A biochar fertilization method, its biochar fertilizer, and its application.

Abstract

This invention belongs to the field of fertilizer technology, specifically relating to a biochar enrichment method, its biochar fertilizer, and its application. The biochar enrichment method includes: drying and pulverizing straw, mixing it with a 0.1 mol / L to 0.3 mol / L sulfuric acid solution at a mass ratio of 100:5 to 10, and pre-calcining at 100℃ to 150℃ for 0.5h to 1h to obtain a pre-calcined material; mixing the pre-calcined material with sodium carbonate at a mass ratio of 100:1 to 2, and calcining at 700℃ to 850℃ for 1h to 2h to obtain modified biochar; and mixing the modified biochar with Viola yedoensis powder at a mass ratio of 1000:1 to 5 to obtain biochar fertilizer. This invention provides a biochar fertilizer with good efficacy and high safety.

Description

Technical Field

[0001] This invention belongs to the field of fertilizer technology, specifically relating to a biochar cultivation method, its biochar fertilizer, and its application. Background Technology

[0002] Biochar, as a soil conditioner, possesses abundant pore structure, large specific surface area, and excellent adsorption properties, effectively improving the physical, chemical, and biological properties of soil and enhancing soil fertility, thus demonstrating great potential in soil improvement. Common biochar improvement methods include doping, granulation, coating, adsorption, and direct application.

[0003] The blending method involves mixing biochar with fertilizer in a specific ratio to create biochar-based fertilizer. This method is simple to operate, low in cost, and can quickly increase the content of nutrients such as nitrogen, phosphorus, and potassium in the soil. However, the effectiveness of biochar-based fertilizer is affected by the nutrient element formula in the blended fertilizer. If the nutrient element formula in the blended fertilizer is unreasonable, it will reduce the growth-promoting effect of the biochar-based fertilizer.

[0004] Granulation involves mixing biochar with fertilizer and then granulating it using methods such as disc granulation or mechanical extrusion. During granulation, binders are typically added to improve the fertilizer's mechanical properties. Compared to blending methods, biochar-based fertilizers produced by granulation have better slow-release effects and can significantly improve the physical and chemical properties of the soil. However, the granulation process is complex.

[0005] Coating is a method of treating fertilizers with a coating material that is poorly soluble in water. By controlling the thickness and properties of the coating material, the slow release of nutrients is achieved. This method can effectively reduce nutrient loss in the soil and improve fertilizer utilization. However, the preparation process for coating is relatively complex. In addition, some coating materials are difficult to degrade, which may pose a potential threat to the environment.

[0006] The adsorption method involves impregnating biochar in a nutrient-rich liquid. Utilizing the porous structure and adsorption properties of biochar, nutrients are adsorbed within it and subsequently released. This method is simple to operate, low in cost, and allows for precise control of the type and quantity of specific nutrients. However, biochar has limited adsorption capacity, which may affect fertilizer efficiency. Therefore, modification is needed to improve the adsorption capacity of biochar.

[0007] Direct application involves applying biochar directly to the soil, where its physical and chemical properties improve soil structure and fertility. This method is simple to operate and requires no complex processing. However, biochar has a low nutrient content and poor growth-promoting effect.

[0008] Plant growth is influenced by various environmental factors such as temperature and humidity. When plants grow rapidly or are under stress, they typically require effective fertilizers. While many biochar fertilization methods exist, fertilizers that can be quickly absorbed by plants do not promote growth effectively. Slow-release fertilizers are not quickly absorbed and cannot meet the plants' urgent nutritional needs, or their safety is questionable. Therefore, it is necessary to develop a method that is both effective and safe. Summary of the Invention

[0009] To address the aforementioned technical problems of "fertilizers that can be quickly absorbed by plants having poor growth-promoting effects, and slow-release fertilizers that cannot be quickly absorbed and cannot meet the urgent nutritional needs of plants or have low safety," this invention provides a biochar fertilization method, its biochar fertilizer, and its application.

