A green manure method suitable for arid and semi-arid regions

Abstract

The application discloses a green manure returning method suitable for arid and semi-arid areas and belongs to the technical field of green manure returning. The green manure crop is harvested to prepare slow-release green manure which is applied to soil, part of water and nutrients in the slow-release green manure can be quickly released after entering the soil, so that the supply of water and nutrients for the early planting of the following crops is ensured, and the remaining slow-release green manure is continuously decomposed in the soil to release nutrients and effectively absorb and retain water in the soil, so that better growth conditions are provided for crop growth and the yield of crops is ensured. The green manure returning method has important significance for yield increase of crops in arid and semi-arid areas.

Description

Technical Field

[0001] This invention relates to the field of green manure return to the field technology, and in particular to a method for returning green manure to the field suitable for arid and semi-arid regions. Background Technology

[0002] In the history of China's agricultural development, chemical fertilizers have made a significant contribution to ensuring food security. However, the indiscriminate and excessive application of chemical fertilizers has not led to a continuous increase in crop yields. Instead, it has damaged soil function to some extent, causing ecological and environmental problems such as declining soil quality, eutrophication of water bodies, and greenhouse gas emissions. Therefore, reducing the application of chemical fertilizers and pesticides and increasing the application of organic materials are considered effective ways to achieve green agricultural production.

[0003] Green manure, as a traditional organic material, is an environmentally friendly crop variety that plays a vital role in improving soil, conserving water and soil, suppressing weeds, and increasing crop productivity. Grain crops have a fallow period between harvest and the next planting season. Planting cover crops during this fallow period not only protects the soil surface but also allows the green manure to be returned to the field, enhancing soil fertility and improving soil physical and chemical properties. The conventional method of returning green manure to the field involves directly plowing it in. However, green manure decomposes slowly in the soil, preventing the timely release of water and nutrients. In arid and semi-arid regions where soil is relatively infertile and water is scarce, planting green manure can lead to competition for water and nutrients. Furthermore, the slow decomposition rate of directly plowing green manure prevents the timely release of water and nutrients, resulting in water and nutrient deficiencies in subsequent crops and reduced yields.

[0004] Therefore, there is a need to find a method for returning green manure to the field that is suitable for arid and semi-arid regions. This would solve the problem that green manure planting in arid and semi-arid regions easily leads to pre-emptive competition for water and nutrients, and that the slow decomposition rate of green manure after direct plowing and returning to the field results in insufficient water and nutrient supply to subsequent crops, leading to reduced yields. Summary of the Invention

[0005] Therefore, the purpose of this invention is to provide a method for returning green manure to the field in arid and semi-arid regions. In arid and semi-arid regions, the planting of green manure can easily lead to pre-emptive competition for water and nutrients. Furthermore, the slow decomposition rate of green manure after direct plowing and returning to the field can result in insufficient water and nutrient supply to subsequent crops, leading to reduced yields.

[0006] The present invention solves the above-mentioned technical problems through the following technical means:

[0007] A method for returning green manure to the field, suitable for arid and semi-arid regions, is as follows:

[0008] (1) Harvest the green manure crops, then crush and pulp them, and filter them to obtain liquid and residue for later use;

[0009] (2) Dissolve gelatin in water to prepare a 10wt% gelatin solution, then add isopropanolamine and stir evenly before spray drying to obtain gelatin-encapsulated microparticles; dissolve xanthan gum in water to prepare a 2wt% xanthan gum solution, adjust the pH of the xanthan gum solution to 5, add nano-silica, stir and react at room temperature for 3-4 hours, then raise the temperature to 50-60℃ and stir and react for 1-2 hours. After the reaction is completed, add the residue, gelatin-encapsulated microparticles and ammonium bicarbonate in sequence and mix evenly. Then put it into a granulator to granulate to obtain granular fertilizer. Dry the granular fertilizer at 50℃ until the moisture content is ≤15% to obtain porous granular fertilizer for later use.

[0010] (3) Dissolve sodium alginate in water to prepare a 15wt% sodium alginate solution, then heat to 50-60℃ and add glyoxylic acid and stir for 4-6 hours. After the reaction is complete, add the liquid and mix evenly. Then add porous granular fertilizer and stir slowly for 20-30 minutes to obtain a mixture. Add 20wt% calcium chloride solution to the mixture and stir to gel the sodium alginate in the mixture. Then put it into a granulator for granulation to obtain slow-release green manure.

