Preparation and application of wormcast loaded nano argillaceous limestone soil conditioner

Abstract

The invention belongs to the field of soil conditioning, and discloses a preparation method of a wormcast loaded nano argillaceous limestone soil conditioner, which comprises the following steps: grinding argillaceous limestone to nano size by a water milling method to obtain nano argillaceous limestone; wormcast is collected, shaded, air-dried, ground and sieved, and wormcast particles are obtained; uniformly mixing the nano argillaceous limestone and the wormcast particles; the wormcast loaded nano argillaceous limestone soil conditioner is used for growth of under-forest polygonatum kingianum, the pH and enzyme activity of soil can be improved, the growth of the under-forest polygonatum kingianum can be promoted, the physicochemical properties and nutrients of the under-forest soil can be improved, and the wormcast loaded nano argillaceous limestone soil conditioner is environmentally friendly, long in acting time and beneficial to production and income increase of farmers.

Description

Technical Field

[0001] The present invention belongs to the field of soil regulation, and particularly relates to the preparation and application of an earthworm manure-loaded nano-argillaceous limestone soil conditioner. Background Art

[0003] Acidified soil usually fixes cations, making them unavailable for plant growth, which is due to the loss of exchangeable cations (including Ca and Mg) and the reduction of soil cation exchange capacity. Due to the possible toxicity of aluminum and manganese, crop yields in strongly acidic soils are usually very low. Soil acidification increases the availability of heavy metals, leading to the deterioration of soil physical and chemical properties and the imbalance of soil microbial community structure, thus threatening crop health and restricting crop growth.

[0004] According to traditional Chinese medicine theory, Polygonatum kingianum Coll. et Hemsl. is sweet in taste, neutral in nature, and enters the spleen, kidney, and lung meridians. It has the effects of tonifying qi and nourishing yin, strengthening the spleen, moistening the lungs, and tonifying the kidneys. It is used for spleen and stomach qi deficiency, fatigue, stomach yin deficiency, dry mouth and less food intake, dry cough due to lung deficiency, coughing up blood due to consumptive disease, insufficient essence and blood, soreness and weakness of the waist and knees, premature whitening of hair, and internal heat and thirst. In recent years, Polygonatum kingianum Coll. et Hemsl. has been widely used in medicine and health products, and the demand for this product has increased sharply, and its planting area has been continuously expanded to meet this growing demand. In this context, the under-forest cultivation of Polygonatum kingianum Coll. et Hemsl. has developed rapidly. Under-forest cultivation provides a suitable growth environment and rich biodiversity, and can alleviate the quality and safety problems caused by the extensive use of chemical fertilizers and pesticides in traditional artificial cultivation. However, due to the accumulation of humus and allelochemicals in forest soil, there are still some problems with soil acidification, which ultimately limits the growth of Polygonatum kingianum Coll. et Hemsl.

[0005] Earthworm manure is considered an excellent organic fertilizer and soil conditioner rich in nutrients, which is derived from the organic matter produced by the digestive system of earthworms and environmental microbial activities. It has the advantages of good porosity, good ventilation, and strong water retention capacity. In addition, earthworm manure can provide a large number of mineral nutrient elements, and promote the absorption of nutrients by plants by improving soil properties and bacterial communities. In addition, carbonate minerals (such as lime and dolomite) are regarded as "green materials" for improving acidified soil, which are cost-effective, environmentally friendly, and efficient; although they are widely used in the field of soil acidification control, it is reported that compared with composite materials used for soil acid control, natural minerals only have a weak stabilizing effect. Therefore, it is very important to produce a functional earthworm manure with optimal performance as an acidified soil conditioner.

