A method for improving acidification of paddy field soil and application thereof

Abstract

The application belongs to the technical field of soil improvement, and particularly relates to a method for improving acidification of paddy field soil and application thereof. By adding slow-release calcium peroxide in an organic-inorganic composite carrier, slow reaction of the slow-release calcium peroxide with water is facilitated, and then oxygen and OH ‑ are released, and the acidification of the paddy field is continuously improved; by appropriately adding the organic-inorganic composite carrier, the biomass and activity of the periphyton are improved, which is beneficial to eliminating the acid barrier of the gley soil paddy field and improving the effective fertility of the paddy field soil.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of soil improvement, and particularly relates to a method for improving acidification of paddy field soil and application thereof. BACKGROUND

[0002] Gleyed paddy field is formed due to long-term immersion of soil horizon by underground water because of high underground water level. It is commonly seen in hilly and valley regions of mountainous areas, low-lying areas of plains and lakes, etc. in southern China, and is a kind of medium and low-yield paddy field. Gleyed paddy field has the characteristics of cold, rot, acid, thin and potential fertility cannot be developed, etc. due to poor aeration which leads to anaerobic mineralization of organic matter and accumulation of reducing substances such as organic acid.

[0003] At present, the improvement measures for gleyed paddy field include water conservancy engineering improvement, such as ditching and drainage to eliminate damage of immersion; changing tillage methods, such as implementing water and dry rotation and plowing and drying to reduce reducing substances in soil; and increasing application of organic fertilizer to improve soil structure and increase soil temperature. However, although the above artificial measures have certain effect in alleviating acidification obstacles of gleyed paddy field, the artificial and economic cost is high, and it is difficult to meet the long-term demand for improvement of acidification of gleyed paddy field. Therefore, how to speed up the conversion of organic acid and eliminate acid obstacles of gleyed paddy field is a technical problem to be solved in the industry. SUMMARY

[0004] The present application aims to provide a method for improving acidification of paddy field soil and application thereof, which has the characteristics of improving acidification of gleyed paddy field and increasing effective fertility of soil by putting organic-inorganic composite carrier into paddy field.

[0005] The present application provides a method for improving acidification of paddy field soil, which comprises the following steps: putting organic-inorganic composite carrier into paddy field, keeping the depth of field water of paddy field at 2-3 cm; putting the organic-inorganic composite carrier into the paddy field again after 20-30 days of putting the organic-inorganic composite carrier; the organic-inorganic composite carrier comprises the following raw materials in mass fraction: crop straw 85-90 parts, slow-release calcium peroxide 20-25 parts and mixture composed of algal species and bacterial species 1-1.5 parts; the amount of the first time of putting the organic-inorganic composite carrier is 200-300 kg / ha; the amount of the second time of putting the organic-inorganic composite carrier is 10-30 kg / ha.

[0006] Preferably, the paddy field comprises gleyed paddy field.

[0007] Preferably, the slow-release calcium peroxide comprises the following components in mass fraction: calcium peroxide 90-100 parts, binder 4-5 parts and ethyl cellulose 6 parts; the purity of the calcium peroxide is 55%-65%.

[0008] Preferably, the particle size of the slow-release calcium peroxide is 2-3 mm.

[0009] Preferably, the timing of the first time of putting the organic-inorganic composite carrier is 3-5 days after the rice seedlings are transplanted.

[0010] Preferably, the mass ratio of the algal species to the bacterial species is (3-4) : 1;

[0011] Preferably, the algal species comprises Chlorella, Nostoc and filamentous algae.

[0012] The bacterial species comprises Bacillus and Pseudomonas.

[0013] Preferably, the mass ratio of Chlorella, Nostoc and filamentous algae is 1 : (1-1.5) : 1;

[0014] The mass ratio of the Bacillus and Pseudomonas is (1-1.5) : 1.

[0015] Preferably, the crop straw comprises rice straw and / or wheat straw.

[0016] The application also provides application of the above method for improving acidification of paddy field soil and / or increasing effective fertility of paddy field soil.

[0017] Beneficial effects:

[0018] The application provides a method for improving acidification of paddy field soil, comprising the following steps: putting an organic-inorganic composite carrier into a paddy field, keeping the water depth of the paddy field at 2-3 cm; after 20-30 days of putting the organic-inorganic composite carrier, putting the organic-inorganic composite carrier again into the paddy field; the organic-inorganic composite carrier comprises the following raw materials in mass fraction: 85-90 parts of crop straw, 20-25 parts of slow-release calcium peroxide and 1-1.5 parts of a mixture of algal species and bacterial species; the amount of the first time of putting the organic-inorganic composite carrier is 200-300 kg / ha; the amount of the second time of putting the organic-inorganic composite carrier is 10-30 kg / ha. By adding slow-release calcium peroxide into the organic-inorganic composite carrier, the slow-release calcium peroxide is beneficial to slow reaction with water, thereby releasing oxygen and OH - , continuously acidifying the paddy field, then putting the organic-inorganic composite carrier in an appropriate amount, increasing the biomass and activity of the periphyton, using the photosynthesis of the periphyton to release oxygen to accelerate the mineralization of small-molecule organic acids, putting the organic-inorganic composite carrier again is beneficial to the continuous growth of the periphyton, and provides a basis for improving acidification of gley soil paddy field.

