Desert soil conditioner and preparation method thereof

Abstract

The invention belongs to the technical field of soil improvement, and particularly relates to a desert soil conditioner and a preparation method thereof.The desert soil conditioner is prepared from, by weight, 70-80% of a core material and 20-30% of a functional additive, the core material comprises 50-60% of biochar and 20-30% of modified bentonite, and the functional additive comprises 20-30% of modified bentonite; the functional auxiliary agent comprises 10-15% of a slow-release fertilizer, 5-10% of a microbial agent, 3-5% of a water-retaining agent and 2-3% of a soil conditioner. According to the desert soil conditioner and the preparation method thereof, the slow-release fertilizer is arranged, and nitrogen, phosphorus and potassium nutrients are wrapped by a composite material film prepared from 50% of cellulose and 50% of polylactic acid by adopting a coating technology, so that the slow-release fertilizer is not easy to damage in the mixing process, and the film can be degraded by microorganisms in the natural environment; therefore, the effect of slowly releasing nutrients is achieved, the fertilizer utilization rate is improved, and nutrient loss is avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of soil improvement, and particularly to a desert soil conditioner and a preparation method thereof. Background Art

[0002] Desert soil, also known as desert soil, refers to the soil type formed in desert areas. Due to the particularity of desert soil, special technologies and methods are required to improve and utilize these soils to ensure sustainable land management and ecological restoration.

[0003] A desert soil conditioner is a product or technology used to improve the soil properties in desert areas, aiming to improve soil fertility and water retention capacity to support plant growth.

[0004] The current soil conditioners can have a certain improvement effect in a short time after use. However, desertified soil is characterized by fine particles, no pores, narrow particle size distribution, and single composition, mainly silica, which cannot retain water and fertilizer. Therefore, the effect of the used soil conditioner lasts for a short time. Summary of the Invention

[0005] Based on the above-mentioned technical problems, the present invention provides a desert soil conditioner and a preparation method thereof.

[0006] The desert soil conditioner provided by the present invention, by weight ratio, the raw materials of the desert soil conditioner include 70-80% of the core material and 20-30% of the functional auxiliaries. The core material includes 50-60% of biochar and 20-30% of modified bentonite. The functional auxiliaries include 10-15% of slow-release fertilizer, 5-10% of microbial inoculum, 3-5% of water retainer, and 2-3% of soil conditioner.

[0007] Preferably, the biochar is made by biomass pyrolysis of crop straws and forestry wastes.

[0008] Through the above technical solution, it has a porous structure, can effectively improve soil air permeability, water retention and adsorption properties, and provides a rich carbon source.

[0009] Preferably, the modified bentonite uses organic cations to replace the natural cations in bentonite.

[0010] Through the above technical solution, the water absorption and water retention capacity and ion exchange capacity of bentonite are enhanced, thereby improving the soil aggregate structure.

[0011] Preferably, the slow-release fertilizer uses a coating technology to wrap nitrogen, phosphorus and potassium.

[0012] Through the above technical solution, slow release is achieved, the fertilizer utilization rate is improved, and nutrient loss is avoided.

[0013] Preferably, the microbial inoculant includes nitrogen-fixing bacteria, phosphorus-solubilizing bacteria, and potassium-solubilizing bacteria.

[0014] Through the above technical solution, soil nutrients can be activated and plant growth can be promoted.

[0015] A preparation method of a desert soil conditioner proposed by the present invention includes the following preparation steps:

[0016] S1. Preparation of biochar: Crop straws and forestry wastes are pyrolyzed under anoxic conditions to produce biochar.

[0017] S2. Preparation of modified bentonite: Bentonite is mixed with an organic modifier and subjected to intercalation modification treatment to improve its water absorption and water retention capacity and ion exchange capacity.

[0018] S3. Preparation of slow-release fertilizer: A composite film is made from cellulose and polylactic acid. By using a film coating mechanism, the air flow drives the fertilizer particles to suspend, and at the same time, the composite film is sprayed onto the surface of the fertilizer particles in a solution state to form a uniform film layer.

[0019] S4. Preparation of functional additives: The slow-release fertilizer, microbial inoculant, water retainer, and soil conditioner are mixed evenly in proportion.