[0011] (4) Apply slow-release green manure to the soil surface, then rotary tillage to mix the slow-release green manure into the topsoil. When planting the next crop, the soil can be tilled and then planted.

[0012] In arid and semi-arid regions, due to poor soil and water scarcity, competition for nutrients and water is common when planting green manure. Conventional methods of directly plowing green manure into the field result in slow decomposition, leading to delayed release of water and nutrients. This can cause insufficient water and nutrient supply for subsequent crops, potentially reducing crop yields. Therefore, this invention prepares slow-release green manure after harvesting and applies it to the soil to ensure a timely supply of water and nutrients for subsequent crops, while simultaneously improving soil physicochemical properties to promote healthy growth.

[0013] Specifically, this invention involves harvesting green manure crops, crushing and pulping them to separate the liquid and residue. The residue is then mixed with binders such as xanthan gum and nano-silica to prepare porous granular fertilizer. Sodium alginate is mixed with the liquid and added to the porous granular fertilizer for further mixing. Calcium chloride is then added for gelation, followed by granulation to obtain slow-release green manure. During this process, the sodium alginate gelation encapsulates and fills the liquid within and on the surface of the porous granular fertilizer. After application to the soil, the water and nutrients fixed by the sodium alginate gel are released into the soil, replenishing the soil's moisture and nutrients. The remaining porous granular fertilizer continues to decompose in the soil to release the remaining nutrients. This ensures timely supply of water and nutrients for subsequent crops while also enabling efficient utilization of nutrients in the green manure.

[0014] To enable the water and nutrients in the sodium alginate gel encapsulation solution to be released into the soil more quickly to replenish the water and nutrients competitively absorbed during green manure planting, this invention adds glyoxylic acid and sodium alginate to react. The glyoxylic acid binds to the sodium alginate molecular chain, changing its chemical stability and thus accelerating the degradation rate of the sodium alginate gel in the soil. This allows the water and nutrients in the sodium alginate encapsulation solution to be released into the soil for rapid replenishment as the sodium alginate gel rapidly degrades.

[0015] In arid and semi-arid regions, soil nutrients are relatively poor, water content is low, and the number and activity of soil microorganisms are also low, resulting in slow degradation of residual granular fertilizer. Therefore, this invention uses gelatin to encapsulate isopropanolamine to prepare gelatin-encapsulated microparticles, which are then mixed into porous granular fertilizer. The gelatin rapidly degrades in the soil, releasing isopropanolamine. The isopropanolamine then acts on the chemical bonds formed by xanthan gum and nano-silica, breaking them and causing the granular fertilizer structure to disintegrate and become loose. Xanthan gum has good stability and can remain stable in the soil for a long time. After the granular fertilizer structure loosens, xanthan gum... Xanthan gum can fully expand, absorb, and retain a large amount of water, thereby improving soil water retention and soil properties. At the same time, both xanthan gum and gelatin can provide better nutrition for soil microorganisms. Therefore, the loosened granular fertilizer can provide better water and nutrient supply for microorganisms, allowing them to colonize and proliferate in the loose granular fertilizer, thus accelerating its decomposition and providing better nutrients for subsequent crops. The decomposition of granular fertilizer improves soil fertility and water retention, providing better conditions for the growth of subsequent crops.

[0016] Furthermore, the green manure crop in step (1) is any one or two of the following: hyacinth bean, Sudan grass, pea, alfalfa, oat, hairy vetch, and milkvetch.

[0017] Furthermore, in step (2), the mass ratio of gelatin solution to isopropanolamine is (2.5-4.5):(0.02-0.04).

[0018] Furthermore, in step (2), the mass ratio of xanthan gum solution, nano silica, slag, gelatin-encapsulated microparticles, and ammonium bicarbonate is (8-10):(1-2):(8-10):(0.2-0.4):(0.1-0.2).

[0019] Furthermore, the ammonium bicarbonate particle size in step (2) is 100 μm.

[0020] Furthermore, in step (2), the granulation diameter of the granulated fertilizer is 3-4 mm.

[0021] Furthermore, in step (3), the mass ratio of sodium alginate solution, glyoxylic acid, liquid material, porous granular fertilizer, and calcium chloride solution is (10-15):(0.1-0.2):(25-35):(10-15):(0.2-0.5).

[0022] Furthermore, the granulation particle size in step (3) is 5-8 mm.

[0023] Furthermore, in step (4), the rotary tillage depth is 5-10cm and the plowing depth is 15-25cm.

