Carbonation stabilizer and preparation method thereof for sandy soil

Abstract

This invention provides a carbon-enhancing, carbon-stabilizing, and carbon-retaining agent for sandy soils and its preparation method. The carbon-retaining agent comprises fermented plant straw solids and water. The preparation method of the fermented plant straw solids involves preparing a slurry, enzymatically hydrolyzing the slurry using pectin methyl esterase, xylanase, α-amylase, and α-glucosidase, fermenting with photosynthetic bacteria to prepare a fermentation broth, and drying. The preparation method of the carbon-enhancing, carbon-stabilizing, and carbon-retaining agent involves mixing the fermented plant straw solids and water before adding the carbon-enhancing, carbon-stabilizing, and carbon-retaining agent to the sandy soil. This carbon-retaining agent can introduce organic carbon into the soil, and through the synergistic effect of plant fibers and pectin, it can reduce the loss of organic carbon caused by water erosion, allowing organic carbon to be retained in the soil for a longer period of time, thus achieving the purpose of increasing and stabilizing carbon.

Description

Technical Field

[0001] This invention relates to the field of soil improvement technology, specifically to a carbon-enhancing, carbon-stabilizing, and carbon-retaining agent for sandy soil and its preparation method. Background Technology

[0002] Sandy soil is mainly composed of sand particles. There are no cohesive particles such as clay between the sand particles, which makes sandy soil loose. The large gaps between the sand particles also give sandy soil good air permeability and water permeability.

[0003] The aforementioned characteristics of sandy soil result in poor water and fertilizer retention capacity and large diurnal temperature variations, making it difficult for sandy soil to be suitable for crop cultivation.

[0004] Therefore, providing a water-retention agent that can improve the water and fertilizer retention capacity of sandy soil is of great significance for improving the fertility of sandy soil. Summary of the Invention

[0005] In view of this, the present invention provides a carbon-enhancing, carbon-stabilizing, and carbon-retaining agent for sandy soil and its preparation method. This carbon-retaining agent can carry organic carbon into the soil, and with the synergistic effect of plant fibers and pectin, it can reduce the loss of organic carbon caused by water erosion, so that organic carbon can be retained in the soil for a longer period of time, thereby achieving the purpose of increasing and stabilizing carbon.

[0006] The technical solution of the present invention is as follows:

[0007] A carbon-enhancing, carbon-stabilizing, and carbon-retaining agent for sandy soils comprises fermented plant straw solids and water, wherein the preparation method of the fermented plant straw solids is as follows:

[0008] S1. Crush the plant straw, add a 0.3% sodium hydroxide solution until the solution covers the plant straw, and soak at room temperature for 10-20 hours; then add water and stir to obtain a slurry.

[0009] Crushing straw allows plant fibers to maintain their integrity as much as possible while remaining highly loose, thus effectively improving the water absorption of the fibers and helping to retain moisture and fertilizer. After adding sodium hydroxide solution, the hemicellulose and cellulose in the plant straw are separated and enter the pulp.

[0010] S2. Adjust the pH of the slurry to 5.7-6.2, then add pectin methyl esterase, xylanase, α-amylase, and α-glucosidase to the slurry; the amount of pectin methyl esterase added is 1.7-2.2 u / g, the amount of xylanase added is 2.5-3.0 u / g, the amount of α-amylase added is 2.1-2.5 u / g, and the amount of α-glucosidase added is 4.3-4.7 u / g. The enzymatic hydrolysis temperature is 40-45℃, the enzymatic hydrolysis time is 3.5-4.5 hours, and the enzymes are inactivated to obtain the enzymatic hydrolysate.

[0011] S3. Sterilized magnesium sulfate, disodium hydrogen phosphate, disodium bicarbonate, and ammonium sulfate are added to the enzymatic hydrolysate to obtain the fermentation substrate. Photosynthetic bacteria powder is added to the fermentation substrate, and the wavelength of the light source is controlled at 700-720nm and the light intensity at 1800-2000 lux, with intermittent light irradiation. Then, anaerobic fermentation is carried out at 35±0.5℃ for 5-7 days, followed by sterilization to obtain the fermentation broth.