[0020] S5. Mixed granulation: The biochar, modified bentonite, and functional additives are mixed evenly in proportion and granulated by a granulator to form particles with a particle size of 2 - 5 mm.

[0021] S6. Drying and packaging: The particles are dried to reduce their moisture content to less than 10%, and then packaged.

[0022] Preferably, the composite film in S3 is made of 50% cellulose and 50% polylactic acid.

[0023] Through the above technical solution, both cellulose and polylactic acid are biodegradable materials. Moreover, cellulose has a porous structure, which can adjust the nutrient release time, and the degradation rate of polylactic acid is relatively slow, which can extend the nutrient release time. Therefore, the film made by combining the two can be degraded by microorganisms in the natural environment. At the same time, the prepared composite film has balanced mechanical properties and biodegradation speed, enabling the degradation efficiency and permeability of the film to be precisely regulated, thereby achieving slow release of nutrients.

[0024] Preferably, the film coating mechanism includes a conveyor belt. The upper surface of the conveyor belt of the conveyor belt is provided with air outlets distributed in a rectangular array. An aggregate box is placed above the air outlets. A groove is provided on the inner bottom wall of the aggregate box. The inner wall of the groove is communicated with the inner wall of the air outlet. A driving motor is fixedly installed on one side surface of the aggregate box. One end of the output shaft of the driving motor extends into the inner wall of the aggregate box and is fixedly sleeved with a rotating shaft. The surface of the rotating shaft is installed on the inner wall of the aggregate box through a bearing. Gears are fixedly sleeved at both ends of the rotating shaft. A sliding groove is provided on one side surface of the aggregate box. The inner wall of the sliding groove is communicated with the inner wall of the groove. A sealing plate is slidably clamped in the inner wall of the sliding groove. Rack bars are symmetrically distributed and installed on the upper surface of the sealing plate. The two gears are respectively meshed with the two rack bars.

[0025] Through the above technical solution, the rotation of the output shaft of the driving motor drives the rotating shaft connected thereto to rotate. The rotation of the rotating shaft drives the two gears connected thereto to rotate synchronously. The rotation of the gears drives the rack bars engaged therewith to move, thereby driving the sealing plate to move, facilitating the opening or closing of the groove.

[0026] Preferably, a support plate is fixedly installed on the inner surface of the support of the conveyor belt. A blower is fixedly installed on the upper surface of the support plate. The air outlet of the blower is communicated with the inner wall of the air outlet. A support frame is arranged on the outer surface of the conveyor belt. A transparent cover is fixedly sleeved on the surface of the support frame. Spray heads are annularly and arrayedly installed on the inner wall of the transparent cover. An annular pipe is installed on the inner surface of the support frame through a buckle. A tank body is fixedly installed on the upper surface of the support frame. The bottom of the tank body is communicated with the annular pipe through a pipeline.

[0027] Through the above technical solution, the wind blown by the blower enables the fertilizer particles in the aggregate box to enter the transparent cover, making the fertilizer particles suspended in the transparent cover. Then, the spray heads are started, so that the solution in the tank body enters the annular pipe through the pipeline and enters the spray heads from the annular pipe to coat the fertilizer particles with a film.

[0028] Preferably, the mixing time in S4 and S5 is 10 - 20 minutes, and medium and low speed mixing is adopted.

[0029] Through the above technical solution, high-speed stirring is avoided to cause damage to the coating layer of the coated slow-release fertilizer. At the same time, too short mixing time may lead to unevenness, while too long mixing time may damage the coating layer.

[0030] The beneficial effects in the present invention are as follows:

[0031] 1. By setting slow-release fertilizers, nutrients such as nitrogen, phosphorus, and potassium are wrapped with a composite film made of 50% cellulose and 50% polylactic acid using a coating technology. This makes it easy for the slow-release fertilizers not to break easily during mixing and enables the film to be degraded by microorganisms in the natural environment, thus achieving the effect of slow nutrient release, improving fertilizer utilization rate, and avoiding nutrient loss.

