comparative example also provides a preparation method of the soil conditioner, which is basically the same as that of Example 1, except that oyster shells are not added.

[0104] This comparative example also provides an application method of the soil conditioner, which is the same as that of Example 1.

[0105] Comparative Example 4

[0106] This comparative example provides a soil conditioner that is substantially the same as Example 1, except that volcanic ash is not included.

[0107] This comparative example also provides a preparation method of the soil conditioner, which is substantially the same as that of Example 1, except that volcanic ash is not included.

[0108] This comparative example also provides an application method of the soil conditioner, which is the same as that of Example 1.

[0109] Comparative Example 5

[0110] This comparative example provides a soil conditioner that is substantially the same as Example 1, except that bamboo charcoal activated carbon is not included.

[0111] This comparative example also provides a preparation method of the soil conditioner, which is substantially the same as that of Example 1, except that the addition of bamboo charcoal activated carbon is not included.

[0112] This comparative example also provides an application method of the soil conditioner, which is the same as that of Example 1.

[0113] Comparative Example 6

[0114] This comparative example provides a soil conditioner that is substantially the same as Example 1, except that silicon fertilizer is not included.

[0115] This comparative example also provides a preparation method of the soil conditioner, which is basically the same as that of Example 1, except that the addition of silicon fertilizer is not included.

[0116] This comparative example also provides an application method of the soil conditioner, which is the same as that of Example 1.

[0117] Comparative Example 7

[0118] This comparative example provides a soil conditioner that is substantially the same as Example 1, except that humic acid is not included.

[0119] This comparative example also provides a preparation method of the soil conditioner, which is substantially the same as that of Example 1, except that humic acid is not added.

[0120] This comparative example also provides an application method of the soil conditioner, which is the same as that of Example 1.

[0121] Comparative Example 8

[0122] This comparative example provides a soil conditioner that is substantially the same as Example 1, except that it does not include rice husks.

[0123] This comparative example also provides a preparation method of the soil conditioner, which is basically the same as that of Example 1, except that husks are not added.

[0124] This comparative example also provides an application method of the soil conditioner, which is the same as that of Example 1.

[0125] Comparative Example 9

[0126] This comparative example provides a soil conditioner comprising only the guano phosphate rock in Example 1.

[0127] This comparative example also provides a method for preparing the above-mentioned soil conditioner, comprising the following steps:

[0128] The guano phosphate rock is crushed and passed through an 80-mesh sieve. The sieve-undersized material is made into particles with a diameter of 3 mm by a granulator, which is a soil conditioner.

[0129] This comparative example also provides an application method of the soil conditioner, which is the same as that of Example 1.

[0130] Comparative Example 10

[0131] This comparative example provides a soil conditioner comprising only the zeolite in Example 1.

[0132] This comparative example also provides a method for preparing the above-mentioned soil conditioner, comprising the following steps:

[0133] The zeolite is crushed and passed through an 80-mesh sieve. The sieve material is calcined at 500°C for 3 hours, cooled naturally to room temperature, and made into particles with a diameter of 3 mm by a granulator, which is the soil conditioner.

[0134] This comparative example also provides an application method of the soil conditioner, which is the same as that of Example 1.

[0135] Comparative Example 11

[0136] This comparative example provides a soil conditioner comprising only the oyster shells in Example 1.

[0137] This comparative example also provides a method for preparing the above-mentioned soil conditioner, comprising the following steps:

[0138] The oyster shells are crushed and passed through an 80-mesh sieve. The sieved material is calcined at 500°C for 3 hours, naturally cooled to room temperature, and made into particles with a diameter of 3 mm by a granulator, which is the soil conditioner.

[0139] This comparative example also provides an application method of the soil conditioner, which is the same as that of Example 1.

[0140] Comparative Example 12

[0141] This comparative example provides a soil conditioner comprising only the volcanic ash in Example 1.

[0142] This comparative example also provides a method for preparing the above-mentioned soil conditioner, comprising the following steps:

[0143] The volcanic ash is crushed and passed through an 80-mesh sieve. The sieve-undersized material is passed through a granulator to form particles with a diameter of 3 mm, which is the soil conditioner.

[0144] This comparative example also provides an application method of the soil conditioner, which is the same as that of Example 1.

[0145] Comparative Example 13

[0146] This comparative example provides a soil conditioner, which only includes the bamboo charcoal activated carbon in Example 1.

[0147] This comparative example also provides a method for preparing the above-mentioned soil conditioner, comprising the following steps:

[0148] The bamboo charcoal activated carbon is crushed and passed through an 80-mesh sieve. The sieve-undergrowth is made into particles with a diameter of 3 mm by a granulator, which is a soil conditioner.

[0149] This comparative example also provides an application method of the soil conditioner, which is the same as that of Example 1.

[0150] Comparative Example 14

[0151] This comparative example provides a soil conditioner, which only includes the silicon fertilizer in Example 1.

[0152] This comparative example also provides a method for preparing the above-mentioned soil conditioner, comprising the following steps:

[0153] The silicon fertilizer is crushed and passed through an 80-mesh sieve. The sieve-under-size material is made into particles with a diameter of 3 mm by a granulator, which is the soil conditioner.

