A biochar-based multi-purpose soil conditioner and a method of making the same

Abstract

The application discloses a kind of biochar-based multiple-effect soil conditioner and preparation method thereof, belong to soil remediation technical field.It is made of the following weight parts of raw materials: modified biochar 100-120 parts, microbial inoculum 10-20 parts, modified red mud 20-30 parts, diatomite 20-30 parts, poultry manure 80-100 parts, activator 10-20 parts;The microbial inoculum is Brevibacillus laterosporus, Trichoderma koningii, Streptomyces celluloxys and is composed according to the mass ratio of 1:1:1.The biochar-based multiple-effect soil conditioner prepared by the application can effectively improve the physical and chemical properties of soil through the synergistic effect of multiple components, such as increasing the pH value of acidic soil, increasing the organic matter content of soil, improving soil structure, increasing soil enzyme activity, etc., thereby significantly improving the fertility and health level of soil, which helps to promote the growth and development of plants and improve the yield and quality of crops.At the same time, the modified biochar and modified red mud are used in the application to improve the aeration and water permeability of soil, reduce the compactness of soil, improve the physical properties of soil, and also can combine with heavy metal ions in soil, reduce the biological availability of heavy metals, reduce the pollution of heavy metals to soil and crops, have excellent multiple soil improvement effect, and have wide market application prospect.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of soil remediation, and particularly relates to a biochar-based multi-effect soil conditioner and a preparation method thereof. BACKGROUND

[0002] In recent years, the agricultural production level in China has been continuously improved, but a series of problems such as resource waste, ecological degradation, environmental pollution and soil compaction caused by the high-consumption, low-efficiency and extensive production mode have become the bottleneck restricting the sustainable development of China's agriculture, which not only damages the immediate interests of the majority of farmers, but also aggravates the deterioration of the soil ecological environment. At present, the overall situation of the soil environment in China is not optimistic, and the soil pollution exceeding standard rate in China is 16.1%. The quality of the cultivated land soil environment is particularly worrying, and the farmland polluted by organic pollutants has reached 36 million hectares, and the land polluted by heavy metals has reached 20 million hectares, of which the seriously polluted land is more than 700,000 hectares. Soil pollution has posed a threat to the sustainable use of land resources and the ecological safety of agricultural products. Due to excessive application of chemical fertilizers and lack of organic fertilizers, soil pollution by heavy metals and organic matters is becoming increasingly serious, and problems such as soil pollution, acidification, compaction, salinization, and frequent occurrence of soil-borne diseases are becoming increasingly prominent. In terms of cultivated land soil: the plough layer is thinning, and the nutrients are imbalanced; pollution by heavy metals, pesticides and poor-quality chemical fertilizers is aggravated; acidification, salinization, drought and desertification are serious; there is a general lack of organic matter and trace elements; continuous cropping of crops leads to an increase in soil-borne diseases; soil fertility is declining, microbial activity is poor, and productivity is declining. In terms of fertilizer utilization: nitrogen loss, phosphorus fixation, and potassium loss have occurred. This has seriously affected the sustainable development of China's agriculture.

[0003] Soil conditioners are also known as soil improvement and remediation agents, which can improve the physical and chemical properties of soil, promote nutrient absorption of crops, and reduce heavy metal accumulation in crops. Different soils and crops have different physical and chemical indicators and nutrient promotion needs that need to be improved. Biochar is generally a carbonaceous solid material converted from biomass or solid waste (agricultural waste, sludge, animal manure) under anaerobic or anoxic conditions. Biochar is considered a renewable "carbon neutral" material because the amount of CO2 emitted during the thermal conversion of biomass to biochar is equivalent to the amount of CO2 fixed from the environment during photosynthesis. Compared with non-renewable solidifying agents such as cement, biochar can effectively stabilize heavy metals in contaminated soil, and biochar can improve the physical and chemical properties of soil and is beneficial to plant growth, and has a wide application in soil remediation. However, the adsorption and fixation effect of biochar as a soil conditioner is limited by the structure and composition of the raw material, and in the face of complex pollution conditions in the actual soil environment, biochar as a soil conditioner often fails to achieve the expected remediation effect. Although the existing biochar-based soil conditioner has certain soil conditioning effect, the function is single, and it cannot provide the necessary nutrients for the growth and development of plants, resulting in low yield increase and poor comprehensive performance. SUMMARY

[0004] The present application aims to provide a biochar-based multi-effect soil conditioner and a preparation method thereof. The biochar-based multi-effect soil conditioner prepared by the present application can effectively improve the physical and chemical properties of soil through the synergistic effect of multiple components, such as increasing the pH value of acidic soil, increasing the organic matter content of soil, improving the soil structure, increasing the soil enzyme activity, etc., thereby significantly improving the fertility and health level of soil, which is helpful to promote the growth and development of plants and improve the yield and quality of crops. At the same time, the modified biochar and modified red mud are used in the present application to improve the aeration and water permeability of soil, reduce the compactness of soil, improve the physical properties of soil, and also can combine with heavy metal ions in soil to reduce the biological availability of heavy metals, reduce the pollution of heavy metals to soil and crops, and has excellent multiple soil improvement effect, which has a wide market application prospect.

[0005] To achieve the above technical purposes, the technical scheme adopted by the present application is:

[0006] A biochar-based multi-effect soil conditioner is prepared from the following raw materials by weight: modified biochar 100-120 parts, microbial agent 10-20 parts, modified red mud 20-30 parts, diatomite 20-30 parts, poultry manure 80-100 parts, and activator 10-20 parts; the microbial agent is composed of Brevibacillus laterosporus, Trichoderma koningii, and Streptomyces cellulans in a mass ratio of 1:1:1.

