Rice cultivation method without nitrogen fertilizer application

Abstract

The invention discloses a rice cultivation method without nitrogen fertilizer application, which comprises the following steps: laying a detachable aeration perforated pipe with a specific specification in a rice field, starting a direct-current aerator by utilizing power supply of a solar panel, carrying out intermittent aeration stirring to uniformly mix water, inputting nitrogen, keeping the dissolved oxygen concentration not more than 0.5 mg / L, and creating a suitable environment for nitrogen-fixing bacteria. 6-10 days before rice planting, nitrogen-fixing flora of clostridium pasteurianum is subjected to enrichment culture, and nitrogen is fixed by the nitrogen-fixing flora. During planting, the water depth of the rice field is controlled to be 5-15 cm, the nitrogen-fixing flora concentration is adjusted for nitrogen supply according to different growth cycle requirements of rice, and no nitrogen fertilizer is added in the whole process. According to the method, the rice grows by using nitrogen fixed by the nitrogen-fixing bacteria as a nitrogen fertilizer, and the nitrogen fertilizer does not need to be additionally applied, so that the rice planting cost is greatly saved, and the pollution of nitrogen to soil, water and air is also reduced; in addition, the solar panel is used for providing electric energy, and energy-consumption-free operation of the whole rice nitrogen-fertilizer-free cultivation system is achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of rice cultivation, and particularly relates to a rice cultivation method without nitrogen fertilizer application. Background Art

[0002] Nitrogen is an essential nutrient for rice growth, and nitrogen fertilizer application has become an important means to increase rice yield. However, excessive nitrogen fertilizer application has long caused many serious problems.

[0003] Excessive fertilization reduces nitrogen fertilizer absorption and utilization, increasing cultivation costs. Environmentally, excessive nitrogen fertilizer application triggers a series of pollution problems. On the one hand, it causes soil compaction and acidification, destroys soil structure, and affects soil microbial activity, thereby reducing soil fertility and threatening the sustainable use of arable land. On the other hand, large amounts of nitrogen enter water bodies through surface runoff, causing eutrophication, triggering algae blooms, disrupting the balance of aquatic ecosystems, and threatening the survival of aquatic plants and animals. Furthermore, the production and application of nitrogen fertilizers also emit greenhouse gases.

[0004] From the perspective of sustainable agricultural development, the traditional rice cultivation model that relies on chemical nitrogen fertilizers is unsustainable. It is urgent to explore methods to reduce dependence on nitrogen fertilizers, minimize environmental pollution, and ensure rice yields. Although biological nitrogen fixation technology offers hope for sustainable agricultural development, and the symbiotic nitrogen fixation system between legumes and rhizobia can effectively reduce the use of chemical nitrogen fertilizers, this system is highly host-specific and only suitable for legumes, making it difficult to extend to rice cultivation. Studies on non-legume nitrogen-fixing microorganisms have found that the nitrogenase activity of most nitrogen-fixing bacteria is inhibited under flooding conditions, making them difficult to adapt to the growth environment of aquatic crops such as rice.

[0005] In recent years, the discovery of flood-tolerant, nitrogen-fixing microorganisms in sewage and paddy water has provided a new opportunity for a greener rice cultivation approach. Against this backdrop, this invention organically combines solar energy utilization, microbial nitrogen fixation, and ecological optimization to innovatively propose a rice cultivation method without the application of nitrogen fertilizer. Summary of the Invention

[0006] To this end, the present invention provides a rice cultivation method without nitrogen fertilizer application, aiming to solve the problems of increased costs, environmental pollution and low nitrogen utilization efficiency caused by excessive application of nitrogen fertilizer in rice cultivation. It uses solar energy and nitrogen-fixing microorganisms to achieve nitrogen fertilizer-free cultivation, reduce dependence on chemical nitrogen fertilizers, reduce pollution, improve the economic benefits of cultivation, and ensure rice growth and yield.

[0007] In order to achieve the above object, the present invention provides the following technical solution: a rice cultivation method without nitrogen fertilizer application, comprising:

[0008] Step 1: Laying detachable aeration perforated pipes in the rice field. The aeration perforated pipes are made of PVC or PE hoses with a diameter of 10-32 mm. The main pipe diameter is 40-80 mm. The aeration perforated pipes are arranged in parallel with an interval of 1-3 meters. The perforated pipes have a diameter of 2.0-5.0 mm and a hole spacing of 5-20 cm. Solar energy is converted into electricity through solar panels and stored in batteries. The electricity is used to start the DC aerator.