[0006] However, so far, there have been few reports on the R & D technology of such soil conditioners, mainly including: 1. Using cow dung and modified minerals (composition: calcium oxide and magnesium oxide) as raw materials, using an earthworm reactor to prepare vermicompost for Eisenia fetida to eat, forming functional earthworm manure (Feng Wang, et al. Using cow dung and mineral vermireactors to produce vermicompost for use as a soil amendment to slow Pb2+ migration. Applied Soil Ecology, Volume 170, February 2022, 104299); 2. Combining three kinds of organic matters, namely water hyacinth, rice straw and cow dung, with three kinds of minerals, namely phosphate rock, dolomite and mica, and then inoculating Trichoderma viride, Azotobacter chroococcum, Bacillus polymyxa and Bacillus firmus respectively, and using them to feed earthworms for 105 days to obtain functional earthworm manure. It is used for the improvement of acidified soil. Research shows that compared with only adding minerals, the earthworm manure formed by using mineral composite organic waste can significantly improve the urease, acid phosphatase activities, microbial biomass carbon and nutrient content in the soil (Debabrata Das, et al. Comparative evaluation of changes in soil bio-chemical properties after application of traditional and enriched vermicompost. Environmental Technology & Innovation 28(1–2), November 2022 102956). 3. Chinese Patent CN106045757A (an acidic soil conditioner for rice planting and its preparation method) discloses that the acidic soil conditioner is made from the following raw materials in parts by weight: 30-40 of waste dry wood, 25-30 of 6-10% dilute sulfuric acid solution, 100-120 of 3-5 mmol / g sodium sulfite solution, 10-15 of oyster shell powder, 15-20 of phosphorite powder, 20-30 of earthworm manure, 6-10 of fly ash, 4-6 of humic acid powder, 7-10 of boric acid, 15-20 of ammonium bicarbonate, 80-100 of well-rotted cow dung, 100-120 of rice straw residue and an appropriate amount of water.4. Chinese Patent CN107325822A (A Soil Conditioner and Its Preparation Method) discloses a soil conditioner, which includes the following raw materials in parts by weight: 10-20 parts of montmorillonite, 7-15 parts of oyster shell, 9-18 parts of earthworm manure, 5-13 parts of sugar residue, 3-8 parts of chlorite, 13-25 parts of straw, 5-10 parts of biogas residue, 7-11 parts of peat soil, 3-5 parts of lignin, 2-7 parts of polyacrylamide, 9-16 parts of rice bran, 3-7 parts of fish meal, 4-8 parts of silkworm excrement, 2-5 parts of humic acid, 1-2 parts of calcium carbonate, 2-3 parts of ammonium dihydrogen phosphate, 3-6 parts of potassium chloride, 1-2 parts of fungicide, and 2-3 parts of activated carbon. 5. Chinese Patent CN107573163A (An Acidic Soil Conditioner with Plant Nutritional Function and Its Preparation Method) discloses an acidic soil conditioner with plant nutritional function and its preparation method, which is composed of a base material and an auxiliary material evenly mixed. The base material is obtained by mixing and fermenting beer dregs, peat soil, Chinese medicine residues, soybean meal powder, straw powder, edible mushroom residues, pineapple mud, apple mud, silkworm excrement, protein hydrolyzing enzyme, nitrogen-fixing bacteria, rhizobia, potassium-dissolving bacteria, cellulose-decomposing bacteria, antibiotic-producing bacteria and water; the auxiliary material is composed of earthworm manure, biochar residue, urea, plant ash, lime powder, urea iron complex and chelated zinc evenly mixed; its preparation method is: A. Prepare the base material, B. Prepare the auxiliary material, C. Prepare the soil conditioner. 6. Chinese Patent CN113999683A (Preparation and Application of an Acidified Soil Conditioner) discloses an acidified soil conditioner, which includes the following components in parts by weight: 100-120 parts of eggshell, 25-30 parts of NaOH-modified fly ash, 15-20 parts of biomass ash, 5-10 parts of baking soda, and 5-10 parts of earthworm manure. 7. Chinese Patent CN111087265A (Acidic Soil Conditioner for Grape Planting and Its Preparation Process) discloses an acidic soil conditioner for grape planting. The acidic soil conditioner for grape planting is composed of the following raw materials in parts by weight: 20-30 parts of limestone, 6-10 parts of bentonite, 10-20 parts of potassium dihydrogen sulfate, 5-15 parts of zinc sulfate, 5-15 parts of potassium phosphate, 5-10 parts of ferrous chloride, 5-15 parts of wheat bran, 10-15 parts of earthworm manure, and 2-5 parts of tolfenpyrad. 8. Chinese Patent CN108441227A (A Soil Conditioner and Its Application Method) discloses a soil conditioner and its application method. The conditioner is composed of a base material and an auxiliary material. The base material is biochar and earthworm manure, and the auxiliary material is calcium oxide, magnesium oxide and silicon oxide.