[0032] 2. By setting modified bentonite, natural cations in bentonite are replaced with organic cations to enhance the water absorption and water retention capacity and ion exchange capacity of bentonite, thereby improving the soil aggregate structure and making its application range wider in harsh environments.

[0033] 3. By setting a film coating mechanism, it is convenient to wrap fertilizers such as nitrogen, phosphorus, and potassium together as needed. The driving motor drives the sealing plate to move, allowing gas to pass through when needed, thus facilitating the transport of fertilizer particles by the aggregate box. At the same time, a blower is used to make these fertilizer particles suspended in the transparent cover, and under the action of the nozzle, the composite film is sprayed onto the surface of the fertilizer particles in a solution state to form a uniform film layer, achieving the effect of rapid film coating. Brief Description of the Drawings

[0034] Figure 1 Schematic diagram of a desert soil conditioner and its preparation method proposed by the present invention;

[0035] Figure 2 Three-dimensional view of the air outlet structure of a desert soil conditioner and its preparation method proposed by the present invention;

[0036] Figure 3 Three-dimensional view of the blower structure of a desert soil conditioner and its preparation method proposed by the present invention;

[0037] Figure 4 Three-dimensional view of the driving motor structure of a desert soil conditioner and its preparation method proposed by the present invention;

[0038] Figure 5 Three-dimensional view of the rack structure of a desert soil conditioner and its preparation method proposed by the present invention;

[0039] Figure 6 Three-dimensional view of the gear structure of a desert soil conditioner and its preparation method proposed by the present invention;

[0040] Figure 7 Three-dimensional view of the transparent cover structure of a desert soil conditioner and its preparation method proposed by the present invention;

[0041] Figure 8 Three-dimensional view of the nozzle structure of a desert soil conditioner and its preparation method proposed by the present invention.

[0042] In the figure: 1. conveyor belt; 101. air outlet; 102. aggregate box; 103. groove; 104. drive motor; 105. rotating shaft; 106. gear; 107. chute; 108. sealing plate; 109. rack; 110. support plate; 111. fan; 112. support frame; 113. transparent cover; 114. nozzle; 115. annular pipe; 116. tank body. Detailed implementation manner

[0043] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments.

[0044] Embodiment 1

[0045] A desert soil conditioner, by weight ratio, the raw materials of the desert soil conditioner include 70% of the core material and 30% of the functional additives. The core material includes 50% of biochar and 20% of modified bentonite. The functional additives include 15% of slow-release fertilizer, 10% of microbial inoculant, 3% of water-retaining agent, and 2% of soil conditioner.

[0046] In order to reduce the environmental pollution caused by the incineration of agricultural waste, biochar is made by pyrolyzing crop straw and forestry waste, so that the biochar has a porous structure, which can effectively improve the air permeability, water retention and adsorption of the soil, and provide a rich carbon source.

[0047] In order to improve the original performance of bentonite, modified bentonite uses organic cations to replace the natural cations in bentonite, enhancing the water absorption and water retention capacity and ion exchange capacity of bentonite, thereby improving the soil aggregate structure.

[0048] In order to slowly release fertilizers, the slow-release fertilizer uses a coating technology to wrap nitrogen, phosphorus and potassium to achieve slow release, improve fertilizer utilization rate, and avoid nutrient loss.

[0049] In order to improve the soil environment, the microbial inoculant includes nitrogen-fixing bacteria, phosphorus-solubilizing bacteria, and potassium-solubilizing bacteria, which can activate soil nutrients and promote plant growth.

[0050] A preparation method of a desert soil conditioner includes the following preparation steps:

[0051] S1. Biochar preparation: Pyrolyze crop straw and forestry waste under anaerobic conditions to make biochar.

[0052] S2. Modified bentonite preparation: Mix bentonite with an organic modifier and perform intercalation modification treatment to improve its water absorption and water retention capacity and ion exchange capacity.

[0053] S3. Preparation of slow-release fertilizer: A composite film is made from cellulose and polylactic acid. By using a film coating mechanism, the air flow drives the fertilizer particles to suspend, and at the same time, the composite film is sprayed onto the surface of the fertilizer particles in a solution state to form a uniform film layer.

[0054] S4. Preparation of functional additives: The slow-release fertilizer, microbial inoculant, water retainer, and soil conditioner are mixed evenly in proportion.