[0019] Based on the technical advantages, the application further provides application of the method in improving acidification of paddy field soil and / or increasing effective fertility of paddy field soil. Experiments show that, compared with the paddy field soil to which only the slow-release calcium peroxide particles are added, the soil pH value in the paddy field is increased by 0.2 units on average, which is conducive to eliminating the acidification obstacle of the gley soil paddy field; the soil available content is significantly increased by 65.5% to 72.3%, and the effective fertility of the soil is significantly improved. DETAILED DESCRIPTION

[0020] The application provides a method for improving acidification of paddy field soil, comprising the following steps: adding an organic-inorganic composite carrier into the paddy field, keeping the depth of the field water of the paddy field at 2-3 cm; adding the organic-inorganic composite carrier into the paddy field again after 20-30 days of adding the organic-inorganic composite carrier; the organic-inorganic composite carrier comprises the following raw materials in mass fraction: 85-90 parts of crop straw, 20-25 parts of slow-release calcium peroxide and 1-1.5 parts of a mixture composed of algal species and bacterial species; the amount of the first addition of the organic-inorganic composite carrier is 200-300 kg / ha; the amount of the second addition of the organic-inorganic composite carrier is 10-30 kg / ha.

[0021] In the application, the rice is managed according to the local planting habits unless otherwise specified. The various raw materials, culture media and the like used in the application are conventionally purchased unless otherwise specified.

[0022] The organic-inorganic composite carrier in the application preferably comprises 88-90 parts of crop straw, more preferably 90 parts, in terms of mass fraction. The crop straw preferably comprises rice straw and / or wheat straw. The particle size of the crop straw in the application is preferably <80 mesh, more preferably ≤50 mesh.

[0023] The organic-inorganic composite carrier in the application preferably comprises 23-25 parts of slow-release calcium peroxide, more preferably 25 parts, in terms of mass fraction of the crop straw. The slow-release calcium peroxide in the application preferably comprises the following components in mass fraction: 90-100 parts of calcium peroxide, 4-5 parts of a binder and 6 parts of ethyl cellulose. The mass fraction of the calcium peroxide in the application is further preferably 95-100 parts, more preferably 100 parts; the binder is preferably a starch binder, and the mass fraction is further preferably 5 parts.

[0024] In the application, the ethyl cellulose preferably comprises an ethyl cellulose coating liquid, the solvent of the ethyl cellulose coating liquid is preferably anhydrous ethanol, and the concentration of the ethyl cellulose coating liquid is preferably 30wt.%-40wt.%, more preferably 40wt.%. The ethyl cellulose coating liquid is used to coat the slow-release calcium peroxide particles, which is more conducive to the slow-release calcium peroxide particles to continuously release oxygen and OH - .

[0025] The slow-release calcium peroxide according to the present application preferably comprises the slow-release calcium peroxide after coating. By adding the slow-release calcium peroxide after coating, the slow-release calcium peroxide is facilitated to slowly react with water, and then release oxygen and OH - , and the acidification of the paddy field is continuously improved.

[0026] The preparation method of the slow-release calcium peroxide according to the present application preferably comprises: mixing the calcium peroxide with a binder to perform granulation, to obtain slow-release calcium peroxide particles;

[0027] The slow-release calcium peroxide particles are coated with an ethyl cellulose coating solution to obtain the slow-release calcium peroxide after coating.

[0028] In the present application, the purity of the calcium peroxide is preferably 55% to 65%, and more preferably 60%. The particle size of the slow-release calcium peroxide particles according to the present application is preferably 2 to 3 mm. By controlling the particle size range of the slow-release calcium peroxide particles, the subsequent compression granulation is facilitated to reduce the damage to the effective components of the slow-release calcium peroxide. The calcium oxide, the binder and the ethyl cellulose according to the present application can be purchased conventionally, and the operation mode of the granulation and the coating does not have special requirements, and the techniques well known in the art can be adopted.

