Nutrient soil and preparation method thereof

Abstract

The invention belongs to the technical field of white spirit byproduct treatment, and relates to nutrient soil and a preparation method thereof, and the preparation method of the nutrient soil comprises the following steps: step 1, preparing a compost material: adopting white spirit brewing sludge as a compost raw material, adding a conditioner and Maotai-flavor white spirit vinasse, uniformly mixing, and adjusting the moisture content to obtain the compost material; step 2, stacking fermentation: carrying out aerobic fermentation on the compost material to obtain fermented soil; 3, nutrient soil preparation, wherein the prepared fermented soil is mixed with phosphogypsum and red mud, and the nutrient soil is obtained. A certain amount of Maotai-flavor liquor vinasse and a regulator are added into the liquor brewing sludge, so that the compost maturity of the liquor brewing sludge can be effectively accelerated, the formation of humus is accelerated, the fermentation period is shortened, and the quality of a compost product is ensured. Meanwhile, nutrient soil prepared by mixing the prepared fermented soil with ardealite and red mud is free of undesirable phenomena such as hardening or root burning and the like when used for planting.

Description

Technical Field

[0001] The invention belongs to the technical field of liquor byproduct processing and relates to nutrient soil and a preparation method thereof. Background Art

[0002] In recent years, with the continuous escalation of the popularity of Maotai-flavor liquor, the amount of Maotai-flavor liquor wastewater has increased year by year. According to research, the amount of Maotai-flavor liquor sludge is about 0.5% of the wastewater discharge, which is huge and easily causes ecological damage and secondary pollution.

[0003] At present, the main treatment method for Maotai liquor sludge is drying + incineration. This treatment method increases the economic cost of the enterprise and also causes a series of environmental problems. High-temperature aerobic fermentation technology refers to the process of converting waste organic matter into stable products through the fermentation of microorganisms under certain moisture, C / N ratio and ventilation conditions under artificial control. High-temperature aerobic composting technology has become a better way to utilize Maotai liquor sludge resources due to its advantages such as simple process and low cost. However, due to the defects of traditional high-temperature fermentation technology such as long fermentation cycle, low fermentation efficiency and low humification degree, it seriously limits the large-scale promotion and application. In addition, the fermentation product has a low degree of humification of organic matter, which seriously affects the subsequent land use.

[0004] At present, the problems of long maturity period and low humification degree in high-temperature aerobic composting are mainly solved by adding exogenous substances. For example: Patent CN201810920196.4 discloses a method for accelerating the composting process by adding straw and humus soil; CN201711485042.9 discloses a method for accelerating composting maturity by using biochar and its thiourea modified materials. However, in the actual process of treating Maotai liquor sludge, these additives cannot be applied to high-temperature aerobic composting on a large scale due to cost or process reasons. At the same time, due to the unique process of Maotai liquor production and the geographical location of the enterprise, the selection of additives should be adapted to local conditions. Summary of the invention

[0005] The object of the present invention is to provide a nutrient soil and a preparation method thereof, which uses Maotai-flavor liquor sludge as a raw material, sawdust as a conditioning agent, and Maotai-flavor liquor lees as an additive, which significantly accelerates the composting maturity of Maotai-flavor liquor sludge, effectively accelerates the formation of humus and shortens the fermentation cycle, and ensures the quality of the compost product. At the same time, the nutrient soil prepared by mixing the obtained fermented soil with local soil is used for planting without undesirable phenomena such as compaction or root burn. Maotai-flavor liquor lees as an additive has the advantages of a wide source and local materials, realizes the full quantitative disposal of Maotai-flavor liquor waste and the enterprise's "waste treatment", and promotes the green development of the Maotai-flavor liquor industry. Solve the problems of long composting maturity period and low humus content of existing Maotai-flavor liquor sludge composting, as well as the low land utilization value of fermentation products.