[0055] S5. Mixed granulation: The biochar, modified bentonite, and functional additives are mixed evenly in proportion and granulated by a granulator to form particles with a particle size of 2 - 5 mm.

[0056] S6. Drying and packaging: The particles are dried to reduce their moisture content to less than 10%, and then packaged.

[0057] In order to make the composite film have both mechanical properties and biodegradation rate, the composite film in S3 is made of 50% cellulose and 50% polylactic acid. Both cellulose and polylactic acid are biodegradable materials. Cellulose has a porous structure, which can adjust the nutrient release time, and the degradation rate of polylactic acid is slower, which can extend the nutrient release time. Therefore, the film made by combining the two can be degraded by microorganisms in the natural environment. At the same time, the made composite film has balanced mechanical properties and biodegradation rate, so that the degradation efficiency and permeability of the film can be precisely controlled, thus realizing the slow release of nutrients.

[0058] As Figures 1 - 6 shown, in order to facilitate driving the fertilizer particles to suspend, the film coating mechanism includes a conveyor belt 1. The upper surface of the conveyor belt of the conveyor belt 1 is provided with air outlets 101 distributed in a rectangular array. Above the air outlets 101, there is an aggregate box 102. The inner bottom wall of the aggregate box 102 is provided with a groove 103. The inner wall of the groove 103 is communicated with the inner wall of the air outlet 101. One side surface of the aggregate box 102 is fixedly installed with a driving motor 104. One end of the output shaft of the driving motor 104 extends into the inner wall of the aggregate box 102 and is fixedly sleeved with a rotating shaft 105. The surface of the rotating shaft 105 is installed on the inner wall of the aggregate box 102 through a bearing. Both ends of the rotating shaft 105 are fixedly sleeved with gears 106. One side surface of the aggregate box 102 is provided with a sliding groove 107. The inner wall of the sliding groove 107 is communicated with the inner wall of the groove 103. The inner wall of the sliding groove 107 is slidably clamped with a sealing plate 108. The upper surface of the sealing plate 108 is symmetrically provided with racks 109. The two gears 106 are respectively engaged with the two racks 109. By the rotation of the output shaft of the driving motor 104, the rotating shaft 105 connected thereto rotates. The rotation of the rotating shaft 105 drives the two gears 106 connected thereto to rotate synchronously. The rotation of the gears 106 drives the racks 109 engaged therewith to move, thereby driving the sealing plate 108 to move, facilitating the opening or closing of the groove 103.

[0059] As Figure 1 and Figures 7 - 8 shown, in order to facilitate the spraying of the solution and form a film, a support plate 110 is fixedly installed on the inner surface of the bracket of the conveyor belt 1. A blower 111 is fixedly installed on the upper surface of the support plate 110. The air outlet of the blower 111 is communicated with the inner wall of the air outlet 101. A support frame 112 is arranged on the outer surface of the conveyor belt 1. A transparent cover 113 is fixedly sleeved on the surface of the support frame 112. Spray heads 114 are installed on the inner wall of the transparent cover 113 in an annular array distribution. An annular pipe 115 is installed on the inner surface of the support frame 112 by means of a buckle. A tank body 116 is fixedly installed on the upper surface of the support frame 112. The bottom of the tank body 116 is communicated with the annular pipe 115 through a pipeline. The wind blown by the blower 111 makes the fertilizer particles in the aggregate box 102 enter the transparent cover 113, so that the fertilizer particles are suspended in the transparent cover 113. Then the spray heads 114 are started, so that the solution in the tank body 116 enters the annular pipe 115 through the pipeline and enters the spray heads 114 from the annular pipe 115 to coat the fertilizer particles with a film.

[0060] In order to prevent the composite material film on the surface of the slow-release fertilizer from being damaged, the mixing time in S4 and S5 is 10 - 20 min, and medium and low speed mixing is adopted to avoid the damage of the coating layer of the coated slow-release fertilizer caused by high-speed stirring. At the same time, too short mixing time may lead to unevenness, while too long mixing time may damage the coating layer.

