A method and coating device for reducing ammonia volatilization in the field by using straw soil slurry coating

Abstract

The present invention discloses a method and a coating device for reducing ammonia volatilization in the field by using a straw soil mud coating. The coating device includes a frame, on which a water storage tank, a stirring mechanism and a water pump are provided. A feeding pipe is horizontally arranged at the bottom of the stirring mechanism. The feeding pipe extends to the rear end of the frame and a discharging pipe is vertically arranged at the end of the feeding pipe. The lower end of the discharging pipe forms a discharging port. A coating plate is arranged behind the discharging pipe, and a smoothing plate is arranged behind the coating plate to smooth the mud layer. A straw box and a soil box are arranged on the upper side of the water storage tank. The outlets of the straw box and the soil box are respectively connected to the stirring tank of the stirring mechanism through screw feeders. The water pump is connected to the water storage tank. The water pump supplies water to the stirring tank on the one hand and sprays water to the smoothing plate on the other hand. The coating device mixes straw, soil and water in proportion to prepare mud, and coats the mud on the soil surface layer between two rows to form a soil covering layer, which not only has the function of moisture conservation, but also reduces ammonia volatilization through the physical isolation of the coating and the absorption of high moisture in the bottom layer.

Description

Technical Field

[0001] The present invention belongs to the technical field of agriculture, and specifically relates to a method and a coating device for reducing ammonia volatilization in the field by using straw mud coating. Background Art

[0002] At present, fertilizers in agricultural production in China are mainly used in two forms: basal fertilizer and top dressing. Among them, basal fertilizer is applied by broadcasting during plowing before sowing or during sowing, and it is the main form of fertilizer use for field crops. After the fertilizer is applied, nitrogen is decomposed and transformed into ionic forms mainly composed of ammonium nitrogen and nitrate nitrogen, and gas forms mainly composed of ammonia gas and N 2 O. The nitrogen conversion rates of different fertilizers are different. Generally, the nitrogen release can reach the peak within 2 to 10 days after fertilization. After the crops are sown, since the nutrients required for seed germination and the early growth stage are mainly provided by the seeds themselves, and the seedling roots are weak and the nutrient absorption ability is limited, the utilization of various forms formed by the conversion of fertilizers in the soil is relatively low at this time, resulting in a time difference between the release of fertilizer efficiency and the nutrient requirements of the crops. During this period, a part of the free ammonia formed by the conversion of fertilizers is adsorbed in the soil, and the other part overflows through the soil surface layer, causing nutrient loss and air pollution.

[0003] To reduce soil ammonia volatilization caused by fertilizer use, measures such as adding biochar, water-retaining agents to the soil, and increasing the soil water content can be taken. Among them, the water-retaining agent mainly binds more free ammonia by increasing the water content in the soil, thereby reducing ammonia overflow. The porous structure and large specific surface area of biochar have a certain adsorption and fixation effect on ammonia, and can reduce ammonia volatilization to a certain extent. However, these measures do not cut off the ammonia volatilization channel in the soil. Especially when the surface soil contacts the air, free ammonia can directly enter the atmosphere.

[0004] Blocking the ammonia migration channel in the soil can not only reduce the volatilization of free ammonia, but also intercept this part of free ammonia in the soil layer for the use of crop roots. Soil and straw are the most basic materials in agricultural production. Moist soil has good ammonia adsorption and fixation ability; straw not only has the ability to absorb water and ammonia, but can also be mixed in the mud to reduce the cracking after the mud dries, and keep the mud having a certain shape and strength. Using straw-containing mud to cover the soil surface layer can effectively block the soil ammonia volatilization channel, reduce ammonia loss, and at the same time, the straw-containing mud coating has a certain effect on maintaining soil moisture. When the crops grow for a certain period of time, under the action of rainfall or irrigation, the structure of the mud coating is damaged, and the soil returns to the natural state. At this time, the crop roots have developed completely, and the mud coating will not affect the growth of the crops. Summary of the Invention

[0005] The purpose of the present invention is to provide a method and a coating device for reducing ammonia volatilization in the field by using straw mud coating, which can make full use of the existing resources in the field to reduce fertilizer ammonia volatilization and improve fertilizer utilization efficiency.