[0006] In a first aspect, the present invention provides a method for preparing nutrient soil, comprising the following steps:

[0007] Step 1, preparing compost material: using liquor brewing sludge as compost raw material, adding conditioner and Maotai liquor lees, mixing, adjusting moisture content, and obtaining compost material;

[0008] Step 2, stacking and fermentation: aerobic fermentation of the compost material to obtain fermented soil;

[0009] Step 3, preparing nutrient soil: mixing the obtained fermented soil with phosphogypsum and red mud to obtain nutrient soil.

[0010] In some embodiments, the mixing ratio of the liquor brewing sludge to the conditioning agent is 80-100:10;

[0011] Preferably, the mixing ratio of the liquor brewing sludge and the conditioner is 85-95:10.

[0012] In some embodiments, the ratio of the Maotai-flavor liquor lees added is 5-15% of the compost material;

[0013] Preferably, the added proportion of the Maotai-flavor liquor lees accounts for 8-10% of the compost material.

[0014] In some embodiments, the moisture content of the compost material is 50-60%;

[0015] Preferably, the moisture content of the compost material is 52-56%.

[0016] In some embodiments, in the composting fermentation step, the compost needs to be turned during the composting fermentation process, and the method of turning the compost is specifically as follows: turning the compost once every 1-5 days in the early stage of composting, and turning the compost once every 3-10 days in the late stage of composting;

[0017] Preferably, the method of turning the compost is as follows: turning the compost every 2-4 days in the early stage of composting, and turning the compost every 5-7 days in the late stage of composting.

[0018] In some embodiments, the stack fermentation period is 40-45 days;

[0019] Preferably, the period of the stacking fermentation is 41-43 days.

[0020] In some embodiments, during the stack fermentation process, oxygen is supplied by intermittent aeration forced ventilation;

[0021] Preferably, the aeration flow rate is 0.010-0.014m 3 / Kg compost raw material*h

[0022] Preferably, the aeration flow rate is 0.010-0.013m 3 / Kg composting raw materials*h.

[0023] In some embodiments, the mixing ratio of the fermented soil, phosphogypsum and red mud is 70-80 parts of fermented soil, 10-20 parts of phosphogypsum and 10-20 parts of red mud.

[0024] In some embodiments, the moisture content during the stack fermentation process is 50% to 60%.

[0025] In a second aspect, the present invention provides a nutrient soil prepared by any one of the above-mentioned preparation methods.

[0026] In summary, the present application includes at least one of the following beneficial technical effects:

[0027] By adding a certain amount of Maotai-flavor liquor lees and regulators to liquor brewing sludge, the composting maturity of liquor brewing sludge can be effectively accelerated, the formation of humus can be accelerated, the fermentation cycle can be shortened, and the quality of the compost product can be guaranteed. At the same time, the nutrient soil prepared by mixing the fermented soil with phosphogypsum and red mud will not cause adverse phenomena such as compaction or root burn when used for planting. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a temperature change diagram of the fermentation process of Examples 1-2 of the present invention and Comparative Example 1;

[0029] Figure 2 It is a diagram showing the change of moisture content during the fermentation process of Examples 1-2 of the present invention and Comparative Example 1;

[0030] Figure 3 It is a GI index diagram of the fermentation process of Examples 1-2 of the present invention and Comparative Example 1;

[0031] Figure 4 is a graph showing changes in humus content during the fermentation process of Examples 1-2 of the present invention and Comparative Example 1;

[0032] Figure 5 It is a three-dimensional spectrum characterization diagram of Examples 1-2 of the present invention and Comparative Example 1;

[0033] Figure 6 It is a graph showing the contents of humic acids, fulvic acids, proteins and terrestrial humus in Examples 1-2 of the present invention and Comparative Example 1. DETAILED DESCRIPTION

[0034] The technical solution of the present invention is further described below by specific embodiments, which do not limit the protection scope of the present invention. Some non-essential modifications and adjustments made by others based on the concept of the present invention still fall within the protection scope of the present invention.

