Biochar compound and method for reducing influence of soil residual film on crops by biochar compound

Abstract

The invention relates to a biochar compound and a method for reducing the influence of soil film residue on crops, the biochar compound comprises the following components by weight: 10-15% of bentonite, 3-5% of polyacrylamide, 0.1-0.2% of EPS, 3-5% of a yeast extract, 0.5-1% of a pine extract, 0.1-0.3% of a mint extract, 0.01-0.03% of iron oxide, 0.01-0.03% of molybdenum disulfide, and the balance of water. And the balance of charcoal. By adopting the combination of the porous material, the thallus enrichment material, the residual film decomposition aid and the slow-release material, on one hand, the permeability of soil containing the residual film can be effectively improved, and the influence of the residual film on crop growth is reduced; on the other hand, degradation of the residual film can be effectively promoted, and then the content of the residual film in the soil is reduced.

Description

Technical Field

[0001] The invention relates to a biochar composite and a method for reducing the influence of residual soil film on crops, belonging to the technical field of reducing farmland pollution. Background Art

[0002] The mulching technology can significantly increase soil temperature, increase soil moisture, maintain soil moisture, and increase crop yields, playing an irreplaceable role in increasing and stabilizing crop yields in my country. However, because people have long focused on the use of mulching films and ignored recycling, the recycling rate of agricultural films in the season is less than 2 / 3, and mulching film residues exist in farmland in various mulching areas to varying degrees. Since the main components of mulching films are polymer materials such as polyethylene, these materials have a large molecular weight and a stable structure, and are difficult to decompose under natural conditions. At present, the pollution of mulching film residues in farmland in my country is relatively serious, and the amount of mulching film residues in long-term mulching farmland is between 71.9–259.1 kg / hm2. Due to the influence of agricultural machinery operations, the residual film is mainly distributed in the tillage layer, that is, the 0–30 cm soil layer, and the amount of residual film in the deeper soil layer is relatively small compared to the upper layer. The size and shape of the residual film in the soil are diverse, mainly in the form of sheets, curled cylinders, and curled balls, and are randomly distributed in the soil along horizontal, inclined, and vertical angles. Residual plastic film brings a series of problems. Residual plastic film destroys soil structure, changes soil aeration, affects soil water and fertilizer migration and microbial community, hinders the growth of underground crops, and reduces crop yields. There are two existing methods to solve residual plastic film. One is to collect residual plastic film from the soil by mechanical or manual means to achieve the purpose of removal, but the overall cost is high and the recycling efficiency is low. Another method is to add porous materials such as biochar to farmland to improve soil permeability. Reference 1 (Chao G, Xiaohou S, Xu Y, et al. Effects of Biochar and Residual Plastic Film on Soil Properties and Root of Flue-Cured Tobacco [J]. Journal of Irrigation and Drainage Engineering, 2022, 148 (4):) used biochar to test tobacco fields containing residual plastic film. The results showed that adding an appropriate amount of biochar can improve the soil environment of RPF, increase the saturated water content of the soil by 4.5% to 11.4%, and increase the root activity by 6.3% to 13.4%. In addition, the density of flue-cured tobacco roots has also increased significantly, which can alleviate the soil cultivation obstacles caused by residual mulch film, improve the soil's water holding and water release capacity, and optimize the tobacco plant growth environment. However, adding porous materials can only change the morphology of soil residual film, and has little effect on the overall growth and development of crops, and does not reduce the content of soil residual film. Summary of the invention

[0003] The present invention provides a biochar composite and a method for reducing the impact of residual film in soil on crops, which solves the problem that it is difficult to effectively reduce the residual film content and improve the growth and development of crops by adding porous materials such as biochar to the existing soil containing production.

[0004] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0005] A biochar composite comprises, by weight percentage, 10-15% bentonite, 3-5% polyacrylamide, 0.1-0.2% EPS, 3-5% yeast extract, 0.5-1% pine extract, 0.1-0.3% mint extract, 0.01-0.03% iron oxide, 0.01-0.03% molybdenum disulfide, and the balance is biochar.

