Efficient conversion and application method of selenium-based bio-fertilizer

Abstract

The invention provides an efficient conversion and application method of a selenium-based bio-fertilizer, and belongs to the technical field of fertilizers. The selenium-based bio-organic fertilizer contains living cell algae mud, water, a nano hollow carbon sphere carrier and sodium selenite, the mass ratio of the living cell algae mud to the water to the nano hollow carbon sphere carrier is (1-2): (4-5): (1-2), and the addition amount of the sodium selenite is 10-13mg / L based on the total amount of the water. The selenium-based bio-organic fertilizer disclosed by the invention has the effect of high selenium absorption rate, is also beneficial to improving the selenium content of crop fruits, can also improve the oxidation resistance of the fruits, enhance the stress resistance, disease resistance and the like of crops, and promotes the improvement of the yield of the crops.

Description

Technical Field

[0001] The invention belongs to the technical field of fertilizers, and in particular relates to a method for efficiently converting and applying selenium-based biological fertilizers. Background Art

[0002] Selenium (Se) is an essential trace element for the human body. It has the effects of preventing cancer, anti-tumor, improving body immunity and delaying aging. Long-term selenium deficiency can induce symptoms such as Keshan disease, Kaschin-Beck disease, hypothyroidism and weakened immune system.

[0003] Since the selenium content in natural soil is not high, the selenium content in crop fruits will be low if no fertilizer is added. In agricultural production, the selenium content in crops is mainly increased by directly applying sodium selenate and sodium selenite.

[0004] However, since the safe application range of inorganic selenium fertilizers such as sodium selenate and sodium selenite is relatively narrow, directly applying high concentrations of inorganic selenium fertilizers such as sodium selenate and sodium selenite will have a certain toxic effect on crops, and the absorption and conversion efficiency of crops for selenium is relatively low. Summary of the invention

[0005] In view of this, the object of the present invention is to provide a selenium-based bio-organic fertilizer that can improve the conversion efficiency of selenium and increase the yield and selenium content of crops.

[0006] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0007] A selenium-based bio-organic fertilizer comprises living cell algae mud, water, nano hollow carbon ball carrier and sodium selenite, wherein the mass ratio of the living cell algae mud, water and nano hollow carbon ball carrier is (1-2):(4-5):(1-2), and the addition amount of the sodium selenite is 10-13 mg / L based on the total amount of water.

[0008] Another object of the present invention is to provide a preparation method of the selenium-based biological organic fertilizer, comprising the following steps: mixing anhydrous ethanol, ammonia water and water to obtain a first mixed solution, dripping tetraethoxysilane into the first mixed solution, stirring and standing to obtain a second mixed solution; adding dopamine hydrochloride to water to obtain a dopamine hydrochloride solution, dripping the dopamine hydrochloride solution into the second mixed solution, stirring, centrifuging, filtering, washing with water, and drying to obtain a reaction material; calcining the reaction material under the protection of an inert gas, cooling it to room temperature and mixing it with a hydrofluoric acid solution, stirring, filtering, washing to neutrality, and drying to obtain a preliminary nano hollow carbon sphere carrier; performing functional modification treatment on the preliminary nano hollow carbon sphere carrier to obtain a nano hollow carbon sphere carrier; adding the composite microalgae to the culture solution for culturing, and centrifugally collecting the living cell algae mud after the cultivation is completed; and mixing the living cell algae mud, water, the nano hollow carbon sphere carrier and sodium selenite to obtain the selenium-based biological organic fertilizer.

[0009] Preferably, the functional modification treatment includes adding the preliminary nano hollow carbon sphere carrier to the treatment liquid, stirring at 70-78° C. for 18-22 hours, then filtering, washing with water to neutrality, and drying to obtain the nano hollow carbon sphere carrier.

[0010] Preferably, the mass fraction of sulfuric acid in the treatment liquid is 18% to 22%, the mass fraction of nitric acid is 75% to 85%, and the rest is water; the mass ratio of the preliminary nano hollow carbon sphere carrier to the treatment liquid is 1:(8 to 10).

[0011] Preferably, the calcination includes calcination under nitrogen protection, the heating rate of the calcination treatment is 8°C / min, the temperature is raised to 710-730°C, and then the temperature is kept for calcination for 3 hours.

[0012] Preferably, the composite microalgae is a mixture of Chlorella pyrenoidosa, Chlamydomonas debarkan and nitrogen-fixing Anabaena in a mass ratio of (2-3):1:1.

[0013] Preferably, the culture medium comprises: 35.0 g / L sodium nitrate, 1.02 g / L potassium hydrogen phosphate, 1.2 g / L magnesium sulfate, 3.8 g / L citric acid, 3.3 g / L ammonium ferric citrate, 0.45 g / L tetrasodium EDTA, 16.0 g / L calcium chloride, 20.0 g / L sodium carbonate, 12.3 g / L boric acid, 9.04 g / L manganese chloride, 1.12 g / L zinc sulfate, 1.85 g / L sodium molybdate, 0.44 g / L copper sulfate and 16.5 g / L sodium selenite.