[0012] Photosynthetic bacteria utilize substances such as glucose in the enzymatic hydrolysate, and after fermentation, while ensuring the pectin and cellulose content in the fermentation broth, they increase the organic carbon content in the fermentation broth.

[0013] S4. After drying the fermentation liquid, plant straw fermentation solids are obtained.

[0014] Fermented solids from plant straw contain a large amount of plant fiber. The presence of plant fiber has two functions: first, it can increase and stabilize carbon; second, it can absorb and store water in the soil, thus retaining trace elements in the soil and providing nutrients for plant growth. In addition, the fiber in the soil can provide space for crop respiration and promote root reproduction.

[0015] Preferably, in step S1, the plant straw includes one of wheat straw, corn straw, peanut straw, and rice straw.

[0016] Preferably, in step S1, the plant straw is turned over once every 3 hours during the soaking process; the weight ratio of plant straw to water is 1:3-5.

[0017] Preferably, in step S2, the intermittent lighting control is as follows: 3 hours of lighting followed by 3 hours of off lighting, and then repeated.

[0018] Preferably, in step S3, 0.5-0.7g of magnesium sulfate, 0.5-1.0g of disodium hydrogen phosphate, 0.7-1.5g of disodium bicarbonate, and 1.0-2.0g of ammonium sulfate are added per 1kg of enzymatic hydrolysate.

[0019] Preferably, in step S3, the weight ratio of photosynthetic bacteria powder to fermentation substrate is 50-70:1000; the effective viable bacteria count in the photosynthetic bacteria powder is ≥5 billion / g.

[0020] Preferably, in the above-mentioned carbon-enhancing, carbon-stabilizing, and carbon-retaining agent for sandy soil, the weight ratio of fermented plant straw solids to water is 90-95:5-10.

[0021] After enzymatic hydrolysis, the fermented solids of plant straw contain pectin. When pectin combines with water, its viscosity increases. When the resulting carbon-enhancing and carbon-stabilizing agent is applied to sandy soil, it can improve the cohesion between sandy soil particles. Even with rainwater erosion, the fibers can still remain well in the sandy soil, giving it good water and fertilizer retention capacity. Furthermore, because the fermented solids of plant straw produce amino acids and organic acids after fermentation by photosynthetic bacteria, while pectin improves the water retention capacity of sandy soil, it can effectively retain organic matter in the sandy soil. This increases the organic carbon content of the sandy soil and ensures that the organic carbon is stably retained in the sandy soil, thus achieving the purpose of fertilizer retention.

[0022] The preparation method of the above-mentioned carbon-enhancing, carbon-stabilizing, and carbon-retaining agent for sandy soil specifically involves mixing the carbon-enhancing, carbon-stabilizing, and carbon-retaining agent before adding it to the sandy soil, as follows:

[0023] (1) Place the fermented solids of plant straw in a mixing container, control the mixing speed to 30-50 r / min, and mix for 20-30 min;

[0024] (2) While stirring, spray water into the stirring container. The water enters in the form of water mist. After spraying, continue stirring for 10-15 minutes to obtain carbon-increasing, carbon-stabilizing and storage agent.

[0025] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0026] 1. In this invention, straw is used as raw material. After crushing, soaking in alkali, enzymatic hydrolysis, and fermentation, the resulting fermented solid plant straw is rich in pectin, fiber, and organic carbon. When the fermented solid plant straw is mixed with water, the resulting carbon-enhancing, carbon-stabilizing, and carbon-retaining agent for sandy soil is added to the sandy soil, which can increase the cohesion between the sand particles. Moreover, the solution absorbed by the fiber expansion contains organic carbon produced by fermentation. Therefore, after the fermented solid plant straw is in the soil, the pectin and fiber can work together to better retain the organic matter in the fermentation products in the soil, thereby achieving the purpose of increasing and stabilizing carbon.