[0006] Furthermore, preferably: the bentonite is calcium-based bentonite; and the polyacrylamide is cationic polyacrylamide.

[0007] Further, preferably: the EPS extraction method is: take a certain amount of sludge, centrifuge at a speed of 5000-6000r / min, discard the supernatant, add 1% NaCl solution to the original volume, and stir to make the sludge suspended; repeat the above steps several times to complete the cleaning of the sludge; place the cleaned sludge in a water bath at 70-90°C, add NaOH to adjust the pH to 10-11, and react for 30-40min; then cool to room temperature, centrifuge at a speed of 4000-5000r / min for 20-30min, take the supernatant, and dry at a low temperature of 50-60°C to obtain EPS.

[0008] Furthermore, preferably: the biochar is powdered wood particle biochar.

[0009] A method for preparing a biochar composite comprises the following steps:

[0010] (1) 1 / 5-1 / 3 of bentonite is uniformly mixed with EPS, yeast extract, pine extract and peppermint extract to obtain a mixture I for later use;

[0011] (2) 1 / 5-1 / 3 of bentonite is uniformly mixed with iron oxide and molybdenum disulfide to obtain a mixture II for later use;

[0012] (3) dissolving polyacrylamide in water to form a polyacrylamide solution with a mass concentration of 5%;

[0013] (4) Spraying mixture I and mixture II with 1 / 4 polyacrylamide solution respectively and mixing them evenly;

[0014] (5) mixing mixture I sprayed with the polyacrylamide solution and mixture II uniformly to obtain mixture III;

[0015] (6) Spraying mixture III with 1 / 4 polyacrylamide solution, mixing evenly, drying at 50-60° C. for 1 h, and obtaining mixture IV;

[0016] (7) Mix the mixture IV with the biochar and the remaining bentonite, and then spray with the remaining polyacrylamide solution, mix evenly, and dry at 50-60° C. for 6-8 hours to reduce the moisture content to less than 15%, thereby obtaining a biochar composite.

[0017] The present invention also provides a method for reducing the impact of residual film in soil on crops, wherein the biochar composite prepared by the present invention is added during the crop planting process.

[0018] Furthermore, preferably: the addition amount of the biochar composite is 5-10t / hm2.

[0019] Beneficial effects of the present invention:

[0020] The present invention adopts a combination of porous materials (bentonite and biochar), bacterial enrichment materials (EPS and yeast extract), residual film decomposition aids (pine extract, mint extract, iron oxide and molybdenum disulfide) and slow-release materials (polyacrylamide), which can effectively improve the permeability of soil containing residual film and reduce the impact of residual film on crop growth on the other hand, and effectively promote the degradation of residual film, thereby reducing the content of residual film in the soil.

[0021] Porous materials: Bentonite has good adsorption and expansion properties, which can effectively improve the air permeability and water retention of the soil and increase the porosity of the soil; biochar has a porous structure, which can improve the water and fertilizer retention capacity of the soil. The combined use of the two can further optimize the soil structure and provide a good soil environment for the growth of crops. At the same time, the porous structure in biochar can also provide more attachment area, which is conducive to the growth and reproduction of microorganisms, further promote the activity of rhizosphere microorganisms, and effectively enrich bacteria that can degrade residual film. The adsorption of bentonite can accelerate the transfer and transformation of residual film decomposition products and reduce the pollution of residual film to the soil.

[0022] Bacteria enrichment material: EPS, as a high molecular polymer secreted by microorganisms, can provide a matrix for microbial growth in anaerobic environments, while yeast extract contains a variety of biologically active ingredients. The combined use of the two can significantly enhance the activity of soil microorganisms, enrich bacteria, and accelerate the biodegradation of residual films, thereby reducing its negative impact on soil and crop growth.