[0061] Example Two

[0062] A desert soil conditioner, by weight ratio, the raw materials of the desert soil conditioner include 80% of core materials and 20% of functional auxiliaries. The core materials include 60% of biochar and 20% of modified bentonite. The functional auxiliaries include 10% of slow-release fertilizer, 5% of microbial inoculum, 3% of water-retaining agent and 2% of soil conditioner.

[0063] In order to reduce the environmental pollution caused by the incineration of agricultural waste, the biochar is made by biomass pyrolysis of crop straws and forestry waste, so that the biochar has a porous structure, which can effectively improve the air permeability, water retention and adsorption of the soil, and provide a rich carbon source.

[0064] In order to improve the original performance of bentonite, the modified bentonite uses organic cations to replace the natural cations in bentonite, enhancing the water absorption and water retention capacity and ion exchange capacity of bentonite, thereby improving the soil aggregate structure.

[0065] In order to slowly release the fertilizer, the slow-release fertilizer uses a coating technology to wrap nitrogen, phosphorus and potassium to achieve slow release, improve the fertilizer utilization rate and avoid nutrient loss.

[0066] To improve the soil environment, the microbial inoculant includes nitrogen-fixing bacteria, phosphorus-solubilizing bacteria, and potassium-solubilizing bacteria, which can activate soil nutrients and promote plant growth.

[0067] A preparation method of a desert soil conditioner includes the following preparation steps:

[0068] S1. Preparation of biochar: Pyrolyze crop straws and forestry waste under anaerobic conditions to produce biochar.

[0069] S2. Preparation of modified bentonite: Mix bentonite with an organic modifier and conduct intercalation modification treatment to improve its water absorption and water retention capacity and ion exchange capacity.

[0070] S3. Preparation of slow-release fertilizer: Make a composite material film from cellulose and polylactic acid. Use a film coating mechanism to make the airflow drive the fertilizer particles to suspend, and at the same time spray the composite material film onto the surface of the fertilizer particles in a solution state to form a uniform film layer.

[0071] S4. Preparation of functional additives: Mix the slow-release fertilizer, microbial inoculant, water-retaining agent, and soil conditioner evenly in proportion.

[0072] S5. Mixing granulation: Mix the biochar, modified bentonite, and functional additives evenly in proportion, and granulate through a granulator to form particles with a particle size of 2 - 5 mm.

[0073] S6. Drying and packaging: Conduct drying treatment on the particles to reduce their moisture content to below 10%, and then conduct packaging.

[0074] In order to make the composite material film have both mechanical properties and biodegradation rate, the composite material film in S3 is made of 50% cellulose and 50% polylactic acid. Both cellulose and polylactic acid are biodegradable materials. Cellulose has a porous structure, which can adjust the nutrient release time, and the degradation rate of polylactic acid is slower, which can extend the nutrient release time. Therefore, the film made by combining the two can be degraded by microorganisms in the natural environment. At the same time, the made composite material film has balanced mechanical properties and biodegradation rate, so that the degradation efficiency and permeability of the film can be precisely regulated, thereby realizing the slow release of nutrients.

[0075] To facilitate driving the fertilizer particles to suspend, the film covering mechanism includes a conveyor belt 1. The upper surface of the conveyor belt of the conveyor belt 1 is provided with air outlets 101 distributed in a rectangular array. An aggregate box 102 is placed above the air outlets 101. A groove 103 is opened on the inner bottom wall of the aggregate box 102. The inner wall of the groove 103 is communicated with the inner wall of the air outlet 101. A driving motor 104 is fixedly installed on one side surface of the aggregate box 102. One end of the output shaft of the driving motor 104 extends into the inner wall of the aggregate box 102 and is fixedly sleeved with a rotating shaft 105. The surface of the rotating shaft 105 is installed on the inner wall of the aggregate box 102 through a bearing. Both ends of the rotating shaft 105 are fixedly sleeved with gears 106. A sliding groove 107 is opened on one side surface of the aggregate box 102. The inner wall of the sliding groove 107 is communicated with the inner wall of the groove 103. A sealing plate 108 is slidably clamped on the inner wall of the sliding groove 107. Rack bars 109 are symmetrically installed on the upper surface of the sealing plate 108. The two gears 106 are respectively engaged with the two rack bars 109. By the rotation of the output shaft of the driving motor 104, the rotating shaft 105 connected thereto rotates. The rotation of the rotating shaft 105 drives the two gears 106 connected thereto to rotate synchronously. The rotation of the gears 106 drives the rack bars 109 engaged therewith to move, thereby driving the sealing plate 108 to move, facilitating the opening or closing of the groove 103.

