Livestock and poultry manure and crop straw mixed composting method

Abstract

The invention relates to a livestock and poultry manure and crop straw mixed composting method, and belongs to the technical field of composting. The method comprises the following steps: A, purification: purifying attapulgite powder, wherein the mineral content of purified palygorskite is more than 89.5%; b, modifying, namely calcining the purified attapulgite powder at 150-250 DEG C for 2-3 hours, and cooling to ambient temperature to obtain modified attapulgite powder; c, composting: uniformly mixing livestock and poultry manure with crop straw and the modified attapulgite powder, and composting. The attapulgite is subjected to separation, purification and thermal modification, and the compost quality can be improved by driving decomposition of organic matters and preservation of nitrogen. The loss of nitrogen is effectively reduced; the preservation of nutritional ingredients is improved. The fertilizer obtained by the method is good in nutrition.

Description

Technical Field

[0001] The invention relates to a method for mixed composting of livestock and poultry excrement and crop straw, belonging to the technical field of composting. Background Art

[0002] With economic development, demand for agricultural and livestock products has increased, and the livestock and animal husbandry industries are becoming increasingly large-scale, intensive, regionalized, and specialized. However, with the in-depth development of livestock and poultry farming and agriculture, agricultural waste, such as livestock and poultry manure and crop straw, has increased dramatically, posing a serious threat to the environment. Pollution from livestock and poultry manure and the burning of crop straw are particularly prominent.

[0003] Aerobic composting, as a biological stabilization method for treating organic solid waste, can transform waste into green fertilizer. It has low operating costs, a safe and stable fermentation process, and both social and environmental benefits. Livestock manure fermentation starts quickly and is rich in nutrients. The addition of straw can compensate for the low C / N ratio of livestock manure, improve the pH and aeration of the compost, and co-composting the two is an effective approach to treating agricultural waste. However, compost products suffer from drawbacks such as long composting times, low humification levels, and nutrient loss. The fermentation process also emits foul odors and produces greenhouse gases. Ammonia volatilization and heavy metal bioavailability result in nitrogen losses of 16% to 76% during aerobic composting. This nitrogen loss not only reduces the agricultural value of the compost product but also causes various environmental problems.

[0004] The commonly used measures to control nitrogen loss during the composting process include the following: optimizing composting parameters (C / N, moisture content and aeration rate, etc.), inoculating microbial agents (white rot fungi, Streptomyces and Bacillus, etc.), adding conditioners (sawdust, wheat bran and straw, etc.), chemical additives (rhamnolipids, glucose, sulfuric acid, bamboo vinegar, sulfuric acid and superphosphate, etc.) and mineral additives (bentonite, medical stone, zeolite, palygorskite, fly ash and lime, etc.).

[0005] Among them, clay minerals such as bentonite, zeolite, medical stone, and attapulgite, with their unique pore structure and physical and chemical properties, can effectively preserve nutrients during the composting process and mitigate adverse environmental effects. While existing mineral additives used in aerobic composting can address some of the challenges of composting, they still face problems such as low maturity, poor nutrient stability, slow organic matter decomposition, long composting cycles, large nitrogen losses, and the generation of odors and greenhouse gases. For example, while zeolite, bentonite, clay, vermiculite, and medical stone have a certain effect in reducing nitrogen losses and improving compost quality, adding too high a proportion of bentonite will reduce the seed germination index, and overall it is difficult to completely resolve the existing deficiencies of composting. Summary of the Invention

[0006] The first object of the present invention is to provide a novel method for composting livestock and poultry excrement and crop straw.

[0007] To achieve the first object of the present invention, the method comprises:

[0008] A. Purification: Purify the attapulgite powder to obtain a palygorskite mineral content of more than 89.5% after purification;

[0009] B. Modification: calcining the purified attapulgite powder at 150°C to 250°C for 2h to 3h and cooling to ambient temperature to obtain modified attapulgite powder;

[0010] C. Composting: Mix livestock and poultry manure with crop straw and attapulgite for composting. The dry weight ratio of livestock and poultry manure to crop straw is 1:5.5 to 1:10, and the modified attapulgite powder is 5% to 10% of the total dry weight of livestock and poultry manure and crop straw. The initial C / N ratio of the compost matrix is controlled to be 25:1 to 30:1, the moisture content is 65% to 75%, and the pH is 7.5 to 8.5. During the composting process, the moisture content is controlled to be 65% to 75%.

[0011] In a specific embodiment, the purification method in step A comprises: mixing attapulgite powder with an aqueous solution of sodium hexametaphosphate, stirring for 0.5 h to 1 h, and then standing for 30 to 45 min, taking the upper suspension for solid-liquid separation, and then drying the solid to obtain purified attapulgite powder; preferably, the drying is performed at 60° C. to 70° C. for 3 h to 5 h;

[0012] Preferably, the recovery rate of the purification is above 75.82%.

[0013] In a specific embodiment, the concentration of the sodium hexametaphosphate aqueous solution is 2.1 to 2.5 g / L, and the mass ratio of the sodium hexametaphosphate to the attapulgite powder is preferably 2.1:70 to 2.5:70.

[0014] In a specific embodiment, before the calcination in step B, the attapulgite powder is crushed and passed through a 200-mesh sieve, and the sieve residue is calcined.

[0015] In one embodiment, the heating rate of the calcination in step B is 5-10° C. / min.

[0016] In one embodiment, the aeration rate of the compost in step C is set to 0.68 to 1 L·min -1 kg -1 , aerate for 45 minutes with a 5-minute break.

[0017] In a specific embodiment, during the composting process in step C, a water bath is set to keep warm according to the real-time measured temperature. The water temperature of the water bath is set to 35-40°C during the composting heating period; the water temperature of the water bath is set to 40-45°C during the thermophilic period; the water temperature of the water bath is set to 30-40°C during the cooling period; and the water temperature of the water bath is set to room temperature during the composting maturity period.

[0018] In a specific embodiment, during the composting process in step C, the compost is not turned over in the first three days. After the compost temperature drops below 50°C, the compost is turned over every three days. After the compost temperature drops below 40°C, the compost is turned over every seven days.

[0019] In a specific embodiment, before composting, step C further includes naturally air-drying the livestock and poultry manure and crop straw, crushing them into small pieces of 1 to 2 cm, and removing stone impurities.