[0024] Beneficial effects:

[0025] This invention involves crushing and pulping green manure to separate it into liquid and residue. The liquid and residue are then further processed into slow-release green manure, which is applied to the soil. The slow-release green manure can quickly release some of the water and nutrients to replenish the water and nutrients that are competitively absorbed during the green manure planting period, ensuring the water and nutrient supply for the subsequent crop in the early stages of planting. The remaining residue continues to decompose in the soil to improve soil fertility and enhance the soil's water absorption and retention capacity, thus better ensuring the healthy growth of crops and increasing crop yield. Attached Figure Description

[0026] Figure 1 : Images showing the growth status of Sudan grass, a green manure crop of this invention;

[0027] Figure 2 : This is a picture of the growth status of winter wheat in experimental group 1 during the greening period in the experiment of this invention. Detailed Implementation

[0028] The present invention will now be described in detail with reference to specific embodiments and accompanying drawings:

[0029] This invention discloses a method for returning green manure to the field in arid and semi-arid regions. The specific method involves first preparing the green manure into slow-release green manure and then applying it to the soil for returning to the field according to a specific method. Therefore, this invention first prepares the green manure into slow-release green manure, as shown below.

[0030] Example 1: Preparation of slow-release green manure

[0031] (1) Harvest Sudan grass, a green manure crop, then crush, pulp, and filter to separate the liquid and residue for later use;

[0032] (2) Dissolve gelatin in water to prepare 3.5 kg of 10 wt% gelatin solution, then add 0.03 kg of isopropanolamine and stir evenly. Spray dry under the conditions of inlet air temperature of 150℃, outlet air temperature of 80℃, and feed flow rate of 20 mL / min to obtain gelatin-encapsulated microparticles; Dissolve xanthan gum in water to prepare 9 kg of 2 wt% xanthan gum solution, adjust the pH of xanthan gum solution to 5, add 1.5 kg of nano silica, stir and react at room temperature for 3.5 h, then heat to 55℃ and stir and react for 1.5 h. After the reaction is completed, add 9 kg of residue, 0.3 kg of gelatin-encapsulated microparticles, and 0.15 kg of ammonium bicarbonate with a particle size of 100 μm in sequence, mix evenly, and put into a granulator to prepare granular fertilizer with a particle size of about 3 mm. Dry the granular fertilizer at 50℃ to a moisture content of about 10% to obtain porous granular fertilizer for later use.

[0033] (3) Dissolve sodium alginate in water to prepare 12 kg of 15 wt% sodium alginate solution. Then heat to 55°C and add 0.15 kg of glyoxylic acid and stir for 5 h. After the reaction is complete, add 30 kg of liquid and mix evenly. Then add 12 kg of porous granular fertilizer and stir slowly for 25 min to obtain a mixture. Add 0.3 kg of 20 wt% calcium chloride solution to the mixture to gel the sodium alginate in the mixture. Then put it into a granulator to prepare particles with a particle size of about 6 mm to obtain slow-release green manure.

[0034] Example 2: Preparation of slow-release green manure

[0035] (1) Harvest Sudan grass, a green manure crop, then crush, pulp, and filter to separate the liquid and residue for later use;

[0036] (2) Dissolve gelatin in water to prepare 2.5 kg of 10 wt% gelatin solution, then add 0.02 kg of isopropanolamine and stir evenly. Spray dry under the conditions of inlet air temperature of 150℃, outlet air temperature of 80℃, and feed flow rate of 20 mL / min to obtain gelatin-encapsulated microparticles; Dissolve xanthan gum in water to prepare 8 kg of 2 wt% xanthan gum solution, adjust the pH of xanthan gum solution to 5, add 1 kg of nano silica, stir and react at room temperature for 3 h, then heat to 50℃ and stir and react for 1 h. After the reaction is completed, add 8 kg of residue, 0.2 kg of gelatin-encapsulated microparticles, and 0.1 kg of ammonium bicarbonate with a particle size of 100 μm in sequence, mix evenly, and put into a granulator to prepare granular fertilizer with a particle size of about 3 mm. Dry the granular fertilizer at 50℃ to a moisture content of about 10% to obtain porous granular fertilizer for later use.