[0035] The composting research of brewery sludge has the advantages of low investment and convenient promotion, and has great development prospects in the resource utilization research of brewery sludge. The single sludge composting cycle is long, the effect is poor, and it is easy to cause a large amount of nitrogen loss. A certain proportion of conditioners (straw, rice straw, wood chips, domestic garbage, etc.) are added to the sludge, and the organic matter therein is oxidized and decomposed and converted into humus-like substances by using microbial communities under sufficient oxygen and water. The pathogens and eggs of the sludge that have been composted and fermented have been killed, and the texture is loose. The nutrients in it are also easily absorbed by plants. In addition, sludge composting can passivate heavy metals and reduce biological toxicity. In addition, Guizhou Province is mostly mountainous, with defects such as thin soil layer and poor fertility, so it is of great significance to use brewery sludge to make nutrient soil that can be used in the mountainous soil of Guizhou Province.

[0036] As a waste product produced after seven distillations and seven fermentations, the properties of Maotai-flavor liquor lees are significantly different from those of Luzhou-flavor and Light-flavor liquor lees. Maotai-flavor liquor lees are rich in basic chemical components such as crude fiber, crude starch, crude protein, and are also rich in small molecules such as phenols, acids, alcohols, esters, aldehydes and ketones. According to research, amino acids, fibers, phenols and other substances can all be used as precursors to promote the formation of humus. In addition, Maotai-flavor liquor lees are rich in N, P, K and other elements, which can improve the quality of fermented products. At present, there are no reports on the use of Maotai-flavor liquor lees as an additive to accelerate the composting of Maotai-flavor liquor sludge.

[0037] The present invention adopts Maotai-flavor liquor sludge as a composting raw material, adds a conditioner and liquor lees for stacking and fermentation, and finds that Maotai-flavor liquor lees, due to the advantages mentioned above, can better accelerate the composting maturity of Maotai-flavor liquor sludge and promote the formation of humus, while lees of other flavors, such as light-flavor liquor, are not as effective as Maotai-flavor liquor lees in accelerating the composting maturity of Maotai-flavor liquor sludge under the same fermentation conditions.

[0038] Using brewing sludge, Maotai liquor lees and sawdust as raw materials, a nutrient soil that can be used in mountain fertile soil in Guizhou Province is produced. On the one hand, it can eliminate the economic costs and environmental risks generated by the incineration process of brewing sludge. On the other hand, it can make full use of the nutrients in brewing sludge, transform it into nutrient soil and use it in plant cultivation.

[0039] The determination method of the physical and chemical indicators of the present invention is as follows:

[0040] Moisture content: Determine the moisture content by drying at 105℃ for 24h;

[0041] Pile temperature: Use an engineering thermometer to measure the pile temperature in the morning, noon and evening;

[0042] Seed germination index (GI): measured according to the GI index method in the NY / T525-2021 "Organic Fertilizer" standard;

[0043] Humus: The humus component is extracted by the International Humic Substances Association method, using a mixture of sodium pyrophosphate and sodium hydroxide for extraction. The formation process is identified by three-dimensional fluorescence spectroscopy, and the concentration is determined by a total organic carbon analyzer.

[0044] Carbon-nitrogen ratio: The nitrogen content of the material is determined by the Kjeldahl nitrogen method. The material is dried at 550°C for 6 hours, and the percentage of the loss mass in the dried sample multiplied by 0.58 is the carbon content of the material.

[0045] Water-soluble organic carbon: fresh compost material was mixed with deionized water at a ratio of 1:10 (m / m), shaken on a horizontal shaker for 24 hours, centrifuged at 12000r / min for 15 minutes, the supernatant was filtered with a 0.45um filter membrane, and the filtrate was diluted to an appropriate concentration before measuring the water-soluble organic carbon with an instrument;

[0046] Three-dimensional fluorescence characterization: The humification process of the samples was measured using a Hitachi F7100 fluorescence spectrometer.

[0047] Example 1

[0048] A method for preparing nutrient soil comprises the following steps:

[0049] Step 1: Prepare compost materials

[0050] (1) Collect liquor brewing sludge, Maotai liquor lees and conditioning agent. In this embodiment, the conditioning agent is sawdust, and the liquor brewing sludge is Maotai liquor sludge. The moisture content of Maotai liquor sludge, Maotai liquor lees and sawdust are measured respectively. The moisture content of Maotai liquor sludge is 62%, the moisture content of Maotai liquor lees is 8.3%, and the moisture content of sawdust is 5%.