[0027] 2. The addition of enzymes in this invention can specifically hydrolyze pectin, hemicellulose, and starch in the pulp while maintaining fiber integrity, resulting in looser fibers with higher water absorption. Furthermore, the enzymatic hydrolysate contains glucose, which can be used as a carbon source, providing carbon for photosynthetic bacteria fermentation and reducing the sugar content in the fermented solids of plant straw. Therefore, when this preservative is added to the soil, it can reduce microbial activity under low-sugar conditions. This allows the fibers and pectin to remain in the soil for a longer period, improving the water and fertilizer retention capacity of sandy soils. It also reduces the amount of nutrients provided by microbial metabolites to pests, thereby reducing soil-borne diseases and pests.

[0028] 3. The retention agent of the present invention can carry organic carbon into the soil, and with the synergistic effect of plant fiber and pectin, it can reduce the loss of organic carbon caused by water erosion, so that organic carbon can be retained in the soil for a longer period of time, thereby achieving the purpose of increasing and stabilizing carbon.

[0029] 4. In this invention, plant straw is used as raw material, which has the advantages of low cost and renewability, and can improve the resource utilization of plant straw.

[0030] 5. When using the preservative of the present invention, the preservative is sprinkled on sandy soil, then the soil is turned over to mix the preservative with the sandy soil, and then plants are planted as needed. Detailed Implementation

[0031] To enable those skilled in the art to better understand the technical solutions of this invention, the technical solutions of this invention will be clearly and completely described below in conjunction with the embodiments of this invention. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this invention.

[0032] In the following embodiments and comparative examples of the present invention, the reagents and raw materials used are all commercially available products.

[0033] Example 1

[0034] A carbon-enhancing, carbon-stabilizing, and carbon-retaining agent for sandy soils comprises fermented plant straw solids and water, wherein the weight ratio of fermented plant straw solids to water is 92:8.

[0035] The preparation method of fermented solids from plant straw is as follows:

[0036] S1. Crush the wheat straw, add a 0.3% sodium hydroxide solution until the solution covers the wheat straw, and soak at room temperature for 15 hours; then add water and stir to obtain a slurry;

[0037] During the soaking process, the wheat straw should be turned over once every 3 hours; the weight ratio of wheat straw to water should be 1:4.

[0038] S2, adjust the pH of the slurry to 5.9, then add pectin methyl esterase, xylanase, α-amylase and α-glucosidase to the slurry; the amount of pectin methyl esterase added is 2.0 u / g, the amount of xylanase added is 2.8 u / g, the amount of α-amylase added is 2.3 u / g, and the amount of α-glucosidase added is 4.4 u / g. The enzymatic hydrolysis temperature is 42℃, the enzymatic hydrolysis time is 4 hours, and the enzymes are inactivated to obtain the enzymatic hydrolysate;

[0039] S3. Sterilized magnesium sulfate, disodium hydrogen phosphate, disodium bicarbonate, and ammonium sulfate were added to the enzymatic hydrolysate to obtain the fermentation substrate. Photosynthetic bacteria powder was added to the fermentation substrate, and the wavelength of the light source was controlled at 710 nm and the light intensity at 1900 lux, with intermittent light irradiation. Then, anaerobic fermentation was carried out at 35±0.1℃ for 6 days, followed by sterilization to obtain the fermentation broth.

[0040] Add 0.6g magnesium sulfate, 0.7g disodium hydrogen phosphate, 1.3g disodium bicarbonate, and 1.5g ammonium sulfate to every 1kg of enzymatic hydrolysate.

[0041] The weight ratio of photosynthetic bacteria powder to fermentation substrate is 60:1000; the effective viable bacteria count in the photosynthetic bacteria powder is 6 billion / g;

[0042] Intermittent light control is as follows: 3 hours of light exposure, 3 hours of darkness, and repeat.