[0014] Preferably, the culture conditions of the composite microalgae are: the culture temperature is 26-27° C., the light intensity is 3000-3500 lx, and the light-dark cycle is 18h:6h.

[0015] Another object of the present invention is to provide a fertilization method for the selenium-based bio-organic fertilizer, wherein the selenium-based bio-organic fertilizer is applied in combination with basal application and foliar spraying, wherein the basal application is applied into the soil before crop cultivation, and the application amount is 50-55 kg / mu, and the foliar spraying is performed on the leaves during the critical period of crop growth, and the spraying amount is 3-4 g / mu; the critical period includes the jointing stage and the booting stage.

[0016] Another object of the present invention is to provide the application of the selenium-based bio-organic fertilizer or the preparation method or the fertilization method in increasing crop yield or increasing the selenium content of crops.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] The present invention provides a selenium-based bio-organic fertilizer, which contains a large amount of beneficial microorganisms, rich trace elements and nutrients, and can not only significantly improve soil fertility, but also effectively promote the growth of crops, and improve the yield and quality of crops. The selenium-based bio-organic fertilizer of the present invention can also change the soil microenvironment through the active cells contained in itself, reduce soil pollution, improve the ecological environment of crops, and greatly improve the absorption and conversion efficiency of crops to selenium.

[0019] The selenium-based biological organic fertilizer of the present invention has the effect of high selenium absorption rate, and at the same time helps to increase the selenium content of crop fruits, and can also improve the antioxidant capacity of the fruits, enhance the stress resistance and disease resistance of crops, and promote the increase of crop yield. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 Selenium content in brown rice obtained for each treatment group. DETAILED DESCRIPTION

[0021] The present invention provides a selenium-based bio-organic fertilizer, which contains living cell algae mud, water, nano hollow carbon ball carrier and sodium selenite, wherein the mass ratio of the living cell algae mud, water and nano hollow carbon ball carrier is (1-2): (4-5): (1-2), and the preferred mass ratio is 1.5: (4.3-4.7): 1.5; the amount of sodium selenite added is 10-13 mg / L based on the total amount of water. The organic fertilizer provided by the present invention contains a large number of beneficial microorganisms, rich trace elements and nutrient elements, and has a high selenium conversion rate. The water described in the present invention is preferably distilled water.

[0022] The invention also provides a preparation method of the selenium-based biological organic fertilizer, comprising the following steps: mixing anhydrous ethanol, ammonia water and water to obtain a first mixed solution, dripping tetraethoxysilane into the first mixed solution, stirring and then standing to obtain a second mixed solution; adding dopamine hydrochloride to water to obtain a dopamine hydrochloride solution, dripping the dopamine hydrochloride solution into the second mixed solution, stirring, centrifuging, filtering, washing with water, and drying to obtain a reaction material; calcining the reaction material under the protection of an inert gas, cooling it to room temperature and then mixing it with a hydrofluoric acid solution, stirring, filtering, washing to neutrality, and drying to obtain a preliminary nano hollow carbon ball carrier; performing functional modification treatment on the preliminary nano hollow carbon ball carrier to obtain a nano hollow carbon ball carrier; adding composite microalgae to a culture solution for culturing, and centrifugally collecting live cell algae mud after the culturing is completed; and mixing the live cell algae mud, water, the nano hollow carbon ball carrier and sodium selenite to obtain the selenium-based biological organic fertilizer.

[0023] In the preparation method of the present invention, anhydrous ethanol, ammonia water and water are mixed in a volume ratio of (20-22): (1-1.5): (60-65), preferably in a volume ratio of 21: 1.2: 62, the mass fraction of the ammonia water is 19%-21%, preferably 20%, and the first mixed solution is obtained after stirring for 20 minutes after mixing. The volume ratio of tetraethoxysilane to ammonia water is (1.1-1.5): 1, preferably in a volume ratio of 1.2: 1, and the tetraethoxysilane is added dropwise to the first mixed solution and stirred, the stirring speed is 450-550r / min, preferably 500r / min, the stirring time is 0.5-1.5h, preferably 1h, and the stirring is allowed to stand for 0.8-1.5h, preferably 1h, to obtain a second mixed solution. In the dopamine hydrochloride solution, the ratio of dopamine hydrochloride to water is (0.4-0.6) g:10 mL, preferably 0.5 g:10 mL; when the dopamine hydrochloride solution is added dropwise to the second mixed solution, the mass ratio of the dopamine hydrochloride solution to the second mixed solution is 1:(6-8), and the mixture is added dropwise while being stirred. The stirring speed is 450-550 r / min, preferably 500 r / min, and the stirring time is 20-22 h, preferably 21 h. After the stirring, the mixture is centrifuged at a speed of 5000-6000 r / min, preferably 5500 r / min, and the centrifugation time is 8-15 min, preferably 10 min. The precipitate is collected by filtration, washed with water, and dried to obtain a reaction material. The obtained reaction material is calcined under the protection of an inert gas, wherein the inert gas is preferably nitrogen, and the heating rate of the calcination treatment is 8°C / min, the temperature is raised to 710-730°C, and then the temperature is kept at 710-730°C for 3h, preferably raised to 720°C, and after cooling to room temperature, mixed with a hydrofluoric acid solution, wherein the mass fraction of the hydrofluoric acid solution is 8%-12%, preferably 10%, and the mass ratio of the calcined reaction material to the hydrofluoric acid solution is 0.8-1.5:3, preferably 1:3, and stirred after mixing, the stirring time is 12-14h, and then filtered, washed to neutrality and then dried, the drying temperature is 55-65°C, preferably the drying temperature is 60°C, the time is 3-5 hours, preferably 4 hours, to obtain a preliminary nano hollow carbon sphere carrier.The functional modification treatment includes adding a preliminary nano hollow carbon sphere carrier to a treatment liquid, wherein the mass fraction of sulfuric acid in the treatment liquid is 18% to 22%, preferably 20%, the mass fraction of nitric acid is 75% to 85%, preferably 80%, and the rest is water, and the mass ratio of the preliminary nano hollow carbon sphere carrier to the treatment liquid is 1: (8 to 10), and then stirring at 70 to 78°C for 18 to 22 hours, the stirring temperature is preferably 75°C, and the stirring time is preferably 20 hours, and then filtering, washing with water to neutrality, and drying. As an practicable method, the drying is vacuum drying, the vacuum drying temperature is 60 to 68°C, preferably the drying temperature is 65°C, and the drying time is 3 to 5 hours, preferably 4 hours, to obtain the nano hollow carbon sphere carrier.