[0007] Currently, the measures to improve acidified soil using earthworm cast composite mineral materials are mainly divided into three categories: A, the above-mentioned technologies 1 and 2; B, the above-mentioned technologies 3 - 7; C, the above-mentioned technology 8. The advantages of category A technologies lie in their strong stability, while the disadvantages are weak and slow acid reduction effects (reason: when minerals pass through the earthworm intestine, they will be wrapped by both organic waste and intestinal organic matter). The advantages of category B technologies are good and fast acid reduction and growth promotion effects, but the disadvantage is that the addition of chemically synthesized substances will affect the sustainability of agriculture. The advantages of category C technologies are environmental friendliness and strong sustainability, but the disadvantage is that the acid reduction effect is average (reason: the mineral particles are relatively large and the acid reduction time is long).

[0008] In the existing improvement technologies for acidified soil in the field of agriculture and forestry, earthworm cast composite nano-mineral materials have not been used as improvement materials.

[0009] Argillaceous limestone is a natural mineral rich in carbonate and alkaline (pH 8.25). It is a waste mineral, and its nano-particles have excellent acid reduction effects. However, earthworm cast composite argillaceous limestone has not been used as a precedent in the improvement technologies for acidified soil in the field of agriculture and forestry. Therefore, the present invention first proposes a preparation method of an earthworm cast loaded nano-argillaceous limestone soil conditioner, which has the characteristics of being green and safe, stable in nature, good in acid reduction and growth promotion effects, and strong in sustainability. It is used for the improvement of acidified soil in agriculture and forestry, and can provide a reliable basis for the growth and yield increase of understory crops. Summary of the Invention

[0010] To solve the above problems, the present invention proposes a green and long-acting soil conditioner for promoting the growth of Polygonatum kingianum in forests. Using argillaceous limestone as the raw material, after being ground into nano-particles by water milling and modified, it is fermented and loaded with earthworm cast to form a new type of soil conditioner, which can increase the pH and enzyme activity of the soil, have a certain promoting effect on the growth of Polygonatum kingianum in forests, and can improve the physical and chemical properties and nutrients of the understory soil. Moreover, it is environmentally friendly, has a long action time, and is beneficial to farmers' increase in production and income.

[0011] The technical solution of the present invention is as follows: A preparation method of an earthworm cast loaded nano-argillaceous limestone soil conditioner, comprising the following steps: (1) Using the water milling method, grind argillaceous limestone to nano-size to obtain nano-argillaceous limestone; (2) Collect earthworm cast, shade and air-dry it, grind and sieve it to obtain earthworm cast particles; (3) Mix the nano-argillaceous limestone obtained in step (1) and the earthworm cast particles obtained in step (2); (4) Ferment and granulate to obtain an earthworm cast loaded nano-argillaceous limestone soil conditioner.

[0012] The particle size of the nano-argillaceous limestone will affect the improvement effect. If the size is too large, the acid reduction effect will be reduced; if the size is too small, the argillaceous limestone will agglomerate. Therefore, in the step (1), the particle size of the nano-argillaceous limestone is preferably 67.9 - 872 nm.

[0013] Preferably, in the step (2), the sieving is through a 5 - 20 mesh sieve; preferably through a 10 mesh sieve; this is because if the size of the earthworm cast is too large, the acid reduction effect will be reduced, and if the size is too small, the conditioner will agglomerate.

[0014] Preferably, in the step (3), the mass ratio of the nano-argillaceous limestone to the earthworm cast particles is 3 - 10:100, preferably 5:100. Considering the pores of the earthworm cast particles, the acid reduction effect of the argillaceous limestone and the cost, this range can load the nano-argillaceous limestone with the highest efficiency and improve the cost performance.

[0015] Preferably, in the step (4), the fermentation is carried out in a blender, the rotation speed is set at 30 - 50 r / min, the temperature is set at 35 - 45 °C, and the fermentation lasts for 4 - 8 h; preferably, the rotation speed is set at 38 - 42 r / min, the temperature is set at 38 - 42 °C, and the fermentation lasts for 5 - 7 h. Specifically, the rotation speed is set at 40 r / min, the temperature is set at 40 °C, and the fermentation lasts for 6 h. This can ensure the full combination of the earthworm cast and the nano-argillaceous limestone while maintaining the integrity of the microbial community structure of the earthworm cast.