[0029] The organic-inorganic composite carrier according to the present application preferably comprises a mixture of algae and bacteria 1 part or 1.5 parts, based on the mass fraction of crop straw. The mass ratio of the algae to the bacteria in the mixture of algae and bacteria according to the present application is preferably (3 to 4) to 1, and more preferably 3 to 1 or 4 to 1. In the present application, the algae preferably comprises Chlorella vulgaris, Nostoc commune and filamentous algae, and more preferably comprises Chlorella vulgaris, Nostoc commune and filamentous algae which are first cultured and then dried, and the mass ratio of the dried Chlorella vulgaris, Nostoc commune and filamentous algae is preferably 1 to (1 to 1.5) to 1, and more preferably 1 to 1 to 1 or 1 to 1.5 to 1.

[0030] The preparation method of the algae according to the present application preferably comprises: inoculating Chlorella vulgaris, Nostoc commune and filamentous algae into WC liquid medium respectively to perform culture, to obtain Chlorella vulgaris culture solution, Nostoc commune culture solution and filamentous algae culture solution respectively;

[0031] The Chlorella vulgaris culture solution, the Nostoc commune culture solution and the filamentous algae culture solution are sequentially subjected to centrifugation and concentration respectively, to obtain Chlorella vulgaris concentrate, Nostoc commune concentrate and filamentous algae concentrate respectively;

[0032] The Chlorella vulgaris concentrate, the Nostoc commune concentrate and the filamentous algae concentrate are mixed with a protective agent respectively and freeze-dried, to obtain dried Chlorella vulgaris, dried Nostoc commune and dried filamentous algae respectively;

[0033] The dried Chlorella vulgaris, the dried Nostoc commune and the dried filamentous algae are mixed to obtain algae for preparing the organic-inorganic composite carrier.

[0034] In the present application, the inoculation amount of the Chlorella is preferably 2.8% to 3.5% of the volume of the WC liquid medium, and more preferably 3%. The culture conditions in the present application preferably include: temperature is preferably 23 to 26℃, and more preferably 25℃; time is preferably 7 to 10 days, and more preferably 9 days; light intensity is preferably 2000 to 3000 lux, and more preferably 2500 lux; and light time is preferably 10 to 14 hours per day, and more preferably 12 hours per day. The speed of centrifugation in the present application is preferably 6000 to 8000 r / min, and more preferably 7000 r / min, and the time is 8 to 12 minutes, and more preferably 10 minutes. The type of the protective agent is preferably trehalose, and the addition amount of the trehalose is preferably 0.9% to 1.2% of the mass of the Chlorella concentrate, and more preferably 1%. The present application does not have special requirements for the components of the WC liquid medium and the process of freeze-drying, and the techniques well known in the art can be used.

[0035] In the present application, the inoculation amount of the Chlorella is preferably 2.8% to 3.5% of the volume of the WC liquid medium, and more preferably 3%. The culture conditions in the present application preferably include: temperature is preferably 23 to 26℃, and more preferably 25℃; time is preferably 7 to 10 days, and more preferably 9 days; light intensity is preferably 2000 to 3000 lux, and more preferably 2500 lux; and light time is preferably 10 to 14 hours per day, and more preferably 12 hours per day. The speed of centrifugation in the present application is preferably 6000 to 8000 r / min, and more preferably 7000 r / min, and the time is 8 to 12 minutes, and more preferably 10 minutes. The type of the protective agent is preferably trehalose, and the addition amount of the trehalose is preferably 0.9% to 1.2% of the mass of the Chlorella concentrate, and more preferably 1%. The present application does not have special requirements for the components of the WC liquid medium and the process of freeze-drying, and the techniques well known in the art can be used.

[0036] In the present application, the inoculation amount of the filamentous algae is preferably 2.8%-3.5% of the volume of the WC liquid medium, and more preferably 3%. The culture conditions in the present application preferably include: the temperature is preferably 23-26℃, and more preferably 25℃; the time is preferably 7-10d, and more preferably 9d; the light intensity is preferably 2000-3000lux, and more preferably 2500lux; and the light time is preferably 10-14h / d, and more preferably 12h / d. The centrifugation speed in the present application is preferably 7000-9000r / min, and more preferably 8000r / min, and the time is 8-12min, and more preferably 10min; the type of the protective agent is preferably trehalose, and the addition amount of the trehalose is preferably 0.9%-1.2% of the mass of the filamentous algae concentrate, and more preferably 1%. The present application does not have special requirements for the components of the WC liquid medium and the freeze-drying process, and the techniques well known in the art can be used.

[0037] The bacterial strain in the present application preferably includes Bacillus and Pseudomonas, and further preferably Bacillus and Pseudomonas that are first cultured and then dried; the mass ratio of the dried Bacillus and Pseudomonas is preferably (1-1.5):1, and further preferably 1:1 or 1.5:1; the effective viable count of the dried Bacillus is preferably ≥10 7 CFU / g; and the effective viable count of the dried Pseudomonas is preferably ≥10 7 CFU / g.

