A biological method for activating organic phosphorus in a submerged paddy soil

Abstract

This invention provides a biological method for activating organic phosphorus in gleyed paddy soil, belonging to the field of soil improvement technology. The biological method involves introducing green algae into the paddy field after the rice seedlings have turned green, artificially cultivating a periclump biological community. This community utilizes the photosynthetic oxygen release from the periclump to increase the soil's redox potential and soil microbial activity, accelerating organic matter mineralization. Simultaneously, the method introduces phosphate-solubilizing bacteria into the paddy field after the rice enters the tillering stage, increasing the abundance and activity of phosphate-solubilizing bacteria in the soil. These bacteria then produce phosphatases, further accelerating organic phosphorus mineralization. The biological method provided by this invention effectively increases the abundance and activity of phosphate-solubilizing bacteria in gleyed paddy soil, thereby increasing the available phosphorus content in the soil.

Description

Technical Field

[0001] This invention belongs to the field of soil improvement technology, and in particular relates to a biological method for activating latent organic phosphorus in paddy field soil. Background Technology

[0002] Gleyed paddy fields are low- to medium-yield paddy fields formed due to excessively high groundwater levels and long-term immersion of the soil in groundwater. Although gleyed paddy soils are rich in organic matter and total nutrients, their low soil mineralization, high organic phosphorus content, and low available phosphorus content restrict rice yield. Accelerating the mineralization and activation of organic phosphorus in gleyed paddy soils is of great significance for increasing available phosphorus levels and improving the quality and efficiency of rice cultivation. Summary of the Invention

[0003] The purpose of this invention is to provide a biological method for activating latent organic phosphorus in paddy field soil. This biological method can accelerate the mineralization of soil organic phosphorus, thereby increasing the available phosphorus content in the soil.

[0004] This invention provides a biological method for activating latent organic phosphorus in paddy field soil, comprising the following steps:

[0005] After the rice seedlings turn green again, green algae are released into the paddy field;

[0006] Phosphate-solubilizing bacteria are introduced into the paddy field after the rice enters the tillering stage.

[0007] Preferably, the green algae includes filamentous algae and microalgae; the mass ratio of the filamentous algae to microalgae is (5-8):(10-15).

[0008] Preferably, the green algae is applied in the form of a green algae suspension; the green algae suspension uses BG11 culture medium as a solvent and includes components with the following concentrations: an effective algal cell concentration of not less than 1×10⁻⁶. 6 The green algae suspension contains 1–2 g / L of NaCl, 0.05–0.1 g / L of MgCl2, and 1.5–2.5 g / L of homogenizing agent; the pH of the green algae suspension is 4.5–5.5; the amount of green algae added, based on the effective number of algal cells, is not less than 1.5 × 10⁻⁶ cells / mL. 11 Cells / ha.

[0009] Preferably, the homogenizer includes agar powder, dextran, and sodium alginate; the mass ratio of agar powder, dextran, and sodium alginate is (10-15):(4-6):(1-1.5).

[0010] Preferably, after adding the green algae suspension, the water depth on the surface of the paddy field is maintained at 2-3 cm.

[0011] Preferably, the phosphate-solubilizing bacteria include a phosphate-solubilizing bacterial group; the phosphate-solubilizing bacterial group is obtained through artificial induction and screening; the screening method for the phosphate-solubilizing bacterial group includes the following steps:

[0012] Mix paddy soil and water to obtain a bacterial suspension stock solution;

[0013] The bacterial suspension stock solution and organophosphorus culture medium were mixed and cultured in the first stage to obtain the sample solution.

[0014] The organic phosphorus culture medium is an aqueous solution of lecithin; the mass concentration of lecithin in the aqueous solution of lecithin is 8-12 g / L.

[0015] The sample solution and the induction matrix were mixed and cultured in the second stage to obtain phosphate-solubilizing bacteria.

[0016] The induction substrate includes peanut shells and well-rotted chicken manure.

[0017] Preferably, the temperature of the first stage of cultivation is 25-30℃; and the cultivation time of the first stage is 2-3 days.