[0007] Preferably, the preparation method of the modified biochar is as follows: clean plant straw is mixed with 0.1 mol / L nickel chloride solution according to a solid-liquid ratio, magnetically stirred at room temperature for 24 h, dried after centrifugation, and ground into fine powder, then the straw powder is calcined in a high-temperature furnace, calcined at 500 DEG C for 1 h, then calcined at 700 DEG C for 30 min, then naturally cooled to room temperature after 4 h of heat preservation to obtain the modified biochar.

[0008] Preferably, the solid-liquid ratio of the plant straw and the 0.1 mol / L nickel chloride solution is 1g:50ml.

[0009] Preferably, the preparation method of the modified red mud is as follows:

[0010] (1) Hydrochloric acid solution is mixed with red mud according to a liquid-solid ratio, then reacted at 80 DEG C for 1.5 h in a water bath, then washed to neutral with deionized water, dried at 100 DEG C for 24 h, then calcined at 550 DEG C for 6 h in a muffle furnace to obtain acid-treated red mud; the concentration of the hydrochloric acid solution is 1 mol / L;

[0011] (2) 1 mol / L Cu(NO3)2·3H2O solution is mixed with the acid-treated red mud obtained in step (1) according to a liquid-solid ratio of 50ml:1g, magnetically stirred at room temperature for 24 h, then centrifuged and dried to obtain a solid product, finally the solid product is calcined at 550 DEG C for 5 h in a muffle furnace, then taken out and ground into 80 mesh powder to obtain the modified red mud.

[0012] Preferably, the liquid-solid ratio in step (1) is 10ml:1g.

[0013] Preferably, the activator is a mixture of 2 mol / L zinc chloride solution and 1 mol / L phosphoric acid solution according to a volume ratio of 1:1.

[0014] Preferably, the Brevibacillus laterosporus has a preservation number of CGMCC No.1.15087, is selected from the China General Microbiological Culture Collection Center, and the preservation date is February 15, 2015; the Trichoderma koningi has a preservation number of CGMCC No.3.17875, is selected from the China General Microbiological Culture Collection Center, and the preservation date is December 15, 2015; the Streptomyces celluloxylanophilus has a preservation number of CGMCC No.4.6365, is selected from the China General Microbiological Culture Collection Center, and the preservation date is September 3, 2008. The Brevibacillus laterosporus, the Trichoderma koningi, and the Streptomyces celluloxylanophilus used in the application can be purchased through the preservation center strain catalog, and do not need to be additionally preserved.

[0015] Preferably, the preparation method of the microbial inoculant is as follows: Bacillus laterosporus, Trichoderma koningii and Streptomyces cellulans are respectively inoculated into sterilized beef extract peptone culture medium 500 mL shake flask, and cultured at 37 DEG C, 250 r / min vibration for 24h, to obtain bacterial suspension, then the bacterial suspensions are mixed according to the mass ratio of 1:1:1 to obtain the microbial inoculant. The beef extract peptone culture medium used is purchased from Qingdao High-tech Industrial Park Haibo Biotechnology Co., Ltd.

[0016] A preparation method of the above-mentioned biochar-based multi-effect soil conditioner, comprising the following steps:

[0017] (1) preparing a microbial inoculant;

[0018] (2) preparing modified biochar;

[0019] (3) preparing modified red mud;

[0020] (4) mixing the modified biochar obtained in step (2) with 2 times the volume of deionized water uniformly, then adding an activator into it, stirring and reacting at room temperature for 24h, then filtering to obtain the filter residue, washing with deionized water until neutral, and drying in an oven at 80 DEG C to obtain active biochar;

[0021] (5) mixing poultry manure, diatomite and modified red mud uniformly according to weight parts, adding water to make the water content 50%, then adding the prepared microbial inoculant into it, stirring uniformly, and then composting and fermenting, controlling the pile temperature to be not higher than 55 DEG C by turning the pile, continuously fermenting for 10 days, then adding the active biochar obtained in step (4) into it, stirring uniformly, and then continuously fermenting for 12h, after the fermentation is completed, drying and crushing the fermentation product, and using a granulator to granulate into 4-5mm particles to obtain the biochar-based multi-effect soil conditioner.

[0022] The raw materials used in the present application are commercially available unless otherwise specified.

[0023] The microbial inoculant is prepared by culturing the three strains of Bacillus laterosporus, Trichoderma koningii and Streptomyces cellulans, wherein the Streptomyces cellulans and Trichoderma koningii have significant bacteriostatic ability, can prevent and control various plant soil-borne diseases or inhibit pathogens, can also secrete various enzyme active substances, promote new root formation, and grow strong root, and quickly build a healthy and powerful root system; the Bacillus laterosporus not only has significant nematicidal function, but also can decompose toxic and harmful residual pesticides and other organic pollutants in the soil, and adsorb and prevent heavy metals from entering the plant. The three strains are used in equal proportions, and together with other components, they have a good conditioning effect on the soil.

[0024] Red mud, also known as bauxite residue, is an industrial by-product generated during the extraction of alumina from bauxite. As of 2020, the global stockpile of red mud has exceeded 5 billion tons, with China's red mud inventory exceeding 800 million tons. Due to the high cost of safe disposal of red mud, the current disposal method mainly adopts dry stacking, which not only causes serious waste of land resources but also brings a large amount of pollution problems. Therefore, it is necessary to comprehensively utilize red mud. Red mud itself has a unique structure rich in oxides (especially iron and aluminum oxides), surface hydroxyl groups, and porosity, and has certain heavy metal adsorption potential, and can be used as an environmental remediation material. The red mud modified by copper nitrate in the application improves the adsorption activity of red mud to heavy metal ions, effectively reducing the heavy metal pollution in the soil.