[0038] In the present application, the preparation method of the bacterial strain preferably includes: inoculating Bacillus and Pseudomonas into LB liquid medium respectively for shaking culture to obtain Bacillus culture solution and Pseudomonas culture solution respectively;

[0039] The Bacillus culture solution and the Pseudomonas culture solution are respectively concentrated by centrifugation to obtain Bacillus concentrate and Pseudomonas concentrate respectively;

[0040] The Bacillus concentrate and the Pseudomonas concentrate are respectively mixed with glycerol and freeze-dried to obtain dried Bacillus and Pseudomonas respectively;

[0041] The dried Bacillus and Pseudomonas are mixed to obtain a bacterial strain for preparing the organic-inorganic composite carrier.

[0042] The inoculation amount of the bacillus in the application is preferably 0.04% to 0.06% of the volume of the LB liquid medium, and more preferably 0.05%. In the application, the conditions of the shaking culture preferably include: the rotation speed is preferably 160 to 200 r / min, and more preferably 180 r / min; the temperature is preferably 28 to 32℃, and more preferably 30℃; and the time is preferably 18 to 24 h, and more preferably 24 h. The speed of the centrifugation in the application is preferably 6500 to 8000 r / min, and more preferably 7500 r / min, and the time is 8 to 12 min, and more preferably 10 min; and the addition amount of the glycerol is preferably 0.8% to 1.2% of the mass of the bacillus concentrate, and more preferably 1%. The application does not have special requirements for the components of the LB liquid medium and the process of freeze-drying, and the techniques well known in the art can be used.

[0043] The inoculation amount of the bacillus in the application is preferably 0.04% to 0.06% of the volume of the LB liquid medium, and more preferably 0.05%. In the application, the conditions of the shaking culture preferably include: the rotation speed is preferably 160 to 200 r / min, and more preferably 180 r / min; the temperature is preferably 28 to 32℃, and more preferably 30℃; and the time is preferably 18 to 24 h, and more preferably 24 h. The speed of the centrifugation in the application is preferably 6500 to 8000 r / min, and more preferably 7500 r / min, and the time is 8 to 12 min, and more preferably 10 min; and the addition amount of the glycerol is preferably 0.8% to 1.2% of the mass of the bacillus concentrate, and more preferably 1%. The application does not have special requirements for the components of the LB liquid medium and the process of freeze-drying, and the techniques well known in the art can be used.

[0044] In the application, the organic-inorganic composite carrier preferably includes a granular organic-inorganic composite carrier, and the particle size of the organic-inorganic composite carrier is preferably ≤2 cm.

[0045] The preparation method of the organic-inorganic composite carrier in the application preferably includes: mixing the crop straw, the coated slow-release calcium peroxide, and a mixture composed of algal species and bacterial species to obtain a mixture; and sequentially performing extrusion granulation, drying, and cooling on the mixture to obtain the organic-inorganic composite carrier.

[0046] In the application, the crop straw is preferably crushed and finely ground, and screened to obtain crop straw powder. In the application, the mesh number of the crop straw during screening is preferably 45 to 60 mesh, and more preferably 50 mesh. By processing the crop straw, the subsequent preparation of the organic-inorganic composite carrier is more conducive. The application does not have special requirements for the crushing and grinding method, and the techniques well known in the art can be used.

[0047] After obtaining the crop straw powder, the crop straw powder, the slow-release coated calcium peroxide and the mixture of algal species and bacterial species are mixed to obtain a mixture according to the present application. The preparation method of the slow-release coated calcium peroxide and the mixture of algal species and bacterial species has been specifically limited and described in the above technical solutions, and will not be repeated. The mixing is preferably uniform mixing, and the mixing method is not particularly limited as long as uniform mixing is ensured.

[0048] After obtaining the mixture, the mixture is preferably sequentially subjected to extrusion granulation, drying and cooling to obtain the organic-inorganic composite carrier. The temperature of the drying is preferably ≤30°C. The extrusion granulation and cooling are not particularly required in the present application, and the techniques well known in the art can be used. The granulation is beneficial to better release of nutrients by the organic-inorganic composite carrier and increase of the biomass of the paddy field periphyton.

[0049] After obtaining the organic-inorganic composite carrier, the organic-inorganic composite carrier is applied to the paddy field. The paddy field is preferably a gleization paddy field, more preferably a paddy field in a mountainous hilly valley and / or a paddy field in a plain lake marsh low-lying area. The application of the organic-inorganic composite carrier is beneficial to the improvement of the gleization paddy soil.

