Method for promoting humification by adding pyroligneous liquor in composting cooling period

Abstract

The invention relates to the technical field of organic fertilizer preparation, and particularly discloses a preparation method for promoting humification by adding pyroligneous liquor in a composting cooling period. The method comprises the following steps: pyrolyzing cotton stalk particles, collecting pyrolysis gas, condensing, standing for more than one month, and filtering to obtain refined wood vinegar; and adding the pyroligneous liquor into an aerobic composting pile body in a composting cooling period, and carrying out aerobic composting fermentation to finally obtain the organic fertilizer. The core of the invention is that the livestock and poultry manure is used as a basic raw material, and the wood vinegar is added as a composting accelerant in a cooling period, so that the effective components of the wood vinegar are efficiently utilized. According to the method, the humification degree and the nutrient content of the prepared organic fertilizer are remarkably improved.

Description

Technical Field

[0001] This invention relates to the field of organic fertilizer technology, specifically to a method for preparing cotton stalk wood vinegar fertilizer. Background Technology

[0002] Aerobic composting is a dynamic, multi-stage, and complex biochemical process. The microbial community structure, enzyme activity, and material transformation pathways differ significantly at different stages (initial stage, high-temperature stage, cooling stage, and maturation stage). Wood vinegar, rich in organic acids, phenols, and other bioactive substances, demonstrates potential value in the resource utilization of agricultural waste, especially in aerobic composting. Existing research indicates that adding wood vinegar at the initial stage of aerobic composting can promote organic matter decomposition and humification to a certain extent, positively impacting composting efficiency and quality. However, current technologies are mostly limited to single-stage addition at the initial stage of composting, failing to fully utilize the targeted regulatory potential of wood vinegar's active components at different composting stages, thus hindering the overall optimization of composting efficiency and product quality.

[0003] Therefore, existing technologies urgently need to break through the limitations of single addition timing and develop a regulation method that accurately adds wood vinegar at key periods based on the dynamic characteristics of the aerobic composting process. Summary of the Invention

[0004] This invention aims to explore the promoting effect of wood vinegar on the core reactions at each stage of composting by designing a strategy of adding wood vinegar at different composting stages (initial stage, high temperature stage, cooling stage, and maturation stage), in order to more effectively accelerate composting maturation, reduce nutrient loss, improve the degree of humification, and enhance the nutrient content, stability, and environmental friendliness of the final organic fertilizer product.

[0005] This invention provides a method for preparing wood vinegar fertilizer, which produces wood vinegar fertilizer with stable quality, high nutrient content, and is environmentally friendly.

[0006] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0007] This invention provides a method for preparing wood vinegar fertilizer, comprising the following steps:

[0008] (1) Pyrolyze the cotton stalk particles to obtain the remaining solid and gas; the remaining solid is cotton stalk char; collect the gas, condense it, let it stand for more than a month, and filter it to obtain refined wood vinegar;

[0009] (2) After mixing the wood vinegar obtained in step (1) with pig manure and crop straw, aerobic composting is carried out to obtain wood vinegar fertilizer.

[0010] Preferably, the cotton stalk particles in step (1) are obtained by crushing cotton stalks; the length of the cotton stalk particles is ≤2cm.

[0011] Preferably, the pyrolysis temperature in step (1) is 300-500°C, and the pyrolysis time is 10-14 hours.

[0012] Preferably, the mass of the wood vinegar in step (2) is 0.65% to 1.75% of the mass of the feces.

[0013] Preferably, in step (2), the mass ratio of manure to crop straw is 10:1.

[0014] Preferably, the crop straw in step (2) includes at least one of rice straw, corn straw, sorghum straw, and sunflower straw.

[0015] Preferably, in step (2), the aerobic composting process is maintained at a temperature above 50°C for more than three days; the aerobic composting time is 30 to 40 days.

[0016] Preferably, in step (2), the aerobic compost pile is turned over every 4 to 6 days.