[0025] The modified biochar prepared in the application has metal nickel ions attached to the surface of the porous biochar, which changes the pore structure of the biochar and also changes the types of surface chemical functional groups. The modified biochar has a larger specific surface area, adjustable pore structure, and abundant active functional sites, which can effectively remove pollutants in the soil environment. At the same time, the activator used in the application can further improve the activity of multiple functional groups of the modified biochar, which not only can improve the physical properties of the soil, but also can combine with heavy metal ions in the soil to reduce the bioavailability of heavy metals and reduce the pollution of heavy metals to the soil and crops.

[0026] The biochar-based multi-effect soil conditioner of the application can be mixed with chemical fertilizers, and the dosage is 80-100 kg / acre. Through adsorption and slow-release effect, the loss and volatilization of chemical fertilizers are reduced, and the utilization efficiency of chemical fertilizers is improved. This not only can reduce the amount of chemical fertilizers and lower the cost of agricultural production, but also can reduce the pollution and damage to the environment.

[0027] The beneficial effects of the application are: the modified biochar and the modified red mud are mixed according to a specific ratio, the modified red mud as a mineral particle can be distributed in the porous carbon structure of the biochar, and under the joint action of the two, the pH of the acid soil can be significantly improved and the content of heavy metal ions in the soil can be reduced. At the same time, after the composite use of the porous structure of the modified biochar and the particle structure of the modified red mud, a suitable place for a large number of microorganisms to survive and reproduce is provided, which greatly improves the colonization success rate of microorganisms, effectively increases the number of microorganisms in the plant soil environment, and a large number of microorganisms acting on the soil can significantly improve the physical and chemical properties of the soil, improve the plant's disease and pest resistance, and improve the soil fertility. The soil conditioner of the application is also rich in various trace elements and vitamins, which provides comprehensive nutritional support for plants, and the organic matter and microorganisms can increase the organic matter content of the soil and improve the structure and aeration of the soil. DETAILED DESCRIPTION

[0028] The technical solutions of the present application are further described below in combination with specific examples, but are not limited thereto. The red mud used in the present application is a solid waste discharged by a certain aluminum plant in Shandong Province for preparing alumina by sintering method, and its specific chemical composition is shown in Table 1.

[0029] Table 1 Chemical composition of red mud

[0030]

[0031] Example 1

[0032] A biochar-based multi-effect soil conditioner is prepared from the following raw materials in parts by weight: modified biochar 100 parts, microbial agent 10 parts, modified red mud 20 parts, diatomite 20 parts, poultry manure 80 parts, and activating agent 10 parts; the microbial agent is composed of Brevibacillus laterosporus, Trichoderma koningii and Streptomyces cellulans in a mass ratio of 1:1:1.

[0033] The modified biochar is prepared as follows: clean plant straw is mixed with 0.1 mol / L nickel chloride solution at a solid-liquid ratio, and stirred magnetically at room temperature for 24 h, then dried and ground into fine powder after centrifugation, and then the straw powder is calcined in a high-temperature furnace, calcined at 500℃ for 1 h and then calcined at 700℃ for 30 min, and then naturally cooled to room temperature after holding for 4 h to obtain the modified biochar.

[0034] The solid-liquid ratio of the plant straw to 0.1 mol / L nickel chloride solution is 1 g:50 ml.

[0035] The modified red mud is prepared as follows:

[0036] (1) Hydrochloric acid solution is mixed with red mud at a liquid-solid ratio, and then reacted in a water bath at 80℃ for 1.5 h, then washed with deionized water until neutral, and dried at 100℃ for 24 h, and then calcined in a muffle furnace at 550℃ for 6 h to obtain acid-treated red mud; the concentration of the hydrochloric acid solution is 1 mol / L; the liquid-solid ratio is 10 ml:1 g;

[0037] (2) 1 mol / L Cu(NO3)2·3H2O solution is mixed with the acid-treated red mud obtained in step (1) at a liquid-solid ratio of 50 ml:1 g, and then stirred magnetically at room temperature for 24 h, then dried by centrifugation to obtain a solid product, and finally the solid product is calcined in a muffle furnace at 550℃ for 5 h, and then ground into 80-mesh powder to obtain the modified red mud.

[0038] The activating agent is a mixture of 2 mol / L zinc chloride solution and 1 mol / L phosphoric acid solution in a volume ratio of 1:1.

[0039] The B. laterosporus has a preservation number of CGMCC No. 1.15087, is selected from the China General Microbiological Culture Collection Center, and is preserved on February 15, 2015; the T. koningii has a preservation number of CGMCC No. 3.17875, is selected from the China General Microbiological Culture Collection Center, and is preserved on December 15, 2015; and the S. cellulans has a preservation number of CGMCC No. 4.6365, is selected from the China General Microbiological Culture Collection Center, and is preserved on September 3, 2008. The B. laterosporus, the T. koningii and the S. cellulans used in the present application can be purchased through the catalog of the preservation center, and do not need to be additionally preserved.

[0040] The preparation method of the microbial agent is as follows: the B. laterosporus, the T. koningii and the S. cellulans are respectively inoculated into 500 mL of sterilized beef extract peptone medium in a shake flask, and are cultured at 37℃ and 250 r / min for 24 h, to obtain bacterial suspensions, and then the bacterial suspensions are mixed according to a mass ratio of 1:1:1 to obtain the microbial agent. The beef extract peptone medium used is purchased from Qingdao Gaosi Technology Industrial Park Haibo Biotechnology Co., Ltd.