[0050] In the present application, the first application amount of the organic-inorganic composite carrier is preferably 200-300 kg / ha, further preferably 250-290 kg / ha, and more preferably 280 kg / ha. The reasonable optimization of the first application amount of the organic-inorganic composite carrier in the present application is beneficial to the acceleration of the mineralization of small-molecule organic acids by the periphyton and the growth of the periphyton on the composite carrier.

[0051] The organic-inorganic composite carrier is preferably first applied 3-5 days after the rice seedling transplanting, and more preferably 4 days after the rice seedling transplanting. Since the rice seedling is small at this time, on the one hand, it does not form a shelter for the periphyton, and on the other hand, it can form a relatively vigorous periphyton before the end of the rice tillering period, so as to ensure that the function of the periphyton is fully exerted. The application method of the organic-inorganic composite carrier is not particularly required in the present application, and the techniques well known in the art can be used.

[0052] The organic-inorganic composite carrier is preferably re-discharged 20-30 days after the first time of discharging the organic-inorganic composite carrier 20-30 days, preferably 20-25 days, more preferably 20 days or 25 days; the re-discharge amount of the organic-inorganic composite carrier is preferably 10-30 kg / ha, more preferably 10 kg / ha or 20 kg / ha. By twice discharging the organic-inorganic composite carrier added with slow-release calcium peroxide, the biomass and activity of the periphyton are improved, and the slow reaction of the slow-release calcium peroxide and water is continuously utilized to continuously release oxygen and OH - The rice field is acidified and improved.

[0053] When the organic-inorganic composite carrier is first discharged and the organic-inorganic composite carrier is re-discharged, the water depth of the rice field is preferably 2-3 cm, more preferably 2 cm. By maintaining the water depth of the rice field, the flooding environment is maintained to facilitate the growth of periphyton, and the growth of periphyton is also avoided due to the excessive water depth.

[0054] Experiments show that, compared with the rice field soil only discharged with slow-release calcium peroxide particles, the soil pH value in the rice field is increased by an average of 0.2 units, which is beneficial to eliminate the acid barrier of the gleyed rice field; the soil available content is significantly increased by 65.5%-72.3%, and the effective fertility of the soil is significantly improved.

[0055] In order to further illustrate the present application, the method for improving the acidification of rice field soil and its application provided by the present application are described in detail below in conjunction with examples, but they should not be understood as limiting the scope of protection of the present application.

[0056] Unless otherwise specified, the irrigation and drainage time and frequency during the growth of rice are performed according to the growth requirements of rice and combined with the local management habits.

[0057] Example 1

[0058] A method for improving the acidification of rice field soil, comprising the following steps:

[0059] (1) Select a gleyed rice field and divide it into 5m x 5m experimental plots. Apply base fertilizer, the specific amount is: nitrogen fertilizer 150 kg N / ha, phosphorus fertilizer 60 kg P / ha. Use a rotary cultivator to rotary cultivate the rice planting area, the rotary cultivation depth is 10 cm, then irrigate, and keep the water depth at 3 cm;

[0060] (2) Transplant rice seedlings to the rice planting area, and keep the water depth at 2 cm;

[0061] (3) After the seedlings are greened for 4 days, the organic-inorganic compound carrier is put into the field water, and the dosage is 240 kg / ha;

[0062] The organic-inorganic compound carrier is composed of rice straw, a mixture composed of algae species and bacterial species, and slow-release calcium peroxide after coating.

[0063] The rice straw is dried, crushed, finely ground, and sieved through a 50-mesh sieve for standby use.

[0064] The chlorella is inoculated into the WC liquid medium in a volume ratio of 3% for greenhouse culture. The culture conditions are 25°C and 12h light per day. After 9 days of culture, a chlorella culture solution is obtained. The chlorella culture solution is centrifuged and concentrated, wherein the centrifugation conditions of the chlorella culture solution are 7000r / min for 10min. The sediment obtained after centrifugation is chlorella mud. 1% of trehalose is added as a protective agent according to the mass of the chlorella mud, and then freeze-drying is performed to obtain dried chlorella for standby use.

[0065] The nostoc is inoculated into the WC liquid medium in a volume ratio of 3% for greenhouse culture. The culture conditions are 25°C and 12h light per day. After 9 days of culture, a nostoc culture solution is obtained. The nostoc culture solution is centrifuged and concentrated, wherein the centrifugation conditions of the nostoc culture solution are 7000r / min for 10min. The sediment obtained after centrifugation is nostoc mud. 1% of trehalose is added as a protective agent according to the mass of the nostoc mud, and then freeze-drying is performed to obtain dried nostoc for standby use.