[0016] Preferably, the matrix sources of the earthworm cast include cow dung, corn straw, pine needles, waste stems and leaves of Chinese rose, and waste leaves of walnut. The reasons are as follows: The annual waste amount of cow dung in China is about 1.4 billion tons, accounting for 37% of the total livestock manure. Cow dung is rich in incompletely decomposed organic matter, providing a rich food source for earthworms. Earthworms feed on organic waste and decompose it into more nutritious earthworm cast (organic fertilizer). The cellulose, hemicellulose and a small amount of protein contained in cow dung are ideal foods for earthworms. The humidity of cow dung is usually 70% - 80%, close to the humidity condition required by earthworms (60% - 90%). In addition, the structure of cow dung is loose, with good air permeability, facilitating the activities and reproduction of earthworms. Cow dung contains a large number of microorganisms, which can not only promote the decomposition of organic matter, but also become an important food source for earthworms. The intermediate products of microbial decomposition, such as fatty acids and amino acids, can also be directly utilized by earthworms.

[0017] In addition, the reason for choosing corn straw is that based on the annual corn output in China of about 200 million tons, the annual output of straw is estimated to be about 160 - 240 million tons. The mixture of cow dung and corn straw further optimizes C:N. The cellulose supplement of straw can improve the fiber ratio of cow dung and increase the earthworm yield.

[0018] Pine needles belong to agricultural and forestry waste, and the leaching species thereof are rich in allelochemicals such as α-terpineol and 2,3-butanediol, which have inhibitory effects on pathogenic bacteria. The annual output range of waste stems and leaves of Chinese roses is estimated to be 3 million tons to 10.5 million tons, and the annual output range of waste leaves of Chinese walnuts is roughly 1.5 million tons to 5.5 million tons. Therefore, waste stems and leaves of roses and waste leaves of walnuts can also be used as substrate sources.

[0019] Preferably, the substrate of earthworm feces also includes Tinospora sagittata. Tinospora sagittata contains chemical components such as clerodane diterpenoids, alkaloids, and steroids, among which clerodane diterpenoids are its characteristic chemical components. Tinospora sagittata has biological activities such as anti-inflammatory, antioxidant, and antibacterial.

[0020] In the substrate of earthworm feces, cow dung is used as the main source of protein and the basic food ingredient; Tinospora sagittata is used as a natural antibiotic to improve the activity of earthworms and play a role in increasing production. Corn straw, pine needles, waste stems and leaves of roses, and waste leaves of walnuts are used as auxiliary materials. Preferably, the mass ratio of the cow dung, corn straw, pine needles, waste stems and leaves of roses, waste leaves of walnuts, and Tinospora sagittata is 5-8:0.1-1:0.1-1:0.1-1:0.1-1:1-3; the preferred mass ratio is 6:0.5:0.5:0.5:0.5:2.

[0021] Preferably, the fermentation method of the substrate of earthworm feces is as follows: Mix the substrate components and place them in a compost fermentation tank, water to a moisture content of 55%-65%, raise the temperature to 60°C, keep the temperature stable at 55-60°C and stir, ferment for 12-18 days, and the moisture content of the discharged material is 35-40%; then stir, lower the temperature to 40-45°C, ferment for 2-4 days, and the moisture content of the discharged material is 30-40%; then stir again, lower the temperature to 25-40°C, and stack for 28-32 days; More specifically, mix the substrate components and place them in a compost fermentation tank, water to a moisture content of 55%-65%, raise the temperature to 60°C, keep the temperature stable at 55-60°C and stir, ferment for 15 days, and the moisture content of the discharged material is 35-40%; on the 16th day, stir, lower the temperature to 40-45°C, ferment for 3 days, and the moisture content of the discharged material is 30-40%; on the 19th day, stir, lower the temperature to 25-40°C, and stack for 30 days.