[0023] Residual film decomposition aids: Pine extract and mint extract contain a variety of bioactive ingredients, such as volatile oils and phenolic compounds, which can serve as carbon sources and growth factors for microorganisms, promoting the growth and reproduction of microorganisms that decompose plastics in the soil. Iron oxide and molybdenum disulfide act as catalysts to produce free radicals, which can destroy the chemical structure of residual film, making it easier for microorganisms to decompose it.

[0024] Pine extract and mint extract can improve the chemical environment of the soil and increase the organic matter content of the soil, while the photocatalytic effect of iron oxide and molybdenum disulfide can decompose organic pollutants in the soil, reduce the molecular weight of residual film, make it easier to be recognized and utilized by microorganisms, and provide a more favorable environment for the biodegradation of residual film. Catalytic effect of iron oxide and molybdenum disulfide. At the same time, the organic matter in pine and mint extracts can provide additional carbon sources, further promoting the biodegradation of residual film by microorganisms. At the same time, during the decomposition of residual film, the catalytic effect of iron oxide and molybdenum disulfide can reduce the generation of toxic intermediates or convert them into harmless substances, thereby reducing the potential toxicity of residual film to the soil environment. The combined use of pine extract, mint extract, iron oxide and molybdenum disulfide can effectively promote the decomposition of residual film in the soil through the interaction of multiple mechanisms, while reducing the impact on the environment, and has great application potential.

[0025] As a soil conditioner, polyacrylamide has good water absorption and water retention. It can absorb moisture in the soil and keep it moist, providing a moist environment for microorganisms, which is conducive to the growth of microorganisms and the decomposition of residual film. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0027] Figure 1 This is a diagram of the tobacco root system configuration according to an embodiment of the present invention. DETAILED DESCRIPTION

[0028] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0029] The raw materials used in the following examples of the present invention are as follows:

[0030] The bentonite used was fertilizer bentonite with whiteness ≥90%, colloid value 50, expansion multiple 10-12, Ph 6.5-7.5, purchased from Gongyi Hongle Mineral Products Co., Ltd.

[0031] The polyacrylamide used was cationic polyacrylamide, purchased from Gongyi Top Water Purification Materials Co., Ltd.

[0032] EPS: Take a certain amount of sludge, centrifuge at 6000r / min, discard the supernatant, add 1% NaCl solution to the original volume, and stir to make the sludge suspended; repeat the above steps several times to complete the cleaning of the sludge; place the cleaned sludge in a water bath at 70℃, add NaOH to adjust the pH to 10.5, and react for 40min; then cool to room temperature, centrifuge at 5000r / min for 20min, take the supernatant, and dry at 50℃ to obtain EPS. The sludge was taken from the activated sludge of a water plant in Zhengzhou, with a moisture content of 96.8% and a solid organic matter content of 26.7%.

[0033] The yeast extract used was yeast extract powder from Shandong Xinzhuoyuan Chemical Co., Ltd.

[0034] Pine extract is a substance extracted from the pine needles (pine leaves) and pine bark of pine trees. It contains polyphenols. The extraction method is: take fresh pine needles in winter, crush the pine needles, add 60% ethanol in a volume ratio of 1:5, soak at 80°C for 6 hours, then filter, evaporate the filtrate, dry and crush.

[0035] Peppermint extract was purchased from Zhejiang Shengshi Biotechnology Co., Ltd.

[0036] Iron oxide and molybdenum disulfide were commercially available and of analytical grade.

[0037] Biochar: 200 mesh, purchased from Ningxia Watson Activated Carbon Manufacturing Co., Ltd.

[0038] Example 1

[0039] A biochar composite comprises, by weight percentage, 10% bentonite, 4% polyacrylamide, 0.1% EPS, 3% yeast extract, 0.6% pine extract, 0.1% mint extract, 0.01% iron oxide, 0.01% molybdenum disulfide, and the balance being biochar.