[0009] Step 2: intermittently aerating the paddy water through the aerator for 2-6 minutes and resting for 20-40 minutes to provide nitrogen required for the growth and reproduction of nitrogen-fixing bacteria, while also stirring and mixing the nitrogen-fixing microorganisms. The dissolved oxygen concentration in the water is maintained within 0.5 mg / L, which does not affect the normal growth and reproduction of nitrogen-fixing bacteria.

[0010] Step 3: 6-10 days before rice planting, a nitrogen-fixing bacterial community of Clostridium pasteurianum is enriched and cultured in paddy water with a suspended solids concentration of 4000-8000 mg / L and a volatile suspended solids (VSS) concentration of 3000-5600 mg / L. The nitrogen-fixing mixed bacterial community fixes nitrogen in the air, completing the biological nitrogen fixation process from nitrogen to ammonia and organic nitrogen.

[0011] Step 4: Planting rice, controlling the water depth in the paddy field to 5-15 cm, and controlling the nitrogen supply by adjusting the concentration of the nitrogen-fixing mixed bacterial community according to the nitrogen fertilizer requirements of the rice in different growth cycles, namely the seedling stage, the tillering stage, and the heading stage. No external nitrogen fertilizer is added during the entire rice planting process.

[0012] Step 5: After the rice is harvested, the aeration perforated pipes in the rice field are put away and wait for the next round of planting.

[0013] As a preferred solution for the rice cultivation method without nitrogen fertilizer application, the solar panels are mounted on the periphery of the rice field or on the ridge of the field using a bracket type. The solar modules used are monocrystalline silicon or polycrystalline silicon panels. The power of one set of solar modules is 200-600W. The supporting batteries are lead-acid maintenance-free batteries or lithium batteries with a capacity of 100-300Ah. The DC variable frequency aerator uses an air volume of 200-500L / min and a power of 100-1200W. It takes 5-15m to stir and nitrogenize 1 mu (666.67 square meters) of rice field with a water depth of 15cm. 3 / h ventilation rate, equipped with 2 sets of solar panels of the above specifications, 1 DC aerator and a battery, to control the dissolved oxygen concentration in the surface water of the rice paddy to not exceed 0.5 mg / L.

[0014] As a preferred solution for the rice cultivation method without nitrogen fertilizer application, the solar panel bracket adopts an adjustable angle aluminum alloy bracket. The angle is adjusted by rotating the adjustment rod or the electric push rod. The adjustment range is 15°-45°. The solar altitude angle is adaptively adjusted according to the preset season at the designated location to maximize the amount of sunlight received by the solar panel.

[0015] The bracket adjustment angle of the solar panel is measured by an angle measuring instrument.

[0016] As a preferred solution for the rice cultivation method without nitrogen fertilizer application, the aerator adopts a linear parallel ventilation device and is driven by a 12V-48V low-voltage DC power supply;

[0017] As a preferred solution for the rice cultivation method without nitrogen fertilizer application, the aeration perforated pipes are punched in a staggered manner to allow bubbles to diffuse evenly in the paddy water.

[0018] The drill diameter of the punching equipment is selected to be 2.0-5.0 mm according to the hole diameter requirement of the aeration perforated pipe. During the punching process, the horizontal projection offset distance of two adjacent rows of holes is 1 / 2-2 / 3 of the hole pitch.

[0019] As a preferred method for cultivating rice without nitrogen fertilizer application, the nitrogen-fixing mixed bacterial community directly utilizes microorganisms naturally present in paddy soil and is enriched and cultured in an anaerobic or low dissolved oxygen environment through intermittent aeration in step 2;

[0020] During the enrichment culture process, organic matter rich in carbon sources is added to the water in the paddy field. The organic matter rich in carbon sources includes composted straw powder, and the added amount is 0.5-1.5 kg per cubic meter of water.

[0021] As a preferred method for cultivating rice without nitrogen fertilizer application, since the nitrogen content required by rice in different growth stages is different, the water depth management also needs to be adjusted according to the growth stage. Therefore, the water depth of the rice field is dynamically adjusted according to the rice growth cycle:

[0022] The water depth is 5-10cm during the seedling stage, and 10-15cm from the tillering stage to the heading stage. The nitrogen supply intensity is regulated by increasing or decreasing the amount of nitrogen-fixing bacteria culture.