[0020] In a specific embodiment, step C further comprises, before composting, crushing the modified attapulgite powder, passing it through a 200-mesh sieve, and composting the sieve contents;

[0021] The composting time is preferably 30 to 45 days.

[0022] The livestock and poultry manure is preferably chicken manure, the crop straw is rice straw, the C / N ratio is controlled to be 25, and the dry weight ratio of chicken manure to rice straw is 1:5.5;

[0023] Preferably, the mixing is to divide the livestock and poultry manure, crop straw and attapulgite into three equal parts, first mix one part of the livestock and poultry manure, crop straw and attapulgite, and then add the remaining two parts according to the same steps.

[0024] The second object of the present invention is to provide a compost fertilizer mixed with livestock and poultry excrement and crop straw.

[0025] In order to achieve the second object of the present invention, the fertilizer is prepared by the above method, and preferably the fertilizer has an available phosphorus of 4.17g / Kg or more, a total phosphorus of 5.35g / Kg or more, an available potassium of 14.8g / Kg or more, a total potassium of 32.5g / Kg or more, a nitrate nitrogen of 0.46g / Kg or more, an ammonia nitrogen of 0.3g / Kg or less, a total nitrogen of 18.65g / Kg or more, a dissolved organic matter of 9.3g / Kg or less, and an organic matter content of The content of the raw materials shall be as follows: 1. The carbon content of the raw materials shall be less than 26.3 g / Kg, the electrical conductivity shall be less than 1.7 ms / cm, the pH value shall be less than 8.5, the carbon-nitrogen ratio shall be less than 8, the seed germination index shall be more than 185%, the absorbance ratio of humic acid at 445 and 665 nm shall be less than 4.5, the ratio of humic acid to fulvic acid shall be more than 2.7, the humic acid content shall be more than 94.6 g / Kg, the fulvic acid content shall be less than 34.8 g / Kg, and the humus content shall be more than 129.4 g / Kg.

[0026] Beneficial Effects: The structure and properties of the attapulgite of the present invention can be further improved through separation, purification, and thermal modification. This can improve the quality of compost by driving the decomposition of organic matter and preserving nitrogen. This effectively reduces nitrogen loss and improves the preservation of nutrients, promoting the humification process of the compost. The fertilizer obtained by the method of the present invention is highly nutritious and has a promoting effect on seed germination. Specifically,

[0027] 1. The method of the present invention has the best composting-promoting effect: a. The thermophilic period during composting lasts long, and the maximum compost fermentation temperature is high; b. The pH value is high during composting, and the mineralization rate of organic matter is faster. At the end of composting, the pH is less than 8.5, which meets the standard; c. The conductivity value is lower at the beginning of composting and is less than 4ms / cm at the end of composting, indicating that the method of the present invention has strong ion adsorption capacity.

[0028] 2. The product obtained by composting of the present invention has good nutrients: low organic matter content, low dissolved organic matter DOC, high total nitrogen, high nitrate nitrogen, high total potassium, and low ammonia nitrogen.

[0029] 3. The composted product of the present invention has excellent humic parameters: high humus content, low fulvic acid content, high humic acid content, high humic acid to fulvic acid ratio, low absorbance ratio of humic acid at 445 and 665 nm, high seed germination index, and low C / N ratio at the end of composting. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 Scanning electron microscope images of the original attapulgite and the thermally modified attapulgite calcined at 200℃ for 2h; (a) and (b) are the original attapulgite; (c) and (d) are the thermally modified attapulgite calcined at 200℃ for 2h; (a) and (c) are magnified 20,000 times, and (b) and (d) are magnified 40,000 times. DETAILED DESCRIPTION

[0031] To achieve the first object of the present invention, the method comprises:

[0032] A. Purification: Purify the attapulgite powder to obtain a palygorskite mineral content of more than 89.5% after purification;

[0033] B. Modification: calcining the purified attapulgite powder at 150°C to 250°C for 2h to 3h and cooling to ambient temperature to obtain modified attapulgite powder;

[0034] C. Composting: Mix livestock and poultry manure with crop straw and attapulgite for composting. The dry weight ratio of livestock and poultry manure to crop straw is 1:5.5 to 1:10, and the modified attapulgite powder is 5% to 10% of the total dry weight of livestock and poultry manure and crop straw. The initial C / N ratio of the compost matrix is controlled to be 25:1 to 30:1, the moisture content is 65% to 75%, and the pH is 7.5 to 8.5. During the composting process, the moisture content is controlled to be 65% to 75%.

[0035] In a specific embodiment, the purification method in step A comprises: mixing attapulgite powder with an aqueous solution of sodium hexametaphosphate, stirring for 0.5 h to 1 h, and then standing for 30 to 45 min, taking the upper suspension for solid-liquid separation, and then drying the solid to obtain purified attapulgite powder; preferably, the drying is performed at 60° C. to 70° C. for 3 h to 5 h;

[0036] Preferably, the recovery rate of the purification is above 75.82%.

[0037] After a large number of experiments, it was found that the purification method of the present invention using sodium hexametaphosphate has the best final effect, and the effects of using sodium pyrophosphate, sodium silicate, and dry purification are weakened in order.

[0038] In a specific embodiment, the concentration of the sodium hexametaphosphate aqueous solution is 2.1 to 2.5 g / L, and the mass ratio of the sodium hexametaphosphate to the attapulgite powder is preferably 2.1:70 to 2.5:70.

[0039] In a specific embodiment, before the calcination in step B, the attapulgite powder is crushed and passed through a 200-mesh sieve, and the sieve residue is calcined.

[0040] In one embodiment, the heating rate of the calcination in step B is 5-10° C. / min.

[0041] In one embodiment, the aeration rate of the compost in step C is set to 0.68 to 1 L·min -1 kg -1 , aerate for 45 minutes with a 5-minute break.

[0042] In a specific embodiment, during the composting process in step C, a water bath is set to keep warm according to the real-time measured temperature. The water temperature of the water bath is set to 35-40°C during the composting heating period; the water temperature of the water bath is set to 40-45°C during the thermophilic period; the water temperature of the water bath is set to 30-40°C during the cooling period; and the water temperature of the water bath is set to room temperature during the composting maturity period.