[0154] This comparative example also provides an application method of the soil conditioner, which is the same as that of Example 1.

[0155] Comparative Example 15

[0156] This comparative example provides a soil conditioner, which only includes the humic acid in Example 1.

[0157] This comparative example also provides a method for preparing the above-mentioned soil conditioner, comprising the following steps:

[0158] The humic acid is crushed and passed through an 80-mesh sieve. The sieve-undergrowth is made into particles with a diameter of 3 mm by a granulator, which is a soil conditioner.

[0159] This comparative example also provides an application method of the soil conditioner, which is the same as that of Example 1.

[0160] Comparative Example 16

[0161] This comparative example provides a soil conditioner comprising only the rice husks in Example 1.

[0162] This comparative example also provides a method for preparing the above-mentioned soil conditioner, comprising the following steps:

[0163] The husks are crushed and passed through an 80-mesh sieve, and the sieve material is made into particles with a diameter of 3 mm by a granulator, which is the soil conditioner.

[0164] This comparative example also provides an application method of the soil conditioner, which is the same as that of Example 1.

[0165] Comparative Example 17

[0166] In this comparative example, no soil conditioner was applied, and rice was planted according to a conventional method.

[0167] Comparative Example 18

[0168] In this comparative example, no soil conditioner was applied, and corn was planted according to a conventional method.

[0169] Experimental example

[0170] Before planting crops, five soil samples (1 kg each) were collected in a triangular pattern at the planting site. Selenium content in each soil sample was determined using the NY / T 1104-2006 method, "Determination of Total Selenium in Soil," with a calculated average value of 0.53 mg / kg. Strontium content in each soil sample was determined using the HJ 974-2018 method, "Determination of 11 Elements in Soil and Sediment by Alkali Fusion-Inductively Coupled Plasma-Emission Spectrometry," with a calculated average value of 59.7 mg / kg. Cadmium content in each soil sample was determined using the NY / T 4433-2023 method, "Determination of Cadmium in Agricultural Soil by Solid-State Electrothermal Evaporation Atomic Absorption Spectrometry," with a calculated average value of 1.21 mg / kg. The lead and chromium content of each soil sample was determined using NY / T 4435-2023, "Determination of Copper, Zinc, Lead, Chromium, and Arsenic in Soil - Energy Dispersive X-ray Fluorescence Spectrometry," with an average calculated lead content of 207.4 mg / kg and an average chromium content of 346.8 mg / kg. The mercury content of each soil sample was determined using NY / T 1121.10-2006, "Soil Testing - Part 10: Determination of Total Mercury in Soil," with an average calculated value of 0.55 mg / kg. The pH of each soil sample was determined using NY / T 1377-2007, "Determination of Soil pH," with an average calculated value of 4.8. The differences between the selenium, strontium, cadmium, lead, chromium, mercury, and pH values ​​of the five soil samples and their respective averages were all less than 5%, indicating good uniformity across the planting site.

[0171] After the rice of Examples 1 to 3 and Comparative Examples 1 to 17 matured, three rice fields were randomly selected from the planting bases corresponding to Examples 1 to 3 and Comparative Examples 1 to 17, with an area of ​​10 m2 per field. 2 , harvest the rice in each paddy field, weigh the rice after drying, and divide it by the harvested area to get the value per m 2 Rice yield data (the yield in Table 1 is per m 2 Yield data*667m 2 ). At the same time, 3 portions of rice were randomly harvested, each weighing 5 kg. After drying, they were milled with a rice mill into polished rice that meets the requirements of GB / T 1354-2018 "Rice", crushed, and the selenium, strontium, cadmium, lead, chromium, and mercury contents in the rice were detected in accordance with GB 5009.268-2016 "National Food Safety Standard - Determination of Multiple Elements in Food". The test results are shown in Table 1. The results in Table 1 are the average values ​​of the values ​​measured in the three rice fields. After the corns of Example 4 and Comparative Example 18 matured, three corn fields were randomly selected from the planting bases corresponding to Example 4 and Comparative Example 18, and the area of ​​each corn field was 40 m 2Corn from each cornfield was harvested, dried, and weighed. The weight was then divided by the harvested area to obtain corn yield data. Three 5kg portions of corn were also randomly harvested. After sun-drying, the kernels were collected and crushed. Selenium, strontium, cadmium, lead, chromium, and mercury were tested according to GB 5009.268-2016, "National Food Safety Standard - Determination of Multiple Elements in Food." The test results are shown in Table 1, which represents the average of the values ​​measured across the three cornfields.