[0017] This invention provides a method for preparing wood vinegar fertilizer. First, cotton stalk particles are pyrolyzed to obtain a residual solid and a gas; the residual solid is cotton stalk charcoal. The gas is collected, condensed, and allowed to stand for more than one month. After filtration, refined wood vinegar solution is obtained. This wood vinegar solution is then mixed with manure and crop straw, and aerobic composting is performed to obtain wood vinegar fertilizer. This invention uses pig manure as the base material and wood vinegar solution as an additive, synergistically promoting aerobic composting. This significantly improves the utilization rate of effective chemical components in the wood vinegar solution and substantially enhances the quality stability and nutrient content of the prepared wood vinegar fertilizer. This invention significantly improves the degree of humification and nutrient content of the prepared organic fertilizer. Results from the examples show that at the end of composting, the degree of humification in Example 1 is higher than in the other comparative examples. Overall, Example 1 is more suitable for organic fertilizer composting, containing higher nutrient content suitable for plant growth. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the structure of the self-made compost bin used in Embodiment 1 and Comparative Examples 1-4 of the present invention;

[0019] Figure 2 The graph shows the changes in compost temperature and ambient temperature over time for aerobic composting in Example 1 and Comparative Examples 1-4 of the present invention.

[0020] Figure 3 The graph shows the change of humic acid (HA) in the compost pile of the aerobic compost of Example 1 and Comparative Examples 1-4 of the present invention over time.

[0021] Figure 4The ratio of humic acid to fulvic acid (HI) in the aerobic compost of Examples 1 and Comparative Examples 1-4 of this invention is an important physicochemical indicator in the evaluation of organic fertilizers. It can be used to measure the stability and maturity of organic matter. The higher the HI value, the more stable the compost is and the higher the degree of decomposition.

[0022] Figure 5 This is a graph showing the change in seed germination rate (GI) over time in the aerobic compost piles of Examples 1 and 1-4 of the present invention. Detailed Implementation

[0023] This invention provides a method for preparing wood vinegar fertilizer, comprising the following steps:

[0024] (1) Pyrolyze the cotton stalk particles to obtain the remaining solid and gas; the remaining solid is cotton stalk char; collect the gas, condense it, let it stand for more than a month, and filter it to obtain refined wood vinegar;

[0025] (2) After mixing the wood vinegar obtained in step (1) with manure and crop straw, aerobic composting is carried out to obtain wood vinegar fertilizer.

[0026] Unless otherwise specified, all raw materials used in this invention are commercially available products in the art.

[0027] In this invention, the cotton stalk particles are preferably obtained by crushing cotton stalks. The length of the cotton stalk particles is preferably ≤2cm. By controlling the length of the cotton stalk particles, this invention facilitates subsequent pyrolysis, resulting in a wood vinegar solution with better overall performance.

[0028] In this invention, the pyrolysis temperature is preferably 300–500°C, more preferably 300°C. The pyrolysis time is preferably 10–14 hours, more preferably 12 hours. By controlling the pyrolysis temperature and time within the above ranges, this invention promotes the complete pyrolysis of cotton stalk particles, resulting in a wood vinegar solution with good overall performance.

[0029] The present invention does not impose any special restrictions on the condensation method; any technical solution well known in the art can be used to obtain the wood vinegar.

[0030] In this invention, the preferred mass of the wood vinegar is 1.75% of the mass of the feces. This invention controls the mass of the wood vinegar within the above range to facilitate the full reaction between the effective components in the wood vinegar and the feces during aerobic composting, resulting in wood vinegar fertilizer with stable quality and high nutrient content.

[0031] In this invention, the preferred mass ratio of the excrement to crop straw is 10:1.

[0032] In this invention, the feces are preferably pig manure.

[0033] In this invention, the crop straw preferably includes at least one of rice straw, corn straw, sunflower straw, and sorghum straw, and more preferably rice straw.

[0034] In this invention, the aerobic composting is preferably carried out outdoors in good sunlight. In this invention, the temperature is preferably maintained above 50°C for at least three days during the aerobic composting process. In this invention, the aerobic composting time is preferably 30-40 days, more preferably 35 days.