[0043] In a specific embodiment, during the composting process in step C, the compost is not turned over in the first three days. After the compost temperature drops below 50°C, the compost is turned over every three days. After the compost temperature drops below 40°C, the compost is turned over every seven days.

[0044] In a specific embodiment, before composting, step C further includes naturally air-drying the livestock and poultry manure and crop straw, crushing them into small pieces of 1 to 2 cm, and removing stone impurities.

[0045] In a specific embodiment, step C further comprises, before composting, crushing the modified attapulgite powder, passing it through a 200-mesh sieve, and composting the sieve contents;

[0046] The composting time is preferably 30 to 45 days.

[0047] The livestock and poultry manure is preferably chicken manure, the crop straw is rice straw, the C / N ratio is controlled to be 25, and the dry weight ratio of chicken manure to rice straw is 1:5.5;

[0048] Preferably, the mixing is to divide the livestock and poultry manure, crop straw and attapulgite into three equal parts, first mix one part of the livestock and poultry manure, crop straw and attapulgite, and then add the remaining two parts according to the same steps.

[0049] The second object of the present invention is to provide a compost fertilizer mixed with livestock and poultry excrement and crop straw.

[0050] In order to achieve the second object of the present invention, the fertilizer is prepared by the above method, and preferably the fertilizer has an available phosphorus of 4.17g / Kg or more, a total phosphorus of 5.35g / Kg or more, an available potassium of 14.8g / Kg or more, a total potassium of 32.5g / Kg or more, a nitrate nitrogen of 0.46g / Kg or more, an ammonia nitrogen of 0.3g / Kg or less, a total nitrogen of 18.65g / Kg or more, a dissolved organic matter of 9.3g / Kg or less, and an organic matter content of The content of the raw materials shall be as follows: 1. The carbon content of the raw materials shall be less than 26.3 g / Kg, the electrical conductivity shall be less than 1.7 ms / cm, the pH value shall be less than 8.5, the carbon-nitrogen ratio shall be less than 8, the seed germination index shall be more than 185%, the absorbance ratio of humic acid at 445 and 665 nm shall be less than 4.5, the ratio of humic acid to fulvic acid shall be more than 2.7, the humic acid content shall be more than 94.6 g / Kg, the fulvic acid content shall be less than 34.8 g / Kg, and the humus content shall be more than 129.4 g / Kg.

[0051] The specific embodiments of the present invention are further described below in conjunction with examples, but the present invention is not limited to the scope of the examples.

[0052] Example 1

[0053] Experimental equipment: analytical balance, electronic scale, 1000mL volumetric flask, beaker, crucible, mortar, glass rod, spray bottle, plastic bag, electronic thermometer, etc.

[0054] Ultrapure water: To control the moisture content of the pile to be between 60% and 70%, water with a resistivity of 18MΩ*cm (25°C) is taken from the laboratory.

[0055] Composting experiments were conducted in an aerobic fermentation reactor equipped with a water bath heater at the bottom to regulate temperature during the composting process. Furthermore, a stirring motor and blower were installed at the top of the reactor to ensure ventilation and oxygen supply. The compost temperature could be measured via a switchable port located on the upper side of the reactor.

[0056] Attapulgite ore, raw attapulgite stone and thermally modified attapulgite

[0057] Unprocessed attapulgite ore, sourced from Mingguang, Anhui Province, is a magnesium-aluminum-rich silicate clay mineral. The active mineral component is palygorskite, along with significant amounts of associated minerals such as dolomite, quartz, and kaolin. Its main chemical composition is shown in Table 1. The attapulgite ore is an opaque, grayish-white powder with a specific gravity of 2.32 and a Mohs strength of 2. It exhibits strong water absorption.

[0058] Table 1 Main chemical composition of attapulgite ore

[0059]

[0060] Preparation of attapulgite raw stone: The attapulgite raw ore is wet-purified, dried, crushed and passed through a 200-mesh sieve for later use, which is the attapulgite raw stone for testing.

[0061] Wet purification of attapulgite ore: Add 2.1g of sodium hexametaphosphate to a large beaker filled with 1000mL of ultrapure water. Stir magnetically at 40°C for 30 minutes. Add 70g of crushed, dried, unprocessed attapulgite. Continue stirring for 1 hour, then let it sit for 30 minutes. Remove the upper suspension and centrifuge. Transfer the bottom liquid to a Petri dish and dry it in an electric forced-air drying oven at 60°C for 5 hours to obtain the purified attapulgite. Grind it finely, pass it through a 200-mesh sieve, and store it in a plastic bag.

[0062] The BET, XRD and SEM tests of the purified attapulgite raw stone showed that its specific surface area was 136.0432 m 2 ·g -1 After purification, the content of palygorskite minerals increased from 36.8% to 89.5%, and the purification recovery rate was 75.82%. The unique "rod crystal structure" of the purified attapulgite raw stone was obvious under the scanning electron microscope. Figure 1 (a) and (b), the pores are loose and the layer chain structure is clear.

[0063] Preparation of thermally modified attapulgite: Take the wet-purified attapulgite raw powder, set the maximum calcination temperature to 200℃ and the calcination duration to 2h, and calcine it in a muffle furnace at a heating rate of 5℃ / min. After the calcined sample cools to ambient temperature, the thermally modified attapulgite is obtained, which is ground into powder, passed through a 200-mesh sieve, and stored in a plastic bag. The SEM image of the thermally modified attapulgite is shown in Figure 1 (c) and (d).

[0064] Chicken manure and rice straw

[0065] Fresh chicken manure and rice straw were collected from a rural area in Qingbaijiang District, Chengdu, Sichuan Province. After air-drying, weeds, plastic, gravel, and other impurities were removed. The chicken manure was crushed as finely as possible, and the rice straw was shredded into 1-2 cm long pieces using a hay chopper and stored in a dry, well-ventilated area until ready for use. The basic physical and chemical properties of the compost materials are shown in Table 2.