[0010] The first objective of this invention is to provide a biochar cultivation method, comprising:

[0011] After drying, the straw is crushed and mixed with a 0.1 mol / L to 0.3 mol / L sulfuric acid solution at a mass ratio of 100:5 to 10. The mixture is then pre-calcined at 100℃ to 150℃ for 0.5 h to 1 h to obtain a pre-calcined product. The pre-calcined product is then mixed with sodium carbonate at a mass ratio of 100:1 to 2 and calcined at 700℃ to 850℃ for 1 h to 2 h to obtain modified biochar.

[0012] Modified biochar and Viola yedoensis powder were mixed at a mass ratio of 1000:1 to 5 to obtain biochar fertilizer.

[0013] The method of this invention first pre-calcines the straw powder with a 0.1 mol / L to 0.3 mol / L sulfuric acid solution to destroy the molecular structure of the straw and expose active sites. The modification effect is best when the pre-calcination time is controlled between 0.5 h and 1 h. If the time is too short, the straw structure cannot be destroyed; if the time is too long, the straw structure is excessively destroyed, resulting in severe loss of active sites and a decrease in adsorption efficiency. After pre-calcination, sodium carbonate is added to the pre-calcined material for further calcination to enhance the adsorption active sites in the biochar, thereby improving the adsorption performance of the biochar and increasing the specific surface area, resulting in a modified biochar product. Next, the modified biochar is mixed with Viola yedoensis powder. The combination of the two powders can adsorb a larger amount of nutrients, resulting in biochar fertilizer. When applied to the plant growth environment, the biochar fertilizer can be quickly absorbed by plants, showing good results. This invention is the first to discover that Viola yedoensis powder can promote plant growth and enhance the fertility of modified biochar. This invention does not use encapsulating agents or other recalcitrant substances, making it environmentally safe and beneficial.

[0014] It should be noted that the ratio of straw to sulfuric acid solution and sodium carbonate also affects the activity of modified biochar; the content of sulfuric acid solution and sodium carbonate should not be too high or too low. Furthermore, this invention emphasizes the synergistic combination of pre-calcination involving sulfuric acid solution and calcination involving sodium carbonate. If only the calcination step involving sodium carbonate is used, precipitation will occur on the surface of the biochar, reducing its adsorption performance. If only the pre-calcination step involving sulfuric acid solution is used, the specific surface area of ​​the obtained modified biochar will also be significantly reduced.

[0015] Preferably, in the above-mentioned biochar fertilization method, the pulverization refers to pulverizing the dried straw into powder of 60 mesh to 200 mesh.

[0016] Preferably, in the above-mentioned biochar fertilization method, the Viola yedoensis powder is pulverized to a mesh size of 60-200 mesh.

[0017] Preferably, in the above-mentioned biochar fertilization method, the Viola yedoensis powder is made by drying and pulverizing the whole Viola yedoensis plant.

[0018] Preferably, in the above-mentioned biochar enrichment method, the pre-calcined material is cooled to room temperature before being mixed with sodium carbonate.

[0019] Preferably, the above-mentioned biochar enrichment method further includes the addition of nutrient elements, with the following steps:

[0020] Biochar fertilizer is immersed in a liquid containing nutrients, allowed to stand, filtered, the precipitate collected, and dried to obtain a compound fertilizer. For example, it may be allowed to stand for more than 2 hours, or more specifically, 2, 3, 4, or 5 hours.

[0021] Preferably, in the above-mentioned biochar fertilization method, the nutrient element is at least one selected from soluble nitrogen, soluble phosphorus, and soluble potassium.

[0022] Preferably, the soluble nitrogen element is provided by at least one of the following components:

[0023] Urea is an organic nitrogen fertilizer with a high nitrogen content. It is decomposed into ammonium nitrogen by urease in the soil, and then absorbed and utilized by plants, resulting in high fertilizer efficiency.

[0024] Ammonium nitrate: Ammonium nitrate contains nitrogen in two forms: ammonium nitrogen and nitrate nitrogen. Both can be quickly absorbed by plants, resulting in rapid fertilizer effect and making it suitable for top dressing.