[0041] A preparation method of the above-mentioned biochar-based multi-effect soil conditioner, which comprises the following steps:

[0042] (1) preparing a microbial agent;

[0043] (2) preparing modified biochar;

[0044] (3) preparing modified red mud;

[0045] (4) mixing the modified biochar obtained in step (2) with 2 times the volume of deionized water, then adding an activating agent thereto, stirring and reacting at room temperature for 24 h, then filtering to obtain filter residue, washing the filter residue with deionized water until neutral, and drying the filter residue in an oven at 80℃ to obtain active biochar;

[0046] (5) mixing poultry manure, diatomite and modified red mud according to weight parts, adding water to make the water content 50%, then adding the prepared microbial agent thereto, stirring uniformly, and then composting and fermenting, wherein the temperature of the compost is controlled to be not higher than 55℃, and after continuous fermentation for 10 days, the active biochar obtained in step (4) is added thereto and stirred uniformly, and then the fermentation is continued for 12 h, and after the fermentation is completed, the fermentation product is dried, crushed and granulated into 4-5 mm particles by using a granulator to obtain the biochar-based multi-effect soil conditioner.

[0047] Example 2

[0048] A biochar-based multi-effect soil conditioner is made from the following raw materials by weight: modified biochar 120 parts, microbial agent 20 parts, modified red mud 30 parts, diatomite 30 parts, poultry manure 100 parts, and activator 20 parts; the microbial agent is composed of Brevibacillus laterosporus, Trichoderma koningii, and Streptomyces celluloxys in a mass ratio of 1:1:1.

[0049] The modified biochar is prepared as follows: clean plant straw is mixed with a 0.1 mol / L nickel chloride solution at a solid-liquid ratio, stirred magnetically at room temperature for 24 h, dried after centrifugation, ground into fine powder, then calcined in a high-temperature furnace, calcined at 500℃ for 1 h and then at 700℃ for 30 min, then naturally cooled to room temperature after 4 h of heat preservation to obtain the modified biochar.

[0050] The solid-liquid ratio of the plant straw to the 0.1 mol / L nickel chloride solution is 1 g:50 ml.

[0051] The modified red mud is prepared as follows:

[0052] (1) Hydrochloric acid solution is mixed with red mud at a liquid-solid ratio, then reacted in a water bath at 80℃ for 1.5 h, then washed with deionized water until neutral, dried at 100℃ for 24 h, then calcined in a muffle furnace at 550℃ for 6 h to obtain acid-treated red mud; the concentration of the hydrochloric acid solution is 1 mol / L; the liquid-solid ratio is 10 ml:1 g;

[0053] (2) 1 mol / L Cu(NO3)2·3H2O solution is mixed with the acid-treated red mud obtained in step (1) at a liquid-solid ratio of 50 ml:1 g, magnetically stirred at room temperature for 24 h, then centrifuged and dried to obtain a solid product, which is finally calcined in a muffle furnace at 550℃ for 5 h, then ground into 80-mesh powder to obtain the modified red mud.

[0054] The activator is a mixture of 2 mol / L zinc chloride solution and 1 mol / L phosphoric acid solution at a volume ratio of 1:1.

[0055] The Brevibacillus laterosporus has the preservation number CGMCC No.1.15087, is selected from the China General Microbiological Culture Collection Center, and was preserved on February 15, 2015; the Trichoderma koningii has the preservation number CGMCC No.3.17875, is selected from the China General Microbiological Culture Collection Center, and was preserved on December 15, 2015; the Streptomyces celluloxys has the preservation number CGMCC No.4.6365, is selected from the China General Microbiological Culture Collection Center, and was preserved on September 3, 2008. The Brevibacillus laterosporus, Trichoderma koningii, and Streptomyces celluloxys used in the present application can be purchased through the preservation center's catalog, and do not need to be additionally preserved.

[0056] The preparation method of the microbial agent is as follows: Bacillus laterosporus, Trichoderma koningii and Streptomyces celluloxylanofaciens are respectively inoculated into 500 mL sterilized beef extract peptone culture medium in a shake flask, and cultured at 37°C and 250 r / min for 24 h, to obtain bacterial suspensions, which are then mixed according to a mass ratio of 1:1:1 to obtain the microbial agent. The beef extract peptone culture medium is purchased from Qingdao Gaosi Technology Industrial Park Haibo Biotechnology Co., Ltd.

[0057] A preparation method of the above-mentioned biochar-based multi-effect soil conditioner, which comprises the following steps:

[0058] (1) preparing a microbial agent;

[0059] (2) preparing modified biochar;

[0060] (3) preparing modified red mud;

[0061] (4) mixing the modified biochar obtained in step (2) with 2 times the volume of deionized water uniformly, then adding an activator thereto, stirring and reacting at room temperature for 24 h, then filtering to obtain filter residue, washing with deionized water until neutral, and drying in an oven at 80°C to obtain active biochar;

[0062] (5) uniformly mixing poultry manure, diatomite and modified red mud according to weight parts, adding water to make the water content 50%, then adding the prepared microbial agent thereto, uniformly stirring, and composting and fermenting, wherein the temperature of the compost is controlled to be not higher than 55°C by turning, and after continuous fermentation for 10 days, the active biochar obtained in step (4) is added thereto, uniformly stirred, and then continuously fermented for 12 h, and after the fermentation is completed, the fermentation product is dried, crushed and granulated into 4-5 mm particles by a granulator to obtain the biochar-based multi-effect soil conditioner.