[0035] In this invention, the aerobic compost pile is preferably turned over every 4-6 days, more preferably every 5 days. This invention improves oxygen supply by completely turning the aerobic compost pile: turning increases the oxygen supply in the aerobic compost, improves the uniformity of oxygen distribution, thereby enhancing the metabolic and decomposition capabilities of aerobic microorganisms; it promotes the reproduction of aerobic microorganisms: intermittent turning creates suitable environmental conditions conducive to the reproduction and metabolism of aerobic microorganisms, promoting the degradation and stabilization of organic matter; and it reduces reaction time: intermittent turning shortens the reaction cycle, increases composting speed, reduces processing time, and saves energy consumption and economic costs.

[0036] The method for preparing wood vinegar fertilizer provided by this invention is simple to operate, has mild reaction conditions, and is suitable for large-scale production.

[0037] The technical solutions of this invention will be clearly and completely described below with reference to the embodiments thereof. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0038] Example 1

[0039] The preparation method of wood vinegar fertilizer includes the following steps:

[0040] (1) Crush the cotton stalks to obtain cotton stalk particles with a length ≤2cm;

[0041] The cotton stalk particles were placed into a pyrolysis device and pyrolyzed at 300°C for 12 hours to obtain a residual solid and a gas; the residual solid was cotton stalk char; after standing for more than one month, it was filtered to obtain refined wood vinegar.

[0042] (2) The wood vinegar obtained in step (1) is mixed with 25 kg of pig manure and 2.5 kg of rice straw and composted for 12 days (i.e., cooling period). Then, it is kept outdoors in full sunlight at a temperature above 50°C for more than three days. The aerobic compost pile is turned over every 5 days and aerobic composting is carried out for 35 days to obtain wood vinegar fertilizer.

[0043] The wood vinegar is 1.75% of the mass of pig manure; the mass ratio of pig manure to rice straw is 10:1.

[0044] The rice straw used in step (2) of Example 1 was taken from farmland of the 16th Regiment, and the pig manure used was provided by a breeding farm of the 11th Regiment of Alar. The pH was measured by a PHS-3C pH meter, the moisture content was measured by drying method, the organic carbon was measured by potassium dichromate-sulfuric acid combustion method, and the total nitrogen was measured by Kjeldahl nitrogen analyzer. The pH, moisture content, total nitrogen, total organic carbon, and C / N of the pig manure and rice straw were measured and are shown in Table 1 below.

[0045] Table 1

[0046] materials pH Moisture content Total nitrogen (mass fraction) Total organic carbon C / N pig manure 6.04 52.17％ 0.68％ 15.28％ 22.47 rice straw 4.30 6.8％ 0.47％ 40.63％ 86.44

[0047] In step (2) of Example 1, the aerobic composting uses a self-made composting box. The self-made composting box is 60cm long, 45cm wide, and 30cm high. The structural diagram of the self-made composting box is shown below. Figure 1 As shown, temperature sensors inserted inside the reactor are displayed in real time via a temperature display.

[0048] Comparative Example 1

[0049] Wood vinegar fertilizer was prepared according to the method of Example 1, except that the mass of the wood vinegar liquid was 0% of the mass of pig manure, that is, no wood vinegar liquid was added.

[0050] Comparative Example 2

[0051] Wood vinegar fertilizer was prepared according to the method of Example 1, except that the wood vinegar solution was added to the compost pile on the first day (i.e., the initial stage) of composting.

[0052] Comparative Example 3

[0053] Wood vinegar fertilizer was prepared according to the method of Example 1, except that the wood vinegar solution was added to the compost pile on the third day of composting (i.e., the high-temperature period).

[0054] Comparative Example 4

[0055] Wood vinegar fertilizer was prepared according to the method of Example 1, except that the wood vinegar solution was added to the compost pile on the 21st day (i.e., the maturation period).