[0043] S4. After drying the fermentation liquid, fermented plant straw solids are obtained.

[0044] The preparation method of the above-mentioned carbon-enhancing, carbon-stabilizing, and carbon-retaining agent for sandy soil specifically involves mixing the carbon-enhancing, carbon-stabilizing, and carbon-retaining agent before adding it to the sandy soil, as follows:

[0045] (1) Prepare the fermented solids of plant straw and water according to the specified ratio;

[0046] (2) Place the fermented solids of plant straw in a mixing container, control the mixing speed at 40 r / min, and mix for 25 min;

[0047] (2) While stirring, spray water into the stirring container. The water enters in the form of water mist. After spraying, continue stirring for 12 minutes to obtain carbon-increasing, carbon-stabilizing and storage agent.

[0048] Comparative Example 1

[0049] The difference from Example 1 is that step S2 is as follows:

[0050] The pH of the slurry was adjusted to 5.9, and then pectin methyl esterase, xylanase, α-amylase, and α-glucosidase were added to the slurry. The addition amounts of pectin methyl esterase were 1.5 u / g, xylanase was 2.8 u / g, α-amylase was 2.3 u / g, and α-glucosidase was 4.4 u / g. The enzymatic hydrolysis temperature was 42℃, and the enzymatic hydrolysis time was 4 hours. The enzymes were then inactivated to obtain the enzymatic hydrolysate.

[0051] The rest is the same as in Example 1.

[0052] Comparative Example 2

[0053] The difference from Example 1 is that step S2 is as follows:

[0054] The pH of the slurry was adjusted to 5.9, and then pectin methyl esterase, xylanase, α-amylase, and α-glucosidase were added to the slurry. The addition amounts of pectin methyl esterase were 2.4 u / g, xylanase was 2.8 u / g, α-amylase was 2.3 u / g, and α-glucosidase was 4.4 u / g. The enzymatic hydrolysis temperature was 42℃, and the enzymatic hydrolysis time was 4 hours. The enzymes were then inactivated to obtain the enzymatic hydrolysate.

[0055] The rest is the same as in Example 1.

[0056] Comparative Example 3

[0057] The difference from Example 1 is that step S1 is as follows:

[0058] Crush wheat straw to 2-3 mm, add 0.3% sodium hydroxide solution until the solution covers the wheat straw, and soak at room temperature for 15 hours; then add water and stir to obtain a slurry;

[0059] The rest is the same as in Example 1.

[0060] Comparative Example 4

[0061] The difference from Example 1 is that step S1 is as follows:

[0062] Crush the wheat straw, add a 0.3% sodium hydroxide solution until the solution covers the wheat straw, and soak at room temperature for 9 hours; then add water and stir to obtain a slurry;

[0063] The rest is the same as in Example 1.

[0064] Example 2

[0065] A carbon-enhancing, carbon-stabilizing, and carbon-retaining agent for sandy soils comprises fermented plant straw solids and water, wherein the weight ratio of fermented plant straw solids to water is 90:10.

[0066] The preparation method of fermented solids from plant straw is as follows:

[0067] S1. Crush the wheat straw, add a 0.3% sodium hydroxide solution until the solution covers the wheat straw, and soak at room temperature for 10 hours; then add water and stir to obtain a slurry;

[0068] During the soaking process, the wheat straw should be turned over once every 3 hours; the weight ratio of wheat straw to water should be 1:3.