[0006] A coating device includes a frame. Walking wheels are provided below the frame. A water storage tank, a stirring mechanism, and a water pump are provided on the frame. A feeding pipe is horizontally provided at the bottom of the stirring mechanism. An adjusting control valve is provided on the feeding pipe. The feeding pipe extends to the rear end of the frame and a discharge pipe is vertically provided at the end of the feeding pipe. The lower end of the discharge pipe forms a discharge port, and the discharge port is strip-shaped. A coating plate is provided behind the discharge pipe to coat the extruded slurry into a slurry layer on a flat surface. A leveling plate is provided behind the coating plate to level the slurry layer. A straw bin and a soil bin are provided on the upper side of the water storage tank. The outlets of the straw bin and the soil bin are respectively connected to the stirring tank of the stirring mechanism through screw feeders. The inlet of the water pump is connected to the water storage tank through a pipeline. The water pump is provided with two outlet pipelines. The end of one outlet pipeline extends above the stirring tank to form a water injection port for injecting stirring water into the stirring tank. The other outlet pipeline is a spray pipe, and the outlet of the spray pipe forms a water spray port for spraying water on the leveling plate.

[0007] Further, a stirring shaft is provided in the stirring tank of the stirring mechanism, and stirring blades are provided on the stirring shaft.

[0008] Further, the coating plate is provided with coating support rods, and the coating support rods of the coating plate are fixedly connected to the discharge pipe. The leveling plate is provided with leveling plate support rods, and the leveling plate support rods are fixedly connected to the coating support rods.

[0009] Further, the working surfaces of the coating plate and the leveling plate are inclined, and the angles between the working surfaces of the coating plate and the leveling plate and the ground are both 30°.

[0010] A method for reducing ammonia volatilization in the field by using a straw slurry coating uses the above coating device to mix straw, soil, and water in proportion to prepare slurry, and coats the slurry on the soil surface between two rows during sowing to form a slurry coating to block the ammonia volatilization path.

[0011] Preferably, the particle size of the straw used is 2 - 20 mm, of which 10 - 20 mm is not less than 20%, and 2 - 5 mm is not more than 5%; the particle size of the soil particles does not exceed 5 mm. The soil used is screened to remove substances such as plastics, sand, gravel, films, and crop stubbles, and only the part with a particle size not exceeding 5 mm is used. During use, the straw and soil are evenly mixed, and water is added and stirred to be mixed into slurry. The mass ratio of straw, soil, and water is 2:4:4. During the use process, the slurry is kept stirred to prevent stratification. The slurry is covered during crop sowing. The slurry coating is located between two rows, and the edge of the coating is not less than 3 - 5 cm away from the seed sowing position. The thickness of the coating is 3 - 5 mm. The width of the slurry coating for planting wheat is 15 - 17 cm, and the width of the slurry coating for planting corn is 50 - 55 cm.

[0012] In use, the coating device can be an integral structure with the seeder or work independently. When the coating device and the seeder are of an integral structure, a stubble cleaner and a press wheel are provided on the seeder frame. When working independently, a stubble cleaner and a press wheel are provided on the coating device frame. During operation, the coating produced by the coating device should accurately cover the soil surface layer between two rows.

[0013] The rear power output of the tractor drives the stubble cleaner through a coupling and a gearbox. The press wheel is located directly in front of the coating plate. The press wheel, coating plate, and leveling plate can be replaced according to the row spacing of the sown crops. The seeder is connected to the coating device through a drawbar to form an integral structure with the coating device.

[0014] The stirring paddles are arranged in three layers: upper, middle, and lower. The feeding port of the spiral feeder is connected to the outlet of the hopper, and the end is located inside the conveying pipe. The water spraying port is located below the leveling plate, and the water is evenly sprayed on the leveling plate. To ensure the coating effect, a stubble cleaner and a press wheel are also provided. The stubble cleaner crushes the residual stubble and large soil clods on the soil surface layer, and the subsequent press wheel flattens the soil. Then, the coating device mixes straw, soil, and water in proportion to prepare slurry, and coats the slurry on the soil surface layer between two rows to form a soil covering layer, which not only has the function of moisture conservation, but also the physical isolation of the coating and the absorption of high moisture at the bottom reduce ammonia volatilization. The stubble cleaner is located in front of the scraping plate and is a rotary structure, which crushes weeds and stubble during high-speed rotation. The press wheel is located between the scraping plate and the coating plate, and also plays a supporting role for the system bracket. The stubble cleaner, coating plate, scraping plate, press wheel, and leveling plate can all be replaced according to the crop row spacing or the required soil layer thickness. Among them, the widths of the stubble cleaner, coating plate, and leveling plate should be 3 - 5 cm smaller than the crop row spacing; the width of the press wheel is about 1 - 2 cm larger than the size of the leveling plate.