[0018] Preferably, the peanut shells are crushed peanut shells; the mass ratio of peanut shells to chicken manure is (1-1.5):1; the moisture content of the induction substrate is 40%-60%; the temperature of the second stage of cultivation is 25-30℃; the second stage of cultivation is carried out under aerobic conditions; and the cultivation time of the second stage is 7 days.

[0019] Preferably, the application rate of the phosphate-solubilizing bacteria is not less than 20 kg / ha.

[0020] This invention also provides the application of the biological method described above in any of the following:

[0021] 1) Increase the abundance and activity of phosphate-solubilizing bacteria in the soil of gleyed paddy fields;

[0022] 2) Accelerate the mineralization of organic phosphorus in gleed paddy field soils;

[0023] 3) Increase the available phosphorus content in the soil of gleyed paddy fields.

[0024] This invention provides a biological method for activating organic phosphorus in gleyed paddy soil, comprising the following steps: introducing green algae into the paddy field after the rice seedlings have turned green; and introducing phosphate-solubilizing bacteria into the paddy field after the rice enters the tillering stage. The biological method of this invention, by introducing green algae into the paddy field after the rice seedlings have turned green, artificially cultivates a periclinal biological community. The photosynthetic oxygen release of the periclinal organisms increases the soil redox potential and soil microbial activity, accelerating organic matter mineralization. Simultaneously, the biological method of this invention, by introducing phosphate-solubilizing bacteria into the paddy field after the rice enters the tillering stage, increases the abundance and activity of phosphate-solubilizing bacteria in the soil, and utilizes the phosphate-solubilizing bacteria to produce phosphatases, etc., to accelerate organic phosphorus mineralization. The biological method provided by this invention is beneficial for increasing the abundance and activity of phosphate-solubilizing bacteria in gleyed paddy soil, thereby achieving the effect of increasing the available phosphorus content in gleyed paddy soil. Detailed Implementation

[0025] This invention provides a biological method for activating latent organic phosphorus in paddy field soil, comprising the following steps: introducing green algae into the paddy field after the rice seedlings turn green again; introducing phosphorus-solubilizing bacteria into the paddy field after the rice enters the tillering stage.

[0026] In this invention, after the rice seedlings turn green again, green algae are introduced into the paddy field. The rapid growth of green algae accelerates the formation of the periclump biological community. The periclump biological community improves the soil reducing state by photosynthesizing and releasing oxygen, and secretes extracellular active substances to enhance the activity of soil microorganisms, improve the soil physicochemical state, and promote the proliferation of phosphate-solubilizing bacteria.

[0027] In this invention, the green algae preferably includes filamentous algae and Chlorella; in a specific implementation of this invention, the green algae is composed of filamentous algae (Ulothrix) and Chlorella; the mass ratio of filamentous algae to Chlorella is (5-8):(10-15), preferably 5:10 or 8:15; in a specific implementation of this invention, the green algae is applied in the form of a green algae suspension; the green algae suspension uses BG11 culture medium as a solvent, and preferably includes components with the following concentrations: an effective algal cell concentration of not less than 1×10⁻⁶. 6 The solution consists of green algae (cells / mL), 1–2 g / L NaCl, 0.05–0.1 g / L MgCl2, and 1.5–2.5 g / L homogenizer. In this specific embodiment, the green algae suspension uses BG11 culture medium as the solvent and comprises the following components at concentrations: an effective algal cell concentration of not less than 1 × 10⁻⁶ cells / mL. 6 The green algae suspension contains 1–2 g / L of NaCl, 0.05–0.1 g / L of MgCl2, and 1.5–2.5 g / L of homogenizing agent; the pH of the green algae suspension is 4.5–5.5.

[0028] In this invention, NaCl and MgCl2 are used to increase the salinity of the suspension to improve the survival rate of algal cells. In this invention, a homogenizing agent is used to maintain the homogeneity of the algal cells during storage.

[0029] In one embodiment of the present invention, the concentration of NaCl in the green algae suspension is 2.0 g / L, the concentration of MgCl2 is 0.1 g / L, and the concentration of the homogenizer is 2 g / L.