[0063] Example 3

[0064] A biochar-based multi-effect soil conditioner, which is prepared from the following raw materials in parts by weight: modified biochar 110 parts, microbial agent 15 parts, modified red mud 25 parts, diatomite 20-30 parts, poultry manure 90 parts, and activator 15 parts; the microbial agent is composed of Bacillus laterosporus, Trichoderma koningii and Streptomyces celluloxylanofaciens according to a mass ratio of 1:1:1.

[0065] The preparation method of the modified biochar is as follows: clean plant straw is mixed with 0.1 mol / L nickel chloride solution according to a solid-liquid ratio, and magnetically stirred at room temperature for 24 h, then centrifuged, dried and ground into fine powder, and then the straw powder is calcined in a high-temperature furnace, calcined at 500°C for 1 h, then calcined at 700°C for 30 min, then kept for 4 h, and then naturally cooled to room temperature to obtain the modified biochar.

[0066] The plant straw is mixed with 0.1 mol / L nickel chloride solution at a solid-liquid ratio of 1g:50ml.

[0067] The preparation method of the modified red mud is as follows:

[0068] (1) The hydrochloric acid solution is mixed with the red mud according to a liquid-solid ratio, and then reacted in a water bath at 80 DEG C for 1.5h, and then washed with deionized water until neutral, and dried at 100 DEG C for 24h, and then calcined in a muffle furnace at 550 DEG C for 6h to obtain the acid-treated red mud; the concentration of the hydrochloric acid solution is 1 mol / L; the liquid-solid ratio is 10ml:1g;

[0069] (2) The 1 mol / L Cu(NO3)2.3H2O solution is mixed with the acid-treated red mud obtained in step (1) according to a liquid-solid ratio of 50ml:1g, and then magnetically stirred at room temperature for 24h, and then centrifuged and dried to obtain a solid product, and finally the solid product is placed in a muffle furnace and calcined at 550 DEG C for 5h, and then taken out and ground into 80 mesh powder to obtain the modified red mud.

[0070] The activator is a 2 mol / L zinc chloride solution and a 1 mol / L phosphoric acid solution mixed according to a volume ratio of 1:1.

[0071] The Brevibacillus laterosporus has a preservation number of CGMCC No.1.15087, is selected from the China General Microbiological Culture Collection Center, and is preserved on February 15, 2015; the Trichoderma koningii has a preservation number of CGMCC No.3.17875, is selected from the China General Microbiological Culture Collection Center, and is preserved on December 15, 2015; and the Streptomyces celluloxylanophilus has a preservation number of CGMCC No.4.6365, is selected from the China General Microbiological Culture Collection Center, and is preserved on September 3, 2008. The Brevibacillus laterosporus, the Trichoderma koningii and the Streptomyces celluloxylanophilus used in the present application can be purchased through the preservation center strain catalog, and do not need to be additionally preserved.

[0072] The preparation method of the microbial agent is as follows: the Brevibacillus laterosporus, the Trichoderma koningii and the Streptomyces celluloxylanophilus are respectively inoculated into sterilized beef extract peptone culture medium 500 mL shake flasks, and are cultured at 37 DEG C and 250 r / min for 24h to obtain bacterial suspensions, and then the bacterial suspensions are mixed according to a mass ratio of 1:1:1 to obtain the microbial agent. The beef extract peptone culture medium is purchased from Qingdao Haibo Biotechnology Co., Ltd.

[0073] A preparation method of the above-mentioned biochar-based multi-effect soil conditioner, which comprises the following steps:

[0074] (1) preparing a microbial agent;

[0075] (2) Preparation of modified biochar;

[0076] (3) Preparation of modified red mud;

[0077] (4) The modified biochar obtained in step (2) is mixed with 2 times the volume of deionized water, then an activating agent is added, stirred at room temperature for 24 h, then filtered to obtain the residue, washed with deionized water until neutral, and dried in an oven at 80°C to obtain active biochar;

[0078] (5) The poultry manure, diatomite and modified red mud are mixed uniformly according to the weight parts, water is added to make the water content 50%, then the prepared microbial agent is added, stirred uniformly, and composted and fermented, the temperature of the compost is controlled to be not higher than 55°C by turning, and after continuous fermentation for 10 days, the active biochar obtained in step (4) is added, stirred uniformly, and then fermented for 12 h, and after the fermentation is completed, the fermentation product is dried, crushed and granulated into 4-5 mm particles by a granulator to obtain a biochar-based multi-effect soil conditioner.

[0079] Comparative Example 1

[0080] A biochar-based multi-effect soil conditioner, which is basically the same as Example 3 in terms of raw material composition and preparation method, except that the biochar used is unmodified biochar, and the preparation method is as follows: clean plant straw is dried and ground into fine powder, then the straw powder is placed in a high-temperature furnace for calcination, calcined at 500°C for 1 h, then calcined at 700°C for 30 min, then kept for 4 h and naturally cooled to room temperature to obtain unmodified biochar.

[0081] Comparative Example 2

[0082] A biochar-based multi-effect soil conditioner, which is basically the same as Example 3 in terms of raw material composition and preparation method, except that the red mud used is unmodified red mud, and the red mud discharged from the sintering process for preparing alumina purchased from an aluminum plant in Shandong is directly used as a raw material.

[0083] Comparative Example 3

[0084] A biochar-based multi-effect soil conditioner, which is basically the same as Example 3 in terms of raw material composition and preparation method, except that the raw material does not contain modified biochar and the corresponding preparation method step. The preparation method of the above-mentioned biochar-based soil conditioner is as follows:

[0085] (1) Preparation of microbial agent;

[0086] (2) Preparation of modified red mud;

[0087] (3) mixing poultry manure, diatomite, modified red mud and activator uniformly according to weight parts, adding water to make the water content 50%, then adding the prepared microbial agent, stirring uniformly, composting and fermenting, controlling the temperature of the pile body not higher than 55°C by turning the pile, after continuous fermentation for 10 days, drying and crushing the fermentation product, and using a granulator to granulate into 4-5mm particles to obtain the biochar-based multi-effect soil conditioner.