[0076] To facilitate spraying the solution to form a film, a support plate 110 is fixedly installed on the inner surface of the support of the conveyor belt 1. A blower 111 is fixedly installed on the upper surface of the support plate 110. The air outlet of the blower 111 is communicated with the inner wall of the air outlet 101. A support frame 112 is arranged on the outer surface of the conveyor belt 1. A transparent cover 113 is fixedly sleeved on the surface of the support frame 112. Spray heads 114 are annularly arrayed and installed on the inner wall of the transparent cover 113. An annular pipe 115 is installed on the inner surface of the support frame 112 through a buckle. A tank body 116 is fixedly installed on the upper surface of the support frame 112. The bottom of the tank body 116 is communicated with the annular pipe 115 through a pipeline. The wind blown by the blower 111 enables the fertilizer particles in the aggregate box 102 to enter the transparent cover 113, making the fertilizer particles suspend in the transparent cover 113. Then, the spray heads 114 are started, enabling the solution in the tank body 116 to enter the annular pipe 115 through the pipeline and enter the spray heads 114 from the annular pipe 115 to coat the fertilizer particles with a film.

[0077] To prevent the composite material film on the surface of the slow-release fertilizer from being damaged, the mixing time in S4 and S5 is 10 - 20 min, and medium and low speeds are adopted for mixing to avoid the damage of the coating layer of the coated slow-release fertilizer caused by high-speed stirring. At the same time, too short mixing time may lead to unevenness, while too long mixing time may damage the coating layer.

[0078] Example Three

[0079] A desert soil conditioner, by weight ratio, the raw materials of the desert soil conditioner include 70% of the core material and 30% of the functional additives. The core material includes 50% of biochar and 20% of modified bentonite, and the functional additives include 15% of slow-release fertilizer, 7% of microbial inoculum, 5% of water retainer and 3% of soil conditioner.

[0080] In order to reduce the environmental pollution caused by the incineration of agricultural waste, biochar is made by pyrolyzing crop straws and forestry waste, so that the biochar has a porous structure, which can effectively improve the soil air permeability, water retention and adsorption, and provide a rich carbon source.

[0081] In order to improve the original properties of bentonite, the modified bentonite uses organic cations to replace the natural cations in bentonite, enhancing the water absorption and retention capacity and ion exchange capacity of bentonite, thereby improving the soil aggregate structure.

[0082] In order to slowly release fertilizers, the slow-release fertilizer uses a coating technology to wrap nitrogen, phosphorus and potassium, achieving slow release, improving the fertilizer utilization rate and avoiding nutrient loss.

[0083] In order to improve the soil environment, the microbial inoculum includes nitrogen-fixing bacteria, phosphorus-solubilizing bacteria and potassium-solubilizing bacteria, which can activate soil nutrients and promote plant growth.

[0084] A preparation method of a desert soil conditioner includes the following preparation steps:

[0085] S1. Biochar preparation: Pyrolyze crop straws and forestry waste under anaerobic conditions to make biochar.

[0086] S2. Modified bentonite preparation: Mix bentonite with an organic modifier and conduct intercalation modification treatment to improve its water absorption and retention capacity and ion exchange capacity.

[0087] S3. Slow-release fertilizer preparation: Make a composite material film through cellulose and polylactic acid, use a film coating mechanism to make the air flow drive the fertilizer particles to suspend, and at the same time spray the composite material film onto the surface of the fertilizer particles in a solution state to form a uniform film layer.

[0088] S4. Functional additive preparation: Mix the slow-release fertilizer, microbial inoculum, water retainer and soil conditioner evenly in proportion.

[0089] S5. Mixing and granulation: Mix the biochar, modified bentonite and functional additives evenly in proportion, and granulate through a granulator to form particles with a particle size of 2-5 mm.