[0066] Table 2 Basic physical and chemical properties of compost materials

[0067]

[0068] compost:

[0069] Calculated by dry weight, 5.5 kg of rice straw and 1 kg of chicken manure were prepared. Thermally modified attapulgite was added at a ratio of 5% to the total dry weight of the rice straw and chicken manure. The chicken manure, rice straw, and attapulgite were divided into three equal portions. One portion of chicken manure, straw, and attapulgite was added to the bottom of the fermenter, followed by stirring to mix thoroughly. The remaining two portions were then added in the same manner. The initial C / N ratio of the pile was 25:1, and the moisture content was 65%. To ensure oxygen supply, forced aeration was employed, with an air flow rate of 1 L / kg·min and an aeration rate of 10 L / min. Each 5-minute aeration period was followed by a 45-minute pause. Aerobic fermentation experiments were conducted for approximately 30 days. During the composting process, the water bath insulation is set according to the real-time measured temperature. The water temperature of the water bath is set to 35-40°C during the composting temperature rising period; the water temperature of the water bath is set to 40-45°C during the thermophilic period; the water temperature of the water bath is set to 30-40°C during the cooling period; and the water temperature of the water bath is set to room temperature during the composting period.

[0070] The reaction samples were taken on the 1st, 4th, 7th, 14th, 21st and 30th days of fermentation for subsequent analysis.

[0071] During aerobic fermentation, the compost mixture was temperature-measured twice daily at 9:00 AM and 7:00 PM. The compost was regularly turned and watered. No turning was performed during the first three days of composting. Turning was performed every three days after the compost temperature dropped below 50°C, and every seven days after the compost temperature dropped below 40°C. The moisture content was maintained between 65% and 75% to ensure oxygen supply and microbial survival. During sampling, the compost mixture was thoroughly stirred, and samples were collected from the top, middle, and bottom of the compost pile before being mixed thoroughly. The collected samples were divided into two parts: one part was air-dried, crushed, and sieved, and used as a dry sample for determination of physical and chemical parameters. The other part was stored in a refrigerator at -20°C and used as a fresh compost sample for microbial analysis, enzyme activity, and some physical and chemical measurements. Data were analyzed using one-way analysis of variance in SPSS 18.0 software, with a significance level of p < 0.05.

[0072] Example 2

[0073] Similar to Example 1, the only difference is that the addition ratio of the heat-modified attapulgite in Example 2 is 10% of the total dry weight of the rice straw + chicken manure materials.

[0074] Comparative Example 1

[0075] Similar to Example 1, the only difference is that the preparation of the thermally modified attapulgite in Example 1 is carried out at a calcination temperature of 100°C.

[0076] Comparative Example 2

[0077] Similar to Example 1, the only difference is that the preparation of the thermally modified attapulgite in Comparative Example 2 is carried out at a calcination temperature of 300°C.

[0078] Comparative Example 3

[0079] Similar to Example 1, the only difference is that the attapulgite raw stone of Comparative Example 3 is not thermally modified but is thiol-modified.

[0080] The thiol modification method for raw attapulgite is as follows: 2.00 g of wet-purified attapulgite is weighed, 150 mL of 3-mercaptopropyltrimethoxysilane ethanol solution is added, and 0.4 g of polyethylene glycol-20000 is added. The mixture is shaken at 180 rpm for 30 minutes. The pH of the solution is adjusted to 8±0.5 with 1 mol / L NaOH and 1 mol / L HCl. The mixture is stirred at 25°C for 30 minutes, allowed to stand, centrifuged at 3000 rpm for 10 minutes, washed with water until neutral, dried in a 65°C oven, and ground through a 200-mesh sieve to obtain thiol-modified attapulgite powder, which is stored in a plastic bag for future use.

[0081] Comparative Example 4

[0082] Similar to Example 1, the only difference is that the attapulgite raw stone of Example 4 is not thermally modified but is modified with hydrochloric acid.

[0083] The hydrochloric acid modification method for raw attapulgite is as follows: 2.50 g of wet-purified attapulgite is weighed, 125 mL of a 3 mol / L hydrochloric acid solution (solid-to-liquid ratio of 1:50) is added, and 0.4 g of polyethylene glycol-20000 is added as a dispersant. The mixture is placed in a 60°C water bath and reacted with magnetic stirring for 5 hours. After the reaction, the mixture is allowed to stand and centrifuged at 3000 rpm for 10 minutes to separate the solids. The sample is then washed repeatedly with distilled water until neutral (pH ≈ 7). The sample is then transferred to a 65°C oven and dried for 12 hours. It is then ground through a 200-mesh sieve to obtain hydrochloric acid-modified attapulgite and sealed for future use.

[0084] Comparative Example 5

[0085] Similar to Example 1, the only difference is that no heat-modified attapulgite powder is added, and pure chicken manure straw compost is used.

[0086] Comparative Example 6

[0087] Similar to Example 1, the only difference is that attapulgite raw stone powder is added and no thermal modification is performed.

[0088] Comparative Example 7

[0089] Similar to Example 1, the only difference is that sodium silicate is used instead of sodium hexametaphosphate in the purification of the attapulgite raw stone powder.

[0090] The composting experiment results are shown in Table 3-21, in which CK: pure chicken manure straw compost of Comparative Example 5; T1: 5% unmodified attapulgite compost added to Comparative Example 6; T2: 5% 200°C heat-modified attapulgite compost added to Example 1; T3: 10% heat-modified attapulgite compost added to Example 2; T4: 5% 100°C heat-modified attapulgite compost added to Comparative Example 1; T5: 5% 300°C heat-modified attapulgite compost added to Comparative Example 2; T6: 5% thiol-modified attapulgite compost added to Comparative Example 3; T7: 5% hydrochloric acid-modified attapulgite compost added to Comparative Example 4; T8: sodium silicate-purified attapulgite compost added to Comparative Example 7.