[0022] Preferably, the methods of inoculating, managing, and harvesting earthworms are as follows: Spread the substrate evenly in the breeding tank with a thickness of 15 cm, inoculate healthy and lively earthworm seedlings, and the inoculation amount is 30,000 earthworms per tank. Ensure that the moisture content of the substrate is about 70% and replenish water appropriately; one day before collecting the earthworm feces, place 5 kg of cow dung at a fixed site in the breeding tank, and use the bait collection method to capture earthworms and collect earthworm feces.

[0023] Using earthworm castings loaded with nano-marl soil conditioner for the growth of Polygonatum kingianum Coll. et Hemsl. under forest, the more suitable application rate is 3.9 - 4.6 tons per mu, preferably 4.3 tons per mu.

[0024] In comparison with the prior art, the beneficial effects of the present invention are as follows: (1) It has the characteristics of being green and safe, stable in nature, good in acid reduction and growth promotion effects, and strong sustainability.

[0025] (2) Avoid the use of chemical fertilizers, thus saving costs.

[0026] (3) It has a long action time and improves the industrial benefits of Polygonatum kingianum Coll. et Hemsl. under forest. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 : Effects of different soil conditioners on the pH and nutrient content of the rhizosphere soil of Polygonatum kingianum Coll. et Hemsl. under forest; (Note: The data on the figure are all mean ± standard deviation (n = 3); Different lowercase letters on the figure indicate that there are statistically significant differences between treatments (P < 0.05)); Figure 2 Effects of different soil conditioners on the carbon components of the rhizosphere soil of Polygonatum kingianum Coll. et Hemsl. under forest; (Note: The data on the figure are all mean ± standard deviation; (n = 3); Different lowercase letters on the figure indicate that there are statistically significant differences between treatments (P < 0.05)); Figure 3 Effects of different soil conditioners on the enzyme activities of the rhizosphere soil of Polygonatum kingianum Coll. et Hemsl. under forest; (Note: The data on the figure are all mean ± standard deviation (n = 3); Different lowercase letters on the figure indicate that there are statistically significant differences between treatments (P < 0.05)). DETAILED DESCRIPTION OF THE INVENTION

[0028] To more clearly elaborate the purpose, technical solution and advantages of the present invention, the following will be described in detail with specific embodiments. The present invention can be implemented in various forms, and its design concept and core technology are not limited by the embodiments. The purpose of providing these embodiments is to make it easier for technicians to understand the principle, structure and function of the present invention, so as to better master and apply its technical solution. The terms used in this specification are only for describing specific embodiments and do not constitute a limitation to the present invention.

[0029] Example 1: Earthworm breeding (I) Preparation of earthworm breeding pond Use red bricks and cement to construct an earthworm breeding pond, and the specific parameters are as follows: length × width × height 5m × 1m × 0.5m, slope ≤ 2 degrees, and the diameter of the circular liquid drainage port at the lowest part is 30mm.

[0030] (II) Preparation of earthworm substrate The earthworm substrate is composed of air-dried cow dung, air-dried corn straw, air-dried pine needles, air-dried waste stems and leaves of Chinese roses, air-dried waste leaves of walnuts, and air-dried Tinospora sagittata. The specific mass ratios are shown in Table 1 below: Table 1 Mass ratios of the earthworm substrate

[0031] Mix the above substrates T1 - T4 respectively, place them evenly in the compost fermentation tank, water until the water content is 55% - 65%, raise the temperature to 60°C, stir according to the temperature stabilized at 55 - 60°C, ferment for 15 days, and the water content of the discharged material is 35% - 40%.

[0032] Stir on the 16th day, lower the temperature to 40 - 45°C, ferment for 3 days, and the water content of the discharged material is 30% - 40%.

[0033] Stir on the 19th day, lower the temperature to 25 - 40°C, stack for 30 days and then pack for standby.

[0034] (III) Earthworm inoculation, management and harvesting Take the above 4 kinds of composted earthworm substrates T1 - T4 and spread them evenly in the breeding pond with a thickness of 15 cm. Set 3 replicates for each ratio, inoculate healthy and lively earthworm seedlings, and the inoculation amount is 30,000 earthworms per pond.

[0035] Randomly place 3 humidity monitors in each breeding pond to ensure appropriate water replenishment when the water content of the substrate is about 70%.

[0036] (IV) Earthworm cast collection One day before collecting the earthworm casts, put 5 kg of cow dung at a fixed site in the breeding pond and use the bait collection method to capture earthworms.