[0025] Ammonium sulfate: It is a physiologically acidic fertilizer. When used in acidic soils, it should be used in conjunction with alkaline substances such as lime to adjust the soil pH.

[0026] Soluble phosphorus is provided by at least one of the following components:

[0027] Superphosphate: It can quickly provide phosphorus to plants and is suitable for various soils and crops.

[0028] Potassium dihydrogen phosphate: It not only provides phosphorus but also potassium, and has multiple functions such as promoting crop growth and improving crop resistance.

[0029] Soluble potassium is provided by at least one of the following components:

[0030] Potassium chloride: It is a physiologically acidic fertilizer. Long-term use in acidic soils may increase soil acidity. It is suitable for crops such as rice, wheat, and corn.

[0031] Potassium sulfate: Suitable for various crops, such as tobacco, tea trees, grapes, etc., and can be used as base fertilizer, top dressing and seed fertilizer.

[0032] Potassium nitrate: It is a chlorine-free potassium fertilizer that also contains nitrogen, providing both potassium and nitrogen nutrients. It is suitable for various soils and crops, and is especially suitable for use on cash crops such as vegetables and fruits.

[0033] The second objective of this invention is to provide a biochar fertilizer prepared by the above method.

[0034] The third objective of this invention is to provide an application of biochar fertilizer, specifically, the biochar fertilizer has a growth-promoting effect on wheat, rice, or corn.

[0035] Preferably, promoting growth refers to increasing chlorophyll content, increasing plant height, and increasing stem diameter.

[0036] Compared with the prior art, the present invention has the following beneficial effects:

[0037] 1. The method of this invention first uses a 0.1mol / L to 0.3mol / L sulfuric acid solution to pre-calcine the straw powder, thereby destroying the molecular structure of the straw and exposing active sites. After the pre-calcination, sodium carbonate is added to the pre-calcined material for calcination to enhance the adsorption active sites in the biochar, thereby improving the adsorption performance of the biochar and increasing the specific surface area to obtain a modified biochar product. The modified biochar is mixed with Viola yedoensis powder and applied to the plant growth environment, where it can be quickly absorbed by the plants and has good effects.

[0038] 2. The invention is the first to discover that Viola yedoensis powder can promote plant growth and enhance the fertility of modified biochar.

[0039] 3. This invention does not use encapsulating agents or other recalcitrant substances, making it environmentally friendly, safe, and conducive to environmental protection.

[0040] 4. The biochar fertilizer of this invention can also be mixed with nutrient elements, wherein the nutrient elements are at least one of soluble nitrogen, soluble phosphorus, and soluble potassium. These nutrient elements are adsorbed by the mixture of modified biochar and Viola yedoensis powder to form a nutrient-rich compound fertilizer, which can effectively promote plant growth after application. Different types of nitrogen, phosphorus, and potassium-containing substances can be combined according to the different elemental needs of different plants, providing high flexibility. Attached Figure Description

[0041] Figure 1 This is a technical roadmap for Embodiment 1 of the present invention.

[0042] Figure 2 This is a technical roadmap for Embodiment 12 of the present invention. Detailed Implementation

[0043] To enable those skilled in the art to better understand and implement the technical solutions of the present invention, the present invention will be further described below in conjunction with specific embodiments and accompanying drawings.

[0044] Unless otherwise specified, all reagents used in this invention are commercially available, and all methods used are conventional techniques in the art.

[0045] Example 1

[0046] A biochar cultivation method, referring to Figure 1 ,include:

[0047] Corn stalks were dried and crushed into 60-mesh stalk powder, which was then mixed with 0.1 mol / L sulfuric acid solution at a mass ratio of 100:5 and pre-calcined at 100℃ for 1 h to obtain pre-calcined material. After the pre-calcined material was cooled to room temperature, it was mixed with sodium carbonate at a mass ratio of 100:1 and calcined at 700℃ for 2 h to obtain modified biochar.