[0091] Table 3 Compost temperature / ℃

[0092] Time / day Room temperature CK T1 T2 T3 T4 T5 T6 T7 T8 1 36.0 46.8 47.2 47.4 47.1 45.4 37.3 42.5 44.3 46.5 2 31.9 51.1 53.2 56.1 55.2 47.4 40.2 43.4 46.4 51.8 3 30.3 55.9 56.6 60.0 58.8 50.7 41.3 47.5 50.3 52.2 4 26.7 55.4 57.8 60.3 61.0 50.2 45.6 50.2 52.1 56.3 5 27.9 55.5 57.3 62.4 61.1 51.2 50.2 47.5 53.2 56.5 6 27.5 55.6 57.2 61.4 60.8 52.7 51.2 48.3 52.1 55.2 7 28.2 55.6 57.3 59.5 59.2 53.5 47.5 46.6 48.5 53.5 8 30.7 55.1 56.3 55.7 56.4 44.3 44.3 47.3 47.6 52.5 9 32.1 49.9 51.4 54.0 53.0 44.6 43.2 46.5 48.5 48.7 10 32.9 48.8 50.4 53.3 52.8 43.8 42.4 46.4 47.4 46.5 11 31.4 48.3 49.4 51.3 50.5 46.4 44.3 45.4 47.5 46.6 12 32.0 47.6 48.3 48.3 46.7 44.3 45.2 45.4 46.6 45.6 13 28.1 47.1 47.9 47.2 46.2 45.7 43.2 46.3 46.7 45.3 14 32.3 46.8 47.5 47.3 46.6 43.6 44.1 44.4 47.4 45.3 15 34.4 45.4 46.5 46.7 46.8 42.7 42.7 44.8 46.5 44.6 16 34.9 45.4 46.2 46.9 46.8 43.5 40.3 43.9 45.5 44.2 17 33.6 45.0 46.0 46.6 46.6 42.8 40.2 44.7 44.4 43.9 18 35.0 44.6 45.8 46.6 46.6 41.2 40.5 42.2 43.7 43.6 19 34.4 44.4 45.4 46.5 46.2 40.4 40.6 40.8 43.6 42.5 20 34.3 44.2 45.4 46.4 45.9 40.2 39.4 38.7 43.2 41.6 21 33.9 44.1 45.5 46.4 45.7 41.0 39.5 37.6 39.5 41.0 22 32.8 43.6 44.3 46.1 46.4 37.5 38.8 37.4 37.5 40.5 23 28.5 38.5 38.3 45.7 45.6 37.5 37.8 38.0 36.4 38.6 24 32.8 36.6 37.3 44.6 44.0 36.8 36.4 37.2 35.3 36.5 25 28.0 30.0 29.4 38.3 36.4 35.3 36.5 36.4 28.7 31.4 26 29.0 29.4 29.4 33.6 31.9 32.0 27.5 32.1 26.6 30.9 27 28.2 27.7 28.1 27.3 26.6 24.6 25.4 28.6 25.8 28.7 28 28.4 26.8 27.0 25.8 25.7 25.4 26.0 26.5 27.4 27.3 29 25.7 25.5 26.3 25.5 25.4 24.3 24.8 25.0 25.4 26.4 30 24.9 24.8 25.2 24.8 25.5 24.1 24.2 25.3 24.3 23.6

[0093] The main factors to consider are the duration of the thermophilic phase and the maximum temperature. A better thermophilic phase indicates a more successful composting process. Table 3 shows that the compost treated with 5% 200°C thermal modification significantly outperformed the other treatments in both duration of the thermophilic phase (>50°C) and maximum temperature. A thermophilic phase duration of 5 days or longer meets the minimum compost quality requirement. The compost treated with thiol modification, hydrochloric acid modification, and 300°C thermal modification did not even meet this minimum requirement.

[0094] Table 4 Compost pH test

[0095]

[0096]

[0097] A pH below 8.5 at the end of composting meets the quality standard. Higher pH values during composting may indicate faster mineralization of organic matter, or perhaps enhanced compost fermentation. Table 4 shows that at the end of composting, the pH of the 300°C heat-modified and thiol-modified groups exceeded the compost quality requirement of less than 8.5, indicating low compost quality. The group containing 5% heat-modified attapulgite maintained a higher pH than the other groups throughout most of the composting period, demonstrating its greatest compost-promoting effect.

[0098] Table 5 Compost conductivity ms / cm

[0099] Time / day CK T1 T2 T3 T4 T5 T6 T7 T8 1 2.32 2.03 1.71 1.55 2.36 2.23 2.19 2.17 2.21 4 1.07 1.13 1.08 1.01 1.15 1.05 1.20 1.32 1.24 7 1.47 1.53 1.27 1.33 1.27 1.16 1.46 1.28 1.15 14 1.527 1.58 1.37 1.23 1.23 1.70 1.56 1.38 1.56 21 1.65 1.56 1.62 1.47 1.47 1.74 1.60 1.52 1.46 30 1.67 1.58 1.69 1.49 1.70 1.95 1.68 1.63 1.65

[0100] The conductivity requirement at the end of composting is less than 4ms / cm. As shown in Table 5, all treatment groups met the quality requirement of less than 4 at the end of composting, but the experimental group with 5% 200℃ thermally modified attapulgite added had a lower conductivity value at the beginning of composting, proving that thermal modification at 200℃ is most effective in enhancing the ion adsorption capacity of attapulgite.

[0101] Table 6 Humic matter content g / kg

[0102] Time / day CK T1 T2 T3 T4 T5 T6 T7 T8 1 100.78 103.31 107.76 107.14 106.53 98.76 102.04 97.83 100.97 4 101.84 111.03 111.74 101.09 112.23 99.05 100.54 104.64 108.56 7 97.36 102.3 107.74 105.03 101.85 86.43 101.44 104.66 104.64 14 97.43 102.94 110.89 109.56 102.04 95.42 99.37 108.53 104.35 21 106.47 111.8 118.17 120.81 114.63 94.33 100.85 110.45 107.56 30 111.28 119.42 140.60 129.47 115.04 93.68 101.44 109.35 112.01

[0103] Humus is a key product of composting, beneficial for soil improvement and plant growth. At the end of composting, the experimental group containing 5% attapulgite heat-modified at 200°C showed significantly higher total humus content than the other groups. However, the final humus content of the compost groups modified with thiol, hydrochloric acid, and heat-modified at 100 and 300°C was even lower than that of the CK group, demonstrating poor composting effectiveness. The humus content of the T8 group was lower than that of the T1 group, but higher than that of the thiol, hydrochloric acid, and 300°C groups.