[0069] S2, adjust the pH of the slurry to 5.7, then add pectin methyl esterase, xylanase, α-amylase and α-glucosidase to the slurry; the amount of pectin methyl esterase added is 1.7 u / g, the amount of xylanase added is 2.5 u / g, the amount of α-amylase added is 2.1 u / g, and the amount of α-glucosidase added is 4.3 u / g. The enzymatic hydrolysis temperature is 40℃, the enzymatic hydrolysis time is 3.5 hours, and the enzymes are inactivated to obtain the enzymatic hydrolysate;

[0070] S3. Sterilized magnesium sulfate, disodium hydrogen phosphate, disodium bicarbonate, and ammonium sulfate were added to the enzymatic hydrolysate to obtain the fermentation substrate. Photosynthetic bacteria powder was added to the fermentation substrate, and the wavelength of the light source was controlled at 700 nm and the light intensity at 1800 lux, with intermittent light irradiation. Then, anaerobic fermentation was carried out at 35±0.1℃ for 7 days, followed by sterilization to obtain the fermentation broth.

[0071] Add 0.5g magnesium sulfate, 0.5g disodium hydrogen phosphate, 0.7g disodium bicarbonate, and 1.0g ammonium sulfate to every 1kg of enzymatic hydrolysate.

[0072] The weight ratio of photosynthetic bacteria powder to fermentation substrate is 70:1000; the effective viable bacteria count in the photosynthetic bacteria powder is 5 billion / g;

[0073] Intermittent light control is as follows: 3 hours of light exposure, 3 hours of darkness, and repeat.

[0074] S4. After drying the fermentation liquid, fermented plant straw solids are obtained.

[0075] The preparation method of the above-mentioned carbon-enhancing, carbon-stabilizing, and carbon-retaining agent for sandy soil specifically involves mixing the carbon-enhancing, carbon-stabilizing, and carbon-retaining agent before adding it to the sandy soil, as follows:

[0076] (1) Place the fermented solids of plant straw in a mixing container, control the mixing speed at 30 r / min, and mix for 20 min;

[0077] (2) While stirring, spray water into the stirring container. The water enters in the form of water mist. After spraying, continue stirring for 10 minutes to obtain carbon-increasing, carbon-stabilizing and storage agent.

[0078] Example 3

[0079] A carbon-enhancing, carbon-stabilizing, and carbon-retaining agent for sandy soils comprises fermented plant straw solids and water, wherein the weight ratio of fermented plant straw solids to water is 95:5.

[0080] The preparation method of fermented solids from plant straw is as follows:

[0081] S1. Crush the wheat straw, add a 0.3% sodium hydroxide solution until the solution covers the wheat straw, and soak at room temperature for 20 hours; then add water and stir to obtain a slurry;

[0082] During the soaking process, turn the plant straw over once every 3 hours; the weight ratio of wheat straw to water is 1:5.

[0083] S2, adjust the pH of the slurry to 6.2, then add pectin methyl esterase, xylanase, α-amylase and α-glucosidase to the slurry; the amount of pectin methyl esterase added is 2.2 u / g, the amount of xylanase added is 3.0 u / g, the amount of α-amylase added is 2.5 u / g, and the amount of α-glucosidase added is 4.7 u / g. The enzymatic hydrolysis temperature is 45℃, the enzymatic hydrolysis time is 4.5 hours, and the enzymes are inactivated to obtain the enzymatic hydrolysate;

[0084] S3. Sterilized magnesium sulfate, disodium hydrogen phosphate, disodium bicarbonate, and ammonium sulfate were added to the enzymatic hydrolysate to obtain the fermentation substrate. Photosynthetic bacteria powder was added to the fermentation substrate, and the wavelength of the light source was controlled at 720 nm and the light intensity at 2000 lux, with intermittent light irradiation. Then, anaerobic fermentation was carried out at 35±0.5℃ for 5 days, followed by sterilization to obtain the fermentation broth.

[0085] Add 0.7g magnesium sulfate, 1.0g disodium hydrogen phosphate, 1.5g disodium bicarbonate, and 2.0g ammonium sulfate to every 1kg of enzymatic hydrolysate.

[0086] The weight ratio of photosynthetic bacteria powder to fermentation substrate is 50:1000; the effective viable bacteria count in the photosynthetic bacteria powder is 8 billion / g;

[0087] Intermittent light control is as follows: 3 hours of light exposure, 3 hours of darkness, and repeat.