[0030] In this invention, the preparation method of the green algae suspension includes the following steps: *Fibrophyta* and *Chlorella* are cultured to the logarithmic growth phase to obtain *Fibrophyta* culture medium and *Chlorella* culture medium, respectively; the *Fibrophyta* culture medium and *Chlorella* culture medium are centrifuged to obtain *Fibrophyta* algal sludge and *Chlorella* algal sludge, respectively; the *Fibrophyta* algal sludge, *Chlorella* algal sludge, BG11 culture medium, homogenizer, NaCl, and MgCl2 are mixed, and the pH is adjusted to 4.5–5.5 to obtain the green algae suspension. In this invention, the culture medium used for the expansion culture is BG11 medium; the temperature for the expansion culture is 23–25°C; the photoperiod for the expansion culture is 12L:12D; and the light intensity for the expansion culture is 2000–3000 lux, preferably 2500 lux. In this invention, the reagent used to adjust the pH is preferably hydrochloric acid with a volume ratio of 1:1. This invention does not have specific limitations on the centrifugation conditions; conventional centrifugation conditions in the art are acceptable.

[0031] In this invention, the homogenizing agent preferably comprises agar powder, dextran, and sodium alginate. In a specific implementation of this invention, the homogenizing agent is composed of agar powder, dextran, and sodium alginate; the mass ratio of agar powder, dextran, and sodium alginate is (10-15):(4-6):(1-1.5), preferably 12:5:1. The homogenizing agent of this invention can maintain the uniformity of algal cells during the preservation of the green algae suspension.

[0032] In the specific implementation of this invention, the green algae is introduced 3-5 days after rice seedling transplanting, when the rice seedlings have turned green again and the soil and water in the paddy field have entered a relatively stable state. After the green algae is introduced, it can grow rapidly and form periclumps. The amount of green algae introduced, based on the number of effective algal cells, is not less than 1.5 × 10⁻⁶. 11 Cells / ha, more preferably (1.6–2) × 10⁻⁶. 11 Cells / ha, more preferably 1.8 × 10⁻⁶ 11 Cells / ha; the preferred application rate of the green algae suspension is 100-150 L / ha, more preferably 120 L / ha.

[0033] After adding the green algae suspension, the present invention maintains the water depth of the paddy field at 2-3 cm to meet the water requirements for the growth of green algae and surrounding organisms.

[0034] As rice absorbs phosphorus from the soil, it is prone to insufficient available phosphorus in the soil after entering the tillering stage. Based on the demand pattern of rice for phosphorus fertilizer, this invention introduces phosphorus-solubilizing bacteria into the paddy field after the rice enters the tillering stage, which increases the abundance of soil phosphorus-solubilizing bacteria and the secretion and activity of phosphatase, strengthens the network relationship between periphytes and soil phosphorus-solubilizing bacteria, accelerates the mineralization of organic phosphorus in gleed paddy field soil, and increases the available phosphorus content in the soil.

[0035] In the specific implementation of this invention, the phosphate-solubilizing bacteria include a phosphate-solubilizing bacterial community. In the specific implementation of this invention, the phosphate-solubilizing bacterial community is obtained through artificial induction and screening; further, the phosphate-solubilizing bacterial community is obtained by preparing a bacterial suspension stock solution, an organic phosphorus culture medium, and a phosphate-solubilizing bacterial induction substrate for screening and propagation; in this invention, the phosphate-solubilizing bacterial community is applied in the form of a bacterial community plus an induction substrate; the screening method for the phosphate-solubilizing bacterial community includes the following steps: mixing paddy soil and water to obtain a bacterial suspension stock solution; mixing the bacterial suspension stock solution and an organic phosphorus culture medium for a first-stage culture to obtain a sample solution; the organic phosphorus culture medium is an aqueous solution of lecithin; the mass concentration of lecithin in the aqueous solution of lecithin is 8-12 g / L; mixing the sample solution and an induction substrate for a second-stage culture to obtain the phosphate-solubilizing bacterial community; the induction substrate includes peanut shells and chicken manure.