[0015] The straw slurry coating is carried out synchronously during crop sowing. When sowing crops, the stubble cleaner first performs stubble cleaning on the surface soil between the sowing rows, breaking up the straw stubble and large soil particles. Subsequently, the scraping plate levels the surface soil after stubble cleaning, and the press wheel then compacts the soil between two rows to form a flat surface. The slurry extruded from the outlet forms a slurry layer on the flat surface below under the action of the coating plate. Then, the leveling plate levels the slurry layer to form a slurry layer with uniform thickness. At the same time, the water spraying port evenly sprays water at the position where the leveling plate contacts the slurry to prevent the slurry from adhering to the leveling plate.

[0016] The measures of adding other functional substances such as biochar and water retainers to the straw slurry to improve the slurry performance and achieve the suppression and emission reduction of soil gas pollutants belong to the protection scope of the present invention. Description of the Drawings

[0017] Figure 1 is a schematic structural diagram of the present invention;

[0018] Figure 2Isometric view of the present invention;

[0019] Figure 3 Structural diagram of seeding and coating arrangement of the present invention;

[0020] Figure 4 Cross-sectional view of the stirring mechanism of the present invention;

[0021] Figure 5 Rear view of the stirring mechanism of the present invention;

[0022] Figure 6 Cross-sectional view of the straw box or soil box of the present invention;

[0023] In the figure: 1, seed box; 2, seed metering device; 3, straw box; 4, soil box; 5, screw feeder; 6, stirring mechanism; 7, water pump; 8, water storage tank; 9, press wheel; 10, scraping plate; 11, stubble cleaner; 12, tractor; 13, seed delivery pipe; 14, water injection port; 15, water spray pipe; 16, material delivery pipe; 17, coating plate; 18, smoothing plate; 19, water spray opening; 20, discharge port; 21, furrow opener; 22, frame; 23, stirring paddle; 24, regulating control valve; 25, pull rod; 26, gearbox; 27, coupling. Detailed implementation manners

[0024] 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 of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0025] Embodiment 1

[0026] A coating device, such as Figures 1 to 6As shown in the figure, it includes a frame 22. Walking wheels are provided below the frame 22. A water storage tank 8, a stirring mechanism 6 and a water pump 7 are provided on the frame 22. A feeding pipe 16 is horizontally provided at the bottom of the stirring mechanism 6. An adjusting control valve 24 is provided on the feeding pipe 16. The feeding pipe 16 extends to the rear end of the frame 22 and a discharge pipe is vertically provided at the end of the feeding pipe 16. The lower end of the discharge pipe forms a discharge port 20. The discharge port 20 is strip-shaped. A coating plate 17 is provided behind the discharge pipe to coat the extruded mud into a mud layer on a flat surface. A leveling plate 18 is provided behind the coating plate 17 to level the mud layer; a straw bin 3 and a soil bin 4 are provided on the upper side of the water storage tank 8. The outlets of the straw bin 3 and the soil bin 4 are respectively connected to the stirring tank of the stirring mechanism 6 through screw feeders 5. The inlet of the water pump 7 is connected to the water storage tank 8 through a pipeline. The water pump 7 is provided with two outlet pipelines. The end of one outlet pipeline extends above the stirring tank to form a water injection port 14 for injecting stirring water into the stirring tank. The other outlet pipeline is a water spray pipe 15. The outlet of the water spray pipe 15 forms a water spray port 19 for spraying water on the leveling plate 18.

[0027] A stirring shaft is provided in the stirring tank of the stirring mechanism 6, and stirring blades 23 are provided on the stirring shaft.

[0028] The coating plate 17 is provided with coating support rods. The coating support rods of the coating plate 17 are fixedly connected to the discharge pipe. The leveling plate 18 is provided with leveling plate support rods. The leveling plate support rods are fixedly connected to the coating support rods.

[0029] The working surfaces of the coating plate 17 and the leveling plate 18 are inclined, and the angles between the working surfaces of the coating plate 17 and the leveling plate 18 and the ground are both 30°.

[0030] The method for reducing ammonia volatilization in the field of the present invention is to mix crushed straw, soil and water in proportion to prepare mud, and coat the mud on the soil surface between two rows through a coating device during sowing to form a mud layer to block ammonia volatilization. The particle size of the straw used is 2 - 20 mm, of which 10 - 20 mm is not less than 20%, and 2 - 5 mm is not more than 5%; the particle size of the soil particles does not exceed 5 mm; the soil used is screened to remove plastics, sand, films, crop stubbles and other substances, and only the part with a particle size not exceeding 5 mm is used. During use, the straw and soil are mixed evenly, and water is added and stirred to be mixed into mud. The mass ratio of straw, soil and water is 2:4:4. The mud is kept stirred to prevent stratification. When sowing crops, the mud is covered at the same time. The mud layer is located between two rows, and the distance from the edge of the coating to the seed sowing position is not less than 3 - 5 cm, and the coating thickness is 3 - 5 mm. The width of the mud coating for planting wheat is 15 - 17 cm, and the width of the mud coating for planting corn is 50 - 55 cm.