[0051] Among them, the pH value of Maotai liquor sludge ranges from 6.5 to 7.5, the length of sawdust is less than 5mm, and the width is less than 1mm. The Maotai liquor lees are the waste lees produced in the wine-making workshop, containing a small amount of cellar mud, and the pH value ranges from 5 to 6.

[0052] In other embodiments, the conditioning agent may also be straw, rice straw and / or domestic garbage, etc., which can have a fluffy effect when mixed with the brewing sludge.

[0053] (2) Using Maotai liquor sludge as a composting raw material, adding sawdust as a composting auxiliary material conditioner, and then adding Maotai liquor lees as an additive, mixing evenly, adjusting the moisture content, and obtaining a composting material.

[0054] Among them, the mixing ratio of Maotai liquor sludge and sawdust is 90:10, and the added ratio of Maotai liquor lees accounts for 8% of the composting material. After uniform stirring, the moisture content of the total material is about 52%, and the carbon-nitrogen ratio of the total material is 25:1, and composting material is obtained.

[0055] In other embodiments, in order to maintain the ability of microorganisms to absorb nutrients, the moisture content of the obtained compost material can also be 50-60%, such as the moisture content of the compost material is 50%, the moisture content of the compost material is 51%, the moisture content of the compost material is 53%, the moisture content of the compost material is 58%, etc. When the moisture content of the compost material is too high, the oxygen content will be reduced, affecting the oxidative decomposition of organic matter, but when the moisture content is too low, the water content will be too little, which will also affect the oxidative decomposition of organic matter, thereby affecting the composting effect. Therefore, considering the demand for oxygen and water, the moisture content of the compost material is more suitable within the range of 50-60%.

[0056] In other embodiments, the carbon-nitrogen ratio of the obtained compost material is 25-30:1, such as a carbon-nitrogen ratio of 28:1, a carbon-nitrogen ratio of 26:1, a carbon-nitrogen ratio of 30:1, etc., which provides appropriate organic matter for stacking fermentation and better promotes decomposition.

[0057] In other embodiments, the mixing ratio of Maotai-flavor liquor sludge and sawdust is 80-100:8-15, for example, the mixing ratio of Maotai-flavor liquor sludge and sawdust is 80:15, the mixing ratio of Maotai-flavor liquor sludge and sawdust is 85:8, the mixing ratio of Maotai-flavor liquor sludge and sawdust is 83:10, the mixing ratio of Maotai-flavor liquor sludge and sawdust is 100:15, etc. The material ratio within this range can better promote the formation of humus and improve the quality of fermented products.

[0058] In other embodiments, the proportion of Maotai-flavor liquor lees added is 5-20% of the compost material, such as 5% of the compost material, 10% of the compost material, 20% of the compost material, etc. The proportion of Maotai-flavor liquor lees added affects the content of organic matter and nutrients, thereby affecting the rate of decomposition.

[0059] Step 2: Stacking and fermentation

[0060] The compost material is subjected to aerobic fermentation to obtain fermented soil.

[0061] Specifically, the compost material is transferred to a fermentation tank for aerobic fermentation. An aeration pipe is laid at the bottom of the fermentation tank. During the fermentation process, a high-pressure blower is used to intermittently aerate and force ventilation to supply oxygen and maintain 0.012m 3 / (Kg composting raw material*h), the whole pile fermentation cycle is 42 days, and the temperature of the pile is monitored daily during the fermentation process. In the first 21 days of composting, the initial temperature rises quickly and the pile is turned over every 3 days; the temperature rise slows down in the later stage of composting, and the pile is turned over every 5 days until the fermentation is completed, and fermented soil is obtained after the fermentation is completed.