[0040] The preparation method thereof comprises the following steps:

[0041] (1) uniformly mixing 1 / 5 of bentonite with EPS, yeast extract, pine extract and peppermint extract to obtain a mixture I for later use;

[0042] (2) uniformly mixing 1 / 5 of the bentonite with iron oxide and molybdenum disulfide to obtain a mixture II for later use;

[0043] (3) dissolving polyacrylamide in water to form a polyacrylamide solution with a mass concentration of 5%;

[0044] (4) Spraying mixture I and mixture II with 1 / 4 polyacrylamide solution respectively and mixing them evenly;

[0045] (5) mixing mixture I sprayed with the polyacrylamide solution and mixture II uniformly to obtain mixture III;

[0046] (6) Spraying mixture III with 1 / 4 polyacrylamide solution, mixing evenly, drying at 60° C. for 1 h, and obtaining mixture IV;

[0047] (7) Mix the mixture IV with the biochar and the remaining bentonite, and then spray with the remaining polyacrylamide solution, mix well, and dry at 60° C. for 6 h to reduce the moisture content to less than 15%, thereby obtaining a biochar composite.

[0048] Example 2

[0049] A biochar composite comprises, by weight percentage, 13% bentonite, 3% polyacrylamide, 0.1% EPS, 5% yeast extract, 0.5% pine extract, 0.2% mint extract, 0.02% iron oxide, 0.03% molybdenum disulfide, and the balance being biochar.

[0050] The preparation method thereof comprises the following steps:

[0051] (1) uniformly mixing 1 / 3 of bentonite with EPS, yeast extract, pine extract and peppermint extract to obtain a mixture I for later use;

[0052] (2) uniformly mixing 1 / 3 of the bentonite with iron oxide and molybdenum disulfide to obtain a mixture II for later use;

[0053] (3) dissolving polyacrylamide in water to form a polyacrylamide solution with a mass concentration of 5%;

[0054] (4) Spraying mixture I and mixture II with 1 / 4 polyacrylamide solution respectively and mixing them evenly;

[0055] (5) mixing mixture I sprayed with the polyacrylamide solution and mixture II uniformly to obtain mixture III;

[0056] (6) Spraying mixture III with 1 / 4 polyacrylamide solution, mixing evenly, drying at 50° C. for 1 h, and obtaining mixture IV;

[0057] (7) Mix the mixture IV with the biochar and the remaining bentonite, and then spray with the remaining polyacrylamide solution, mix well, and dry at 50° C. for 8 h to reduce the moisture content to less than 15%, thereby obtaining a biochar composite.

[0058] Example 3

[0059] A biochar composite comprises, by weight percentage, 15% bentonite, 5% polyacrylamide, 0.2% EPS, 4% yeast extract, 0.7% pine extract, 0.3% mint extract, 0.03% iron oxide, 0.02% molybdenum disulfide, and the balance being biochar.

[0060] The preparation method thereof comprises the following steps:

[0061] (1) uniformly mixing 1 / 4 of bentonite with EPS, yeast extract, pine extract and peppermint extract to obtain a mixture I for later use;

[0062] (2) uniformly mixing 1 / 4 of the bentonite with iron oxide and molybdenum disulfide to obtain a mixture II for later use;

[0063] (3) dissolving polyacrylamide in water to form a polyacrylamide solution with a mass concentration of 5%;

[0064] (4) Spraying mixture I and mixture II with 1 / 4 polyacrylamide solution respectively and mixing them evenly;

[0065] (5) mixing mixture I sprayed with the polyacrylamide solution and mixture II uniformly to obtain mixture III;

[0066] (6) Spraying mixture III with 1 / 4 polyacrylamide solution, mixing evenly, drying at 60° C. for 1 h, and obtaining mixture IV;

[0067] (7) Mix the mixture IV with the biochar and the remaining bentonite, and then spray with the remaining polyacrylamide solution, mix well, and dry at 60° C. for 8 h to reduce the moisture content to less than 15%, thereby obtaining a biochar composite.

[0068] Example 4

[0069] Basically the same as Example 1, except that: a biochar composite, in terms of weight percentage, includes 12% bentonite, 4% polyacrylamide, 0.1% EPS, 4% yeast extract, 0.8% pine extract, 0.2% mint extract, 0.02% iron oxide, 0.02% molybdenum disulfide, and the balance is biochar.