[0088] Comparative Example 4

[0089] A biochar-based multi-effect soil conditioner, the raw material composition and preparation method of which are basically the same as those of Example 3, the only difference being that the raw material does not contain modified red mud and the corresponding preparation method steps, and the specific preparation method of the biochar-based soil conditioner is as follows:

[0090] (1) preparing a microbial agent;

[0091] (2) preparing modified biochar;

[0092] (3) mixing the modified biochar obtained in step (2) with 2 times the volume of deionized water uniformly, then adding an activator, stirring at room temperature for 24h, then filtering to obtain the filter residue, washing with deionized water until neutral, and drying in an oven at 80°C to obtain active biochar;

[0093] (4) mixing poultry manure and diatomite uniformly according to weight parts, adding water to make the water content 50%, then adding the prepared microbial agent, stirring uniformly, composting and fermenting, controlling the temperature of the pile body not higher than 55°C by turning the pile, after continuous fermentation for 10 days, adding the active biochar obtained in step (3) and stirring uniformly, then continuing to ferment for 12h, after the fermentation is completed, drying and crushing the fermentation product, and using a granulator to granulate into 4-5mm particles to obtain the biochar-based multi-effect soil conditioner.

[0094] Comparative Example 5

[0095] A biochar-based multi-effect soil conditioner, the raw material composition and preparation method of which are basically the same as those of Example 3, the only difference being that it does not contain an activator and the step of preparing active biochar, and the corresponding preparation method of the biochar-based soil conditioner is as follows:

[0096] (1) preparing a microbial agent;

[0097] (2) preparing modified biochar;

[0098] (3) preparing modified red mud;

[0099] (4) mixing poultry manure, diatomite and modified red mud uniformly according to weight parts, adding water to make the water content 50%, then adding the prepared microbial inoculum, stirring uniformly, composting and fermenting, controlling the temperature of the pile body to be not higher than 55°C by turning the pile, continuously fermenting for 10 days, then adding the modified biochar obtained in step (2) and stirring uniformly, continuing to ferment for 12 h, after the fermentation is completed, drying and crushing the fermentation product, and using a granulator to granulate into 4-5 mm particles to obtain the biochar-based multi-effect soil conditioner.

[0100] Comparative Example 6

[0101] A biochar-based multi-effect soil conditioner, which is basically the same as Example 3 in terms of raw material composition and preparation method, except that the activator is a 2 mol / L zinc chloride solution.

[0102] Comparative Example 7

[0103] A biochar-based multi-effect soil conditioner, which is basically the same as Example 3 in terms of raw material composition and preparation method, except that the activator is a 1 mol / L phosphoric acid solution.

[0104] Comparative Example 8

[0105] A biochar-based multi-effect soil conditioner, which is basically the same as Example 3 in terms of raw material composition and preparation method, except that the microbial inoculum is composed of Brevibacillus laterosporus and Trichoderma koningii in a mass ratio of 1:1. The preparation method of the microbial inoculum is as follows: Brevibacillus laterosporus and Trichoderma koningii are respectively inoculated into 500 mL sterile beef extract peptone medium in a shake flask, and cultured at 37°C and 250 r / min for 24 h, to obtain bacterial suspensions, which are then mixed in a mass ratio of 1:1 to obtain the microbial inoculum. The beef extract peptone medium is purchased from Haibo Biotechnology Co., Ltd. in Qingdao High-tech Industrial Park.

[0106] Comparative Example 9

[0107] A biochar-based multi-effect soil conditioner, which is basically the same as Example 3 in terms of raw material composition and preparation method, except that the microbial inoculum is composed of Brevibacillus laterosporus and Streptomyces cellulophilus in a mass ratio of 1:1. The preparation method of the microbial inoculum is as follows: Brevibacillus laterosporus and Streptomyces cellulophilus are respectively inoculated into 500 mL sterile beef extract peptone medium in a shake flask, and cultured at 37°C and 250 r / min for 24 h, to obtain bacterial suspensions, which are then mixed in a mass ratio of 1:1 to obtain the microbial inoculum. The beef extract peptone medium is purchased from Haibo Biotechnology Co., Ltd. in Qingdao High-tech Industrial Park.

[0108] Comparative Example 10

[0109] A biochar-based multi-effect soil conditioner, the raw material composition and preparation method are basically the same as those of Example 3, the only difference is that the microbial agent is composed of Trichoderma koningii and Streptomyces cellulans in a mass ratio of 1:1. The preparation method of the microbial agent is as follows: Trichoderma koningii and Streptomyces cellulans are respectively inoculated into sterilized beef extract protein peptone medium 500 mL shake flask, and cultured at 37°C, 250 r / min for 24 h, to obtain bacterial suspension, then the bacterial suspensions are mixed in a mass ratio of 1:1 to obtain the microbial agent. The beef extract protein peptone medium used is purchased from Qingdao High-tech Industrial Park Haibo Biotechnology Co., Ltd.

[0110] Planting test

[0111] In order to further illustrate the technical effect of the present application, the biochar-based multi-effect soil conditioner prepared by the present application is applied to rice planting.

[0112] Test site: A moderately contaminated land in a certain administrative village of Shizilu Town, JUNan County, Shandong Province is selected as the test plot, the physical and chemical properties of the test soil are shown in Table 2, and the heavy metal content of the test soil is shown in Table 3.