[0048] Modified biochar was mixed with 60-mesh dried Viola yedoensis whole herb powder at a mass ratio of 1000:1 to obtain biochar fertilizer.

[0049] Example 2

[0050] A biochar cultivation method, comprising:

[0051] Corn stalks were dried and crushed into 60-mesh stalk powder, which was then mixed with 0.3 mol / L sulfuric acid solution at a mass ratio of 100:5 and pre-calcined at 100℃ for 1 h to obtain pre-calcined material. After the pre-calcined material was cooled to room temperature, it was mixed with sodium carbonate at a mass ratio of 100:1 and calcined at 700℃ for 2 h to obtain modified biochar.

[0052] Modified biochar was mixed with 60-mesh dried Viola yedoensis whole herb powder at a mass ratio of 1000:1 to obtain biochar fertilizer.

[0053] Example 3

[0054] A biochar cultivation method, comprising:

[0055] Corn stalks were dried and crushed into 60-mesh stalk powder, which was then mixed with 0.1 mol / L sulfuric acid solution at a mass ratio of 100:10 and pre-calcined at 100℃ for 1 h to obtain pre-calcined material. After the pre-calcined material was cooled to room temperature, it was mixed with sodium carbonate at a mass ratio of 100:1 and calcined at 700℃ for 2 h to obtain modified biochar.

[0056] Modified biochar was mixed with 60-mesh dried Viola yedoensis whole herb powder at a mass ratio of 1000:1 to obtain biochar fertilizer.

[0057] Example 4

[0058] A biochar cultivation method, comprising:

[0059] Corn stalks were dried and crushed into 60-mesh stalk powder, which was then mixed with 0.1 mol / L sulfuric acid solution at a mass ratio of 100:5 and pre-calcined at 100℃ for 0.5 h to obtain pre-calcined material. After the pre-calcined material was cooled to room temperature, it was mixed with sodium carbonate at a mass ratio of 100:1 and calcined at 700℃ for 2 h to obtain modified biochar.

[0060] Modified biochar was mixed with 60-mesh dried Viola yedoensis whole herb powder at a mass ratio of 1000:1 to obtain biochar fertilizer.

[0061] Example 5

[0062] A biochar cultivation method, comprising:

[0063] Corn stalks were dried and crushed into 60-mesh stalk powder, which was then mixed with 0.1 mol / L sulfuric acid solution at a mass ratio of 100:5 and pre-calcined at 150℃ for 1 hour to obtain a pre-calcined product. After the pre-calcined product was cooled to room temperature, it was mixed with sodium carbonate at a mass ratio of 100:1 and calcined at 700℃ for 2 hours to obtain modified biochar.

[0064] Modified biochar was mixed with 60-mesh dried Viola yedoensis whole herb powder at a mass ratio of 1000:1 to obtain biochar fertilizer.

[0065] Example 6

[0066] A biochar cultivation method, comprising:

[0067] Corn stalks were dried and crushed into 60-mesh stalk powder, which was then mixed with 0.1 mol / L sulfuric acid solution at a mass ratio of 100:5 and pre-calcined at 100℃ for 1 h to obtain pre-calcined material. After the pre-calcined material was cooled to room temperature, it was mixed with sodium carbonate at a mass ratio of 100:2 and calcined at 700℃ for 2 h to obtain modified biochar.

[0068] Modified biochar was mixed with 60-mesh dried Viola yedoensis whole herb powder at a mass ratio of 1000:1 to obtain biochar fertilizer.

[0069] Example 7

[0070] A biochar cultivation method, comprising:

[0071] Corn stalks were dried and crushed into 60-mesh stalk powder, which was then mixed with 0.1 mol / L sulfuric acid solution at a mass ratio of 100:5 and pre-calcined at 100℃ for 1 hour to obtain a pre-calcined product. After the pre-calcined product was cooled to room temperature, it was mixed with sodium carbonate at a mass ratio of 100:1 and calcined at 850℃ for 2 hours to obtain modified biochar.