[0062] In other embodiments, the flow rate of oxygen supply can be maintained at 0.010-0.014 m / s. 3 / (Kg compost raw material*h), for example 0.012m 3 / (Kg compost raw material*h), 0.011m 3 / (Kg compost raw material*h), 0.014m 3 / (Kg compost raw material*h), etc., which can provide sufficient oxygen for pile fermentation, but will also cause excessive water loss and affect the fermentation effect.

[0063] In other embodiments, during the first 21 days of composting, the temperature rises quickly in the initial stage, and the compost is turned every 2-4 days; the temperature rises slowly in the later stage of composting, and the compost is turned every 5-7 days in the later stage of composting.

[0064] The pH value of the sludge fermentation process is controlled within the range of 6 to 8. Under neutral or slightly alkaline conditions, bacteria and actinomycetes grow best. In order to maintain the ability of microorganisms to absorb nutrients, the moisture content can be adjusted by adding dry materials such as sawdust during the fermentation process. The moisture content of the pile is controlled at 50% to 60%.

[0065] After 2-3 days of pile fermentation, the temperature can rise to above 55℃, and then continue to rise and stabilize for a period of time. During the fermentation, pathogens and parasite eggs are killed, humus begins to form, and the fermentation reaches initial maturity. As most of the organic matter has been degraded in the main fermentation stage, the fermentation will be maintained at 30-40℃, and finally reach deep maturity.

[0066] Maotai liquor lees and sawdust add organic matter and nutrients to the compost. Maotai liquor lees and sawdust have loose texture. Turning the compost every 3 days in the early stage of composting also ensures that there is sufficient oxygen entering the compost pile to participate in the fermentation reaction. The temperature of the compost rises rapidly in the early stage, reaching nearly 70°C, and quickly enters the thermophilic period (>50°C). The thermophilic period is maintained for more than 22 days. After 25 days, the temperature gradually decreases and approaches the ambient temperature. This shows that the combined fermentation of lees and brewing sludge can significantly stimulate the activity of microorganisms and accelerate the decomposition of organic matter.

[0067] (4) Preparation of nutrient soil

[0068] The fermented soil is mixed with phosphogypsum and red mud to prepare nutrient soil.

[0069] Specifically, the mixing ratio of fermented soil, phosphogypsum and red mud is 70-80 parts of fermented soil, 10-20 parts of phosphogypsum and 10-20 parts of red mud. In this embodiment, 75 parts of fermented soil, 15 parts of phosphogypsum and 15 parts of red mud are mixed and further stacked for 7 days to form nutrient soil.

[0070] Example 2

[0071] A method for preparing nutrient soil, which is different from Example 1 in that the proportion of Maotai-flavor liquor lees added is 16% of the compost material.

[0072] Comparative Example 1

[0073] A method for preparing nutrient soil, which is different from Example 1 in that the proportion of Maotai-flavor liquor lees added is 0% of the compost material.

[0074] Effect verification

[0075] In the present invention, two experimental groups (C1 for Example 1 and C2 for Example 2) and a control group (CK for Comparative Example 1) are set; the compost raw materials are Maotai-flavor liquor sludge and sawdust. The addition amount of Maotai-flavor liquor lees in experimental groups C1 and C2 is 8% and 16% respectively. The compost raw materials of group CK are Maotai-flavor liquor sludge and sawdust, and the addition amount of Maotai-flavor liquor lees is 0.

[0076] 1. Determine the temperature change during the fermentation of Examples 1-2 and Comparative Example 1. Use an engineering pointer thermometer to monitor the compost temperature at 5 fixed locations every day. The results are as follows: Figure 1 As shown, C1 represents Example 1, C2 represents Example 2, and CK represents Comparative Example 1. The high temperature periods of C1, C2, and CK lasted for 26 days, 30 days, and 22 days, respectively, indicating that the addition of Maotai liquor lees significantly stimulated the growth and reproduction of thermophilic microorganisms, accelerating the degradation of organic matter and the formation of humus.