[0024] In the present invention, the composite microalgae is a mixture of Chlorella pyrenoidosa, Chlamydomonas debarka and Anabaena in a mass ratio of (2-3):1:1. The culture solution includes: 35.0 g / L sodium nitrate, 1.02 g / L potassium hydrogen phosphate, 1.2 g / L magnesium sulfate, 3.8 g / L citric acid, 3.3 g / L ammonium ferric citrate, 0.45 g / L tetrasodium EDTA, 16.0 g / L calcium chloride, 20.0 g / L sodium carbonate, 12.3 g / L boric acid, 9.04 g / L manganese chloride, 1.12 g / L zinc sulfate, 1.85 g / L sodium molybdate, 0.44 g / L copper sulfate and 16.5 g / L sodium selenite. The composite microalgae is inoculated into the culture solution, and the mass ratio of the composite microalgae to the culture solution is (3-4):100. The culture conditions of the composite microalgae are: the culture temperature is 26-27°C, the light intensity is 3000-3500lx, and the light-dark cycle is 18h:6h. After 8-9d of culture, the living cell algae mud is collected by centrifugation, the centrifugal speed is 5500-6000r / min, and the centrifugal time is 10-15min. In a specific embodiment of the present invention, Chlorella pyrenoidosa, Chlamydomonas deba and nitrogen-fixing Anabaena were purchased from the freshwater algae seed bank of the Chinese Academy of Sciences.

[0025] The present invention also provides a fertilization method for the selenium-based bio-organic fertilizer, wherein the selenium-based bio-organic fertilizer is applied in combination with basal application and foliar spraying, wherein the basal application is applied to the soil before crop cultivation, and the application amount is 50-55 kg / mu, preferably 52 kg / mu, and the foliar spraying is performed during the critical period of crop growth, and the spraying amount is 3-4 g / mu; the critical period includes the jointing stage and the booting stage. When the present invention performs foliar spraying, the selenium-based bio-organic fertilizer is diluted 50 times with water before spraying.

[0026] Mix selenium-based bio-organic fertilizer with conventional base fertilizer in a mass ratio of 1:50 and apply to the soil. The conventional base fertilizer is the basic fertilizer: N:P:K=22:7:9.

[0027] The selenium-based bio-organic fertilizer provided by the present invention is applied in combination with conventional base fertilizer, which can not only improve the physical and chemical properties of the soil, promote the absorption of nutrients by the roots of crops, but also improve the effectiveness of selenium and promote the absorption by the roots of crops. The selenium-based bio-organic fertilizer provided by the present invention has higher mobility and, at the same time, will also produce a certain chelation effect on the original selenium in the soil, which can promote the absorption of selenium by the roots.

[0028] When the present invention is applied to crops by foliar spraying, the crops absorb the fertilizer effect of the selenium-based biological organic fertilizer mainly through the leaves, while the conventional foliar selenium fertilizer stays on the leaf surface for a relatively short time, and the adsorption amount of the selenium fertilizer by the leaves is relatively low. The present invention can significantly increase the adsorption amount of the biological fertilizer by the leaves by introducing nano hollow carbon ball carriers, thereby directly affecting the absorption and utilization efficiency of the fertilizer effect by the crop leaves, wherein the absorption efficiency of the selenium element is significantly improved.

[0029] The present invention improves the absorption and accumulation of selenium in the leaves of crop plants through the combination of soil fertilization and foliar fertilization, and the selenium can be better absorbed into the fruits of crops in the later stage, with high conversion efficiency.

[0030] The present invention also provides the application of the selenium-based biological organic fertilizer or the preparation method or the fertilization method in increasing crop yield or increasing the selenium content of crops, and the preferred crops include rice and wheat.

[0031] The technical solutions provided by the present invention are described in detail below in conjunction with the embodiments, but they should not be construed as limiting the protection scope of the present invention.