[0072] Modified biochar was mixed with 60-mesh dried Viola yedoensis whole herb powder at a mass ratio of 1000:1 to obtain biochar fertilizer.

[0073] Example 8

[0074] A biochar cultivation method, comprising:

[0075] Corn stalks were dried and crushed into 60-mesh stalk powder, which was then mixed with 0.1 mol / L sulfuric acid solution at a mass ratio of 100:5 and pre-calcined at 100℃ for 1 hour to obtain pre-calcined material. After cooling the pre-calcined material to room temperature, it was mixed with sodium carbonate at a mass ratio of 100:1 and calcined at 700℃ for 1 hour to obtain modified biochar.

[0076] Modified biochar was mixed with 60-mesh dried Viola yedoensis whole herb powder at a mass ratio of 1000:1 to obtain biochar fertilizer.

[0077] Example 9

[0078] A biochar cultivation method, comprising:

[0079] Corn stalks were dried and crushed into 60-mesh stalk powder, which was then mixed with 0.1 mol / L sulfuric acid solution at a mass ratio of 100:5 and pre-calcined at 100℃ for 1 h to obtain pre-calcined material. After the pre-calcined material was cooled to room temperature, it was mixed with sodium carbonate at a mass ratio of 100:1 and calcined at 700℃ for 2 h to obtain modified biochar.

[0080] Modified biochar was mixed with 60-mesh dried Viola yedoensis whole herb powder at a mass ratio of 1000:5 to obtain biochar fertilizer.

[0081] Example 10

[0082] A biochar cultivation method, comprising:

[0083] Corn stalks were dried and crushed into 200-mesh stalk powder, which was then mixed with 0.1 mol / L sulfuric acid solution at a mass ratio of 100:5 and pre-calcined at 100℃ for 1 h to obtain a pre-calcined product. After the pre-calcined product was cooled to room temperature, it was mixed with sodium carbonate at a mass ratio of 100:1 and calcined at 700℃ for 2 h to obtain modified biochar.

[0084] Modified biochar was mixed with 60-mesh dried Viola yedoensis whole herb powder at a mass ratio of 1000:1 to obtain biochar fertilizer.

[0085] Example 11

[0086] A biochar cultivation method, comprising:

[0087] Corn stalks were dried and crushed into 60-mesh stalk powder, which was then mixed with 0.1 mol / L sulfuric acid solution at a mass ratio of 100:5 and pre-calcined at 100℃ for 1 h to obtain pre-calcined material. After the pre-calcined material was cooled to room temperature, it was mixed with sodium carbonate at a mass ratio of 100:1 and calcined at 700℃ for 2 h to obtain modified biochar.

[0088] Modified biochar was mixed with 200-mesh dried Viola yedoensis whole herb powder at a mass ratio of 1000:1 to obtain biochar fertilizer.

[0089] Example 12

[0090] A biochar cultivation method, referring to Figure 2 ,include:

[0091] Corn stalks were dried and crushed into 60-mesh stalk powder, which was then mixed with 0.1 mol / L sulfuric acid solution at a mass ratio of 100:5 and pre-calcined at 100℃ for 1 h to obtain pre-calcined material. After the pre-calcined material was cooled to room temperature, it was mixed with sodium carbonate at a mass ratio of 100:1 and calcined at 700℃ for 2 h to obtain modified biochar.

[0092] Modified biochar was mixed with 60-mesh dried Viola yedoensis whole herb powder at a mass ratio of 1000:1 to obtain biochar fertilizer.

[0093] Adding Nutrient Elements: The biochar fertilizer is immersed in a liquid containing nutrient elements, allowed to stand for 2 hours, filtered through a 200-mesh filter, the precipitate is collected, and naturally air-dried to obtain a compound fertilizer. The liquid containing nutrient elements is a 0.1 mol / L ammonium chloride solution.