[0036] The present invention first mixes paddy soil and water to obtain a bacterial suspension mother liquor.

[0037] In this invention, the water is preferably sterile water; the paddy soil is preferably gleyed paddy soil to improve the adaptability and phosphorus-solubilizing activity of phosphate-solubilizing bacteria to gleyed soil; the mass ratio of paddy soil to water is preferably 1:(8-10). After mixing, this invention further includes shaking the mixed material on a shaker for 30 minutes.

[0038] After obtaining the bacterial suspension stock solution, the present invention mixes the bacterial suspension stock solution with an organophosphorus culture medium and performs a first-stage culture to obtain a sample solution; the organophosphorus culture medium is an aqueous solution of lecithin rich in organophosphorus; the mass concentration of lecithin in the aqueous solution of lecithin is 8-12 g / L, preferably 10 g / L.

[0039] In this invention, the purpose of the first stage of cultivation is to screen microorganisms and increase the abundance of phosphate-solubilizing bacteria in the microbial community.

[0040] In a specific implementation of this invention, the preferred volume ratio of the bacterial suspension mother liquor to the organophosphorus culture medium is (0.8–1.2):10, more preferably 1:10; the temperature of the first stage of cultivation is 25–30°C, and the cultivation time is 2–3 days; the first stage of cultivation is conducted in a shaker. In one embodiment of this invention, the temperature of the first stage of cultivation is 30°C, and the cultivation time is 2 days.

[0041] After obtaining the sample solution, the present invention mixes the sample solution with the induction matrix and carries out a second stage of culture to obtain phosphate-solubilizing bacteria; the induction matrix includes peanut shells and well-rotted chicken manure; the well-rotted chicken manure contains rich nutrients and microorganisms.

[0042] In the specific implementation of this invention, mixing the sample solution and the induction matrix includes pouring the sample solution into the induction matrix; the peanut shells are crushed peanut shells; the dry weight ratio of the peanut shells to chicken manure is (1-1.5):1; the moisture content of the mixture of the sample solution and the induction matrix is ​​40%-60%, preferably 50%, which keeps the mixture moist and is conducive to the growth of phosphate-solubilizing bacteria. After mixing and before the second stage of cultivation, this invention preferably further includes wrapping the mixed material in tin foil and punching several small holes in the tin foil to increase air permeability. In this invention, the temperature of the second stage of cultivation is 25-30℃; the second stage of cultivation is carried out under aerobic conditions; the second stage of cultivation lasts for 7 days; the second stage of cultivation is a propagation cultivation.

[0043] In this invention, the purpose of the second stage of cultivation is to accelerate the proliferation of phosphate-solubilizing bacteria and increase their quantity.

[0044] In the specific implementation of this invention, the application rate of the phosphate-solubilizing bacteria is not less than 20 kg / ha, preferably 20 to 25 kg / ha.

[0045] In this invention, the gleying paddy field is preferably a moderately or severely gleying paddy field; the indicators for judging the degree of gleying include: soil active reducing substances, redox potential, and Fe. 2+ For details on content, please refer to [Ma Yijie, Lu Yanchun, Zhao Meizhi, Pan Shuzhen. Development trend and improvement and utilization of soil gleying and marshland in the plain lake area of ​​the middle reaches of the Yangtze River. Soil, 1997, 29(1):1-5].

[0046] The biological method of the present invention improves the activity of soil microorganisms and accelerates soil organic phosphorus mineralization by adding green algae suspension and phosphate-solubilizing bacteria to the soil of gleyed paddy fields, thereby increasing the available phosphorus content of the soil.

[0047] The preferred biological method of the present invention further includes the following steps: applying base fertilizer, rotary tillage, and irrigation in sequence before planting rice. In the specific implementation of the present invention, the application of base fertilizer includes the application of nitrogen fertilizer, phosphorus fertilizer, and potassium fertilizer, and the application amounts of nitrogen fertilizer, phosphorus fertilizer, and potassium fertilizer are applied according to the standard for base fertilizer application in rice planting areas; the depth of rotary tillage is 8-15 cm, preferably 10-12 cm; after irrigation, the water depth is set at 2-3 cm, and the time is 2-4 days; the surface depth of the field after irrigation is preferably 2 cm; and the irrigation time is preferably 3 days.