[0104] Table 7 Fulvic acid content g / kg

[0105] Time / day CK T1 T2 T3 T4 T5 T6 T7 T8 1 60.3 62.97 67.63 65.48 61.05 60.02 59.05 61.45 61.56 4 54.88 59.45 54.89 58.28 57.79 58.45 56.85 58.03 58.65 7 50.63 55.22 48.03 51.88 54.34 57.53 55.94 56.03 56.43 14 47.53 50.18 43.69 47.43 46.57 56.32 51.05 54.04 50.54 21 43.11 42.6 38.24 42.2 45.68 52.57 48.05 50.05 43.1 30 39.96 38.19 30.79 34.78 40.04 47.55 43.06 44.07 39.56

[0106] Fulvic acid, a major component of humus, has a low molecular weight, a simple structure, and a low degree of aromatization. The degree of its conversion to humic acid reflects the stability and quality of humus in compost. The lower the final fulvic acid content, the better. During the composting process, the treatment with 5% 200°C heat-modified attapulgite showed the greatest decrease in fulvic acid content.

[0107] Table 8 Humic acid content g / kg

[0108] Time / day CK T1 T2 T3 T4 T5 T6 T7 T8 1 40.48 40.35 40.13 41.66 45.48 38.73 42.99 36.38 39.41 4 46.95 51.58 56.85 42.80 54.44 40.60 43.69 46.61 49.91 7 46.73 47.08 59.72 53.14 47.51 28.91 45.49 48.63 48.21 14 49.91 52.76 67.20 62.12 55.47 39.10 48.32 54.49 53.81 21 63.36 69.20 79.93 78.61 68.95 41.77 52.79 60.40 64.46 30 71.32 81.23 109.80 94.68 75.00 46.14 58.38 65.28 72.45

[0109] Humic acid is also a major component of humus. It has a high molecular weight, a stable structure, and a high degree of aromatization. The higher the final humic acid content, the better. At the end of composting, the group treated with 5% 200°C heat-modified attapulgite had significantly higher humic acid content than the other groups.

[0110] Table 9 Hu Fubi

[0111] Time / day CK T1 T2 T3 T4 T5 T6 T7 T8 1 0.67 0.64 0.59 0.64 0.74 0.65 0.73 0.59 0.64 4 0.86 0.87 1.04 0.73 0.94 0.69 0.77 0.80 0.86 7 0.92 0.85 1.24 1.02 0.87 0.5 0.81 0.87 0.87 14 1.05 1.05 1.54 1.31 1.19 0.69 0.95 1.01 1.02 21 1.47 1.62 2.09 1.86 1.51 0.79 1.10 1.21 1.61 30 1.78 2.13 3.57 2.72 1.87 0.97 1.36 1.48 1.97

[0112] The HA / FA ratio—the ratio of humic acid to fulvic acid—is measured. A higher HA / FA ratio indicates greater stability and complexity (aromatization) in the humus. A ratio greater than 1 at the end of composting indicates the compost is mature. At the end of composting, the HA / FA ratio in the compost group containing 5% attapulgite heat-modified at 200°C was significantly higher than in the other treatments, while the HA / FA ratio in the compost group containing 5% attapulgite heat-modified at 300°C was still below 1. The experimental groups containing 100°C heat-modified attapulgite, hydrochloric acid-modified attapulgite, and mercapto-modified attapulgite even fell short of the CK (no attapulgite) compost.

[0113] Table 10 Absorbance ratio of humic acid at 445 and 665 nm

[0114] Time / day CK T1 T2 T3 T4 T5 T6 T7 T8 1 4.24 4.45 4.33 4.40 4.46 4.45 4.38 4.34 4.36 4 6.08 5.71 5.86 5.47 6.77 5.77 5.69 5.64 5.78 7 6.11 5.59 5.56 5.71 7.02 6.34 6.32 5.80 5.61 14 5.31 5.46 5.24 5.69 6.02 6.36 6.00 6.01 5.66 21 5.03 4.89 5.07 4.97 5.54 6.04 5.86 5.75 4.98 30 4.83 4.54 4.01 4.49 5.10 5.78 5.43 5.36 4.62

[0115] E4 / E6 is the absorbance ratio of humic acid at 445 and 665 nm. Lower values indicate a higher degree of aromatization and stability of the humic matter, indicating higher compost quality. At the end of composting, the E4 / E6 ratio of the compost treated with 5% 200°C heat-modified attapulgite was significantly lower than that of the other treatments.

[0116] Table 11 Seed germination index %

[0117]

[0118]

[0119] The higher the seed germination index value, the better, which proves that the compost product is highly mature, has low toxicity to plants, and has a good growth-promoting effect. At the end of composting, the experimental group with 5% 200-degree Celsius heat-modified attapulgite added was significantly superior to other experimental groups in seed germination index.

[0120] Table 12 Carbon-nitrogen ratio

[0121] Time / day CK T1 T2 T3 T4 T5 T6 T7 T8 1 22.56 22.85 21.43 21.5 23.31 22.83 22.11 23.23 24.07 4 23.59 22.08 20.38 19.07 24.31 24.53 27.93 25.83 21.61 7 21.74 17.9 15.55 14.45 21.78 21.36 24.57 21.65 18.47 14 19.51 14.71 13.44 12.37 18.34 19.29 21.44 19.00 16.76 21 16.09 11.49 10.25 9.70 16.36 16.72 18.33 16.21 13.75 30 13.45 10.56 7.78 7.94 14.21 14.50 16.62 14.16 12.47

[0122] The carbon-nitrogen ratio (C / N) is a key indicator of compost maturity. A C / N ratio below 20 indicates initial maturity, while a ratio below 12 indicates complete compost stability. At the end of composting, the two composts treated with 5% and 10% attapulgite heat-modified at 200°C exhibited significantly lower C / N ratios than the other treatments. Furthermore, the C / N ratios of the other treatments remained above 12 at the end of composting, indicating incomplete compost maturity.

[0123] Table 13 Organic matter content %

[0124] Time / day CK T1 T2 T3 T4 T5 T6 T7 T8 1 51.73 49.76 48.63 49.29 52.46 50.96 51.28 51.46 52.45 4 47.88 44.41 40.37 36.52 48.46 48.45 48.76 47.46 46.43 7 45.81 38.87 35.77 32.95 45.16 45.46 46.65 43.46 40.21 14 45.72 36.99 35.11 32.58 42.65 43.64 46.03 41.42 39.53 21 40.46 32.96 30.04 27.88 41.32 40.45 43.28 40.57 37.64 30 36.80 31.74 26.29 25.54 38.33 37.46 40.26 38.45 35.46

[0125] The lower the final organic matter content, the better. Composting is the process by which organic materials are gradually decomposed and converted into humus by aerobic microorganisms. A greater rate of organic matter degradation and a lower final organic matter content indicate better composting results. The experimental group with 5% 200°C attapulgite added had a significantly higher organic matter degradation rate than the other experimental groups.