[0094] Example 13

[0095] A biochar cultivation method, comprising:

[0096] Corn stalks were dried and crushed into 60-mesh stalk powder, which was then mixed with 0.1 mol / L sulfuric acid solution at a mass ratio of 100:5 and pre-calcined at 100℃ for 1 h to obtain pre-calcined material. After the pre-calcined material was cooled to room temperature, it was mixed with sodium carbonate at a mass ratio of 100:1 and calcined at 700℃ for 2 h to obtain modified biochar.

[0097] Modified biochar was mixed with 60-mesh dried Viola yedoensis whole herb powder at a mass ratio of 1000:1 to obtain biochar fertilizer.

[0098] Adding Nutrient Elements: The biochar fertilizer is immersed in a liquid containing nutrient elements, allowed to stand for 2 hours, filtered through a 200-mesh filter, the precipitate is collected, and naturally air-dried to obtain a compound fertilizer. The liquid containing nutrient elements is a 0.1 mol / L disodium hydrogen phosphate solution.

[0099] Example 14

[0100] A biochar cultivation method, comprising:

[0101] Corn stalks were dried and crushed into 60-mesh stalk powder, which was then mixed with 0.1 mol / L sulfuric acid solution at a mass ratio of 100:5 and pre-calcined at 100℃ for 1 h to obtain pre-calcined material. After the pre-calcined material was cooled to room temperature, it was mixed with sodium carbonate at a mass ratio of 100:1 and calcined at 700℃ for 2 h to obtain modified biochar.

[0102] Modified biochar was mixed with 60-mesh dried Viola yedoensis whole herb powder at a mass ratio of 1000:1 to obtain biochar fertilizer.

[0103] Adding Nutrient Elements: The biochar fertilizer is immersed in a liquid containing nutrient elements, allowed to stand for 2 hours, filtered through a 200-mesh filter, the precipitate is collected, and naturally air-dried to obtain a compound fertilizer. The liquid containing nutrient elements is a 0.1 mol / L potassium chloride solution.

[0104] Compare with Example 1

[0105] A biochar cultivation method, in this comparative example, omits the acid treatment step and involves two calcinations, specifically including:

[0106] Corn stalks were dried and crushed into 60-mesh stalk powder, and then pre-calcined at 100℃ for 1 hour to obtain pre-calcined material. After cooling the pre-calcined material to room temperature, it was mixed with sodium carbonate at a mass ratio of 100:1 and calcined at 700℃ for 2 hours to obtain modified biochar.

[0107] Modified biochar was mixed with 60-mesh dried Viola yedoensis whole herb powder at a mass ratio of 1000:1 to obtain biochar fertilizer.

[0108] Compare with Example 2

[0109] A biochar cultivation method, in this comparative example, does not involve two calcinations but directly mixes three raw materials, specifically including:

[0110] Corn stalks were dried and crushed into 60-mesh stalk powder, which was then mixed with 0.1 mol / L sulfuric acid solution and sodium carbonate in a mass ratio of 100:5:1 and calcined at 700℃ for 2 hours to obtain modified biochar.

[0111] Modified biochar was mixed with 60-mesh dried Viola yedoensis whole herb powder at a mass ratio of 1000:1 to obtain biochar fertilizer.

[0112] Compare with Example 3

[0113] A biochar cultivation method, comprising:

[0114] Corn stalks were dried and crushed into 60-mesh stalk powder, which was then mixed with 0.05 mol / L sulfuric acid solution at a mass ratio of 100:5 and pre-calcined at 100℃ for 1 h to obtain pre-calcined material. After the pre-calcined material was cooled to room temperature, it was mixed with sodium carbonate at a mass ratio of 100:1 and calcined at 700℃ for 2 h to obtain modified biochar.

[0115] Modified biochar was mixed with 60-mesh dried Viola yedoensis whole herb powder at a mass ratio of 1000:1 to obtain biochar fertilizer.