[0037] Measure the earthworm breeding yield, and the results are shown in Table 2 below.

[0038] Table 2 Effects of different ratios of earthworm cast substrates on earthworm yield

[0039] Note: Different lowercase letter superscripts indicate significant differences (P < 0.05).

[0040] It can be seen that when the mass ratio of cow dung, corn straw, pine needles, waste stems and leaves of Chinese roses, waste leaves of walnuts, and Tinospora sagittata is 6:0.5:0.5:0.5:0.5:2, the earthworm yield obtained from breeding is the highest. This is because Tinospora sagittata contains chemical components such as clerodane diterpenoids, alkaloids, and steroids, among which clerodane diterpenoids are its characteristic chemical components. Tinospora sagittata has biological activities such as anti-inflammatory, antioxidant, and antibacterial. Under this condition, it can effectively improve the growth activity of earthworms, and the earthworm yield is the highest.

[0041] Example 2: Preparation of Earthworm Cast Loaded with Nano-argillaceous Limestone Soil Conditioner (1)Shade-dry the collected T4 earthworm casts from Example 1, grind them finely, and sieve them through a 10-mesh sieve for later use.

[0042] (2)Using the water milling method, grind the argillaceous limestone to a particle size of 67.9 - 872 nm to obtain nano-argillaceous limestone.

[0043] (3)According to the ratio of nano-argillaceous limestone: earthworm casts = 5:100 (mass ratio), put the nano-argillaceous limestone and the sieved earthworm cast particles into a blender, set the rotation speed to: 40 r / min, set the temperature to: 40 °C, and ferment for 6 h.

[0044] (4)After sufficient stirring, granulate to obtain the earthworm cast loaded with nano-argillaceous limestone soil conditioner, with a particle size of 1 - 3 mm, and set aside for later use.

[0045] Example 3: Field Experiment Equally apply the earthworm casts (T4 from Example 1) and the earthworm cast loaded with nano-argillaceous limestone soil conditioner from Example 2 into the forest soil where Polygonatum kingianum is planted. Explore their effects on promoting the growth of Polygonatum kingianum and screen out the most suitable soil conditioner.

[0046] Adopt a randomized block design, with a total of 2 treatments (earthworm cast VC group and earthworm cast loaded with nano-argillaceous limestone soil conditioner VCNL group) set, 4 replicates for each treatment, taking no application of any soil conditioner as the control (CK), with a plot area of 16 square meters, and a total of 12 plots. The planting spacing is 0.2 m and the row spacing is 0.3 m. Application rate: earthworm cast VC group: 4.3 tons per mu, earthworm cast loaded with nano-argillaceous limestone soil conditioner VCNL group: 4.3 tons per mu.

[0047] The experimental results are shown in Table 3. Compared with the application of earthworm casts, the application of the earthworm cast loaded with nano-argillaceous limestone soil conditioner significantly increased the plant height, leaf length, leaf width, and root dry weight of Polygonatum kingianum in the forest. The results show that the earthworm cast loaded with nano-argillaceous limestone soil conditioner is more conducive to the growth of Polygonatum kingianum in the forest.

[0048] Table 3 Effects of Different Soil Conditioners on the Agronomic Traits of Polygonatum kingianum in the Forest

[0049] Note: The results are expressed as mean ± standard deviation (n = 3). Different lowercase letters indicate significant differences between treatments ( P <0.05).

[0050] Such as Figure 1As shown, compared with the application of earthworm cast, the application of earthworm cast loaded with nano-argillaceous limestone soil conditioner significantly increased the pH, nitrate nitrogen (NO3 - -N), ammonium nitrogen (NH4 + -N), available phosphorus (AP), and available potassium (AK) contents in the rhizosphere soil of Polygonatum kingianum under forest. The results showed that the earthworm cast loaded with nano-argillaceous limestone soil conditioner was more conducive to increasing soil pH and nutrient contents.

[0051] As Figure 2 shown, compared with the application of earthworm cast, the application of earthworm cast loaded with nano-argillaceous limestone soil conditioner significantly increased the contents of dissolved organic carbon (DOC), easily oxidizable organic carbon (EOC), and particulate organic carbon (POC) in the rhizosphere soil of Polygonatum kingianum under forest. The results showed that the earthworm cast loaded with nano-argillaceous limestone soil conditioner was more conducive to increasing the contents of soil carbon components.