[0070] Example 5

[0071] Basically the same as Example 1, except that: a biochar composite, in terms of weight percentage, includes 14% bentonite, 3% polyacrylamide, 0.2% EPS, 3% yeast extract, 1% pine extract, 0.1% mint extract, 0.01% iron oxide, 0.01% molybdenum disulfide, and the balance is biochar.

[0072] Effects of biochar composites on the decomposition rate of tobacco roots, tobacco leaf products and residual film

[0073] Test variety: Yunyan 87

[0074] Test site: In an experimental base in Zhengzhou, Henan. The matrix is ​​yellow-brown soil, with physical and chemical properties: organic matter 28.67g / kg, total nitrogen 1.69g / kg, alkaline nitrogen 162.35mg / kg, available phosphorus 14.64mg / kg, available potassium 102.36mg / kg, pH 7.2.

[0075] The biochar composite was mixed with soil and applied to the test pots before tobacco transplanting at a rate of 7.5 t / hm 2 . Use residual film to pick up the field, the size is unified to 2cm 2 Square residual film of about 350kg / hm2 2 .

[0076] Soil fertilization: tobacco-specific fertilizer (N:P 2 O 5 :K 2 O=15:15:15), the fertilizer application rate is 150kg / hm 2 .

[0077] The experiment used potted plants with an inner diameter of 40 cm and a height of 35 cm. The various raw materials of the culture medium (matrix, biochar composite, residual film and tobacco-specific fertilizer) were mixed evenly and placed in the experimental pot with a height of 30 cm. The tobacco seedlings required for the experiment were taken from the seedling base of the Tobacco College of Henan Agricultural University. The seedlings were also raised in trays with substrates and cultivated in greenhouses. Defoliation is required before transplanting. The specific method is to remove the leaf tips to increase the stem thickness and improve the survival rate of transplants. The growth period of tobacco is divided into three growth periods: root extension period (0-35 days after transplanting), vigorous growth period (36-65 days after transplanting) and maturity period (66 days after transplanting-end of harvesting). No topdressing is required during the growth of tobacco, just maintain normal moisture.

[0078] The culture medium without additives (film residue, biochar composite and biochar) was used as control example 1, and the culture medium containing biochar and film residue was used as control example 2; the other cultures used the biochar composite and film residue of Examples 1-5 as additives. Each experiment was repeated 3 times.

[0079] Tobacco root system architecture

[0080] When the tobacco is mature and the leaves are picked, the roots of the tobacco are cut off, the test pot is turned upside down to take out the entire root system, the soil is carefully shaken off, the root system of the whole tobacco plant is obtained, and the roots are placed in clean water, the roots are washed, and the moisture of the roots is absorbed with experimental absorbent paper. The roots are taken out and placed on a white background paper, and a ruler is placed next to the roots. Finally, a photo is taken to obtain the root system configuration of the tobacco. The results are as follows Figure 1 shown.

[0081] The tobacco root system has a conical structure, with thicker lateral roots and more adventitious roots on them. The residual film changes the soil structure and hinders the growth of the root system, and the root system cannot penetrate the residual film to extend. Figure 1 It can be seen that in Control Example 1, no residual film was added, the root growth was not hindered, and the root system was the most dense and complete. In Control Example 2, biochar was added alone, and the root system was relatively sparse. In Examples 1-5, the biochar composite was added, and the root system was significantly improved compared with Control Example 2. The root system was denser as a whole, almost the same as Control Example 1. It can be seen that the addition of biochar composite can effectively improve the effect of residual film on the root system and promote the growth and development of tobacco.

[0082] Tobacco leaf biomass

[0083] Tobacco leaf biomass is the tobacco leaf weighing method. At maturity, the stems and leaves are separated from the plants and placed in a drying oven. After being sterilized at 105°C for 30 minutes, they are dried at 75°C for 72 hours to constant weight. The oven is closed and the leaves are weighed after being kept at a constant temperature, and the tobacco leaf yield is calculated.