[0032] Example 1

[0033] A selenium-based bio-organic fertilizer comprises living cell algae mud, water, a nano hollow carbon ball carrier and sodium selenite, wherein the mass ratio of the living cell algae mud, the water and the nano hollow carbon ball carrier is 1:4:1, and the addition amount of the sodium selenite is 10 mg / L based on the total amount of water.

[0034] The preparation method is:

[0035] Anhydrous ethanol, ammonia water and water were added into the reaction kettle in sequence, mixed and stirred for 20 minutes to obtain a first mixed solution; the mass fraction of ammonia water was 20%; the mixing volume ratio of anhydrous ethanol, ammonia water and water was 20:1:60.

[0036] Tetraethoxysilane was added dropwise to the first mixed solution obtained above, and the mixture was stirred at a speed of 500 r / min for 30 min and allowed to stand for 1 hour to obtain a second mixed solution; the volume ratio of tetraethoxysilane to ammonia water was 1.2:1.

[0037] Add dopamine hydrochloride to water, stir and mix evenly to obtain a dopamine hydrochloride solution; the mixing ratio of dopamine hydrochloride to water is 0.5 g:10 mL.

[0038] The dopamine hydrochloride solution obtained above was added dropwise to the second mixed solution, stirred while adding dropwise, stirred for 20 hours, and then centrifuged at a speed of 5500r / min for 10min. After filtering, the mixture was washed with water and dried at 60°C for 4h to obtain a reaction material; the mass ratio of the dopamine hydrochloride solution to the second mixed solution was 1:6.

[0039] The obtained reaction material was calcined under nitrogen protection: the heating rate of the calcination treatment was 8°C / min, the temperature was raised to 720°C, and then calcined at 720°C for 3 hours. After cooling to room temperature, it was mixed with a hydrofluoric acid solution and stirred for 12 hours. Then, it was filtered, washed to neutrality, and dried to obtain a preliminary nano hollow carbon sphere carrier; the mass fraction of the hydrofluoric acid solution was 10%, and the mass ratio of the calcined reaction material to the hydrofluoric acid solution was 1:3.

[0040] The preliminary nano hollow carbon sphere carrier is subjected to functional modification treatment to obtain the nano hollow carbon sphere carrier, and the functional treatment is as follows: the prepared preliminary nano hollow carbon sphere carrier is added to the treatment liquid, the preliminary carrier and the treatment liquid are mixed in a mass ratio of 1:8, the temperature is adjusted to 75°C, the mixture is stirred for 20 hours, and then filtered, the precipitate is washed with water until neutral, and vacuum dried at a drying temperature of 65°C for 4 hours to obtain the nano hollow carbon sphere carrier. The mass fraction of sulfuric acid in the treatment liquid is 20%, the mass fraction of nitric acid is 80%, and the rest is water.

[0041] The composite microalgae was added to the culture solution, the mass ratio of the composite microalgae to the culture solution was 3:100, and the culture was carried out for 8 days. The culture conditions were: the culture temperature was 26°C, the light intensity was 3000lx, and the light-dark cycle was 18h:6h. The composite microalgae was a mixture of protein nucleus Chlamydomonas, Deba Chlamydomonas and nitrogen-fixing fish algae in a mass ratio of 2:1:1. Each 1000mL culture solution included: 35.0g sodium nitrate, 1.02g potassium hydrogen phosphate, 1.2g magnesium sulfate, 3.8g citric acid, 3.3g ammonium ferric citrate, 0.45g tetrasodium EDTA, 16.0g calcium chloride, 20.0g sodium carbonate, 12.3g boric acid, 9.04g manganese chloride, 1.12g zinc sulfate, 1.85g sodium molybdate, 0.44g copper sulfate, 16.5g sodium selenite, and the balance was water.

[0042] After the cultivation, centrifuge at 5500r / min for 10min to collect the living cell algae mud, and then add distilled water, nano hollow carbon ball carrier and sodium selenite according to the above mass ratio and mix well to obtain selenium-based biological organic fertilizer.

[0043] Example 2

[0044] A selenium-based bio-organic fertilizer comprises living cell algae mud, water, a nano hollow carbon ball carrier and sodium selenite, wherein the mass ratio of the living cell algae mud, water and the nano hollow carbon ball carrier is 1.2:4.5:1.2, and the addition amount of the sodium selenite is 10 mg / L based on the total amount of water.

[0045] The preparation method is:

[0046] Anhydrous ethanol, ammonia water and water were added into the reaction kettle in sequence, mixed and stirred for 20 minutes to obtain a first mixed solution; the mass fraction of ammonia water was 20%; the mixing volume ratio of anhydrous ethanol, ammonia water and water was 20:1:60.

[0047] Tetraethoxysilane was added dropwise to the first mixed solution obtained above, and the mixture was stirred at a speed of 500 r / min for 30 min and allowed to stand for 1 hour to obtain a second mixed solution; the volume ratio of tetraethoxysilane to ammonia water was 1.2:1.

[0048] Add dopamine hydrochloride to water, stir and mix evenly to obtain a dopamine hydrochloride solution; the mixing ratio of dopamine hydrochloride to water is 0.5 g:10 mL.