[0037] (3) Dissolve sodium alginate in water to prepare 10 kg of 15 wt% sodium alginate solution. Then heat to 50°C and add 0.1 kg of glyoxylic acid and stir for 4 h. After the reaction is complete, add 25 kg of liquid and mix evenly. Then add 10 kg of porous granular fertilizer and stir slowly for 20 min to obtain a mixture. Add 0.2 kg of 20 wt% calcium chloride solution to the mixture to gel the sodium alginate in the mixture. Then put it into a granulator to prepare particles with a particle size of about 6 mm to obtain slow-release green manure.

[0038] Example 3: Preparation of slow-release green manure

[0039] (1) Harvest Sudan grass, a green manure crop, then crush, pulp, and filter to separate the liquid and residue for later use;

[0040] (2) Dissolve gelatin in water to prepare 4.5 kg of 10 wt% gelatin solution, then add 0.04 kg of isopropanolamine and stir evenly. Spray dry under the conditions of inlet air temperature of 150℃, outlet air temperature of 80℃, and feed flow rate of 20 mL / min to obtain gelatin-encapsulated microparticles; Dissolve xanthan gum in water to prepare 10 kg of 2 wt% xanthan gum solution, adjust the pH of xanthan gum solution to 5, add 2 kg of nano silica, stir and react at room temperature for 4 h, then heat to 60℃ and stir and react for 2 h. After the reaction is completed, add 10 kg of residue, 0.4 kg of gelatin-encapsulated microparticles, and 0.2 kg of ammonium bicarbonate with a particle size of 100 μm in sequence, mix evenly, and put into a granulator to prepare granular fertilizer with a particle size of about 3 mm. Dry the granular fertilizer at 50℃ to a moisture content of about 10% to obtain porous granular fertilizer for later use.

[0041] (3) Dissolve sodium alginate in water to prepare 15 kg of 15 wt% sodium alginate solution. Then heat to 60°C and add 0.2 kg of glyoxylic acid and stir for 4 h. After the reaction is complete, add 35 kg of liquid and mix evenly. Then add 15 kg of porous granular fertilizer and stir slowly for 30 min to obtain a mixture. Add 0.5 kg of 20 wt% calcium chloride solution to the mixture to gel the sodium alginate in the mixture. Then put it into a granulator to prepare particles with a particle size of about 6 mm to obtain slow-release green manure.

[0042] Comparative Example 1: Preparation of Slow-Release Green Manure

[0043] Compared with Example 1, the only difference is that gelatin microparticles were not added in step (2) of the slow-release green manure preparation in Comparative Example 1, as shown below:

[0044] (1) Same as Example 1;

[0045] (2) Dissolve xanthan gum in water to prepare 9 kg of 2wt% xanthan gum solution. Adjust the pH of xanthan gum solution to 5 and add 1.5 kg of nano silica. Stir and react at room temperature for 3.5 h, then heat to 55℃ and stir and react for 1.5 h. After the reaction is complete, add 9 kg of residue and 0.15 kg of ammonium bicarbonate with a particle size of 100 μm. Mix evenly and put into a granulator to prepare granular fertilizer with a particle size of about 3 mm. Dry the granular fertilizer at 50℃ until the moisture content is about 10% to obtain porous granular fertilizer for later use.

[0046] (3) Same as Example 1.

[0047] Comparative Example 2: Preparation of Slow-Release Green Manure

[0048] Compared with Example 1, the only difference is that in Comparative Example 2, gum arabic was used instead of xanthan gum in the preparation of the slow-release green manure, as detailed below:

[0049] (1) Same as Example 1;

[0050] (2) Dissolve gelatin in water to prepare 3.5 kg of 10 wt% gelatin solution, then add 0.03 kg of isopropanolamine and stir evenly. Spray dry under the conditions of inlet air temperature of 150℃, outlet air temperature of 80℃, and feed flow rate of 20 mL / min to obtain gelatin-encapsulated microparticles; Dissolve gum arabic in water to prepare 9 kg of 2 wt% gum arabic, adjust the pH of gum arabic to 5, then add 1.5 kg of nano silica, stir and react at room temperature for 3.5 h, then heat to 55℃ and stir and react for 1.5 h. After the reaction is completed, add 9 kg of residue, 0.3 kg of gelatin-encapsulated microparticles, and 0.15 kg of ammonium bicarbonate with a particle size of 100 μm in sequence, mix evenly, and put into a granulator to prepare granular fertilizer with a particle size of about 3 mm. Dry the granular fertilizer at 50℃ to a moisture content of about 10% to obtain porous granular fertilizer for later use.

[0051] (3) Same as Example 1.