[0023] As a preferred solution for the rice cultivation method without nitrogen fertilizer application, the field section of the aeration perforated pipe is connected to the main pipe via a quick-release joint; the quick-release joint adopts a clamp-type structure, consisting of two semicircular clamps, a bolt, and a sealing rubber ring. When connecting the aeration pipe, the sealing rubber ring is put on the connection of the aeration perforated pipe, the pipe is clamped with the two semicircular clamps, and the clamp is tightened by tightening the bolt to achieve a sealed connection of the pipe.

[0024] As a preferred method for cultivating rice without nitrogen fertilizer application, after the rice is harvested, the rice root residues remaining in the rice field are used as a carbon source for the growth and reproduction of the nitrogen-fixing mixed bacterial community. The nitrogen source released after the nitrogen-fixing mixed bacterial community dies out is absorbed and utilized by the rice of the next season, forming a rice-bacteria synergistic growth cycle.

[0025] After the rice is harvested, a straw return machine is used to crush the rice straw to a length of no more than 5 cm and evenly spread it on the surface of the rice field. Then shallow plowing is carried out with a plowing depth of 10-15 cm to fully mix the straw with the soil.

[0026] The beneficial effects of the present invention are as follows:

[0027] First, there is no need to purchase and apply nitrogen fertilizer, which reduces fertilizer procurement costs; there is no need to carry out fertilization operations, which reduces the labor cost of fertilization, and nitrogen-fixing bacteria are directly enriched in rice fields, which reduces the investment in the inoculation process and improves the economic benefits of farmers.

[0028] Second, using solar energy to drive the aerator can achieve energy-free operation and reduce dependence on traditional energy. As a clean energy, solar energy reduces carbon emissions and is in line with the concept of sustainable development.

[0029] Third, avoid eutrophication of water bodies caused by excessive application of nitrogen fertilizers, and reduce nitrogen pollution to soil, water bodies and air; create an environment for the growth of nitrogen-fixing bacteria, promote the activity and number of nitrogen-fixing bacteria, improve the rhizosphere microenvironment of rice, and enhance nutrient absorption efficiency.

[0030] Fourth, the solar panel installation and system operation parameters can be flexibly adjusted according to the actual conditions of sunlight and rice fields in different regions; it can be combined with intelligent systems to achieve intelligent management.

[0031] Fifth, it creates a new rice cultivation model that combines solar energy utilization, microbial nitrogen fixation and ecological optimization, providing new ideas for agricultural technology innovation and has good demonstration and promotion value. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for the embodiments or the description of the prior art. Obviously, the drawings described below are merely exemplary, and those skilled in the art can, without inventive effort, derive other implementation drawings based on the provided drawings.

[0033] Figure 1 Schematic diagram of an application scenario of the rice cultivation method without nitrogen fertilizer application provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0034] The following describes the implementation of the present invention using specific embodiments. Those skilled in the art will readily understand the other advantages and benefits of the present invention from the disclosure herein. Obviously, the embodiments described are only a portion of the present invention, not all of it. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without inventive effort are intended to fall within the scope of protection of the present invention.

[0035] See also Figure 1 The present invention provides a method for cultivating rice without nitrogen fertilizer application (in a certain place in Changde, Hunan), comprising the following steps:

[0036] S1: Detachable aeration perforated pipes are laid in a one-acre rice field. Solar energy is converted into electricity through solar panels and stored in batteries. The electricity is used to start a DC aerator to provide nitrogen to the rice field through the aeration perforated pipes.

[0037] Specifically, the aeration perforated pipes are 25mm diameter PVC pipes, with the main pipe diameter being 50mm. PVC is highly corrosion-resistant, making it easy to install and later dismantle in rice paddies. The 50mm diameter of the main pipe allows for centralized air supply and reduces pressure loss. The perforated pipes are arranged in parallel, spaced 1.5 meters apart, with 4.0mm perforations perforated in the pipe walls at a spacing of 15cm. This ensures uniform diffusion of air bubbles into the paddy water, ensuring agitation and nitrogen delivery. The DC aerators are powered by solar panels and batteries, achieving energy self-sufficiency and avoiding the costs and environmental issues associated with using traditional electricity.

