1. The chelating type medium and trace element selenium-rich sugar alcohol biological agent is characterized by being prepared from 0.15-0.3 part of selenium salt, 10-30 parts of activated sugar alcohol, 30-50 parts of medium elements, 10-15 parts of fulvic acid, 4-8 parts of trace elements, 3-5 parts of microbial fermentation liquor and 50-100 parts of water.

2. The chelating medium trace element biological agent as claimed in claim 1, wherein the selenium salt is one or more of sodium selenate, sodium selenite, potassium selenate and potassium selenite.

3. The chelating medium trace element biological agent of selenium-enriched sugar alcohol as claimed in claim 1, wherein the preparation method of the activated sugar alcohol is: the sugar alcohol and polyglutamic acid solution were mixed according to a ratio of 10 g: adding 100ml into container, heating to 40-50 deg.C, stirring to dissolve completely, and cooling to room temperature to obtain activated sugar alcohol with polyglutamic acid solution mass concentration of 50%.

4. The chelating medium trace element biological agent as claimed in claim 3, wherein the sugar alcohol is one or more of mannitol, sorbitol, xylitol and maltitol.

5. The chelating medium trace element biological agent as claimed in claim 1, wherein the medium elements are calcium salt and magnesium salt.

6. The chelating medium trace element biological agent as claimed in claim 1, wherein the trace element is at least one inorganic salt of Fe, Mn, Cu, Zn, B and Mo.

7. The chelating medium trace element biological agent of selenium-enriched sugar alcohol as claimed in claim 1, wherein the preparation method of the microbial fermentation liquid is: respectively inoculating Cryptococcus rabbit and Bacillus subtilis on LB solid culture medium, culturing at constant temperature of 25-28 deg.C for 5-8 hr to obtain seed liquid, respectively inoculating the seed liquid in LB liquid culture medium according to 1% inoculum size, and reciprocating shaking table for 150 r.min^-1And culturing at the constant temperature of 28 ℃ for 12h until the bacteria content is O.D600 about 2.0, and mixing according to the volume ratio of 1:1 to obtain the microbial zymogen liquid.

8. The chelating medium trace element biological agent as claimed in claim 7, wherein the Cryptococcus rabbit is CGMCC2.5648 and the Bacillus subtilis is Bacillus subtilis CGMCC 1.14985.

9. The method for preparing the chelating type medium and trace element biological agent of the selenium-enriched sugar alcohol as claimed in any one of claims 1 to 8, which is characterized by comprising the following steps:

(1) the sugar alcohol and polyglutamic acid solution were mixed according to a ratio of 10 g: adding 100ml of the mixture into a container, heating to 40-50 ℃, stirring until the mixture is completely dissolved, and cooling to room temperature to obtain activated sugar alcohol;

(2) sequentially adding activated sugar alcohol and fulvic acid into water according to the weight part, maintaining the temperature of the solution at 60-100 ℃, and stirring until the activated sugar alcohol and the fulvic acid are completely dissolved to obtain a mixture A;

(3) adding the secondary elements and the trace elements into the mixture A according to the parts by weight, maintaining the temperature of the solution at 60-100 ℃, and uniformly stirring for 10-30 minutes to obtain a mixture B;

(4) adding selenium salt into the mixture B according to the weight part, maintaining the temperature of the solution at 60-100 ℃, uniformly stirring for 10-30 minutes, and cooling to room temperature to obtain a mixture C;

(5) and finally adding the microbial fermentation bacteria liquid according to the weight parts, and uniformly stirring at room temperature to obtain a finished product.

Background

Selenium is a necessary trace element for human bodies, and the selenium deficiency of the human bodies can cause dysfunction of some important organs, so that a plurality of serious diseases occur. The people with low selenium or selenium deficiency can prevent tumor, liver disease, etc. by supplementing selenium with proper amount, improve immunity, maintain normal functions of heart, liver, lung, stomach, etc., and prevent senile cardiovascular and cerebrovascular diseases. As a kind of health food, the selenium-rich crops have wide market prospect.

Most trace elements are components of "enzymes" or "coenzymes" that promote photosynthesis, respiration, and substance conversion in plants, and are very active in plants. When some medium and trace elements are lacked in soil, plants can have 'deficiency diseases', the crop yield is reduced, the quality is reduced, and under the condition, the trace element fertilizer is applied, so that the obvious yield increasing effect is usually achieved.

However, the current methods for enriching selenium and supplementing trace elements are basically in a mode of adding organic selenium and inorganic selenium, but the organic selenium and the inorganic selenium are directly added, so that the utilization rate of selenium by crops is extremely low, and the selenium is difficult to convert into the really effective selenium in the crops; the trace elements are added in the form of various metal inorganic salts, and are added after being chelated by a chelating agent.