[0049] The dopamine hydrochloride solution obtained above was added dropwise to the second mixed solution, stirred while adding dropwise, stirred at a speed of 500 r / min for 21 hours, and then centrifuged at a speed of 5500 r / min for 10 minutes. After filtering, the mixture was washed with water and dried at 60°C for 4 hours to obtain a reaction material; the mass ratio of the dopamine hydrochloride solution to the second mixed solution was 1:6.5.

[0050] The obtained reaction material was calcined under nitrogen protection: the heating rate of the calcination treatment was 8°C / min, the temperature was raised to 720°C, and then calcined at 720°C for 3 hours. After cooling to room temperature, it was mixed with a hydrofluoric acid solution and stirred for 13 hours. Then, it was filtered, washed to neutrality, and dried to obtain a preliminary nano hollow carbon sphere carrier; the mass fraction of the hydrofluoric acid solution was 10%, and the mass ratio of the calcined reaction material to the hydrofluoric acid solution was 1:3.

[0051] The preliminary nano hollow carbon sphere carrier is subjected to functional modification treatment to obtain the nano hollow carbon sphere carrier, and the functional treatment is as follows: the prepared preliminary nano hollow carbon sphere carrier is added to the treatment liquid, the preliminary carrier and the treatment liquid are mixed in a mass ratio of 1:9, the temperature is adjusted to 75°C, the mixture is stirred for 20 hours, and then filtered, the precipitate is washed with water until neutral, and vacuum dried at a drying temperature of 65°C for 4 hours to obtain the nano hollow carbon sphere carrier. The mass fraction of sulfuric acid in the treatment liquid is 20%, the mass fraction of nitric acid is 80%, and the rest is water.

[0052] The composite microalgae was added to the culture solution, the mass ratio of the composite microalgae to the culture solution was 3.5:100, and the culture was carried out for 8 days. The culture conditions were: the culture temperature was 26°C, the light intensity was 3200lx, and the light-dark cycle was 18h:6h. The composite microalgae was a mixture of protein nucleus Chlamydomonas, Deba Chlamydomonas and nitrogen-fixing fish algae at a mass ratio of 2.5:1:1. Each 1000mL culture solution included: 35.0g sodium nitrate, 1.02g potassium hydrogen phosphate, 1.2g magnesium sulfate, 3.8g citric acid, 3.3g ammonium ferric citrate, 0.45g tetrasodium EDTA, 16.0g calcium chloride, 20.0g sodium carbonate, 12.3g boric acid, 9.04g manganese chloride, 1.12g zinc sulfate, 1.85g sodium molybdate, 0.44g copper sulfate, 16.5g sodium selenite, and the balance was water.

[0053] After the cultivation, centrifuge at 5500r / min for 10min to collect the living cell algae mud, and then add distilled water, nano hollow carbon ball carrier and sodium selenite according to the above mass ratio and mix well to obtain selenium-based biological organic fertilizer.

[0054] Example 3

[0055] A selenium-based bio-organic fertilizer comprises living cell algae mud, water, a nano hollow carbon ball carrier and sodium selenite, wherein the mass ratio of the living cell algae mud, water and the nano hollow carbon ball carrier is 1.5:4.6:1.5, and the addition amount of the sodium selenite is 10 mg / L based on the total amount of water.

[0056] The preparation method is:

[0057] Anhydrous ethanol, ammonia water and water were added into the reaction kettle in sequence, mixed and stirred for 20 minutes to obtain a first mixed solution; the mass fraction of ammonia water was 20%; the mixing volume ratio of anhydrous ethanol, ammonia water and water was 20:1:60.

[0058] Tetraethoxysilane was added dropwise to the first mixed solution obtained above, and the mixture was stirred at a speed of 500 r / min for 30 min and allowed to stand for 1 hour to obtain a second mixed solution; the volume ratio of tetraethoxysilane to ammonia water was 1.2:1.

[0059] Add dopamine hydrochloride to water, stir and mix evenly to obtain a dopamine hydrochloride solution; the mixing ratio of dopamine hydrochloride to water is 0.5 g:10 mL.

[0060] The dopamine hydrochloride solution obtained above was added dropwise to the second mixed solution, stirred while adding dropwise, stirred at a speed of 500 r / min for 21 hours, and then centrifuged at a speed of 5500 r / min for 10 minutes. After filtering, the mixture was washed with water and dried at 60°C for 4 hours to obtain a reaction material; the mass ratio of the dopamine hydrochloride solution to the second mixed solution was 1:7.5.

[0061] The obtained reaction material was calcined under nitrogen protection: the heating rate of the calcination treatment was 8°C / min, the temperature was raised to 720°C, and then calcined at 720°C for 3 hours. After cooling to room temperature, it was mixed with a hydrofluoric acid solution and stirred for 12 hours. Then, it was filtered, washed to neutrality, and dried to obtain a preliminary nano hollow carbon sphere carrier; the mass fraction of the hydrofluoric acid solution was 10%, and the mass ratio of the calcined reaction material to the hydrofluoric acid solution was 1:3.