[0038] S2: The paddy water is intermittently aerated by the aerator, with aeration for 3 minutes and rest for 30 minutes.

[0039] Specifically, intermittent aeration provides conditions for nitrogen fixation by nitrogen-fixing bacteria. It can also stir and mix the nitrogen-fixing microorganisms so that they are more evenly distributed in the paddy water, increase their contact opportunities with rice roots and nutrients, and promote nitrogen fixation. At the same time, it keeps the dissolved oxygen at no more than 0.5 mg / L to avoid excessive dissolved oxygen inhibiting the growth of nitrogen-fixing bacteria.

[0040] S3: 8 days before rice planting, enrich and culture a nitrogen-fixing mixed bacterial community. The suspended solids concentration in the paddy water is 4000-8000 mg / L, and the volatile suspended solids (VSS) concentration is 3000-5600 mg / L.

[0041] Specifically, the goal of pre-enriching and cultivating a nitrogen-fixing mixed bacterial community (with Clostridium pasteurianum accounting for ≥5%) is to achieve a certain bacterial population size to ensure continuous and stable nitrogen fixation during rice growth. Achieving a corresponding effective bacterial concentration in the rhizosphere soil and water ensures efficient nitrogen fixation. This nitrogen-fixing mixed bacterial community fixes nitrogen from the air, ultimately completing the biological nitrogen fixation process from nitrogen to ammonia and organic nitrogen.

[0042] S4: Planting rice, controlling the water depth in the paddy field to 5-15 cm, and controlling the nitrogen supply by adjusting the concentration of the nitrogen-fixing mixed bacterial community according to the nitrogen fertilizer demand in different growth cycles of rice, namely, the seedling stage, the tillering stage, and the heading stage. No nitrogen fertilizer is added during the entire rice planting process.

[0043] Specifically, a water depth of 5-15cm provides an ideal moisture environment for rice growth. Rice's nitrogen fertilizer requirements vary throughout its growth cycle, with relatively low nitrogen requirements during the seedling stage and increased requirements during the tillering and heading stages. By adjusting the concentration of the nitrogen-fixing bacterial mix, nitrogen production and supply can be controlled to meet the needs of rice at different growth stages, eliminating the need for external nitrogen fertilizer throughout the entire growth cycle.

[0044] S5: After the rice is harvested, the aeration perforated pipes in the rice field are put away and the next round of planting is awaited.

[0045] Specifically, folding up the aeration perforated pipes can, on the one hand, prevent the perforated pipes from being damaged by long-term placement in the field, affecting their service life and performance; on the other hand, it can prevent the perforated pipes from affecting the field operations of the next round of planting, such as plowing and sowing, thereby facilitating the subsequent management and utilization of the rice fields.

[0046] In this embodiment, solar panels are installed around the rice paddies or above the ridges, ensuring that the rice plants receive sufficient sunlight while not affecting their sunlight and growth. Two sets of 500W monocrystalline silicon panels are used, along with a 150Ah maintenance-free lead-acid battery. A 900W DC variable-frequency aerator is installed, providing a 250L / min air flow rate. The DC aerator's air flow is controlled to maintain the dissolved oxygen concentration in the rice surface water at no more than 0.5mg / L.

[0047] In this embodiment, the bracket of the solar panel adopts an adjustable angle aluminum alloy bracket with light weight, high strength and corrosion resistance. The angle is adjusted by rotating the adjustment rod or the electric push rod. The adjustment range is 15°-45°. The bracket is adaptively adjusted according to the solar altitude angle of the preset season at the designated location to maximize the solar panel's reception of sunlight and improve the utilization efficiency of solar energy. The adjustment angle of the solar panel bracket is measured by an angle measuring instrument to ensure the accuracy of the adjustment.

[0048] In this embodiment, the aerator uses a linear parallel ventilation device to make aeration more uniform and ensure that all areas of the rice field water body are fully aerated; it is driven by a 24V low-voltage DC power supply, which matches the output voltage of the solar panel and the battery to achieve low-voltage power supply for the system; the aerator is equipped with a flow adjustment knob to adjust the aeration flow, and the adjustment range is 70% of the rated flow; the aerator is equipped with a frequency conversion controller to adjust the motor speed of the aerator according to the changes in the dissolved oxygen concentration and nitrogen concentration of the rice field water body to adjust the aeration flow, thereby providing sufficient nitrogen while avoiding the adverse effects of excessive dissolved oxygen on nitrogen-fixing bacteria.