[0088] S4. After drying the fermentation liquid, fermented plant straw solids are obtained.

[0089] The preparation method of the above-mentioned carbon-enhancing, carbon-stabilizing, and carbon-retaining agent for sandy soil specifically involves mixing the carbon-enhancing, carbon-stabilizing, and carbon-retaining agent before adding it to the sandy soil, as follows:

[0090] (1) Place the fermented solids of plant straw in a mixing container, control the mixing speed at 50 r / min, and mix for 30 min;

[0091] (2) While stirring, spray water into the stirring container. The water enters in the form of water mist. After spraying, continue stirring for 15 minutes to obtain carbon-increasing, carbon-stabilizing and storage agent.

[0092] Example 4

[0093] The difference from Example 1 is that the plant straw is corn straw.

[0094] Example 5

[0095] The difference from Example 1 is that the plant straw is peanut straw.

[0096] Example 6

[0097] The difference from Example 1 is that the plant straw is rice straw.

[0098] field trials

[0099] 1. Experimental site

[0100] The experimental project was conducted at the Qingguji Town experimental base in Caoxian County, Shandong Province. Flat, well-maintained plots with average soil fertility were selected as the experimental site. The topsoil layer (0-50cm) in the experimental area was sandy loam, which is loose and easy to cultivate, but has poor water and fertilizer retention capacity, low nutrient content, and lacks sustained growth. It resulted in small seedlings that failed to mature properly, poor crop growth, and low yields. The basic physicochemical properties of the soil are shown in Table 1 below.

[0101] Table 1 Basic Physicochemical Characteristics of Soil

[0102]

[0103] 2. Testing Items

[0104] 2.1 Water Holding Capacity

[0105] The method for measuring water holding capacity is as follows:

[0106] ①Dry the sample and remove stones and other impurities; then load the sample with a ring cutter and weigh it to ensure that the loading amount of the ring cutter is consistent each time.

[0107] ② Immerse the ring cutter containing the sample in water, with the water level level with the top of the ring cutter, and soak for 12 hours; remove the ring cutter, wipe the surface of the ring cutter dry, and then soak it again. Repeat the above steps until the ring cutter containing the sample no longer gains weight.

[0108] ③ Remove the ring cutter and allow it to drain naturally at room temperature until no more water flows out. Remove the sample, weigh it, and record the weight as m1.

[0109] ④ Dry the sample at 105℃ to constant weight, record the weight as m2;

[0110] Soil water holding capacity (%) = (m1 - m2) / m2 × 100.

[0111] 2.2 Breathability

[0112] Air permeability is determined using the soil density test method as follows:

[0113] ① Use tools to remove the topsoil at the test point to a depth of 10 cm;

[0114] ② Press the ring cutter vertically into the soil, and when removing it, ensure that the inside is filled with a complete soil column;

[0115] ③ Remove the soil column, weigh it, and record it as m1;

[0116] ④ Dry the soil at 105℃ to constant weight, record the weight as m2;

[0117] Calculate the bulk density = m2 / ring cutter volume.

[0118] 2.3 Soil organic matter

[0119] Soil organic matter content was determined using the ignition loss method.

[0120] 3. Experimental Design

[0121] Test plots: Each plot measures 10m × 10m;

[0122] The experiment used a single-factor randomized block design with a total of 11 treatments, as follows:

[0123] For the experimental group, 15 kg of the water-retaining agent provided in Examples 1-6 was evenly spread on the surface of the experimental plot (the water-retaining agent was applied to the field at a rate of 100 kg / mu), and the soil was plowed to a depth of 30-40 cm to mix the water-retaining agent with the soil.

[0124] For the control group, 15 kg of the water-retaining agent provided in Comparative Examples 1-4 was evenly spread on the surface of the test plot (the water-retaining agent was applied to the field at a rate of 100 kg / mu), and the soil was tilled to a depth of 30-40 cm to mix the water-retaining agent with the soil.