[0062] The preliminary nano hollow carbon sphere carrier is subjected to functional modification treatment to obtain the nano hollow carbon sphere carrier, and the functional treatment is as follows: the prepared preliminary nano hollow carbon sphere carrier is added to the treatment liquid, the preliminary carrier and the treatment liquid are mixed in a mass ratio of 1:9.5, the temperature is adjusted to 75°C, the mixture is stirred for 20 hours, and then filtered, the precipitate is washed with water until neutral, and vacuum dried at a drying temperature of 65°C for 4 hours to obtain the nano hollow carbon sphere carrier. The mass fraction of sulfuric acid in the treatment liquid is 20%, the mass fraction of nitric acid is 80%, and the rest is water.

[0063] The composite microalgae was added to the culture solution, the mass ratio of the composite microalgae to the culture solution was 3.8:100, and the culture was carried out for 8 days. The culture conditions were: the culture temperature was 27°C, the light intensity was 3300lx, and the light-dark cycle was 18h:6h. The composite microalgae was a mixture of protein nucleus Chlamydomonas, Deba Chlamydomonas and nitrogen-fixing fish algae at a mass ratio of 2.5:1:1. Each 1000mL culture solution included: 35.0g sodium nitrate, 1.02g potassium hydrogen phosphate, 1.2g magnesium sulfate, 3.8g citric acid, 3.3g ammonium ferric citrate, 0.45g tetrasodium EDTA, 16.0g calcium chloride, 20.0g sodium carbonate, 12.3g boric acid, 9.04g manganese chloride, 1.12g zinc sulfate, 1.85g sodium molybdate, 0.44g copper sulfate, 16.5g sodium selenite, and the balance was water.

[0064] After the cultivation, centrifuge at 5500r / min for 10min to collect the living cell algae mud, and then add distilled water, nano hollow carbon ball carrier and sodium selenite according to the above mass ratio and mix well to obtain selenium-based biological organic fertilizer.

[0065] Example 4

[0066] A selenium-based bio-organic fertilizer comprises living cell algae mud, water, a nano hollow carbon ball carrier and sodium selenite, wherein the mass ratio of the living cell algae mud, the water and the nano hollow carbon ball carrier is 2:5:2, and the addition amount of the sodium selenite is 10 mg / L based on the total amount of water.

[0067] The preparation method is:

[0068] Anhydrous ethanol, ammonia water and water were added into the reaction kettle in sequence, mixed and stirred for 20 minutes to obtain a first mixed solution; the mass fraction of ammonia water was 20%; the mixing volume ratio of anhydrous ethanol, ammonia water and water was 20:1:60.

[0069] Tetraethoxysilane was added dropwise to the first mixed solution obtained above, and the mixture was stirred at a speed of 500 r / min for 30 min and allowed to stand for 1 hour to obtain a second mixed solution; the volume ratio of tetraethoxysilane to ammonia water was 1.2:1.

[0070] Add dopamine hydrochloride to water, stir and mix evenly to obtain a dopamine hydrochloride solution; the mixing ratio of dopamine hydrochloride to water is 0.5 g:10 mL.

[0071] The dopamine hydrochloride solution obtained above was added dropwise to the second mixed solution, stirred while adding dropwise, stirred at a speed of 500 r / min for 21 hours, and then centrifuged at a speed of 5500 r / min for 10 minutes. After filtering, the mixture was washed with water and dried at 60°C for 4 hours to obtain a reaction material; the mass ratio of the dopamine hydrochloride solution to the second mixed solution was 1:8.

[0072] The obtained reaction material was calcined under nitrogen protection: the heating rate of the calcination treatment was 8°C / min, the temperature was raised to 720°C, and then calcined at 720°C for 3 hours. After cooling to room temperature, it was mixed with a hydrofluoric acid solution and stirred for 14 hours. Then, it was filtered, washed to neutrality, and dried to obtain a preliminary nano hollow carbon sphere carrier; the mass fraction of the hydrofluoric acid solution was 10%, and the mass ratio of the calcined reaction material to the hydrofluoric acid solution was 1:3.

[0073] The preliminary nano hollow carbon sphere carrier is subjected to functional modification treatment to obtain the nano hollow carbon sphere carrier, and the functional treatment is as follows: the prepared preliminary nano hollow carbon sphere carrier is added to the treatment liquid, the preliminary carrier and the treatment liquid are mixed in a mass ratio of 1:10, the temperature is adjusted to 75°C, the mixture is stirred for 20 hours, and then filtered, the precipitate is washed with water until neutral, and vacuum dried at a drying temperature of 65°C for 4 hours to obtain the nano hollow carbon sphere carrier. The mass fraction of sulfuric acid in the treatment liquid is 20%, the mass fraction of nitric acid is 80%, and the rest is water.