[0077] 2. Determine the moisture content of Examples 1-2 and Comparative Example 1 during fermentation. After the composting is completed, bake at 105°C for 12 hours and measure the moisture content by weighing. C1 represents Example 1, C2 represents Example 2, and CK represents Comparative Example 1. Figure 2 As shown in the figure, the moisture content of CK, C1 and C2 at the end of composting was 39.2%, 35.4% and 32.6% respectively. The moisture content of compost is usually related to the degree of maturity, indicating that the addition of Maotai liquor lees promoted the volatilization of compost moisture and accelerated the maturity of compost.

[0078] 3. Determine the GI index during the fermentation of Examples 1-2 and Comparative Example 1. Figure 3As shown: Wherein, C1 represents Example 1, C2 represents Example 2, CK represents Comparative Example 1, and the 33rd day is 65.50%, 71.20% and 74.07% respectively. According to the NY / T525-2021 standard for organic fertilizer, CK is not mature, while C1 and C2 have reached the maturity standard (GI>70%). After the composting is completed, the GIs of C1, C2 and CK are 88.11%, 78.76% and 70.76%, respectively. These results show that the addition of Maotai liquor lees composting cycle is shortened to 33d, and the maturity of Maotai liquor sludge composting is accelerated.

[0079] 4. Determine the humus content of the compost sample, such as Figure 4 As shown. Humus, humic acid and fulvic acid were extracted using the International Humic Association extraction method, and the contents of humus, humic acid and fulvic acid were determined using a TOC instrument. After the composting was completed, C1 represents Example 1, C2 represents Example 2, and CK represents Comparative Example 1. The humic acid contents of CK, C1 and C2 were 7.18 g / kg, 12.48 g / kg, and 13.58 g / kg, respectively; and the fulvic acid contents were 30.00 g / kg, 32.78 g / kg, and 34.15 g / kg, respectively. This shows that the addition of Maotai liquor lees significantly increased the content of humic acid and fulvic acid, which is beneficial to the formation of humus.

[0080] 5. The humus formation process was identified by three-dimensional fluorescence spectroscopy. The three-dimensional spectral characterization results are shown in Figure 5 . Figure 5 AD are the fluorescent component positions of C1, C2, C3, and C4 components, respectively.

[0081] 6. Test the content of humic acid, fulvic acid, protein and terrestrial humus. The results are as follows: Figure 6 As shown in the figure, C1, C2, C3, and C4 represent humic acid, fulvic acid, protein, and terrestrial humus, respectively. The results show that the addition of Maotai liquor lees significantly accelerates the degradation of protein and the formation of humus.

[0082] 7. Test results of nutrient soil fertilizer efficiency

[0083] The fertilizer effect of the nutrient soil is verified by the growth of peas in the later stage. In order to make the nutrient soil prepared by mixing fermented soil, phosphogypsum and red mud more practical for planting crops, the nutrient soil of the present invention is mixed with local soil in different proportions for planting peas. The planting time period is selected in the winter and spring seasons suitable for the growth of peas. Water is poured once during planting, and no manual intervention is subsequently performed. The peas are planted in the open air, and their growth is observed regularly.

[0084] The planting results show that the nutrient soil made from brewing sludge, phosphogypsum and red mud has no adverse effects on plant growth, such as soil compaction or root burning, when used in appropriate amounts. When the ratio of nutrient soil to local soil is 1:6, the plant growth effect is better and the plant leaves are promoted to increase; when the ratio of nutrient soil to local soil increases to 1.5:6, the plant growth effect shows a downward trend. Therefore, the nutrient soil made from brewing sludge has a suitable fertilizer effect at an appropriate amount and can promote plant growth.

[0085] The nutrient soil prepared by the present invention has no adverse phenomena such as soil compaction or root burn for pea growth, and the pea growth effect is better, indicating that the fermented soil formed by fermentation of brewing sludge has a fertilizer effect that promotes plant growth. When the mixing ratio of nutrient soil and local soil is too high, the growth of plants will be inhibited. The reason may be that the new nutrient soil has a loose texture. If the amount is too large, it will lead to poor water absorption capacity of the planting soil, which will cause crops to die due to lack of water. In addition, the nutrient content of the fermented soil is too high, and excessive use will also cause root burn; if the amount of fermented soil is too small, the fertile soil effect of the nutrient soil cannot be reflected.