[0049] In this embodiment, the aeration perforated tubes are punched in a staggered manner to allow bubbles to diffuse evenly in the paddy water, thereby improving the aeration effect. The drill bit diameter of the punching equipment is selected to be 4.0 mm according to the hole diameter requirement of the aeration perforated tubes. During the punching process, the horizontal projection offset distance between two adjacent rows of holes is 2 / 3 of the hole spacing, which can make the bubble distribution more reasonable and ensure that all parts of the paddy water are fully exposed to nitrogen.

[0050] In this embodiment, the nitrogen-fixing mixed bacterial community directly utilizes naturally existing microorganisms in the paddy soil, reducing the cost and operation of additional inoculation of nitrogen-fixing bacteria; intermittent aeration enrichment culture is carried out in step S2; during the enrichment culture process (10 days), organic matter rich in carbon source is added to the paddy water body, and the organic matter rich in carbon source includes composted straw powder, and the addition amount is 0.75 kg per cubic meter of water body, which provides the energy and nutrients required for the growth of nitrogen-fixing microorganisms, can meet the growth needs of microorganisms, and will not deteriorate the water environment due to excessive addition.

[0051] In this embodiment, the water depth of the paddy field is dynamically adjusted according to the rice growth cycle: a shallow water depth of 5 cm during the seedling stage is conducive to rice root growth and light absorption; a deeper water depth of 10 cm from the tillering stage to the heading stage can meet the rice's water demand and provide a more stable environment for rice growth. The nitrogen supply intensity is regulated by increasing or decreasing the amount of nitrogen-fixing bacteria cultured. The number of nitrogen-fixing bacteria is increased during periods when rice requires a lot of nitrogen, thereby increasing the amount of nitrogen fixed.

[0052] In this embodiment, the field section of the aeration perforated pipe is connected to the main pipe via a quick-release joint, which facilitates quick connection and removal of the pipe before and after rice planting. The quick-release joint adopts a clamp structure, consisting of two semicircular clamps, a bolt, and a sealing rubber ring. When connecting the aeration pipe, the sealing rubber ring is put on the connection of the aeration perforated pipe, and the pipe is clamped with the two semicircular clamps. The clamp is tightened by tightening the bolt, and the sealing rubber ring performs a sealing function to prevent gas leakage. Tightening the bolt to tighten the clamp can firmly connect the pipe, ensuring the stability and sealing of the aeration system.

[0053] In this embodiment, after the rice is harvested, a straw return machine is used to crush the rice straw to a length of no more than 5 cm and evenly spread it on the surface of the rice field. The plowing depth is 15 cm, which can not only bury the straw in the soil and fully mix the straw with the soil, but also will not destroy the deep structure of the soil. The residual rice root residues in the rice field are used as a carbon source for the growth and reproduction of the nitrogen-fixing mixed bacteria community, maintaining the activity and quantity of the bacteria community; the nitrogen source released after the nitrogen-fixing mixed bacteria community dies is absorbed and utilized by the rice in the next season, reducing the dependence on external nitrogen fertilizer, reducing production costs, and improving the material cycle efficiency of the ecosystem. At the same time, the oxygen in the soil will be consumed during the decomposition of the straw, creating a relatively anaerobic environment, which is conducive to the growth of some nitrogen-fixing microorganisms and the conduct of nitrogen fixation, forming a rice-bacteria synergistic growth cycle.

[0054] The following are practical cases using the method of the present invention:

[0055] Practical Case 1

[0056] In a double-season rice field (early rice) in Changde, Hunan, a 25mm diameter PVC aeration perforated pipe with a main pipe diameter of 50mm was laid in one acre of rice field. The aeration pipes were arranged in parallel with a spacing of 1.5 meters. The hole diameter was 4.0mm and the hole spacing was 15cm. Two sets of solar energy monocrystalline silicon panels were used with a power of 500W. The supporting battery was a lead-acid maintenance-free battery with a capacity of 150Ah. A DC variable frequency aerator was used with an air volume of 250L / min and a power of 900W. The aeration method was aeration for 3 minutes and stop for 30 minutes. The air volume of the DC aerator was controlled to actually control the dissolved oxygen concentration in the water to not exceed 0.5mg / L. The water depth was 5cm in the early stages of rice planting, and 15cm in the middle and late stages. 0.75kg of composted straw powder was added per cubic meter of water to maintain SS concentrations at 6000±500mg / L and VSS concentrations at 3000±280mg / L in the paddy water. A total of 6kg of superphosphate, 7kg of potassium chloride, and 1kg of zinc sulfate were applied as basal fertilizer, and 5kg of potassium chloride was applied as topdressing. The entire planting cycle lasted 102 days, and no nitrogen fertilizer was applied. The rice grew using nitrogen fixed by nitrogen-fixing bacteria, eliminating the need for additional nitrogen fertilizer and reducing rice cultivation costs. Furthermore, solar panels were used to provide electricity, enabling the entire nitrogen-free rice cultivation system to operate energy-free. The final yield was 582kg / mu.

[0057] Practical Case 2

[0058] In a certain place in Beijing, a single-season rice field with a diameter of 20mm and a PVC aeration perforated pipe with a main pipe diameter of 32mm was laid in a one-acre rice field. The aeration pipes were arranged in parallel with a spacing of 1.8 meters. The hole diameter was 3.0mm and the hole spacing was 10cm. Two sets of solar energy monocrystalline silicon panels were used with a power of 400W. The supporting battery was a lithium iron phosphate with a capacity of 120Ah. A DC variable frequency aerator was used with an air volume of 200L / min and a power of 800W. The aeration method was aeration for 2 minutes and rest for 25 minutes. The air volume of the DC aerator was controlled to actually control the dissolved oxygen concentration in the water to not exceed 0.5mg / L. The water depth was 5cm in the early stage of rice planting and 12cm in the middle and late stages. 0.65kg / cubic meter of water was added with composted straw powder to maintain the SS concentration in the paddy water at 5000±400mg / L and the VSS concentration at 2500±300mg / L. A total of 7kg of superphosphate, 6.5kg of potassium chloride, and 1.5kg of zinc sulfate were applied as base fertilizers, and 5kg of potassium chloride was applied as topdressing fertilizer. No nitrogen fertilizer was applied during the entire process. Rice growth utilized nitrogen fixed by nitrogen-fixing bacteria as nitrogen fertilizer and did not require additional nitrogen fertilizer. The entire planting cycle was 162 days (transplanting in mid-to-late May and harvesting in early October). The final yield was 623kg / mu, which was basically the same as the rice yield of the adjacent plots with normal nitrogen fertilizer application.

[0059] Comparative Case 1

[0060] This comparative case study provides a rice planting method using nitrogen fertilizer: In a double-season rice field (early rice) in Changde, Hunan, a total of 7 kg of urea, 6 kg of superphosphate, 5 kg of potassium chloride, and 1 kg of zinc sulfate were applied as base fertilizers. 4 kg of urea and 3 kg of potassium chloride were applied as topdressing fertilizers during the heading stage. The water depth was 5 cm in the early stage of rice planting and 15 cm in the middle and late stages. The entire planting cycle lasted 102 days (mid-to-late April to late July). A total of 11 kg of urea nitrogen fertilizer was applied, and the final yield was 593 kg / mu.

[0061] Although the present invention has been described in detail above using general descriptions and specific embodiments, it will be apparent to those skilled in the art that modifications and improvements may be made thereto. Therefore, such modifications and improvements, without departing from the spirit of the present invention, are intended to be within the scope of protection claimed herein.