[0066] The filamentous algae is inoculated into the WC liquid medium in a volume ratio of 3% for greenhouse culture. The culture conditions are 25°C and 12h light per day. After 9 days of culture, a filamentous algae culture solution is obtained. The filamentous algae culture solution is centrifuged and concentrated, wherein the centrifugation conditions of the filamentous algae culture solution are 8000r / min for 10min. The sediment obtained after centrifugation is filamentous algae mud. 1% of trehalose is added as a protective agent according to the mass of the filamentous algae mud, and then freeze-drying is performed to obtain dried filamentous algae for standby use.

[0067] The dried chlorella, nostoc and filamentous algae are mixed in a mass ratio of 1:1:1 to obtain algae species for preparing the organic-inorganic compound carrier. The chlorella, nostoc and filamentous algae are all purchased from the Chinese Academy of Sciences Freshwater Algae Culture Collection.

[0068] The bacillus is inoculated into LB liquid medium at a volume ratio of 0.5% for shaking culture, and the culture conditions are as follows: 30°C, 180 r / min for 24 h. Then, the bacillus culture is centrifuged and concentrated at 7500 r / min for 10 min. The obtained precipitate is the bacillus concentrate. Glycerol is added as a protective agent at 1% of the mass of the bacillus concentrate, and then freeze-drying is performed. At this time, the effective viable count of the dried bacillus is ≥10 7 CFU / g, ready for use.

[0069] The pseudomonas is inoculated into LB liquid medium at a volume ratio of 0.5% for shaking culture, and the culture conditions are as follows: 30°C, 180 r / min for 24 h. Then, the pseudomonas culture is centrifuged and concentrated at 7500 r / min for 10 min. The obtained precipitate is the pseudomonas concentrate. Glycerol is added as a protective agent at 1% of the mass of the pseudomonas concentrate, and then freeze-drying is performed. At this time, the effective viable count of the dried pseudomonas is ≥10 7 CFU / g.

[0070] The dried bacillus and pseudomonas are mixed at a mass ratio of 1:1 to obtain the strain for preparing the organic-inorganic composite carrier. Both the bacillus and the pseudomonas are purchased from the China General Microbiological Culture Collection Center.

[0071] The above algal strain and the strain are mixed at a mass ratio of 3:1 to obtain a mixture composed of the algal strain and the strain.

[0072] 90 parts of calcium peroxide with a purity of 60% are mixed with 4 parts of starch binder to obtain uniformly mixed calcium peroxide. Then, the calcium peroxide is granulated to obtain slow-release calcium peroxide particles with a particle size of 2-3 mm. Then, 6 parts of ethyl cellulose coating liquid (the preparation method of the ethyl cellulose coating liquid is as follows: anhydrous ethanol is used to dissolve ethyl cellulose to obtain 40 wt.% ethyl cellulose coating liquid) is used to coat the slow-release calcium peroxide particles, and then the coated slow-release calcium peroxide is dried to obtain the coated slow-release calcium peroxide.

[0073] 90 parts of rice straw powder, 25 parts of the coated slow-release calcium peroxide, and 1 part of the mixture composed of the algal strain and the strain are mixed, and then uniformly mixed. Then, the mixture is subjected to conventional extrusion granulation, 30°C drying, and cooling to obtain an organic-inorganic composite carrier with a particle size of less than 2 cm.

[0074] (4) The organic-inorganic composite carrier is added again 20 days after the first addition of the organic-inorganic composite carrier, and the addition amount is 20 kg / ha to ensure that the periphyton grows vigorously.

[0075] (5) The 0-20 cm soil samples collected from the surface of each plot according to the five-point soil sampling method at the 30th and 60th day after the first addition of the organic-inorganic composite carrier were used as one treatment, and each treatment was repeated three times. The soil pH and available phosphorus content were determined according to the Soil Agricultural Chemistry Analysis Method.

[0076] Comparative Example 1

[0077] The addition of only the slow-release calcium peroxide particles was used as Comparative Example 1, which was carried out in the same rice field as Example 1, and the remaining steps were the same as those of Example 1. The test results in Example were recorded as Example 1-1, Example 1-2, and Example 1-3, and the test results in Comparative Example were recorded as Comparative 1-1, Comparative 1-2, and Comparative 1-3.

[0078] Among them, the slow-release calcium peroxide particles are the slow-release calcium peroxide particles after coating prepared in Example 1, and the addition amount is 51.7 kg / ha.

[0079] Results and analysis:

[0080] Table 1 Test results of improving soil acidification in Example 1 and Comparative Example 1

[0081]

[0082]

[0083] As can be seen from Table 1, the determination results of the paddy field flora and soil pH, available phosphorus, etc. show that after 60 days of addition of the organic-inorganic composite carrier, the average soil pH in the paddy field in Example 1 is 5.4, while that in Comparative Example 1 is 5.2; the average content of available phosphorus in the paddy field in Example 1 is 38.9 mg / kg, while that in Comparative Example 1 is only 37.0 mg / kg.