[0084] Residual film decomposition rate:

[0085] After the tobacco matures, the roots of the tobacco are taken out, the culture medium is sieved with a 50-mesh sieve, the remaining residual film is picked out, and then it is rinsed with water, dried at 75°C for 72 hours to constant weight, and the oven is closed to a constant temperature and then weighed to calculate the residual film reduction rate.

[0086] See Table 1 for specific data.

[0087] Table 1 Tobacco biomass and residual film content in different examples

[0088]

[0089] As shown in Table 1, residual film has an important impact on the amount of tobacco leaves. Compared with the control example 1, the tobacco leaf yield reduction rate of the control example 2 is 23.74%. The addition of biochar composites in Examples 1-5 effectively reduces the impact of residual film on tobacco, and the tobacco leaf yield reduction rate is significantly reduced to between 2.19-4.90%. Compared with the control example 2, the tobacco leaf biomass of Examples 1-5 is significantly increased, and the yield increase rate reaches 24.73-27.62%.

[0090] For residual film, the biochar composite of the present invention can effectively reduce the amount of residual film. Through the combined action of microorganisms and compounds, the residual film can be reduced and decomposed into small particles, effectively reducing the impact of residual film on crop roots. Compared with control example 2, the residual film reduction rate reaches 14.63-17.21%.

[0091] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A biochar composite, characterized in that: Calculated by weight percentage, the invention comprises 10-15% bentonite, 3-5% polyacrylamide, 0.1-0.2% EPS, 3-5% yeast extract, 0.5-1% pine extract, 0.1-0.3% mint extract, 0.01-0.03% iron oxide, 0.01-0.03% molybdenum disulfide, and the balance is biochar.

2. The biochar composite according to claim 1, characterized in that: The bentonite is calcium-based bentonite; the polyacrylamide is cationic polyacrylamide.

3. The biochar composite according to claim 1, characterized in that: The EPS extraction method is as follows: taking a certain amount of sludge, centrifuging at a speed of 5000-6000 r / min, discarding the supernatant, adding 1% NaCl solution to the original volume, and stirring to make the sludge suspended; repeating the above steps several times to complete the cleaning of the sludge; placing the cleaned sludge in a water bath at 70-90° C., adding NaOH to adjust the pH to 10-11, and reacting for 30-40 minutes; Then cool to room temperature, centrifuge at 4000-5000r / min for 20-30min, take the supernatant, and dry at 50-60℃ to obtain EPS.

4. The biochar composite according to claim 1, characterized in that: The biochar is powdered wood particle biochar.

5. A method for preparing a biochar composite according to any one of claims 1 to 4, characterized in that: The following steps are involved: (1) 1 / 5-1 / 3 of bentonite is uniformly mixed with EPS, yeast extract, pine extract and peppermint extract to obtain a mixture I for later use; (2) 1 / 5-1 / 3 of bentonite is uniformly mixed with iron oxide and molybdenum disulfide to obtain a mixture II for later use; (3) dissolving polyacrylamide in water to form a polyacrylamide solution with a mass concentration of 5%; (4) Spraying mixture I and mixture II with 1 / 4 polyacrylamide solution respectively and mixing them evenly; (5) mixing mixture I sprayed with the polyacrylamide solution and mixture II uniformly to obtain mixture III; (6) Spraying mixture III with 1 / 4 polyacrylamide solution, mixing evenly, drying at 50-60° C. for 1 h, and obtaining mixture IV; (7) Mix the mixture IV with the biochar and the remaining bentonite, and then spray with the remaining polyacrylamide solution, mix evenly, and dry at 50-60° C. for 6-8 hours to reduce the moisture content to less than 15%, thereby obtaining a biochar composite.

6. A method for reducing the impact of residual film in soil on crops, characterized in that: The biochar composite prepared in claim 5 is added during the crop planting process.

7. The method according to claim 6, characterized in that: The amount of biochar composite added is 5-10t / hm 2 .

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