[0031] The coating device for mud covering can be an integral structure with the seeder or work independently. When the coating device is an integral structure with the seeder, a stubble cleaner 11 and a press wheel 9 are provided on the seeder frame; when working independently, a stubble cleaner 11 and a press wheel 9 are provided on the coating device frame; during operation, the coating produced by the coating device should accurately cover the soil surface layer between two rows.

[0032] In this application, the coating device is connected to the seeder to form an integral structure.

[0033] Above the frame of the seeder, a tractor 12 and a seed box 1 are provided. Inside the seed box 1, a seed metering device 2 is provided. Outside the seed box 1, a seed tube 13 is provided. Below the frame of the seeder, a stubble cleaner 11, a leveling plate 10, a press wheel 9, and a furrow opener 21 are arranged in sequence from front to back. The seeder is connected to the coating device through a pull rod 25 to form an integral structure between the coating device and the seeder. A gearbox 26 is also provided on the frame of the seeder, and a coupling 27 is provided on the gearbox 26. During use, the rear power output of the tractor drives the stubble cleaner 11 through the coupling 27 and the gearbox 25.

[0034] The stirring paddle blades 23 are arranged in upper, middle, and lower layers. The feed inlet of the screw feeder 5 is connected to the outlets of the straw box 3 and the soil box 4, and the end is located in the mixing pool of the mixing mechanism. The water spraying port 19 is located below the plastering plate 18. During use, a single nozzle or a double nozzle can be installed at the water outlet 19. When the plastering plate 18 is relatively wide, a double nozzle is used, and the water is evenly sprayed on the plastering plate 18. The stubble cleaner 11 is located in front of the leveling plate 10 and is a rotary structure, which breaks weeds and root stubbles during high-speed rotation. The press wheel 9 is located directly in front of the coating plate 17, and the press wheel 9 is located between the leveling plate 10 and the coating plate 17, and at the same time plays a supporting role for the system bracket.

[0035] For the coating device, when sowing crops (with different row spacings), the stubble cleaner 11 first performs stubble cleaning on the surface soil between the sowing rows, breaking the straw root stubbles and large soil particles. Subsequently, the leveling plate 10 levels the surface soil after stubble cleaning. The press wheel 9 then compacts the soil between two rows to form a flat surface. The mud extruded from the discharge port 20 falls on the flat surface below under the action of the coating plate 17 to form a mud layer. Subsequently, the plastering plate 18 levels the mud layer to form a mud layer with uniform thickness. At the same time, the water spraying port 19 evenly sprays water on the contact position between the plastering plate 18 and the mud to prevent the mud from adhering to the plastering plate 18. For the coating device, the stubble cleaner 11, the coating plate 17, the leveling plate 10, the press wheel 9, and the plastering plate 18 can all be replaced according to the crop row spacing or the required soil layer thickness. For the coating device, other functional substances can be added to the straw mud coating to achieve the goals of nitrogen fixation and water fixation.

[0036] Application example:

[0037] Ammonia volatilization experiment with mud coating covering during the summer maize season. For summer maize, the seeds and fertilizers are sown simultaneously. The maize seeding rate is 3.5 kg per mu, the row spacing is 58 cm, and the plant spacing is 30 cm. The compound fertilizer (N-P 2 O 5 -K 2 O mass ratio: 28-6-6) dosage is 45 kg / mu. The soil taken from the field is first sun-dried for 2 days, then crushed and screened, and the fine soil is reserved for use. The wheat straw is kneaded and crushed, and the particles larger than 20 mm and smaller than 2 mm are removed by screening. The proportion of the screened straw particles with a size of 10-20 mm is 35%, and the proportion of those with a size of 2-5 mm is 3%. 2 kg of crushed straw and 8 kg of fine soil are respectively added to straw box 3 and soil box 4, and then water is added to water storage tank 8 to make a slurry until the straw is evenly distributed and there is no soil agglomeration. After sowing, a coating device is used for coating. A small amount of water is sprinkled on the soil layer before plastering the slurry. The coating width is 50 cm and the thickness is 5 mm. The ammonia content volatilized from the soil surface is measured on the 2nd, 4th, 6th, 8th, 10th, 12th, and 14th days after the coating is covered. The measurement of volatilized ammonia adopts the intermittent air extraction method. When measuring, the gas collection tank is placed on the coating without damaging the coating, and the bottom periphery is sealed with fine soil to prevent air leakage. The thickness of the piled soil is 5 cm. The situation of the ammonia volatilization amount is shown in the table. It can be seen from the table that the mud coating covering can not only reduce the ammonia volatilization amount in the early stage after fertilization, but also delay the peak value of ammonia volatilization relatively. It is also found in practice that multiple small cracks begin to appear on the coating on the 3rd day and form large cracks about 2 mm on the 6th day, which may be the reason for the increase in ammonia volatilization amount in the later stage.