Claims

1. A rice cultivation method without nitrogen fertilizer application, characterized in that: include: Step 1: Laying detachable aeration perforated pipes in the rice field. The aeration perforated pipes are made of PVC or PE hoses with a diameter of 10-32 mm. The main pipe diameter is 40-80 mm. The aeration perforated pipes are arranged in parallel with an interval of 1-3 meters. The perforated pipes have a diameter of 2.0-5.0 mm and a hole spacing of 5-20 cm. Solar energy is converted into electricity through solar panels and stored in batteries. The electricity is used to start the DC aerator. Step 2: intermittently aerating the paddy water through the DC aerator for 2-6 minutes and 20-40 minutes, so as to provide nitrogen required for the growth and reproduction of nitrogen-fixing bacteria and at the same time play a role in stirring and mixing the nitrogen-fixing microorganisms. The dissolved oxygen concentration of the water is maintained within 0.5 mg / L, which does not affect the normal growth and reproduction of nitrogen-fixing bacteria; Step 3: 6-10 days before rice planting, enriching and culturing a nitrogen-fixing bacterial community of Clostridium pasteurianum to maintain a suspended solids concentration of 4,000-8,000 mg / L and a volatile suspended solids concentration of 3,000-5,600 mg / L in the paddy water. The nitrogen-fixing mixed bacterial community then fixes nitrogen in the air, completing the biological nitrogen fixation process from nitrogen gas to ammonia and organic nitrogen. Step 4: Planting rice, controlling the water depth in the paddy field to 5-15 cm, and controlling the nitrogen supply by adjusting the concentration of the nitrogen-fixing mixed bacterial community according to the nitrogen fertilizer requirements of the rice in different growth cycles, namely the seedling stage, the tillering stage, and the heading stage. No external nitrogen fertilizer is added during the entire rice planting process. Step 5: After the rice is harvested, the aeration perforated pipes in the rice field are put away and wait for the next round of planting.

2. The rice cultivation method without nitrogen fertilizer application according to claim 1, characterized in that: The solar panels are mounted on the periphery of the rice fields or on the ridges using a bracket type. The solar modules used are monocrystalline silicon or polycrystalline silicon panels. The power of one set of solar modules is 200-600W. The supporting batteries are lead-acid maintenance-free batteries or lithium batteries with a capacity of 100-300Ah. The DC variable frequency aerator uses an air volume of 200-500L / min and a power of 200-1200W. It takes 5-15m to stir and nitrogenize one mu of rice fields with a water depth of 15cm. 3 / h ventilation volume, equipped with 2 sets of solar panels of specified specifications, 1 DC aerator and a battery, to control the dissolved oxygen concentration in the surface water of rice to below 0.5mg / L.

3. The rice cultivation method without nitrogen fertilizer application according to claim 2, characterized in that: The solar panel bracket adopts an adjustable angle aluminum alloy bracket, which can be adjusted by rotating the adjustment rod or electric push rod. The adjustment range is 15°-45°. It is adaptively adjusted according to the solar altitude angle of the preset season at the designated location to maximize the sunlight received by the solar panel. The bracket adjustment angle of the solar panel is measured by an angle measuring instrument.

4. The rice cultivation method without nitrogen fertilizer application according to claim 1, characterized in that: The aeration perforated pipes are punched in a staggered manner to allow bubbles to diffuse evenly in the paddy water. The drill diameter of the punching equipment is selected to be 2.0-5.0 mm according to the hole diameter requirement of the aeration perforated pipe. During the punching process, the horizontal projection offset distance of two adjacent rows of holes is 1 / 2-2 / 3 of the hole pitch.

5. The rice cultivation method without nitrogen fertilizer application according to claim 1, characterized in that: The nitrogen-fixing mixed bacterial community directly utilizes naturally existing microorganisms in paddy soil and is enriched and cultured through intermittent aeration in step 2; During the enrichment culture process, organic matter rich in carbon sources is added to the water in the paddy field. The organic matter rich in carbon sources includes composted straw powder, and the added amount is 0.5-1.5 kg per cubic meter of water.

6. The rice cultivation method without nitrogen fertilizer application according to claim 1, characterized in that: The field section of the aeration perforated pipe is connected to the main pipeline through a quick-release joint; the quick-release joint adopts a clamp structure, consisting of two semicircular clamps, bolts and a sealing rubber ring. When connecting the aeration pipe, the sealing rubber ring is put on the connection of the aeration perforated pipe, and the pipe is clamped with two semicircular clamps. The clamp is tightened by tightening the bolts to achieve a sealed connection of the pipe.

7. The rice cultivation method without nitrogen fertilizer application according to claim 1, characterized in that: After the rice is harvested, the rice root residues remaining in the rice field are used as a carbon source for the growth and reproduction of the nitrogen-fixing mixed bacteria. The nitrogen source released after the nitrogen-fixing mixed bacteria die off is absorbed and utilized by the next season's rice, forming a rice-bacteria synergistic growth cycle. After the rice is harvested, a straw return machine is used to crush the rice straw to a length of no more than 5 cm and evenly spread it on the surface of the rice field. Then shallow plowing is carried out with a plowing depth of 10-15 cm to fully mix the straw with the soil.

Images