[0056] During the aerobic composting process of Examples 1 and Comparative Examples 1-4, the temperatures of the top, middle, and bottom layers of the compost pile, as well as the ambient temperature, were measured daily throughout the entire period. Samples were taken from the top, middle, and bottom layers of the compost pile on days 1, 3, 7, 14, 21, 28, and 35 of the aerobic composting process in Examples 1 and Comparative Examples 1-4. The samples from the top, middle, and bottom layers of the aerobic compost pile on the same number of days were thoroughly mixed, freeze-dried, ground, and sieved through a 100-mesh sieve. The samples were then stored in a refrigerator at -20°C. HA and FA were determined using the sodium pyrophosphate-sodium hydroxide extraction method with potassium dichromate oxidation capacity. The changes in the compost pile temperature and ambient temperature over time during the aerobic composting process of Examples 1 and Comparative Examples 1-4 are shown in the graph below. Figure 2 As shown in the figure, the change of humic acid (HA) over time is as follows: Figure 3 As shown in the figure, the ratio of humic acid to fulvic acid (HI) in the aerobic compost pile changes over time. Figure 4 As shown in the figure, the seed germination rate changes over time. Figure 5 As shown.

[0057] Depend on Figure 2 It can be seen that the temperatures of Example 1 and Comparative Examples 1-4 during the composting process all exhibited a typical four-stage composting temperature pattern (initial stage, high-heat stage, cooling stage, and maturation stage). The time spent above 50°C in Example 1 and Comparative Examples 1-4 all exceeded 9 days, meeting the requirements for stabilization and humification (NY525-2021). In particular, Example 1 lasted as long as 15 days, indicating that adding wood vinegar after the high-temperature stage of natural composting can further promote the humification of the compost pile.

[0058] Depend on Figure 3 It can be seen that at the end of composting, the humic acid content of Example 1 and Comparative Examples 1-4 was all above 14 g / kg. The humic acid content of Example 1 was higher than that of the other treatment groups, indicating that adding wood vinegar during the cooling period is more conducive to composting and humification, and improves the quality of organic fertilizer.

[0059] Depend on Figure 4 It is known that HI is an important physicochemical indicator that can be used to measure the degree of organic fertilizer decomposition in aerobic composting. At the end of composting, the HI of Example 1 was higher than that of other treatment groups, indicating that adding wood vinegar during the cooling period can improve the degree of compost decomposition.

[0060] Depend on Figure 5It can be seen that when cabbage seeds were cultured with extracts from compost samples of Example 1 and Comparative Examples 1-4 at different times, their seed germination rate (GI) was measured. At the end of composting, except for the GI of Comparative Example 1, the GI of the other groups all exceeded 80%, meeting the requirement of GI≥70% in (NY525-2021). Moreover, the GI of Example 1 was as high as 91.5%, indicating that wood vinegar fertilizer produced by adding wood vinegar during the cooling period of composting is more conducive to plant growth and has higher quality.

Claims

1. A method for adding wood vinegar to promote humification during the cooling period of composting, comprising the following steps: (1) Pyrolyze the cotton stalk particles to obtain the remaining solid and gas; the remaining solid is cotton stalk char; collect the gas, condense it, let it stand for more than a month, and filter it to obtain refined wood vinegar; (2) After mixing the wood vinegar obtained in step (1) with the aerobic compost pile in the cooling period, continue aerobic composting to obtain wood vinegar fertilizer.

2. The preparation method according to claim 1, characterized in that, In step (1), the cotton stalk particles are obtained by crushing cotton stalks; the length of the cotton stalk particles is ≤2cm.

3. The preparation method according to claim 1, characterized in that, The pyrolysis temperature in step (1) is 300℃, and the pyrolysis time is 10 to 14 hours.

4. The preparation method according to claim 1, characterized in that, In step (2), the mass of the wood vinegar is 0.65% to 1.75% of the mass of the feces.

5. The preparation method according to claim 1, characterized in that, In step (2), the mass ratio of manure to crop straw is 10:

1.

6. The preparation method according to claim 1, characterized in that, The crop straw in step (2) includes at least one of rice straw, corn straw, sorghum straw, and sunflower straw.

7. The preparation method according to claim 1, characterized in that, In step (2), the aerobic composting process is maintained at a temperature above 50°C for at least 3 days; the aerobic composting time is 30 to 40 days.

8. The preparation method according to claims 1 to 7, characterized in that, In step (2), the aerobic compost pile is turned over every 4 to 6 days.

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