Chemical chelating agents such as EDTA, although having good chelating performance, are not absorbed and utilized by crops and are difficult to degrade, are easy to damage crops due to improper use, and are difficult to apply in the agricultural field. The fulvic acid as the organic chelating agent of the trace elements has excellent conditions, such as natural availability, multiple active groups, safety, environmental protection, high quality and low price, and the like, most of the products sold on the market at present are fulvic acid chelated medium and trace elements, however, the chelation of the fulvic acid and the medium and trace elements is influenced by the properties of humic acid molecular weight, functional groups and the like, and the direct use of fulvic acid chelated medium and trace elements in the compounding process is easy to generate precipitation and influences the absorption of the medium and trace elements by plants. The absorption effect of the trace elements can influence the absorption of the selenium, so that how to promote the utilization of the trace elements by crops and maximize the selenium content of the crops has important significance for increasing the yield of the crops.

Disclosure of Invention

The invention provides a chelating type medium trace element biological agent rich in sugar alcohol and a preparation method thereof, and solves the problems that fulvic acid has poor effect of chelating trace elements in the prior art and crops absorb and utilize trace elements and selenium elements.

In order to achieve the technical purpose, the technical scheme adopted by the invention is as follows:

a chelating type medium-trace element biological bacterial agent rich in selenium sugar alcohol is prepared from selenium salt (0.15-0.3 wt. portions), activated sugar alcohol (10-30), medium element (30-50), fulvic acid (10-15), trace element (4-8), microbial fermented liquid (3-5) and water (50-100).

Further, the selenium salt is one or more of sodium selenate, sodium selenite, potassium selenate and potassium selenite.

Further, the preparation method of the activated sugar alcohol comprises the following steps: the sugar alcohol and polyglutamic acid solution were mixed according to a ratio of 10 g: adding 100ml into container, heating to 40-50 deg.C, stirring to dissolve completely, and cooling to room temperature to obtain activated sugar alcohol with polyglutamic acid solution mass concentration of 50%.

Further, the sugar alcohol is one or more of mannitol, sorbitol, xylitol and maltitol.

Further, the secondary elements are calcium salts and magnesium salts.

Further, the trace elements are inorganic salts of at least one of iron, manganese, copper, zinc, boron and molybdenum.

Further, the preparation method of the microbial fermentation liquid comprises the following steps: respectively inoculating Cryptococcus rabbit and Bacillus subtilis on LB solid culture medium, culturing at constant temperature of 25-28 deg.C for 5-8 hr to obtain seed liquid, respectively inoculating the seed liquid in LB liquid culture medium according to 1% inoculum size, and reciprocating shaking table for 150 r.min^-1And culturing at the constant temperature of 28 ℃ for 12h until the bacteria content is O.D600 approximately equal to 2.0, and then mixing according to the volume ratio of 1:1 to obtain the microbial zymogen liquid.

Further, the composition of the LB medium is: tryptone 20g, yeast extract 5g, NaCl 5g, distilled water 1000mL, pH 7.2-7.4, sterilizing at 121 deg.C for 19min, and adding agar powder 10g into solid culture medium

Further, the cryptococcus rabbit is CGMCC2.5648, and the bacillus subtilis is CGMCC 1.14985.

Further, Cryptococcus rabbit (Cryptococcus cuniculus) of the present invention is purchased from China General Microbiological Culture Collection Center (CGMCC), and has the address: west road No. 1 hospital No. 3, north jing, chaoyang district, preservation date: 2016, 4/20/month, accession number: CGMCC 2.5648.

Further, Bacillus subtilis (CGMCC) of the present invention is purchased from China General Microbiological Culture Collection Center (CGMCC), and has the following address: west road No. 1 hospital No. 3, north jing, chaoyang district, preservation date: no. 12/10 in 2014, accession no: CGMCC 1.14985.

A preparation method of a chelated medium-trace element biological agent rich in selenium sugar alcohol comprises the following steps:

(1) the sugar alcohol and polyglutamic acid solution were mixed according to a ratio of 10 g: adding 100ml of the mixture into a container, heating to 40-50 ℃, stirring until the mixture is completely dissolved, and cooling to room temperature to obtain activated sugar alcohol;

(2) sequentially adding activated sugar alcohol and fulvic acid into water according to the weight part, maintaining the temperature of the solution at 60-100 ℃, and stirring until the activated sugar alcohol and the fulvic acid are completely dissolved to obtain a mixture A;

(3) adding the secondary elements and the trace elements into the mixture A according to the parts by weight, maintaining the temperature of the solution at 60-100 ℃, and uniformly stirring for 10-30 minutes to obtain a mixture B;

(4) adding selenium salt into the mixture B according to the weight part, maintaining the temperature of the solution at 60-100 ℃, uniformly stirring for 10-30 minutes, and cooling to room temperature to obtain a mixture C;

(5) and finally adding the microbial fermentation bacteria liquid according to the weight parts, and uniformly stirring at room temperature to obtain a finished product.