[0084] Example 2

[0085] A method for improving soil acidification in a paddy field, comprising the following steps:

[0086] (1) Select a gleization paddy field and divide it into experimental plots of 5 m x 5 m. Apply base fertilizer, with a specific amount of 150 kg N / ha of nitrogen fertilizer and 60 kg P / ha of phosphorus fertilizer. Use a rotary tiller to rotary till the rice planting area to a depth of 10 cm, then irrigate to maintain a water depth of 3 cm;

[0087] (2) Transplant rice seedlings to the rice planting area and maintain a water depth of 2 cm on the field surface;

[0088] (3) After 5 days of transplanting, add an organic-inorganic composite carrier to the field water, with an addition amount of 280 kg / ha;

[0089] The organic-inorganic composite carrier is composed of rice straw, a mixture of algae species and bacterial species, and slow-release calcium peroxide after coating.

[0090] The rice straw is dried, crushed, finely ground, and sieved through a 50-mesh sieve for standby use;

[0091] The Chlorella vulgaris is inoculated into the WC liquid medium at a volume ratio of 3% for greenhouse culture. The culture conditions are 25°C and 12h light per day. After 9 days of culture, Chlorella vulgaris culture solution is obtained. The Chlorella vulgaris culture solution is centrifuged and concentrated. The centrifugation conditions of the Chlorella vulgaris culture solution are 7000r / min for 10min. The obtained precipitate after centrifugation is Chlorella vulgaris algae mud. Trehalose is added as a protective agent at 1% of the mass of the algae mud. Then, freeze-drying is performed to obtain dried Chlorella vulgaris for standby use.

[0092] The Nostoc commune is inoculated into the WC liquid medium at a volume ratio of 3% for greenhouse culture. The culture conditions are 25°C and 12h light per day. After 9 days of culture, Nostoc commune culture solution is obtained. The Nostoc commune culture solution is centrifuged and concentrated. The centrifugation conditions of the Nostoc commune culture solution are 7000r / min for 10min. The obtained precipitate after centrifugation is Nostoc commune algae mud. Trehalose is added as a protective agent at 1% of the mass of the algae mud. Then, freeze-drying is performed to obtain dried Nostoc commune for standby use.

[0093] The Cladophora sp. is inoculated into the WC liquid medium at a volume ratio of 3% for greenhouse culture. The culture conditions are 25°C and 12h light per day. After 9 days of culture, Cladophora sp. culture solution is obtained. The Cladophora sp. culture solution is centrifuged and concentrated. The centrifugation conditions of the Cladophora sp. culture solution are 8000r / min for 10min. The obtained precipitate after centrifugation is Cladophora sp. algae mud. Trehalose is added as a protective agent at 1% of the mass of the algae mud. Then, freeze-drying is performed.

[0094] The dried Chlorella vulgaris, Nostoc commune, and Cladophora sp. are mixed at a mass ratio of 1:1:1 to obtain algae species for preparing an organic-inorganic composite carrier. The Chlorella vulgaris, Nostoc commune, and Cladophora sp. are purchased from the Freshwater Algae Culture Collection of the Chinese Academy of Sciences.

[0095] The Bacillus sp. is inoculated into the LB liquid medium at a volume ratio of 0.5% for shaking culture. The culture conditions are 30°C and 180r / min for 24h. Then, the Bacillus sp. culture solution is centrifuged and concentrated. The centrifugation conditions are 7500r / min for 10min. The obtained precipitate after centrifugation is Bacillus sp. concentrate. Glycerol is added as a protective agent at 1% of the mass of the Bacillus sp. concentrate. Then, freeze-drying is performed. At this time, the effective viable count of the dried Bacillus sp. is ≥10 7 CFU / g for standby use.

[0096] Pseudomonas is inoculated into LB liquid medium at a volume ratio of 0.5% for shaking culture, and the culture conditions are as follows: 30°C, 180 r / min for 24 h, then the Pseudomonas culture is centrifuged and concentrated, the centrifugation conditions are as follows: 7500 r / min, 10 min; the obtained precipitate after centrifugation is Pseudomonas concentrate, 1% of the Pseudomonas concentrate by mass is added with glycerol as a protective agent, and then freeze-drying is performed, at this time, the effective viable count of the dried Pseudomonas is ≥10 7 CFU / g;

[0097] The dried Bacillus and Pseudomonas are mixed at a mass ratio of 1:1 to obtain a strain for preparing an organic-inorganic composite carrier; both the Bacillus and the Pseudomonas are purchased from the China General Microbiological Culture Collection Center.