[0048] After irrigation, the present invention preferably transplants rice seedlings in the irrigated field and maintains the water depth at the field surface at 2-3 cm.

[0049] The present invention also provides the application of the biological method described above in any of the following: 1) increasing the abundance and activity of phosphate-solubilizing bacteria in gleyed paddy soil; 2) accelerating the mineralization of organic phosphorus in gleyed paddy soil; 3) increasing the available phosphorus content in gleyed paddy soil.

[0050] In this invention, unless otherwise specified, rice is managed with water and fertilizer according to local planting practices; during the rice growing season, the irrigation and drainage time and frequency are carried out according to the rice growth requirements.

[0051] To further illustrate the present invention, the following detailed description of a biological method for activating latent organic phosphorus in paddy field soil provided by the present invention is provided in conjunction with embodiments, but these should not be construed as limiting the scope of protection of the present invention.

[0052] In a specific embodiment of the present invention, the paddy field is located in Zengcheng District, Guangzhou City, Guangdong Province, and the experimental plots selected in each embodiment and comparative example are all from the same paddy field.

[0053] Unless otherwise specified, irrigation and drainage times and frequencies during the rice growing season shall be determined according to the rice growth needs and in accordance with local management practices.

[0054] Example 1

[0055] 1. Preparation of green algae suspension

[0056] The formulation of the green algae suspension is as follows: using BG11 medium as solvent, the concentrations are: 0.1 g / L of filamentous algae mud, 0.2 g / L of Chlorella algae mud, 2.0 g / L of NaCl, 0.1 g / L of MgCl2, and 2 g / L of homogenizer; wherein the mass ratio of filamentous algae to Chlorella is 5:10, and the homogenizer is composed of agar powder, dextran, and sodium alginate, wherein the mass ratio of agar powder, dextran, and sodium alginate is 12:5:1.

[0057] The steps for preparing green algae suspension are as follows:

[0058] (1) Using BG11 medium, filamentous algae and chlorella were cultured to the logarithmic growth phase at 25℃, photoperiod of 12L:12D and light intensity of 2500 lux, respectively, to obtain filamentous algae culture medium and chlorella culture medium.

[0059] (2) The filamentous algae culture medium and the chlorella culture medium were centrifuged to obtain filamentous algae mud and chlorella algae mud, respectively.

[0060] (3) The algal mud, homogenizer, NaCl and MgCl2 are mixed and the pH value is adjusted to 5.5 with hydrochloric acid at a volume ratio of 1:1 to obtain the green algae suspension.

[0061] 2. Preparation of phosphate-solubilizing bacteria

[0062] (1) Mix paddy soil (from moderately gleed paddy fields in Zengcheng District, Guangzhou) with sterile water at a mass ratio of 1:10 and shake on a shaker for 30 minutes to obtain a bacterial suspension mother liquor.

[0063] (2) The bacterial suspension mother liquor and the lecithin aqueous solution with a concentration of 10 g / L were mixed at a volume ratio of 1:10 and cultured at 30°C for 2 days to obtain the sample solution.

[0064] (3) Pour the sample solution into the induction matrix at a mass ratio of 1:1, keep the moisture content of the induction matrix at 50%, then wrap it with tin foil and place it in an aerobic environment at 30℃ for 7 days for propagation and culture. After the culture is completed, the phosphate-solubilizing bacteria are obtained and used for application to the paddy field. The induction matrix is ​​obtained by mixing crushed peanut shells and well-rotted chicken manure at a mass ratio of 1:1.

[0065] 3. An experiment was conducted in paddy fields in Zengcheng District, Guangzhou City to activate soil organic phosphorus.

[0066] (1) Select paddy fields and divide them into experimental plots of 5m×4m. Apply basal fertilizer at the following rates: 50kgN / ha of nitrogen fertilizer and 12kgP / ha of phosphorus fertilizer; apply topdressing twice later. Use a rotary tiller to till the rice planting area to a depth of 10cm, then irrigate and maintain a water depth of 3cm; transplant rice seedlings into the rice planting area 3 days after irrigation, and maintain a water depth of 2cm on the field surface.