[0113] Table 2 Basic physical and chemical properties of the test soil

[0114]

[0115] Table 3 Heavy metal content of the test soil

[0116]

[0117] Test method: The test rice variety is Xiangjing 9407. The test is divided into 14 treatment groups, and each treatment group is named as 1-14, wherein 1-3 is the treatment group of Examples 1-3, 4-13 is the treatment group of Comparative Examples 1-10, and 14 is the blank control group. The specific treatment method of each treatment group is: before planting, the soil conditioner prepared in each treatment group is used as base fertilizer together with conventional chemical fertilizer (N:P2O5:K2O=17-6-20, total nutrient content ≥45%) and applied to the soil by plowing, the dosage of soil conditioner is 100 kg / mu, and the dosage of chemical fertilizer is 40 kg / mu, wherein the blank control group only uses conventional chemical fertilizer as base fertilizer and plows into the soil. The field management measures of each treatment group are kept consistent except for plowing different soil conditioners before planting. At the harvest stage of rice, 30 consecutive rice ears with consistent growth vigor are collected from each treatment group, the above-ground biomass, rice yield and yield component factors are measured, and the results are shown in Table 4.

[0118] Table 4 Results of rice planting test

[0119]

[0120] From the above data, it can be seen that compared with the blank control group, the yield of rice is significantly improved after using the soil conditioner of the application, and the plant height, grain number per ear and thousand grain weight indicators are better than those of the comparative examples 1-10 and the blank control. This is because the biochar-based multiple-effect soil conditioner prepared by the application can effectively improve the physical and chemical properties of the soil through the synergistic effect of multiple components, thereby significantly improving the fertility and health level of the soil, which helps to promote the growth and development of plants and improve the yield and quality of crops.

[0121] After the rice is harvested, surface soil (0-20 cm) samples are collected. According to the S-shaped sampling method, soil samples are collected for each treatment group. When taking soil, the soil drill is punched to a depth of 20 cm at one time, 3 repeated samples are collected for each treatment group, and 3 repeated samples of the same treatment group are mixed into one sample. Visible impurities such as sand, plant roots, etc. are removed, and the soil microorganisms, enzyme activity, basic physicochemical properties of the soil, and effective heavy metal content in the soil are measured in the laboratory. The test results are shown in Tables 5, 6 and 7.

[0122] Test method: soil bulk density adopts cutting ring method; pH value adopts potential method (water: soil = 2.5:1); organic matter content adopts K2Cr2O7 oxidation-external heating method; total nitrogen content adopts mixed catalyst-flow analyzer method; total phosphorus content adopts HClO4+H2SO4 digestion-molybdenum antimony anti colorimetric method; total potassium content adopts NaOH fusion-flame photometric method; alkali-hydrolyzable nitrogen content adopts 1 mol / L KCl extraction-continuous flow analyzer method; available phosphorus content adopts 0.5 mol / L NaHCO3 extraction-molybdenum antimony anti colorimetric method; available potassium content adopts 1 mol / L CH3COONH4 extraction-flame photometric method. The effective state Pb content of soil heavy metal is determined by DTPA extraction-atomic absorption spectrophotometry; the effective state Hg content of soil heavy metal is determined by sodium dihydrogen phosphate extraction-atomic fluorescence method; the effective state Cd of soil heavy metal is determined by HCl-HNO3-HF-HClO4 micro heat digestion-graphite furnace atomic absorption spectrophotometry; the effective state As of soil heavy metal is determined by HNO3-HCl heating digestion-KBH4 reduction-atomic fluorescence method; the effective state Cr of soil heavy metal is determined by HCl-HNO3-HF-HClO4 micro heat digestion-flame atomic absorption spectrophotometry.

[0123] Table 5 Basic physicochemical properties of soil after rice harvest

[0124]

[0125] From the above data, it can be seen that compared with the blank control group, the pH of the soil is improved, the bulk density is reduced, and the organic matter content is significantly improved after using the soil conditioner of the application, which is better than the comparative examples 1-10 and the blank control. This is because the biochar-based multifunctional soil conditioner prepared by the application can effectively improve the physical and chemical properties of the soil through the synergistic effect of multiple components, increase the pH value of the acid soil, increase the soil organic matter content, improve the soil structure, and the comprehensive improvement effect of the soil is remarkable.

[0126] Table 6 Heavy metal content in soil after rice harvest

[0127]

[0128] Soil microbial determination: The number of three microbial groups of soil bacteria, fungi and actinomycetes was determined by dilution plate separation counting method, expressed as the number of colonies per gram of dry soil (cfu). Bacteria were cultured in beef extract peptone medium at 37℃ for 2-3d, fungi were cultured in Martin's-Bengal red medium at 27-28℃ for 3d, and actinomycetes were cultured in Gao's No. 1 medium at 27-28℃ for 6d. The number of colonies of each type of bacteria was recorded, and then the number of colonies per gram of dry soil (cfu) was calculated according to the water content of the soil.

[0129] Soil enzyme activity determination: Soil urease activity was determined by phenol sodium colorimetry; catalase activity was determined by potassium permanganate titration; acid phosphatase activity was determined by kit method; and sucrose activity was determined by nitro-salicylic acid method.