[0125] Control group (CK), soil without the use of soil preservatives;

[0126] Each process is set to 3 repetitions;

[0127] Crops grown:

[0128] The tested crop was Jimai 23;

[0129] One week before planting, apply organic fertilizer as base fertilizer. The organic fertilizer is fully decomposed farmyard manure, and the amount used is 2 tons per mu.

[0130] Use a seeder for row sowing, with a sowing rate of 10-15 kg per mu and a soil covering depth of 3-5 cm;

[0131] Management was carried out in accordance with local conventional agronomic practices and farmers' habits, and soil sampling and wheat yield calculation were completed on June 10, 2024.

[0132] Soil sampling points: sampling before applying base fertilizer, sampling before wheat planting, and sampling when wheat seedlings emerge;

[0133] Among them, samples were taken before applying base fertilizer. The experimental group samples contained the preservative provided in Examples 1-6, and the control group samples contained the preservative provided in Comparative Examples 1-4.

[0134] Wheat samples were taken before planting. The experimental group samples contained the energy-saving agent and base fertilizer provided in Examples 1-6, while the control group samples contained the energy-saving agent and base fertilizer provided in Comparative Examples 1-4.

[0135] Samples were taken when wheat seedlings emerged. The experimental group samples contained the energy-saving agent and basal fertilizer provided in Examples 1-6, while the control group samples contained the energy-saving agent and basal fertilizer provided in Comparative Examples 1-4.

[0136] Soil test results are shown in Tables 2-4 below:

[0137] Table 2 Basic Physicochemical Characteristics of Soil Before Basal Fertilizer Application

[0138]

[0139] Table 3 Basic Physicochemical Characteristics of Soil Before Wheat Planting

[0140]

[0141] Table 4. Basic physical and chemical characteristics of soil at wheat emergence.

[0142]

[0143] As can be seen from Table 2, compared with the control group and the control group, the water-retaining agent prepared by the method of the present invention increases the bulk density, water holding capacity and organic matter content of the soil after being mixed with sandy soil; indicating that the water-retaining agent of the present invention can effectively improve the performance of sandy soil and improve the water retention capacity of sandy soil while maintaining the air permeability of sandy soil.

[0144] As can be seen from Table 3, after the application of base fertilizer, the sandy soil containing the fertilizer retention agent provided in Examples 1-6 has a higher degree of organic matter retention, indicating that the fertilizer retention agent of the present invention can improve the fertilizer retention performance of sandy soil.

[0145] As can be seen from Table 4, as wheat seedlings emerge, the content of organic matter, nitrogen, phosphorus, potassium and other substances in the soil gradually decreases. However, compared with the control group and the control group, the decrease in the sandy soil of the present invention is the lowest. This indicates that, apart from the nutrients required for wheat growth, the sandy soil of the present invention can slow down the loss of organic matter and other substances, further demonstrating that the fertilizer retention agent of the present invention has good fertilizer retention performance.

[0146] The wheat yield results are shown in Table 5 below:

[0147] Table 5 Wheat Yield Calculation

[0148]

[0149] As can be seen from Table 5, the wheat yield was significantly increased after using the water-retaining agent of this invention compared with the control group. Although the control group also showed varying degrees of yield increase, the effect was lower than that of the invention group. It can be seen that although sandy soil has many problems that are not conducive to agricultural production, such as poor water retention and poor fertilizer retention, by improving sandy soil, it can form a tillage layer that is conducive to crop growth.

[0150] Although the present invention has been described in detail with reference to preferred embodiments, it is not limited thereto. Various equivalent modifications or substitutions can be made to the embodiments of the present invention by those skilled in the art without departing from the spirit and essence of the invention, and such modifications or substitutions should all be within the scope of the present invention. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should also be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be determined by the scope of the claims.