[0126] Table 14 Dissolved organic matter content g / kg

[0127] Time / day CK T1 T2 T3 T4 T5 T6 T7 T8 1 28.09 28.96 26.78 26.19 27.45 27.55 28.45 28.45 28.63 4 20.50 16.77 15.00 14.59 20.89 21.45 22.55 23.45 15.46 7 42.65 40.49 35.28 37.45 42.55 41.26 40.45 41.66 42.45 14 17.96 14.41 13.57 13.52 20.45 22.45 23.42 26.46 25.43 21 14.05 13.81 11.07 12.20 17.46 19.65 18.56 20.46 15.43 30 13.30 9.37 6.92 9.28 13.99 14.45 14.42 16.15 12.35

[0128] The lower the final content of dissolved organic matter (DOC), the better. DOC is water-soluble organic matter and an energy source that can be directly utilized by microorganisms. Its degradation rate also reflects the extent of the composting reaction. Only when the DOC content is less than 10g / kg at the end of composting does it meet the quality standards. The DOC degradation rate was also the highest when 5% of 200°C thermally modified attapulgite was added. The DOC content of the five groups without attapulgite, the groups thermally modified at 100 and 300°C, and the groups modified with thiol and hydrochloric acid was still greater than 10g / kg at the end of the composting, indicating low quality.

[0129] Table 15 Total nitrogen content g / kg

[0130] Time / day CK T1 T2 T3 T4 T5 T6 T7 T8 1 13.30 12.63 13.16 13.30 13.05 12.95 13.46 12.85 12.64 4 11.77 11.66 11.49 11.11 11.56 11.46 10.12 10.65 12.45 7 12.22 12.59 13.35 13.22 12.03 12.34 11.02 11.64 12.63 14 13.59 14.58 15.15 15.28 13.49 13.12 12.45 12.64 13.68 21 14.58 16.63 17.00 16.67 14.65 14.03 13.70 14.51 15.88 30 15.87 17.42 19.60 18.65 15.64 14.98 14.05 15.75 16.50

[0131] Total nitrogen is an important nutrient, and the higher its content, the better. At the end of composting, the compost group with 5% 200℃ thermally modified attapulgite added had the highest total nitrogen content and increase rate.

[0132] Table 16 Ammonia nitrogen content g / kg

[0133] Time / day CK T1 T2 T3 T4 T5 T6 T7 T8 1 2.88 2.85 2.47 2.55 2.65 2.56 2.66 2.76 2.87 4 5.32 3.64 3.32 2.88 4.42 3.47 4.54 5.45 3.69 7 2.69 1.84 1.45 1.51 2.5 2.45 2.65 2.67 2.03 14 2.49 1.35 1.23 1.46 2.05 2.12 2.32 2.35 1.55 21 1.28 1.09 1.04 1.02 1.3 1.12 1.22 1.12 1.21 30 0.34 0.24 0.24 0.29 0.36 0.36 0.55 0.28 0.25

[0134] Ammonia nitrogen is the main source of total nitrogen loss during composting, so the lower its content, the better. The two groups of composts that added 5% and 10% of 200°C thermal modification performed best in terms of ammonia nitrogen content, significantly lower than the other groups.

[0135] Table 17 Nitrate nitrogen content g / kg

[0136] Time / day CK T1 T2 T3 T4 T5 T6 T7 T8 1 0.11 0.13 0.12 0.12 0.12 0.11 0.12 0.12 0.14 4 0.12 0.12 0.12 0.11 0.12 0.12 0.12 0.12 0.13 7 0.11 0.12 0.1 0.12 0.13 0.12 0.12 0.12 0.13 14 0.12 0.13 0.13 0.13 0.13 0.12 0.12 0.13 0.12 21 0.16 0.22 0.26 0.23 0.15 0.15 0.15 0.18 0.21 30 0.36 0.47 0.47 0.47 0.34 0.32 0.33 0.35 0.39

[0137] High nitrate-nitrogen content indicates that ammoniation has been over-transformed into nitrification, so the higher the nitrate-nitrogen content, the better the compost quality. The two groups of composts with 5% and 10% addition of 200℃ thermal modification showed the best nitrate-nitrogen content.

[0138] Table 18 Total potassium content g / kg

[0139]

[0140]

[0141] Potassium is an important nutrient element needed by soil and plants. The higher its content, the better. At the end of composting, adding 5% of 200℃ heat-modified attapulgite compost group also has the best effect.

[0142] Table 19 Available potassium content g / kg

[0143] Time / day CK T1 T2 T3 T4 T5 T6 T7 T8 1 3.23 3.48 3.40 3.26 3.25 3.21 3.15 3.12 3.46 4 4.37 4.23 5.84 6.11 4.01 3.99 3.85 3.95 4.27 7 5.62 5.53 7.68 8.27 5.56 4.65 4.56 4.66 5.23 14 6.18 6.97 9.21 9.78 6.05 5.80 5.68 5.65 6.42 21 7.75 8.51 14.84 12.95 7.65 6.89 6.16 6.98 7.43 30 8.07 9.17 17.87 14.80 8.05 7.66 6.99 7.92 8.56

[0144] Quick-acting nutrients are those that plants can directly absorb, and the same applies to total potassium. At the end of composting, adding 5% of 200°C heat-modified attapulgite to the compost group also showed the best results.

[0145] Table 20 Total phosphorus content g / kg

[0146] Time / day CK T1 T2 T3 T4 T5 T6 T7 T8 1 1.45 1.57 1.53 1.59 1.56 1.46 1.48 1.51 1.45 4 1.58 1.63 1.64 1.62 1.60 1.49 1.53 1.58 1.59 7 1.76 1.96 2.18 2.24 1.63 1.62 1.68 1.64 1.86 14 2.29 2.57 2.72 2.75 2.01 1.80 2.04 1.95 2.74 21 2.83 3.42 3.75 3.67 2.72 2.48 2.76 2.85 3.38 30 3.26 4.22 5.99 5.36 3.15 2.87 3.09 3.17 4.10

[0147] Phosphorus is an important nutrient element needed by soil and plants. The higher its content, the better. At the end of composting, adding 5% of 200℃ heat-modified attapulgite compost group also has the best effect.