[0116] Compare with Example 4

[0117] A biochar cultivation method, comprising:

[0118] Corn stalks were dried and crushed into 60-mesh stalk powder, which was then mixed with 0.5 mol / L sulfuric acid solution at a mass ratio of 100:5 and pre-calcined at 100℃ for 1 h to obtain pre-calcined material. After the pre-calcined material was cooled to room temperature, it was mixed with sodium carbonate at a mass ratio of 100:1 and calcined at 700℃ for 2 h to obtain modified biochar.

[0119] Modified biochar was mixed with 60-mesh dried Viola yedoensis whole herb powder at a mass ratio of 1000:1 to obtain biochar fertilizer.

[0120] Compare with Example 5

[0121] A biochar cultivation method, referring to Figure 1 ,include:

[0122] Corn stalks were dried and crushed into 60-mesh stalk powder, which was then mixed with 0.1 mol / L sulfuric acid solution at a mass ratio of 100:5 and pre-calcined at 100℃ for 1 hour to obtain pre-calcined material. After cooling the pre-calcined material to room temperature, it was calcined at 700℃ for 2 hours to obtain modified biochar.

[0123] Modified biochar was mixed with 60-mesh dried Viola yedoensis whole herb powder at a mass ratio of 1000:1 to obtain biochar fertilizer.

[0124] Compare with Example 6

[0125] A biochar cultivation method, comprising:

[0126] Corn stalks were dried and crushed into 60-mesh stalk powder, which was then mixed with 0.1 mol / L sulfuric acid solution at a mass ratio of 100:5 and pre-calcined at 100℃ for 1 h to obtain pre-calcined material. After the pre-calcined material was cooled to room temperature, it was mixed with sodium carbonate at a mass ratio of 100:1 and calcined at 700℃ for 2 h to obtain modified biochar.

[0127] Modified biochar was mixed with 60-mesh dried Viola yedoensis aerial parts powder at a mass ratio of 1000:1 to obtain biochar fertilizer.

[0128] Compare with Example 7

[0129] A biochar cultivation method, comprising:

[0130] Corn stalks were dried and crushed into 60-mesh stalk powder, which was then mixed with 0.1 mol / L sulfuric acid solution at a mass ratio of 100:5 and pre-calcined at 100℃ for 1 h to obtain pre-calcined material. After the pre-calcined material was cooled to room temperature, it was mixed with sodium carbonate at a mass ratio of 100:1 and calcined at 700℃ for 2 h to obtain modified biochar.

[0131] Compare with Example 8

[0132] Only 60-mesh Viola yedoensis whole herb powder was used as biochar fertilizer.

[0133] I. Performance Testing of Different Modified Biochar

[0134] (1) Experimental methods

[0135] Prepare several ammonium chloride solutions with a nitrogen concentration of 30 mg / 100 mL. Add 1 g of modified biochar to each solution, stir for 30 min, and then test the nitrogen adsorption capacity. Repeat each group three times and take the average value.

[0136] Prepare several solutions of potassium dihydrogen phosphate with a phosphorus concentration of 20 mg / 100 mL. Add 1 g of modified biochar to each solution, stir for 30 min, and then test the phosphorus adsorption capacity. Repeat each group three times and take the average value.

[0137] In addition, the specific surface area of ​​the biochar was tested.

[0138] (2) Test Results

[0139] Since the modified biochar of Examples 9, 11 to 14 is essentially the same as that of Example 1, its effects are not described again in Table 1.

[0140] Table 1 Performance test results of different modified biochars

[0141]

[0142] Table 1 shows that the modified biochar prepared in the embodiments of the present invention has a large specific surface area and high adsorption capacity for nitrogen and phosphorus. Compared with Example 1, Control Example 1, because it did not have an acid treatment step and only used sodium carbonate for calcination, produced precipitation on the surface of the biochar, reducing the adsorption performance of the biochar. Therefore, the specific surface area of ​​its modified biochar was significantly reduced, indicating that acid treatment contributed to the increase of specific surface area. Compared with Example 1, Control Example 2 did not involve two calcinations and directly mixed the three raw materials. The results showed that the specific surface area of ​​its modified biochar was significantly reduced because the direct mixing of acid and sodium carbonate led to an excessively rapid reaction, resulting in a short time for participation in biochar modification. Compared with Example 1, the sulfuric acid solution concentration in Control Example 3 was too low, and the sulfuric acid solution concentration in Control Example 4 was too high. The specific surface area of ​​their modified biochar was significantly reduced, indicating that the concentration of sulfuric acid solution also has a significant impact on the specific surface area. Compared with Example 1, Control Example 5, which only used acid for calcination, also showed a significantly reduced specific surface area of ​​the modified biochar.