[0098] The above algae and the strain are mixed at a mass ratio of 3:1 to obtain a mixture composed of algae and a strain;

[0099] 90 parts of calcium peroxide with a purity of 60% is mixed with 4 parts of starch binder to obtain a slow-release calcium peroxide granule with a particle size of 2-3 mm, and then 6 parts of ethyl cellulose coating liquid (the preparation method of the ethyl cellulose coating liquid is as follows: ethyl cellulose is dissolved in anhydrous ethanol to obtain a 40 wt.% ethyl cellulose coating liquid) is used to coat the slow-release calcium peroxide granule, and then the coated slow-release calcium peroxide is dried to obtain the coated slow-release calcium peroxide.

[0100] 90 parts of rice straw powder, 20 parts of the coated slow-release calcium peroxide, and 1 part of the mixture composed of algae and a strain are mixed, and then the mixture is uniformly mixed, and then conventional extrusion granulation, 30°C drying, and cooling are performed to obtain an organic-inorganic composite carrier with a particle size of less than 2 cm.

[0101] (4) After 25 days of carrier release, the organic-inorganic composite carrier is added again, and the addition amount is 10 kg / ha, so as to ensure that the microorganisms grow vigorously and secrete bioactive substances such as extracellular polymers and extracellular enzymes during the growth process.

[0102] (5) On the 30th and 60th day after the first addition of the organic-inorganic composite carrier, the surface 0-20 cm soil samples in each experimental plot are collected as one treatment according to the five-point soil sampling method, three replicates are set for each treatment, and the soil pH and available phosphorus content are determined according to the "Soil Agricultural Chemistry Analysis Method".

[0103] Comparative Example 2

[0104] The comparative example 2 and the example 2 were carried out in the same paddy field, and the rest of the steps were the same as the example 2, and the test results in the example were recorded as example 2-1, example 2-2 and example 2-3, and the test results in the comparative example were recorded as comparative example 2-1, comparative example 2-2 and comparative example 2-3 (see Table 2).

[0105] The slow-release calcium peroxide particles were the coated slow-release calcium peroxide particles prepared in the example 2, and the dosage was 50.4 kg / ha.

[0106] Results and analysis:

[0107] Table 2 Test results of improving soil acidification in the example 2 and the comparative example 2

[0108]

[0109]

[0110] As can be seen from Table 2, the determination results of the paddy field flora and the soil pH showed that 60 days after the first time of adding the organic-inorganic composite carrier, the average soil pH in the example 2 was 5.4, and the average soil pH in the comparative example 2 was 5.2; the average soil available phosphorus content in the example 2 was 23.1 mg / kg, and the average soil available phosphorus content in the comparative example 2 was only 19.8 mg / kg.

[0111] Although the above examples have made a detailed description of the present application, it is only a part of the examples of the present application, but not all the examples, and people can also obtain other examples according to the present examples without creativity, and these examples all belong to the protection scope of the present application.

Claims

1. A method for improving soil acidification in paddy fields, characterized in that, Includes the following steps: Add an organic-inorganic composite carrier to the paddy field and maintain the water depth on the paddy field at 2-3 cm. After 20-30 days of application of the organic-inorganic composite carrier, the organic-inorganic composite carrier is applied again to the paddy field. The organic-inorganic composite carrier comprises the following raw materials in parts by weight: The mixture comprises 85-90 parts crop straw, 20-25 parts slow-release calcium peroxide, and 1-1.5 parts a mixture of algae and microorganisms; the mass ratio of algae to microorganisms is (3-4):1; the algae include Chlorella, Nostoc, and filamentous algae; the microorganisms include Bacillus and Pseudomonas. The initial application rate of the organic-inorganic composite carrier is 200–300 kg / ha; The amount of the organic-inorganic composite carrier added again is 10-30 kg / ha.

2. The method according to claim 1, characterized in that, The paddy fields include gleyed paddy fields.

3. The method according to claim 1, characterized in that, The slow-release calcium peroxide comprises the following components in parts by weight: 90-100 parts calcium peroxide, 4-5 parts binder, and 6 parts ethyl cellulose; The purity of the calcium peroxide is 55% to 65%.

4. The method according to claim 1 or 3, characterized in that, The particle size of the slow-release calcium peroxide is 2-3 mm.

5. The method according to claim 1, characterized in that, The first application of the organic-inorganic composite carrier should be done 3-5 days after rice seedling transplanting.

6. The method according to claim 1, characterized in that, The mass ratio of Chlorella, Nostoc, and Fibrophyte is 1:(1-1.5):1; The mass ratio of Bacillus to Pseudomonas is (1-1.5):

1.

7. The method according to claim 1, characterized in that, The crop straw includes rice straw and / or wheat straw.

8. The application of the method according to any one of claims 1 to 7 in improving paddy soil acidification and / or increasing the effective fertility of paddy soil.

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