[0052] As Figure 3 shown, compared with the application of earthworm cast, the application of earthworm cast loaded with nano-argillaceous limestone soil conditioner significantly increased the activity of invertase (S-SC) in the rhizosphere soil of Polygonatum kingianum under forest and significantly decreased the activity of soil acid phosphatase (S-ACP). The results showed that the earthworm cast loaded with nano-argillaceous limestone soil conditioner was more conducive to regulating soil enzyme activity.

[0053] Finally, it should be emphasized that the embodiments provided here are only a part of the embodiments of the present invention, not all of them. Based on the present invention, all other embodiments obtained by those skilled in the art without creative efforts shall fall within the scope of protection of the present invention.

Claims

1. A method for preparing a nano-argillaceous limestone soil conditioner loaded with earthworm castings, characterized in that: The steps include: (1) Grinding mudstone into nanometer size to obtain nano-mudstone; (2) Grinding and sieving the earthworm castings to obtain earthworm casting pellets; (3) mixing the nano-argillaceous limestone of step (1) and the earthworm castings particles of step (2); (4) Fermentation and granulation to obtain earthworm manure loaded nano-mud limestone soil conditioner.

2. The preparation method according to claim 1, characterized in that: In the step (1), grinding is performed by water milling to a particle size of 67.9-872 nm.

3. The preparation method according to claim 1, characterized in that: In the step (2), the earthworm castings are collected, shaded and air-dried, and then ground to pass through a 5-20 mesh sieve, preferably a 10 mesh sieve.

4. The preparation method according to claim 1, characterized in that: In the step (3), the mass ratio of nano-argillaceous limestone to earthworm castings particles is 3-10:100, preferably 5:

100.

5. The preparation method according to claim 1, characterized in that: In the step (4), fermentation is carried out in a mixer with a rotation speed of 30-50 r / min, a temperature of 35-45°C, and a fermentation time of 4-8 h; preferably, the rotation speed is set to 38-42 r / min, the temperature is set to 38-42°C, and the fermentation time is 5-7 h; specifically, the rotation speed is set to 40 r / min, the temperature is set to 40°C, and the fermentation time is 6 h.

6. The preparation method according to claim 1, characterized in that: The substrate source of the earthworm castings is selected from one or more of cow dung, corn stalks, pine needles, discarded stems and leaves of roses, discarded walnut leaves or green cattle gall.

7. The preparation method according to claim 6, characterized in that: The mass ratio of the cow dung, corn stalks, pine needles, discarded rose stems and leaves, discarded walnut leaves, and green cattle gall is 5-8:0.1-1:0.1-1:0.1-1:0.1-1:1-3; the preferred mass ratio is 6:0.5:0.5:0.5:0.5:

2.

8. The preparation method according to claim 7, characterized in that: The fermentation method of the substrate of earthworm manure is as follows: the substrate components are mixed and placed in a composting fermentation tank, watered to a moisture content of 55%-65%, the temperature is raised to 60°C, stirred at a temperature stable at 55-60°C, fermented for 12-18 days, and the moisture content of the discharged material is 35-40%; then stirred, the temperature is lowered to 40-45°C, the fermentation time is 2-4 days, and the moisture content of the discharged material is 30-40%; then stirred again, the temperature is lowered by 25-40°C, and stacked for 28-32 days; Specifically, the earthworm inoculation, management and harvesting methods are as follows: spread the substrate flat in the breeding pond with a thickness of 15 cm, inoculate healthy and active earthworm seedlings at an inoculation rate of 30,000 per pond, and the substrate moisture content is 70%; use the bait collection method to capture earthworms and collect earthworm castings.

9. A vermicompost-loaded nano-argillaceous limestone soil conditioner prepared by the preparation method according to any one of claims 1 to 8.

10. The use of the earthworm castings loaded nano-argillaceous limestone soil conditioner according to claim 9, characterized in that: It is used for the growth of Polygonatum cyrtonema under the forest, and the application amount is 3.9-4.6 tons / mu, preferably 4.3 tons / mu.

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