The medium and trace nutrient elements are very important for the growth and development of crops, and the yield and the quality of the crops are reduced once the medium and trace nutrient elements are lacked. For example, calcium is a major component of plant cell walls and intercellular layers, and provides strength to crop organs and individuals.

Iron (Fe) is an important component of cytochrome, heme, ferredoxin and various enzymes, plays a role in transferring electrons in plants, and is an essential substance in chlorophyll synthesis. Iron deficiency symptoms of plants: is not easy to move in the plant body, and is firstly displayed on young leaves when in iron deficiency. It is manifested as a greenish-blue pulse, in severe cases the whole young leaves are yellowish-white, and iron deficiency often occurs in high pH soils.

Manganese is a chloroplast component, promotes seed development and early seedling growth, and plays an important role in photosynthesis and protein formation. And (3) the manganese deficiency symptom of the plants: the symptoms begin from new leaves, the leaf veins turn green, the leaf veins are still green, brown or gray spots appear on the leaves and are gradually connected into strips, and when the leaf color turns green and necroses.

Zinc (Zn) is a component and activator of many enzymes, and more than 80 zinc-containing enzymes have been found to be involved in auxin synthesis. The zinc deficiency symptom of the plants: the growth of the plant is hindered, internodes are shortened, and the expansion of leaves is inhibited when old tissues are firstly subjected to zinc deficiency, so that the plant is manifested as lobular fasciculation, which is called lobular disease or fasciculation. The white streak symptom appears in the zinc deficiency of the corn.

Molybdenum (Mo) is an essential element that is required in the minimum amount. MoO 42-is a component of nitrate reductase and azotase; is a component of xanthine dehydrogenase and some oxidase in abscisic acid synthesis, molybdenum is particularly required for nitrogen fixation of leguminous plant rhizobia, and the nitrogen fixation enzyme is composed of ferritin and iron-molybdenum protein. Molybdenum deficiency in plants: new leaf malformation, with blotchiness. Spread over the blades. Poor growth, short and small plants, nitrogen fixation caused by lack of molybdenum in leguminous plants, and incomplete pod grains.

But the medium trace elements are easy to combine with sulfur, phosphorus and the like to generate precipitates, and are not easy to be added into a fertilizer basic system. In the production process of the fertilizer, in order to solve the problem of element coexistence, a chelating agent is often adopted to chelate trace elements. Chemical chelating agents such as ethylenediamine tetraacetic acid and the like have great harm to the soil environment, and organic chelating agents such as fulvic acid, sugar alcohol and the like have poor chelating effect due to easy generation of precipitates in the chelating process, and the crop utilization rate is low.

Aiming at the current problems, the invention provides a microbial preparation for compounding chelated medium and trace elements.

Firstly activating sugar alcohol by polyglutamic acid to serve as a first chelating agent, and then adding fulvic acid to serve as a supplementary chelating agent, wherein the activated sugar alcohol is easier to form a small-molecular organic chelate with medium and trace elements, so that the medium and trace elements exist in the form of amino acid and sugar alcohol chelate to the maximum extent and are transferred into a plant body, and the fulvic acid serves as the supplementary chelating agent, so that the medium and trace elements are chelated on one hand, and inorganic selenium salt can be dissolved on the other hand.

Secondly, the active substances secreted by the rabbit cryptococcus ferment in the microbial fermentation broth can effectively relieve partial antagonism between metal elements and between the metal elements and selenium elements, can promote the absorption of medium trace elements, can promote the inorganic selenium salt dissolved by fulvic acid to be converted into organic selenium which is easy to be absorbed, improves the selenium content of a crop body, and the added bacillus subtilis can also improve the disease resistance of the crop and improve the crop yield.

The liquid biological agent can promote the formation of a soil granular structure, activate hardened soil, enhance the water and fertilizer retention capability of the soil, effectively improve the utilization rate of fertilizer nutrients, has no harm to the environment after long-term use, and has wide economic benefit and social benefit.

Detailed Description

The technical solution of the present invention is further described below with reference to specific embodiments, but is not limited thereto.

Example 1

A selenium-rich sugar alcohol chelate type medium-trace element biological agent is prepared from selenium salt 0.15 parts, activated sugar alcohol 10 parts, medium element 30 parts, fulvic acid 10 parts, trace elements 4 parts, microbial fermentation liquid 3 parts and water 50 parts.