[0074] The composite microalgae was added to the culture solution, the mass ratio of the composite microalgae to the culture solution was 4:100, and the culture was carried out for 8 days. The culture conditions were: the culture temperature was 27°C, the light intensity was 3500lx, and the light-dark cycle was 18h:6h. The composite microalgae was a mixture of protein nucleus Chlamydomonas, Deba Chlamydomonas and nitrogen-fixing fish algae in a mass ratio of 3:1:1. Each 1000mL culture solution included: 35.0g sodium nitrate, 1.02g potassium hydrogen phosphate, 1.2g magnesium sulfate, 3.8g citric acid, 3.3g ammonium ferric citrate, 0.45g tetrasodium EDTA, 16.0g calcium chloride, 20.0g sodium carbonate, 12.3g boric acid, 9.04g manganese chloride, 1.12g zinc sulfate, 1.85g sodium molybdate, 0.44g copper sulfate, 16.5g sodium selenite, and the balance was water.

[0075] After the cultivation, centrifuge at 5500r / min for 10min to collect the living cell algae mud, and then add distilled water, nano hollow carbon ball carrier and sodium selenite according to the above mass ratio and mix well to obtain selenium-based biological organic fertilizer.

[0076] Example 5

[0077] A method of fertilizing.

[0078] Before planting crops, mix selenium-based bio-organic fertilizer with conventional base fertilizer at a mass ratio of 1:50 and apply to the soil. The application amount of selenium-based bio-organic fertilizer is 50kg / mu. Conventional base fertilizer is basic fertilizer: N:P:K=22:7:9.

[0079] On the 5th day from the jointing stage and the 3rd day from the booting stage, spray selenium-based bio-organic fertilizer once respectively: dilute the selenium-based bio-organic fertilizer 50 times with water and then spray, the spraying amount is 150mL / mu.

[0080] Comparative Example 1

[0081] The difference between this comparative example and Example 1 is that the nano hollow carbon sphere carrier is replaced by an activated carbon powder of equal weight (purchased from Jiangsu Hartel Carbon Material Technology Co., Ltd.).

[0082] Comparative Example 2

[0083] The difference between this comparative example and Example 1 is that the composite microalgae only contains Chlorella pyrenoidosa.

[0084] Comparative Example 3

[0085] The difference between this comparative example and Example 1 is that the composite microalgae only contains Chlamydomonas debacansis.

[0086] Comparative Example 4

[0087] The difference between this comparative example and Example 1 is that the composite microalgae only contains nitrogen-fixing Anabaena.

[0088] Example 6

[0089] Effects of using different selenium-based bio-organic fertilizers.

[0090] The test soil pH value was 7.31, the organic matter content was 13.58 g / kg, the total nitrogen content was 1.12 g / kg, the available phosphorus content was 46.38 mg / kg, the available potassium content was 81.03 mg / kg, and the hydrolyzable nitrogen content was 65.97 mg / kg.

[0091] The rice variety tested was “Yuehe Silk Seedling”, and the cultivation method was machine-pit sowing, with a row spacing of 24 cm and a plant spacing of 15 cm. The basic fertilizer was: N:P:K=22:7:9.

[0092] Treatment 1: applying the selenium-based bio-organic fertilizer provided in Example 1, and fertilizing according to the method provided in Example 5;

[0093] Treatment 2: applying the selenium-based bio-organic fertilizer provided in Example 2, and fertilizing according to the method provided in Example 5;

[0094] Treatment 3: applying the selenium-based bio-organic fertilizer provided in Example 3, and fertilizing according to the method provided in Example 5;

[0095] Treatment 4: applying the selenium-based bio-organic fertilizer provided in Example 4, and fertilizing according to the method provided in Example 5;

[0096] Treatment 5: applying the selenium-based bio-organic fertilizer provided in Comparative Example 1, and fertilizing according to the method provided in Example 5;

[0097] Treatment 6: applying the selenium-based bio-organic fertilizer provided in Comparative Example 2, and fertilizing according to the method provided in Example 5;

[0098] Treatment 7: applying the selenium-based bio-organic fertilizer provided in Comparative Example 3, and fertilizing according to the method provided in Example 5;

[0099] Treatment 8: applying the selenium-based bio-organic fertilizer provided in Comparative Example 4, and fertilizing according to the method provided in Example 5;

[0100] Blank control group: no selenium-based bio-organic fertilizer was applied;

[0101] Conventional control group: sodium selenite solution was prepared with the selenium content being the same as that in the biological fertilizer, and an equal amount was used to replace the organic fertilizer.

[0102] Each experimental field has an area of ​​12m 2Each plot was separated by a ridge, and single irrigation and single row were used. The same amount of basic fertilizer was applied. Other field management of treatments 1 to 8, the blank control group and the conventional control group were kept consistent. After the rice was harvested, the rice yield of each treatment was counted, and the results are shown in Table 1. The brown rice obtained from each treatment was placed in a 105℃ oven for 20 minutes, and then dried at 90℃ to constant weight. After the sample was ground through a 0.15mm sieve, the total selenium content of the sample was determined by hydride generation-atomic fluorescence spectrometry. The results are shown in Table 1 and Figure 1 During the rice maturity period, the selenium content in the leaves of each group was detected using the same detection method as that of the selenium content in brown rice. The results are shown in Table 2.