[0090] S6. Drying and packaging: Dry the particles to make their moisture content drop below 10%, and then conduct packaging.

[0091] In order to endow the composite material film with both mechanical properties and biodegradation rate, the composite material film in S3 is made of 50% cellulose and 50% polylactic acid. Both cellulose and polylactic acid are biodegradable materials. Cellulose has a porous structure, which can regulate the nutrient release time, and polylactic acid has a slow degradation rate, which can prolong the nutrient release time. Therefore, the film made by combining the two can be degraded by microorganisms in the natural environment. At the same time, the made composite material film has balanced mechanical properties and biodegradation rate, enabling the degradation efficiency and permeability of the film to be precisely regulated, thus realizing the slow release of nutrients.

[0092] To facilitate driving the fertilizer particles to suspend, the film covering mechanism includes a conveyor belt 1. The upper surface of the conveyor belt of the conveyor belt 1 is distributed with air outlets 101 in a rectangular array. An aggregate box 102 is placed above the air outlet 101. A groove 103 is opened on the inner bottom wall of the aggregate box 102. The inner wall of the groove 103 is communicated with the inner wall of the air outlet 101. A driving motor 104 is fixedly installed on one side surface of the aggregate box 102. One end of the output shaft of the driving motor 104 extends to the inner wall of the aggregate box 102 and is fixedly sleeved with a rotating shaft 105. The surface of the rotating shaft 105 is installed on the inner wall of the aggregate box 102 through a bearing. Gears 106 are fixedly sleeved at both ends of the rotating shaft 105. A sliding groove 107 is opened on one side surface of the aggregate box 102. The inner wall of the sliding groove 107 is communicated with the inner wall of the groove 103. A sealing plate 108 is slidably clamped on the inner wall of the sliding groove 107. Rack bars 109 are symmetrically distributed and installed on the upper surface of the sealing plate 108. The two gears 106 are respectively meshed with the two rack bars 109. By rotating the output shaft of the driving motor 104, the rotating shaft 105 connected thereto rotates. The rotation of the rotating shaft 105 drives the two gears 106 connected thereto to rotate synchronously. The rotation of the gears 106 drives the rack bars 109 meshed therewith to move, thereby driving the sealing plate 108 to move, facilitating the opening or closing of the groove 103.

[0093] To facilitate spraying the solution to form a film, a support plate 110 is fixedly installed on the inner surface of the support of the conveyor belt 1. A blower 111 is fixedly installed on the upper surface of the support plate 110. The air outlet of the blower 111 is communicated with the inner wall of the air outlet 101. A support frame 112 is arranged on the outer surface of the conveyor belt 1. A transparent cover 113 is fixedly sleeved on the surface of the support frame 112. Nozzles 114 are annularly and arrayedly installed on the inner wall of the transparent cover 113. An annular pipe 115 is installed on the inner surface of the support frame 112 through a buckle. A tank body 116 is fixedly installed on the upper surface of the support frame 112. The bottom of the tank body 116 is communicated with the annular pipe 115 through a pipeline. The wind blown by the blower 111 makes the fertilizer particles in the aggregate box 102 enter the transparent cover 113, making the fertilizer particles suspended in the transparent cover 113. Then the nozzles 114 are started, so that the solution in the tank body 116 enters the annular pipe 115 through the pipeline and enters the nozzles 114 from the annular pipe 115 to coat the fertilizer particles with a film.

[0094] To prevent the composite material film on the surface of the slow-release fertilizer from being damaged, the mixing time in S4 and S5 is 10 - 20 minutes, and medium and low speeds are used for mixing to avoid damage to the coating layer of the coated slow-release fertilizer caused by high-speed stirring. At the same time, too short a mixing time may lead to unevenness, while too long a mixing time may damage the coating layer.

[0095] As mentioned above, the above are only the preferred specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, making equivalent substitutions or changes, shall be covered by the protection scope of the present invention.

Claims

1. A desert soil conditioner, characterized in that: By weight, the raw materials of the desert soil conditioner include 70-80% of the core material and 20-30% of the functional adjuvant. The core material includes 50-60% of biochar and 20-30% of modified bentonite. The functional adjuvant includes 10-15% of slow-release fertilizer, 5-10% of microbial inoculum, 3-5% of water retainer and 2-3% of soil conditioner.