Claims

1. A carbon-enhancing, carbon-stabilizing, and carbon-retaining agent for sandy soils, characterized in that, It includes fermented plant straw solids and water, wherein the preparation method of the fermented plant straw solids is as follows: S1. Crush the plant straw, add a 0.3% sodium hydroxide solution until the solution covers the plant straw, and soak at room temperature for 10-20 hours; then add water and stir to obtain a slurry. S2. Adjust the pH of the slurry to 5.7-6.2, then add pectin methyl esterase, xylanase, α-amylase, and α-glucosidase to the slurry; the amount of pectin methyl esterase added is 1.7-2.2 u / g, the amount of xylanase added is 2.5-3.0 u / g, the amount of α-amylase added is 2.1-2.5 u / g, and the amount of α-glucosidase added is 4.3-4.7 u / g. The enzymatic hydrolysis temperature is 40-45℃, the enzymatic hydrolysis time is 3.5-4.5 hours, and the enzymes are inactivated to obtain the enzymatic hydrolysate. S3. Sterilized magnesium sulfate, disodium hydrogen phosphate, disodium bicarbonate, and ammonium sulfate are added to the enzymatic hydrolysate to obtain the fermentation substrate. Photosynthetic bacteria powder is added to the fermentation substrate, and the wavelength of the light source is controlled at 700-720nm and the light intensity at 1800-2000 lux, with intermittent light irradiation. Then, anaerobic fermentation is carried out at 35±0.5℃ for 5-7 days, followed by sterilization to obtain the fermentation broth. S4. After drying the fermentation liquid, plant straw fermentation solids are obtained.

2. The carbon-enhancing, carbon-stabilizing, and carbon-retaining agent for sandy soil as described in claim 1, characterized in that, In step S1, the plant straw includes one of wheat straw, corn straw, peanut straw, and rice straw.

3. The carbon-enhancing, carbon-stabilizing, and carbon-retaining agent for sandy soil as described in claim 1, characterized in that, In step S1, during the soaking process, the plant straw is turned over once every 3 hours; the weight ratio of plant straw to water is 1:3-5.

4. The carbon-enhancing, carbon-stabilizing, and carbon-retaining agent for sandy soil as described in claim 1, characterized in that, In step S2, the intermittent lighting control is as follows: 3 hours of light exposure, 3 hours of off light exposure, and this process is repeated.

5. The carbon-enhancing, carbon-stabilizing, and carbon-retaining agent for sandy soil as described in claim 1, characterized in that, In step S3, 0.5-0.7g of magnesium sulfate, 0.5-1.0g of disodium hydrogen phosphate, 0.7-1.5g of disodium bicarbonate, and 1.0-2.0g of ammonium sulfate are added to every 1kg of enzymatic hydrolysate.

6. The carbon-enhancing, carbon-stabilizing, and carbon-retaining agent for sandy soil as described in claim 1, characterized in that, In step S3, the weight ratio of photosynthetic bacteria powder to fermentation substrate is 50-70:1000; the effective viable bacteria count in the photosynthetic bacteria powder is ≥5 billion / g.

7. The carbon-enhancing, carbon-stabilizing, and carbon-retaining agent for sandy soil as described in claim 1, characterized in that, The weight ratio of fermented solids from plant straw to water is 90-95:5-10.

8. The preparation method of the carbon-enhancing, carbon-stabilizing, and carbon-retaining agent for sandy soil as described in claim 1, characterized in that, Before adding the carbon-enhancing, carbon-stabilizing, and carbon-retaining agent to the sandy soil, it needs to be mixed, as follows: (1) Place the fermented solids of plant straw in a mixing container, control the mixing speed to 30-50 r / min, and mix for 20-30 min; (2) While stirring, spray water into the stirring container. The water enters in the form of water mist. After spraying, continue stirring for 10-15 minutes to obtain carbon-increasing, carbon-stabilizing and storage agent.

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