[0172] Table 1 Measurement results of crops in various embodiments and comparative examples

[0173]

[0174]

[0175] Through comparative analysis of Examples 1 to 4 and Comparative Examples 17 to 18, it was found that after application of the soil conditioner of the present invention, the selenium and strontium contents of rice and corn were greatly increased, with selenium being more than 3 times that of the condition without the soil conditioner, and strontium being more than 2 times that of the condition without the soil conditioner; the cadmium, lead, chromium, and mercury contents of rice and corn were greatly reduced, with cadmium reduced to approximately 10.4%-12.5% ​​of the condition without the soil conditioner, lead reduced to approximately 10.3%-12.7%, chromium reduced to approximately 28.2%-35.6%, and mercury reduced to approximately 33.3%-45.5%, and the yield increased by approximately 26.7%-29.1%. The results show that the soil conditioner of the present invention is very effective in increasing the selenium and strontium content of crops while reducing cadmium, lead, chromium and mercury, and can increase yield, greatly improving the economic benefits of crops, and realizing the safe planting of crops in farmland where the heavy metal content in the soil exceeds the national standard (GB 15618-2018 "Soil Environmental Quality Agricultural Land Soil Pollution Risk Control Standard (Trial)"), and can control the heavy metal content below the national standard limit (GB 2762-2022 "National Food Safety Standard Limits of Contaminants in Food"), effectively solving the problem of excessive heavy metals in agricultural products.

[0176] Through comparative analysis of rice planting in Examples 1 to 3 and Comparative Examples 1 to 8, it was found that guano phosphate occupies a major position in the soil conditioner of the present invention. It is not only the main component for achieving the strontium enrichment effect, but also has the most outstanding contribution to reducing the content of heavy metals such as cadmium, lead, chromium, and mercury and increasing rice yield. At the same time, it also has a significant promoting effect on selenium enrichment; the strontium element provided by oyster shells is also very important for strontium enrichment of crops; silicon fertilizer plays a leading role in the selenium enrichment effect; and the other components are also indispensable in the soil conditioner and make important contributions to the overall effect. The absence of any component will result in the failure to achieve the expected comprehensive effect.

[0177] Furthermore, analysis of rice cultivation experiments conducted in Examples 1-3 and Comparative Examples 9-16 revealed that while the effects of a single component were not significant when applied alone, their addition to the soil conditioner significantly enhanced the effects. This suggests that the presence of other components can enhance the effects of a specific component, demonstrating a significant synergistic effect between the components in the soil conditioner.

[0178] Obviously, the above embodiments are merely examples for clarity of explanation and are not intended to limit the implementation methods. Those skilled in the art will readily appreciate that other variations or modifications based on the above descriptions are possible. It is not necessary and impossible to enumerate all implementation methods here. Obvious variations or modifications arising therefrom remain within the scope of protection of the present invention.

Claims

1. A soil conditioner, characterized in that Including the following raw materials by mass: 30-80 parts of guano phosphate rock, 10-20 parts of zeolite, 10-20 parts of shells, 10-20 parts of volcanic ash, 10-20 parts of activated carbon, 5-10 parts of silicon fertilizer, 5-10 parts of humic acid, and 10-20 parts of rice husk.

2. The soil conditioner according to claim 1, characterized in that The mass fraction of SiO2 in the guano phosphate rock is ≥35%, the mass fraction of CaO is ≥28%, the mass fraction of P2O5 is ≥18%, the mass fraction of organic matter is 6%-7%, the mass fraction of Al2O3 is 2%-2.5%, the mass fraction of Fe2O3 is 1.5%-2%, the mass fraction of K2O is 0.5%-1%, and the mass fraction of SrO is 0.1%-0.3%.

3. The soil conditioner according to claim 1 or 2, characterized in that The shells include one or more of oyster shells, clam shells, and conch shells; The activated carbon includes one or more of bamboo charcoal activated carbon, wood activated carbon, and rice husk activated carbon.

4. The method for preparing the soil conditioner according to any one of claims 1 to 3, characterized in that: The following steps are involved: S1. calcining the zeolite and shells; S2. The material obtained by roasting S1 is mixed with guano phosphate rock, volcanic ash, activated carbon, silicon fertilizer, humic acid, and rice husk to obtain the soil conditioner.

5. The method for preparing a soil conditioner according to claim 4, wherein: The calcination temperature in S1 is 400° C.-500° C., and the calcination time is 2 h-3 h.

6. The method for preparing the soil conditioner according to claim 4 or 5, characterized in that: S2 also includes granulation after mixing; Optionally, the diameter of the particles obtained by granulation is 2 mm to 4 mm.

7. Use of the soil conditioner according to any one of claims 1 to 3 or the soil conditioner prepared by the preparation method of the soil conditioner according to any one of claims 4 to 6 in crop planting.

8. The use according to claim 7, characterized in that The method of application comprises the following steps: (1) Applying soil conditioners to the soil surface and then planting crops; (2) Apply soil conditioner again before crops mature.

9. The use according to claim 8, characterized in that The application amount of the soil conditioner in step (1) is 50kg / mu-150kg / mu.

10. The use according to claim 8 or 9, characterized in that: Step (2) satisfies at least one of the following conditions: (1) When the crops are grain crops or fruit crops, the period before the crops mature is the heading and flowering period of the crops; when the crops are leaf crops or root crops, the period before the crops mature is 28 to 32 days before the crops are harvested; (2) The application amount of the soil conditioner applied again is 20kg / mu to 80kg / mu.

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