[0052] Comparative Example 3: Preparation of Slow-Release Green Manure

[0053] Compared with Example 1, the only difference is that in Comparative Example 3, step (3) of preparing the slow-release green manure did not involve adding glyoxylic acid to treat sodium alginate, as detailed below:

[0054] (1)-(2) are the same as in Example 1;

[0055] (3) Dissolve sodium alginate in water to prepare 12 kg of 15 wt% sodium alginate solution, add 30 kg of liquid and mix evenly, then add 12 kg of porous granular fertilizer and stir slowly for 25 min to obtain a mixture. Add 0.3 kg of 20 wt% calcium chloride solution to the mixture to gel the sodium alginate in the mixture, and then put it into a granulator to prepare particles with a particle size of about 6 mm to obtain slow-release green manure.

[0056] Comparative Example 4: Preparation of Slow-Release Green Manure

[0057] Compared with Example 1, the only difference is that in the preparation of slow-release green manure in Comparative Example 4, sodium alginate was not used in step (3), but gelatin was used instead, as shown below:

[0058] (1)-(2) are the same as in Example 1;

[0059] (3) Dissolve gelatin in water to prepare 12 kg of 15 wt% gelatin solution, then heat to 55℃ and add 0.15 kg of glyoxylic acid and stir for 5 h. After the reaction is completed, add 30 kg of liquid and mix evenly. Then add 12 kg of porous granular fertilizer and stir slowly for 25 min to obtain a mixture. Add 0.3 kg of 20 wt% calcium chloride solution to the mixture to gelatinize sodium alginate in the mixture. Then put it into a granulator to prepare particles with a particle size of about 6 mm to obtain slow-release green manure.

[0060] Example 4: Green Manure Returning Method

[0061] The slow-release green manure prepared in Example 1 was further returned to the field, as follows:

[0062] Apply slow-release green manure to the soil surface, then till to a depth of about 6cm to mix the slow-release green manure into the topsoil. When planting the next crop, winter wheat, till to a depth of about 20cm and then plant using conventional methods.

[0063] Experiment: Detection Experiment on the Effect of Slow-Release Green Manure Returning to the Field

[0064] 1. Experimental Methods: The slow-release green manure prepared in Example 1 and Comparative Examples 1-4 was returned to the field to test its effectiveness. The experiment was conducted at the Changwu Farmland Ecosystem National Field Scientific Observation and Research Station in Shaanxi Province. A plot of land was selected as the experimental area. The initial soil moisture content was measured to be 45.2%, the available nitrogen content was 41.5 mg / kg, and the organic matter content was 8.6 g / kg. The experimental area was divided into 7 regions, each with an area of ​​6 × 10 m, corresponding to experimental group 1, control groups 1-5, and the blank control group, respectively. The methods for returning green manure to the field for each group are as follows:

[0065] Experimental Group 1: Slow-release green manure was prepared using the method in Example 1 and returned to the field according to the method in Example 4;

[0066] Control groups 1-4: The slow-release green manure prepared in comparative examples 1-4 was returned to the field according to the method in Example 4;

[0067] Control group 5: Slow-release green manure was prepared using the method in Example 1. After application to the soil, the rotary tillage depth was 15cm, and the remaining steps were the same as in Example 4.

[0068] Blank control: The alfalfa was not prepared into slow-release green manure and was directly plowed into the field.

[0069] 2. Results Detection: On the 15th day after green manure was returned to the field, the soil moisture content, available nitrogen content, and organic matter content in the 0-20cm soil layer were measured (referred to as moisture content A, available nitrogen content A, and organic matter content A). Sixteen days after green manure was returned to the field, the soil was plowed and winter wheat was planted using conventional methods. The same management methods were applied. Thirty days after winter wheat planting, the soil moisture content, available nitrogen content, and organic matter content in the 0-20cm soil layer were measured again (referred to as moisture content B, available nitrogen content B, and organic matter content B). The yield of winter wheat for each group was recorded, and the data are shown in Table 1.

[0070] Table 1

[0071]

[0072]

[0073] Based on the data analysis in Table 1, we can conclude that:

[0074] (1) The slow-release green manure prepared by this invention can quickly release some nutrients after being applied to the soil. After 15 days of application, the soil moisture content increased significantly, and the contents of alkaline nitrogen and organic matter also increased significantly. When the organic matter content was measured again 30 days after the winter wheat was planted, it increased significantly, indicating that the granular fertilizer in the soil decomposed at a high rate and obtained a large amount of nutrients.