[0038] Ammonia volatilization on the soil surface after sowing (kg / hm 2 •d)

[0039]

[0040] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirits of the present invention. The scope of the present invention is defined by the appended claims and their equivalent effects.

Claims

1. A coating device, characterized in that, it includes a frame. There are traveling wheels arranged below the frame. A water storage tank, a stirring mechanism and a water pump are arranged on the frame. A feeding pipe is horizontally arranged at the bottom of the stirring mechanism. An adjusting control valve is arranged on the feeding pipe. The feeding pipe extends to the rear end of the frame and a discharge pipe is vertically arranged at the end of the feeding pipe. The lower end of the discharge pipe forms a discharge port, and the discharge port is strip-shaped. A coating plate is arranged behind the discharge pipe to coat the extruded mud into a mud layer on a flat surface. A leveling plate is arranged behind the coating plate to level the mud layer to reduce ammonia volatilization in the field; a straw box and a soil box are arranged on the upper side of the water storage tank. The outlets of the straw box and the soil box are respectively connected to the stirring tank of the stirring mechanism through screw feeders. The inlet of the water pump is connected to the water storage tank through a pipeline. The water pump is provided with two outlet pipelines. The end of one outlet pipeline extends above the stirring tank to form a water injection port for injecting stirring water into the stirring tank. The other outlet pipeline is a water spraying pipe, and the outlet of the water spraying pipe forms a water spraying port for spraying water on the leveling plate.

2. The coating device according to claim 1, characterized in that, the coating plate is provided with coating support rods, and the coating support rods of the coating plate are fixedly connected to the discharge pipe. The leveling plate is provided with leveling plate support rods, and the leveling plate support rods are fixedly connected to the coating support rods.

3. The coating device according to claim 1, characterized in that, the working surfaces of the coating plate and the leveling plate are inclined, and the angles between the working surfaces of the coating plate and the leveling plate and the ground are both 30°.

4. A method for reducing ammonia volatilization in the field by using a straw mud coating, characterized in that, the coating device according to any one of claims 1 to 3 is used to mix straw, soil and water in proportion to prepare mud, and the mud is coated on the soil surface layer between two rows during sowing to form a mud coating and block the ammonia volatilization path.

5. The method for reducing ammonia volatilization in the field by using a straw mud coating according to claim 4, characterized in that, the particle size of the straw used is 2 - 20 mm, of which 10 - 20 mm is not less than 20%, and 2 - 5 mm is not more than 5%; the particle size of the soil particles does not exceed 5 mm.

6. The method for reducing ammonia volatilization in the field by using a straw mud coating according to claim 4, characterized in that, the mixed mud is paste-like or creamy, and the mixing mass ratio of straw, soil and water is 2:4:

4. Stirring is maintained during use to prevent stratification.

7. The method for reducing ammonia volatilization in the field by using a straw mud coating according to claim 4, characterized in that, the mud coating is located between two rows of crops, the edge of the coating is 3 - 5 cm away from the seed sowing position, and the coating thickness is 3 - 5 mm.

8. The method for reducing ammonia volatilization in the field by using a straw mud coating according to claim 4, characterized in that, the coating device and the seeder are of an integral structure or the coating device works independently; when the coating device and the seeder are of an integral structure, a stubble cleaner and a press wheel are arranged on the seeder frame; when working independently, a stubble cleaner and a press wheel are arranged on the coating device frame; during operation, the coating generated by the coating device should accurately cover the soil surface layer between two rows.

9. The method for reducing ammonia volatilization in the field by using a straw mud coating according to claim 8, characterized in that, The pressing wheel is located directly in front of the coating plate; the pressing wheel, coating plate, and wiping plate are replaced according to the row spacing of the sown crops; the seeder is connected to the coating device through a pull rod, thus forming an integral structure with the coating device.

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