[0143] II. Effects of Different Biochar Fertilizers on the Growth of Potted Corn

[0144] Apply the fertilizer to potted Shenyu 21 maize plants sown in June of the summer, once a month, for a total of six months, until the maize reaches the milk stage. The application rate for each type of bio-carbon fertilizer is 1 kg / m². 2 The plant height, diameter, and root length of maize were measured at the milk stage, and the results are shown in Table 2.

[0145] Table 2 Effects of different biochar fertilizers on the growth of potted maize

[0146]

[0147]

[0148] The results in Table 2 show that, compared with the control group without fertilizer, the biochar fertilizer of the present invention significantly promoted the growth of maize. Compared with the control group without fertilizer, the application of Viola yedoensis aboveground part powder (control group 6), the application of modified biochar (control example 7), and the application of Viola yedoensis whole herb powder (control example 8) also promoted maize growth, but the promoting effect was not as good as that of the respective example groups.

[0149] It should be noted that when numerical ranges are involved in this invention, it should be understood that both endpoints of each numerical range and any value between the two endpoints can be selected. Since the steps and methods used are the same as in the embodiments, preferred embodiments are described in this invention to avoid redundancy. Although preferred embodiments of this invention have been described, those skilled in the art, once they understand the inventive concept of this invention, can make other changes and modifications to these embodiments, and all such changes and modifications fall within the scope of this invention.

[0150] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. If such modifications and variations fall within the scope of equivalents of this invention, then this invention also intends to include these modifications and variations.

Claims

1. A method for biochar cultivation, characterized in that, include: After drying, the straw is crushed and mixed with a 0.1 mol / L to 0.3 mol / L sulfuric acid solution at a mass ratio of 100:5 to 10. The mixture is then pre-calcined at 100℃ to 150℃ for 0.5 to 1 hour to obtain a pre-calcined product. The pre-calcined product is then mixed with sodium carbonate at a mass ratio of 100:1 to 2 and calcined at 700℃ to 850℃ for 1 to 2 hours to obtain modified biochar. Modified biochar and Viola yedoensis powder were mixed at a mass ratio of 1000:1~5 to obtain biochar fertilizer; Viola powder is made by drying and pulverizing the whole Viola plant.

2. The biochar cultivation method according to claim 1, characterized in that, The term "pulverization" refers to crushing dry straw into straw powder of 60 to 200 mesh.

3. The biochar cultivation method according to claim 1, characterized in that, The powder of Viola yedoensis is pulverized to a mesh size of 60-200 mesh.

4. The biochar cultivation method according to claim 1, characterized in that, After cooling the pre-calcined material to room temperature, it is then mixed with sodium carbonate.

5. The biochar cultivation method according to claim 1, characterized in that, It also includes the addition of nutrients, the steps of which are as follows: Biochar fertilizer is immersed in a liquid containing nutrients, allowed to stand, filtered, the precipitate is collected, and dried to obtain a compound fertilizer.

6. The biochar cultivation method according to claim 5, characterized in that, The nutrient element is at least one of soluble nitrogen, soluble phosphorus, and soluble potassium.

7. Biochar fertilizer prepared by the biochar cultivation method according to any one of claims 1 to 6.

8. The application of biochar fertilizer according to claim 7, characterized in that, The biochar fertilizer has a growth-promoting effect on wheat, rice, or corn.

9. The application of biochar fertilizer according to claim 8, characterized in that, The promotion of growth refers to increasing chlorophyll content, increasing plant height, and increasing stem diameter.

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