[0067] (2) After the rice seedlings turn green again, spray a green algae suspension composed of filamentous algae and chlorella evenly into the water on the field surface, wherein the mass ratio of filamentous algae to chlorella is 5:10, and the spraying amount of green algae suspension is 100L / ha. During the rice growth period, the irrigation and drainage time and frequency are carried out according to the needs of rice growth. Specifically, drainage and field drying are carried out at the end of the rice tillering stage, irrigation is carried out 7 days later, and drainage is carried out at the end of the grain filling stage.

[0068] (3) After rice enters the tillering stage, phosphate-solubilizing bacteria are introduced at a rate of 20 kg / ha.

[0069] (4) On the 30th and 60th day after the green algae suspension was added, soil samples from the top 0-20cm layer were collected, and the available phosphorus content in the soil was determined with reference to the "Soil Agricultural Chemical Analysis Methods".

[0070] Comparative Example 1

[0071] The experiment was conducted in the same planting area according to the method of Example 1, with Comparative Example 1 being the one without the application of green algae suspension and phosphate-solubilizing bacteria, and the rest being the same as in Example 1.

[0072] The results of the soil available phosphorus content test in Example 1 and Comparative Example 1 (samples from 3 parallel experimental plots each) are shown in Table 1 below.

[0073] Table 1. Results of soil available phosphorus content tests in Example 1 and Comparative Example 1

[0074]

[0075]

[0076] As shown in Table 1, the results of the determination of organic phosphorus and available phosphorus content in paddy soil showed that after adding green algae suspension and phosphate-solubilizing bacteria for 60 days, the average organic phosphorus content in paddy soil in Example 1 was 186.8 mg / kg, while that in Comparative Example 1 was 213.5 mg / kg; the average available phosphorus content in paddy soil in Example 1 was 20.4 mg / kg, while that in Comparative Example 1 was 12.3 mg / kg.

[0077] Example 2

[0078] A biological method for activating organic phosphorus in paddy field soil comprises the following steps:

[0079] The methods for preparing green algae suspension and phosphate-solubilizing bacteria are as described in Example 1, wherein the mass ratio of filamentous algae to Chlorella in the green algae suspension is adjusted to 8:15.

[0080] The experiment was conducted in rice paddies in Zengcheng District, Guangzhou.

[0081] (1) Select paddy fields and divide them into experimental plots of 5m×4m. Apply basal fertilizer at the following rates: 50kgN / ha of nitrogen fertilizer and 12kgP / ha of phosphorus fertilizer; apply topdressing twice later. Use a rotary tiller to till the rice planting area to a depth of 10cm, then irrigate and maintain a water depth of 3cm; transplant rice seedlings into the rice planting area 3 days after irrigation, and maintain a water depth of 2cm on the field surface.

[0082] (2) After the rice seedlings turn green again, spray a green algae suspension composed of filamentous algae and chlorella evenly into the paddy water, with a mass ratio of filamentous algae to chlorella of 8:15 and a spraying volume of 120 L / ha. During the rice growth period, the irrigation and drainage time and frequency are carried out according to the needs of rice growth. Specifically, drainage and drying of the field are carried out at the end of the rice tillering stage, followed by irrigation 3 to 7 days later, and drainage is carried out at the end of the grain filling stage.

[0083] (3) After rice enters the tillering stage, phosphate-solubilizing bacteria are introduced at a rate of 25 kg / ha.

[0084] (4) On the 30th and 60th day after the green algae suspension was added, soil samples from the top 0-20cm layer were collected, and the available phosphorus content in the soil was determined with reference to the "Soil Agricultural Chemical Analysis Methods".

[0085] Comparative Example 2

[0086] The experiment was conducted in the same planting area according to the method of Example 2, with Comparative Example 2 being the one without the application of green algae suspension and phosphate-solubilizing bacteria, and the rest being the same as in Example 2.