[0103] Table 1 Rice yield and selenium content in brown rice

[0104] Grouping Rice yield kg / mu Brown rice selenium content μg / kg Process 1 537.6 298.6 Process 2 543.2 302.3 Process 3 539.3 300.5 Process 4 541.0 299.4 Process 5 511.5 276.3 Process 6 483.3 266.9 Process 7 477.2 260.3 Process 8 488.6 271.4 Blank control group 435.2 63.1 Conventional control group 436.4 112.6

[0105] It can be seen from Table 1 that the selenium-based biological organic fertilizer provided by the present invention has the effect of increasing rice yield and can significantly increase the selenium content in brown rice.

[0106] Table 2 Selenium content in leaves

[0107] Grouping Selenium content in leaves μg / kg Process 1 1995.6 Process 5 1926.3 Process 6 1902.4 Process 7 1920.7 Process 8 1918.4 Blank control group 553.1 Conventional control group 1459.6

[0108] It can be seen from Table 2 that the selenium-based bio-organic fertilizer provided by the present invention can significantly improve the absorption rate of selenium by crops.

[0109] It can be seen from Table 1 and Table 2 that the selenium-based biological organic fertilizer provided by the present invention has a higher conversion rate and can significantly promote the accumulation of selenium in brown rice. The conversion rate of brown rice to selenium in leaves is relatively high.

[0110] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A selenium-based bio-organic fertilizer, characterized in that: The selenium-based biological organic fertilizer contains living cell algae mud, water, nano hollow carbon ball carrier and sodium selenite, the mass ratio of the living cell algae mud, water and nano hollow carbon ball carrier is (1-2):(4-5):(1-2), and the addition amount of the sodium selenite is 10-13 mg / L based on the total amount of water.

2. The method for preparing the selenium-based biological organic fertilizer according to claim 1, characterized in that: The steps include: Anhydrous ethanol, ammonia water and water are mixed to obtain a first mixed solution, tetraethoxysilane is added dropwise to the first mixed solution, and the mixture is stirred and allowed to stand to obtain a second mixed solution; dopamine hydrochloride is added to water to obtain a dopamine hydrochloride solution, and the dopamine hydrochloride solution is added dropwise to the second mixed solution, stirred, centrifuged, filtered, washed with water, and dried to obtain a reaction material; the reaction material is calcined under the protection of an inert gas, cooled to room temperature, mixed with a hydrofluoric acid solution, stirred, filtered, washed to neutrality, and dried to obtain a preliminary nano hollow carbon sphere carrier; the preliminary nano hollow carbon sphere carrier is functionalized and modified to obtain a nano hollow carbon sphere carrier; The composite microalgae is added to the culture solution for cultivation, and the living cell algae mud is collected by centrifugation after the cultivation is completed; the living cell algae mud, water, nano hollow carbon ball carrier and sodium selenite are mixed to obtain selenium-based biological organic fertilizer.

3. The preparation method according to claim 2, characterized in that: The functional modification treatment includes adding the preliminary nano hollow carbon sphere carrier to the treatment liquid, stirring at 70-78°C for 18-22 hours, then filtering, washing with water to neutrality, and drying to obtain the nano hollow carbon sphere carrier.

4. The preparation method according to claim 3, characterized in that: The mass fraction of sulfuric acid in the treatment liquid is 18% to 22%, the mass fraction of nitric acid is 75% to 85%, and the rest is water; the mass ratio of the preliminary nano hollow carbon sphere carrier to the treatment liquid is 1:(8-10).

5. The preparation method according to claim 2, characterized in that: The calcination includes calcination under nitrogen protection, the heating rate of the calcination treatment is 8°C / min, the temperature is raised to 710-730°C, and then the temperature is kept for calcination for 3 hours.

6. The preparation method according to claim 2, characterized in that: The composite microalgae is a mixture of Chlorella pyrenoidosa, Chlamydomonas debarkanensis and nitrogen-fixing Anabaena in a mass ratio of (2-3):1:

1.

7. The preparation method according to claim 2, characterized in that: The culture solution includes: 35.0 g / L sodium nitrate, 1.02 g / L potassium hydrogen phosphate, 1.2 g / L magnesium sulfate, 3.8 g / L citric acid, 3.3 g / L ammonium ferric citrate, 0.45 g / L tetrasodium EDTA, 16.0 g / L calcium chloride, 20.0 g / L sodium carbonate, 12.3 g / L boric acid, 9.04 g / L manganese chloride, 1.12 g / L zinc sulfate, 1.85 g / L sodium molybdate, 0.44 g / L copper sulfate and 16.5 g / L sodium selenite.

8. The preparation method according to claim 2, characterized in that: The culture conditions of the composite microalgae are: the culture temperature is 26-27° C., the light intensity is 3000-3500 lx, and the light-dark cycle is 18h:6h.

9. The method for applying selenium-based bio-organic fertilizer according to claim 1, characterized in that: The selenium-based bio-organic fertilizer is applied in combination with basal application and foliar spraying. The basal application is applied into the soil before crop cultivation, with an application amount of 50-55 kg / mu. The foliar spraying is carried out during the critical growth period of the crop, with an application amount of 3-4 g / mu; the critical period includes the jointing period and the booting period.

10. Use of the selenium-based bio-organic fertilizer according to claim 1, the preparation method according to any one of claims 2 to 8, or the fertilization method according to claim 9 in increasing crop yield or increasing the selenium content of crops.

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