[0130] Table 7 Soil microbial and enzyme activity test results

[0131]

[0132] From the data of Table 7, it can be seen that after the soil conditioners prepared by the embodiments 1-3 of the present application are used, both the soil microbial indicators and the soil enzyme activity indicators are significantly higher than those of the comparative examples 1-10 and the blank control group. While the formula composition of the biochar, red mud, activator and microbial inoculant is changed, the soil microbial indicators and the soil enzyme activity indicators are decreased. Soil microorganisms participate in numerous biochemical processes in soil, including the degradation of organic residues, the transformation of organic matter, the mineralization and fixation of nutrients, and the formation and stabilization of soil aggregates, while also storing soil nutrients to provide available nutrients for plant growth. Bacteria play an important role in the transformation of soil organic matter and inorganic matter, and fungi play a huge role in the process of soil carbon and energy circulation. After the porous structure of the modified biochar and the particle structure of the modified red mud are used in combination in the present application, the loose and porous structure, the large specific surface area and the pore distribution can adsorb soluble organic matter, gas, soil nutrients and water, providing a good environment for the aggregation, growth and reproduction of various microorganisms. On the other hand, the soil conditioner of the present application is also rich in carbon, energy and mineral nutrients, which can provide raw materials for the growth of microorganisms after degradation, thereby promoting the growth of specific microorganisms and changing the microbial community structure. After the soil conditioner of the present application is applied to the soil, the various components work together to significantly improve the aeration condition of the soil, promote the formation of soil aggregates, and thus improve the soil gas and water conditions. The overall performance is to increase the soil enzyme activity and increase the number of three major groups of microorganisms in the soil. If any one of the components of the biochar-based multi-effect soil conditioner of the present application is changed or reduced, the corresponding effect will disappear or weaken. Therefore, the components of the biochar-based multi-effect soil conditioner of the present application are complementary and indispensable.

[0133] It should be noted that the above embodiments are only part of the preferred modes of implementing the present application, not all. Obviously, based on the above embodiments of the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor should be within the scope of protection of the present application.

Claims

1. A biochar-based multi-purpose soil conditioner, characterized in that, It is made of the following raw materials by weight: modified biochar 100-120 parts, microbial agent 10-20 parts, modified red mud 20-30 parts, diatomite 20-30 parts, poultry manure 80-100 parts, and activator 10-20 parts; the microbial agent is composed of Brevibacillus laterosporus, Trichoderma koningii, and Streptomyces celluloxys in a mass ratio of 1:1:1; The preparation method of the modified biochar is as follows: clean plant straw is mixed with 0.1 mol / L nickel chloride solution at a solid-liquid ratio of 1 g:50 ml, and the mixture is stirred magnetically at room temperature for 24 h, then dried and ground into fine powder after centrifugation, and then the straw powder is calcined in a high-temperature furnace, calcined at 500℃ for 1 h, then calcined at 700℃ for 30 min, and then naturally cooled to room temperature after 4 h of heat preservation to obtain the modified biochar; The preparation method of the modified red mud is as follows: (1) hydrochloric acid solution is mixed with red mud at a liquid-solid ratio of 10 ml:1 g, and then reacted in a water bath at 80℃ for 1.5 h, then washed with deionized water until neutral, dried at 100℃ for 24 h, and then calcined in a muffle furnace at 550℃ for 6 h to obtain acid-treated red mud; the concentration of the hydrochloric acid solution is 1 mol / L; (2) 1 mol / L Cu(NO3)2·3H2O solution is mixed with the acid-treated red mud obtained in step (1) at a liquid-solid ratio of 50 ml:1 g, and then stirred magnetically at room temperature for 24 h, then centrifuged and dried to obtain a solid product, and finally the solid product is calcined in a muffle furnace at 550℃ for 5 h, then taken out and ground into 80-mesh powder to obtain the modified red mud; The activator is a mixture of 2 mol / L zinc chloride solution and 1 mol / L phosphoric acid solution in a volume ratio of 1:

1.

2. The biochar-based multi-purpose soil conditioner of claim 1, wherein, The Brevibacillus laterosporus has the preservation number CGMCC No.1.15087, is selected from the China General Microbiological Culture Collection Center, and was preserved on February 15, 2015; the Trichoderma koningii has the preservation number CGMCC No.3.17875, is selected from the China General Microbiological Culture Collection Center, and was preserved on December 15, 2015; and the Streptomyces celluloxys has the preservation number CGMCC No.4.6365, is selected from the China General Microbiological Culture Collection Center, and was preserved on September 3, 2008.

3. The biochar-based multi-purpose soil conditioner of claim 1, wherein, The preparation method of the microbial agent is as follows: Brevibacillus laterosporus, Trichoderma koningii, and Streptomyces celluloxys are respectively inoculated into sterilized beef extract peptone medium 500 mL shake flasks, and then cultured at 37℃ and 250 r / min for 24 h to obtain bacterial suspensions, and then the bacterial suspensions are mixed in a mass ratio of 1:1:1 to obtain the microbial agent.

4. A method of making the biochar-based multi-purpose soil conditioner of any one of claims 1-3, characterized in that, It comprises the following steps: (1) preparing a microbial agent; (2) preparing modified biochar; (3) preparing modified red mud; (4) mixing the modified biochar obtained in step (2) with 2 times the volume of deionized water, then adding the activator, stirring at room temperature for 24 h, then filtering to obtain the filter residue, washing with deionized water until neutral, and then drying in an oven at 80℃ to obtain active biochar; (5) mixing poultry manure, diatomite and modified red mud uniformly according to weight parts, adding water to make the water content 50%, then adding the prepared microbial inoculum, stirring uniformly, composting and fermenting, controlling the temperature of the pile body not higher than 55℃ by turning the pile, continuously fermenting for 10 days, then adding the active biochar obtained in step (4) and stirring uniformly, continuing to ferment for 12h, after the fermentation is completed, drying the fermentation product, crushing it, and using a granulator to granulate into 4-5mm particles to obtain the biochar-based multi-effect soil conditioner.

Images