[0087] The results of the soil available phosphorus content test in Example 2 and Comparative Example 2 (samples from 3 parallel experimental plots in each example) are shown in Table 2 below.

[0088] Results and Analysis:

[0089] Table 2. Results of soil organic phosphorus and available phosphorus content tests in Example 2 and Comparative Example 2.

[0090]

[0091]

[0092] As shown in Table 2, the results of the determination of organic phosphorus and available phosphorus content in paddy soil showed that after adding green algae suspension and phosphate-solubilizing bacteria for 60 days, the average organic phosphorus content in paddy soil in Example 2 was 179.9 mg / kg, while that in Comparative Example 2 was 208.5 mg / kg; the average available phosphorus content in paddy soil in Example 2 was 21.3 mg / kg, while that in Comparative Example 2 was 11.7 mg / kg.

[0093] From the above embodiments, it can be concluded that the method provided by the present invention can effectively promote the mineralization of organic phosphorus in gleed paddy field soil and increase available phosphorus.

[0094] Although the above embodiments have provided a detailed description of the present invention, they are only some embodiments of the present invention, and not all embodiments. People can obtain other embodiments based on these embodiments without creative effort, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A biological method for activating latent organic phosphorus in paddy field soil, characterized in that, It consists of the following steps: After the rice seedlings turn green again, green algae are released into the paddy field; Phosphate-solubilizing bacteria are introduced into the paddy field after the rice enters the tillering stage; The timing for releasing the green algae is 3-5 days after the rice seedlings are transplanted; The green algae include filamentous algae and microalgae; the mass ratio of the filamentous algae to microalgae is (5~8):(10~15); The green algae are applied in the form of a green algae suspension; the green algae suspension uses BG11 culture medium as a solvent and includes components with the following concentrations: an effective algal cell concentration of not less than 1×10⁻⁶. 6 The green algae suspension contains 1-2 g / L of NaCl, 0.05-0.1 g / L of MgCl2, and 1.5-2.5 g / L of homogenizing agent; the pH of the green algae suspension is 4.5-5.5; the amount of green algae added, based on the effective number of algal cells, is not less than 1.5 × 10⁻⁶ cells / mL. 11 Cells / ha; After adding the green algae suspension, maintain the water depth in the paddy field at 2-3 cm. The application rate of the phosphate-solubilizing bacteria shall not be less than 20 kg / ha; The phosphate-solubilizing bacteria include a phosphate-solubilizing bacterial group; the phosphate-solubilizing bacterial group is obtained through artificial induction and screening; the screening method for the phosphate-solubilizing bacterial group includes the following steps: Mix paddy soil and water to obtain a bacterial suspension stock solution; The bacterial suspension stock solution and organophosphorus culture medium were mixed and cultured in the first stage to obtain the sample solution. The organic phosphorus culture medium is an aqueous solution of lecithin; the mass concentration of lecithin in the aqueous solution of lecithin is 8~12g / L. The sample solution and the induction matrix were mixed and cultured in the second stage to obtain phosphate-solubilizing bacteria. The induction substrate includes peanut shells and well-rotted chicken manure; The temperature for the first stage of cultivation is 25~30℃; the cultivation time for the first stage is 2~3 days; The water content of the induction substrate is 40%~60%; the temperature of the second stage of cultivation is 25~30℃; the second stage of cultivation is carried out under aerobic conditions; and the cultivation time of the second stage is 7 days.

2. The biological method according to claim 1, characterized in that, The homogenizing agent includes agar powder, dextran, and sodium alginate; the mass ratio of agar powder, dextran, and sodium alginate is (10~15):(4~6):(1~1.5).

3. The biological method according to claim 1, characterized in that, The peanut shells are crushed peanut shells; the mass ratio of the peanut shells to chicken manure is (1~1.5):

1.

4. The application of the biological method according to any one of claims 1 to 3 in any of the following: 1) Increase the abundance and activity of phosphate-solubilizing bacteria in the soil of gleyed paddy fields; 2) Accelerate the mineralization of organic phosphorus in gleed paddy field soils; 3) Increase the available phosphorus content in the soil of gleyed paddy fields.

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