[0075] (2) In control group 1, no gelatin was added to encapsulate microparticles when preparing slow-release green manure. The effect of isopropanolamine in the encapsulated microparticles was lacking. The granular fertilizer structure was firm and difficult to decompose. It also inhibited the swelling performance of xanthan gum, which reduced the water absorption and retention performance. Furthermore, the nutrients provided by gelatin were missing. All of these factors combined to reduce the decomposition capacity of microorganisms and result in a relatively small increase in nutrient content.

[0076] (3) In control group 2, gum arabic was used when preparing slow-release green manure, which decomposes rapidly in the soil and loses its water absorption and retention capacity, resulting in a significant decrease in soil moisture content in the later stage; in control group 3, no glyoxylic acid was added to treat sodium alginate, which slowed down the decomposition rate of sodium alginate, resulting in a reduction in the release of water and nutrients.

[0077] (4) In control group 5, the depth of rotary tillage during the return of slow-release green manure to the field was high, and nutrients entered the lower soil layer. Although the average moisture and nutrient content of the soil layer at a depth of 0-20cm was relatively high, the amount of water and nutrients utilized in the early stage was small, which also led to a significant reduction in winter wheat yield.

[0078] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the present invention, and all such modifications and substitutions should be covered within the scope of the claims of the present invention. Technical aspects, shapes, and structures not described in detail in this invention are all well-known technologies.

Claims

1. A method for returning green manure to the field suitable for arid and semi-arid regions, characterized in that, The method is as follows: (1) Harvest the green manure crops, then crush and pulp them, and filter them to separate the liquid and residue for later use; (2) Dissolve gelatin in water to prepare a 10wt% gelatin solution, then add isopropanolamine and stir evenly before spray drying to obtain gelatin-encapsulated microparticles; dissolve xanthan gum in water to prepare a 2wt% xanthan gum solution, adjust the pH of the xanthan gum solution to 5, add nano silica, stir and react at room temperature for 3-4 hours, then raise the temperature to 50-60℃ and stir and react for 1-2 hours. After the reaction is completed, add the residue, gelatin-encapsulated microparticles and ammonium bicarbonate in sequence and mix evenly. Then put it into a granulator to granulate to obtain granular fertilizer. Dry the granular fertilizer at 50℃ until the moisture content is ≤15% to obtain porous granular fertilizer for later use. (3) Dissolve sodium alginate in water to prepare a 15wt% sodium alginate solution, then heat it to 50-60℃ and add glyoxylic acid and stir for 4-6 hours. After the reaction is completed, add the liquid and mix evenly. Then add porous granular fertilizer and stir slowly for 20-30 minutes to obtain a mixture. Add 20wt% calcium chloride solution to the mixture and stir to gel the sodium alginate in the mixture. Then put it into a granulator for granulation to obtain slow-release green manure. (4) Apply the slow-release green manure to the soil surface, and then rotary tillage to mix the slow-release green manure into the topsoil. When planting the next crop, you can plant it after tilling. In step (2), the mass ratio of gelatin solution to isopropanolamine is (2.5-4.5):(0.02-0.04). In step (2), the mass ratio of xanthan gum solution, nano-silica, slag, gelatin-encapsulated microparticles, and ammonium bicarbonate is (8-10):(1-2):(8-10):(0.2-0.4):(0.1-0.2). In step (3), the mass ratio of sodium alginate solution, glyoxylic acid, liquid material, porous granular fertilizer, and calcium chloride solution is (10-15):(0.1-0.2):(25-35):(10-15):(0.2-0.5).

2. The method for returning green manure to the field in arid and semi-arid regions according to claim 1, characterized in that, The green manure crop is any one or two of the following: hyacinth bean, Sudan grass, pea, alfalfa, oat, hairy vetch, and milkvetch.

3. The method for returning green manure to the field in arid and semi-arid regions according to claim 2, characterized in that, In step (2), the ammonium bicarbonate particle size is 100 μm.

4. A method for returning green manure to the field in arid and semi-arid regions according to claim 3, characterized in that, In step (2), the granulation diameter of the granulated fertilizer is 3-4 mm.

5. A method for returning green manure to the field in arid and semi-arid regions according to claim 4, characterized in that, In step (3), the granulation particle size is 5-8 mm.

6. A method for returning green manure to the field in arid and semi-arid regions according to claim 5, characterized in that, In step (4), the rotary tillage depth is 5-10cm and the plowing depth is 15-25cm.

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