[0086] In summary, adding an appropriate amount of Maotai liquor lees to the Maotai liquor sludge compost not only provides organic matter and lignin and other nutrient elements to the pile, but also makes the pile loose and breathable, ensuring that there is sufficient oxygen to participate in the fermentation reaction, so that the fermentation of brewing sludge enters the thermophilic period faster, and the temperature of the pile can reach about 70℃ in 2 days, and the thermophilic period lasts longer, which is conducive to stimulating the activity of microorganisms, increasing the decomposition of protein and ammonia production, and maintaining the stability of the pH of the pile (7.43 is appropriate). On the one hand, high temperature also kills harmful and toxic substances and insect eggs in the pile. On the other hand, the long high temperature period also accelerates the volatilization of water in the pile, which is of great significance for achieving the harmlessness and reduction of solid waste in the Maotai liquor industry. The nutrient soil prepared by mixing with phosphogypsum, red mud, etc. can effectively promote the growth of plants, and there is no adverse phenomenon such as soil compaction or root burning. At the same time, this type of nutrient soil can also be further used for landscaping, mine reclamation, etc., with good environmental and economic benefits.

[0087] It is to be understood that the present invention is described by some embodiments, and it is known to those skilled in the art that various changes or equivalent substitutions may be made to these features and embodiments without departing from the spirit and scope of the present invention. In addition, under the teachings of the present invention, these features and embodiments may be modified to adapt to specific circumstances and materials without departing from the spirit and scope of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application are within the scope of protection of the present invention.

Claims

1. A method for preparing nutrient soil, characterized in that: The following steps are involved: Step 1, preparing compost material: using liquor brewing sludge as compost raw material, adding conditioner and Maotai liquor lees, mixing, adjusting moisture content, and obtaining compost material; Step 2, stacking and fermentation: aerobic fermentation of the compost material to obtain fermented soil; Step 3, preparing nutrient soil: mixing the obtained fermented soil with phosphogypsum and red mud to obtain nutrient soil.

2. The preparation method according to claim 1, characterized in that The mixing ratio of the liquor brewing sludge and the conditioning agent is 80-100:10; Preferably, the mixing ratio of the liquor brewing sludge and the conditioner is 85-95:

10.

3. The preparation method according to claim 1, characterized in that: The proportion of the Maotai-flavor liquor lees added is 5-15% of the compost material; Preferably, the added proportion of the Maotai-flavor liquor lees accounts for 8-10% of the compost material.

4. The preparation method according to claim 1, characterized in that: The moisture content of the compost material is 50-60%; Preferably, the moisture content of the compost material is 52-56%.

5. The preparation method according to claim 1, characterized in that: In the stacking and fermentation step, the stacking and fermentation process needs to be turned over, and the specific method of turning over the stacking is: turning over the stacking once every 1-5 days in the early stage of composting, and turning over the stacking once every 3-10 days in the late stage of composting; Preferably, the method of turning the compost is as follows: turning the compost every 2-4 days in the early stage of composting, and turning the compost every 5-7 days in the late stage of composting.

6. The preparation method according to claim 1, characterized in that: The period of the stacking fermentation is 40-45 days; Preferably, the period of the stacking fermentation is 41-43 days.

7. The preparation method according to claim 1, characterized in that: During the stacking fermentation process, oxygen is supplied by intermittent aeration forced ventilation; Preferably, the aeration flow rate is 0.010-0.014m 3 / Kg compost raw material*h; Preferably, the aeration flow rate is 0.010-0.013m 3 / Kg composting raw materials*h.

8. The preparation method according to claim 1, characterized in that: The mixing ratio of the fermented soil, phosphogypsum and red mud is: 70-80 parts of fermented soil, 10-20 parts of phosphogypsum and 10-20 parts of red mud.

9. The preparation method according to claim 1, characterized in that: The moisture content of the compost material during the stacking and fermentation process is 50% to 60%.

10. A nutrient soil obtained by the method according to any one of claims 1 to 9.

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