[0148] Table 21 Available phosphorus content g / kg

[0149] Time / day CK T1 T2 T3 T4 T5 T6 T7 T8 1 0.87 0.97 0.97 0.95 0.89 0.92 0.95 0.93 0.98 4 1.12 1.27 1.12 1.04 1.09 1.13 1.01 1.13 1.12 7 1.24 1.32 1.38 1.27 1.15 1.97 1.18 1.27 1.36 14 1.42 2.01 2.22 2.14 1.40 1.36 1.37 1.42 1.87 21 1.99 3.02 3.07 2.99 1.85 1.80 1.76 1.89 2.97 30 2.54 3.83 4.68 4.18 2.46 2.35 2.20 2.50 3.83

[0150] Quick-acting nutrients are those that plants can directly absorb, and the same applies to total phosphorus. At the end of composting, adding 5% of 200°C heat-modified attapulgite to the compost group also achieved the best results.

Claims

1. A method for composting livestock and poultry manure and crop straw, characterized in that: The method comprises: A. Purification: Purify the attapulgite powder to obtain a palygorskite mineral content of more than 89.5% after purification. B. Modification: calcining the purified attapulgite powder at 150°C to 250°C for 2h to 3h and cooling to ambient temperature to obtain modified attapulgite powder; C. Composting: Mix livestock and poultry manure with crop straw and attapulgite for composting. The dry weight ratio of livestock and poultry manure to crop straw is 1:5.5 to 1:10, and the modified attapulgite powder is 5% to 10% of the total dry weight of livestock and poultry manure and crop straw. The initial C / N ratio of the compost matrix is controlled to be 25:1 to 30:1, the moisture content is 65% to 75%, and the pH is 7.5 to 8.

5. During the composting process, the moisture content is controlled to be 65% to 75%.

2. The method for mixed composting of livestock and poultry excrement and crop straw according to claim 1, characterized in that: The purification method in step A comprises: The attapulgite powder is mixed with an aqueous solution of sodium hexametaphosphate, stirred for 0.5 to 1 hour, and then allowed to stand for 30 to 45 minutes. The upper suspension is collected for solid-liquid separation, and the solid is dried to obtain the purified attapulgite powder; preferably, the drying is performed at 60 to 70 degrees Celsius for 3 to 5 hours; Preferably, the recovery rate of the purification is above 75.82%.

3. The method for mixed composting of livestock and poultry excrement and crop straw according to claim 2, characterized in that: The concentration of the sodium hexametaphosphate aqueous solution is 2.1 to 2.5 g / L, and the mass ratio of the sodium hexametaphosphate to the attapulgite powder is preferably 2.1:70 to 2.5:

70.

4. The method for mixed composting of livestock and poultry excrement and crop straw according to claim 1, characterized in that: Before the calcination in step B, the attapulgite powder is crushed and passed through a 200-mesh sieve, and the sieve residue is calcined.

5. The method for mixed composting of livestock and poultry excrement and crop straw according to claim 1, characterized in that: The heating rate of the calcination in step B is 5-10°C / min.

6. The method for mixed composting of livestock and poultry excrement and crop straw according to claim 1, characterized in that: The aeration rate of the compost in step C is set to 0.68-1 L·min -1 kg -1 , aerate for 45 minutes with a 5-minute break.

7. The method for mixed composting of livestock and poultry excrement and crop straw according to claim 1, characterized in that: During the composting process in step C, the water bath is set to maintain temperature according to the real-time measured temperature. The water temperature of the water bath is set to 35-40°C during the composting heating period; the water temperature of the water bath is set to 40-45°C during the thermophilic period; the water temperature of the water bath is set to 30-40°C during the cooling period; and the water temperature of the water bath is set to room temperature during the composting period.

8. The method for mixed composting of livestock and poultry excrement and crop straw according to claim 1, characterized in that: During the composting process in step C, the compost is not turned over in the first three days. After the temperature of the compost drops below 50°C, the compost is turned over every three days. After the temperature of the compost drops below 40°C, the compost is turned over every seven days.

9. The method for mixed composting of livestock and poultry excrement and crop straw according to claim 1, characterized in that: Step C also includes naturally air-drying the livestock and poultry manure and crop straw before composting, crushing them into small pieces of 1 to 2 cm, and removing stones and impurities; Preferably, step C further comprises, before composting, crushing the modified attapulgite powder, passing it through a 200-mesh sieve, and composting the sieve contents; The composting time is preferably 30 to 45 days. The livestock and poultry manure is preferably chicken manure, the crop straw is rice straw, the C / N ratio is controlled to be 25, and the dry weight ratio of chicken manure to rice straw is 1:5.5; Preferably, the mixing is to divide the livestock and poultry manure, crop straw and attapulgite into three equal parts, first mix one part of the livestock and poultry manure, crop straw and attapulgite, and then add the remaining two parts according to the same steps.

10. Compost fertilizer made from livestock and poultry manure and crop straw, characterized in that: The fertilizer is prepared by the method according to any one of claims 1 to 9, and preferably the fertilizer has an available phosphorus content of 4.17 g / Kg or more, a total phosphorus content of 5.35 g / Kg or more, an available potassium content of 14.8 g / Kg or more, a total potassium content of 32.5 g / Kg or more, a nitrate nitrogen content of 0.46 g / Kg or more, an ammonia nitrogen content of 0.3 g / Kg or less, a total nitrogen content of 18.65 g / Kg or more, a dissolved organic matter content of 9.3 g / Kg or less, and an organic matter content of 2 6.3g / Kg or less, electrical conductivity 1.7ms / cm or less, pH value less than 8.5, carbon-nitrogen ratio 8 or less, seed germination index 185% or more, absorbance ratio of humic acid at 445 and 665nm 4.5 or less, ratio of humic acid to fulvic acid 2.7 or more, humic acid content 94.6g / Kg or more, fulvic acid content 34.8g / Kg or less, humus content 129.4g / Kg or more.

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