2. The desert soil conditioner according to claim 1, characterized in that: The biochar is made by pyrolyzing crop straws and forestry wastes.

3. The desert soil conditioner according to claim 1, characterized in that: The modified bentonite uses organic cations to replace the natural cations in bentonite.

4. The desert soil conditioner according to claim 1, characterized in that: The slow-release fertilizer uses coating technology to wrap nitrogen, phosphorus and potassium.

5. The desert soil conditioner according to claim 1, characterized in that: The microbial inoculum includes nitrogen-fixing bacteria, phosphorus-solubilizing bacteria and potassium-solubilizing bacteria.

6. The preparation method of a desert soil conditioner according to claim 1, characterized in that: It includes the following preparation steps: S1. Preparation of biochar: Pyrolyze crop straws and forestry wastes under anaerobic conditions to make biochar. S2. Preparation of modified bentonite: Mix bentonite with an organic modifier and carry out intercalation modification treatment to improve its water absorption and retention capacity and ion exchange capacity. S3. Preparation of slow-release fertilizer: Make a composite material film from cellulose and polylactic acid. Use a film coating mechanism to make the air flow drive the fertilizer particles to suspend, and at the same time spray the composite material film onto the surface of the fertilizer particles in a solution state to form a uniform film layer. S4. Preparation of functional adjuvant: Mix the slow-release fertilizer, microbial inoculum, water retainer and soil conditioner evenly in proportion. S5. Mixing and granulation: Mix the biochar, modified bentonite and functional adjuvant evenly in proportion, and granulate through a granulator to form particles with a particle size of 2-5 mm. S6. Drying and packaging: Dry the particles to reduce their moisture content to less than 10%, and then package them.

7. The preparation method of a desert soil conditioner according to claim 6, characterized in that: The composite material film in S3 is made of 50% cellulose and 50% polylactic acid.

8. The preparation method of a desert soil conditioner according to claim 6, characterized in that: The film coating mechanism includes a conveyor belt (1). The upper surface of the conveyor belt of the conveyor belt (1) is distributed with air outlets (101) in a rectangular array. An aggregate box (102) is placed above the air outlets (101). A groove (103) is opened on the inner bottom wall of the aggregate box (102). The inner wall of the groove (103) is communicated with the inner wall of the air outlet (101). A driving motor (104) is fixedly installed on one side surface of the aggregate box (102). One end of the output shaft of the driving motor (104) extends to the inner wall of the aggregate box (102) and is fixedly sleeved with a rotating shaft (105). The surface of the rotating shaft (105) is installed on the inner wall of the aggregate box (102) through a bearing. Gears (106) are fixedly sleeved at both ends of the rotating shaft (105). A chute (107) is opened on one side surface of the aggregate box (102). The inner wall of the chute (107) is communicated with the inner wall of the groove (103). A sealing plate (108) is slidably clamped on the inner wall of the chute (107). Rack bars (109) are symmetrically distributed and installed on the upper surface of the sealing plate (108). The two gears (106) are respectively engaged with the two rack bars (109).

9. The preparation method of a desert soil conditioner according to claim 8, characterized in that: The inner surface of the bracket of the conveyor belt (1) is fixedly installed with a support plate (110). The upper surface of the support plate (110) is fixedly installed with a blower (111). The air outlet of the blower (111) is communicated with the inner wall of the air outlet (101). The outer surface of the conveyor belt (1) is provided with a support frame (112). The surface of the support frame (112) is fixedly sleeved with a transparent cover (113). The inner wall of the transparent cover (113) is installed with spray heads (114) distributed in an annular array. The inner surface of the support frame (112) is installed with an annular pipe (115) through a buckle. The upper surface of the support frame (112) is fixedly installed with a tank body (116). The bottom of the tank body (116) is communicated with the annular pipe (115) through a pipeline.

10. The preparation method of a desert soil conditioner according to claim 6, characterized in that: The mixing time in S4 and S5 is 10 - 20 min, and medium and low speed mixing is adopted.

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