Further, the selenium salt is sodium selenate.

Further, the preparation method of the activated sugar alcohol comprises the following steps: the sugar alcohol and polyglutamic acid solution were mixed according to a ratio of 10 g: adding 100ml into container, heating to 40-50 deg.C, stirring to dissolve completely, and cooling to room temperature to obtain activated sugar alcohol with polyglutamic acid solution mass concentration of 50%.

Further, the sugar alcohol is mannitol.

Further, the secondary elements are calcium nitrate and magnesium nitrate.

Further, the trace elements are ferrous sulfate, manganese sulfate, zinc sulfate, copper sulfate, boric acid and ammonium heptamolybdate.

Further, the preparation method of the microbial fermentation liquid comprises the following steps: respectively inoculating cryptococcus rabbit and bacillus subtilis on LB solid culture medium, culturing at constant temperature of 25 deg.C for 5 hr to obtain seed liquid, respectively inoculating the seed liquid in LB liquid culture medium according to 1% inoculum size, reciprocating shaking table 150 r.min^-1And culturing at the constant temperature of 28 ℃ for 12h until the bacteria content is O.D600 about 2.0, and mixing according to the volume ratio of 1:1 to obtain the microbial zymogen liquid.

Further, the composition of the LB medium is: tryptone 20g, yeast extract 5g, NaCl 5g, distilled water 1000mL, pH 7.2-7.4, sterilizing at 121 deg.C for 19min, and adding agar powder 10g into solid culture medium

Further, the cryptococcus rabbit is CGMCC2.5648, and the bacillus subtilis is CGMCC 1.14985.

Further, Cryptococcus rabbit (Cryptococcus cuniculus) of the present invention is purchased from China General Microbiological Culture Collection Center (CGMCC), and has the address: west road No. 1 hospital No. 3, north jing, chaoyang district, preservation date: 2016, 4/20/month, accession number: CGMCC 2.5648.

Further, Bacillus subtilis (CGMCC) of the present invention is purchased from China General Microbiological Culture Collection Center (CGMCC), and has the following address: west road No. 1 hospital No. 3, north jing, chaoyang district, preservation date: no. 12/10 in 2014, accession no: CGMCC 1.14985.

A preparation method of a chelated medium-trace element biological agent rich in selenium sugar alcohol comprises the following steps:

(1) the sugar alcohol and polyglutamic acid solution were mixed according to a ratio of 10 g: adding 100ml of the mixture into a container, heating to 40 ℃, stirring until the mixture is completely dissolved, and cooling to room temperature to obtain activated sugar alcohol;

(2) adding activated sugar alcohol and fulvic acid into water in sequence according to the weight part, maintaining the temperature of the solution at 60 ℃, and stirring until the activated sugar alcohol and the fulvic acid are completely dissolved to obtain a mixture A;

(3) adding the secondary elements and the trace elements into the mixture A according to the parts by weight, maintaining the temperature of the solution at 60 ℃, and stirring at a constant speed for 10 minutes to obtain a mixture B;

(4) adding selenium salt into the mixture B according to the weight part, maintaining the temperature of the solution at 60 ℃, uniformly stirring for 10 minutes, and cooling to room temperature to obtain a mixture C;

(5) and finally adding the microbial fermentation bacteria liquid according to the weight parts, and uniformly stirring at room temperature to obtain a finished product.

Example 2

The chelating type medium and trace element biological microbial inoculum rich in selenium sugar alcohol is prepared from 0.2 part of selenium salt, 20 parts of activated sugar alcohol, 40 parts of medium element, 12 parts of fulvic acid, 6 parts of trace element, 4 parts of microbial fermentation liquor and 80 parts of water.

Further, the selenium salt is potassium selenate.

Further, the preparation method of the activated sugar alcohol comprises the following steps: the sugar alcohol and polyglutamic acid solution were mixed according to a ratio of 10 g: adding 100ml into a container, heating to 50 deg.C, stirring to dissolve completely, and cooling to room temperature to obtain activated sugar alcohol with 50% of polyglutamic acid solution.

Further, the sugar alcohol is sorbitol.

Further, the secondary elements are calcium nitrate and magnesium nitrate.

Further, the trace elements are ferrous sulfate, manganese sulfate, zinc sulfate, copper sulfate, boric acid and ammonium heptamolybdate.

Further, the preparation method of the microbial fermentation liquid comprises the following steps: respectively inoculating cryptococcus rabbit and bacillus subtilis on LB solid culture medium, culturing at 28 deg.C for 8 hr to obtain seed liquid, respectively inoculating the seed liquid in LB liquid culture medium according to 1% inoculum size, reciprocating shaking table 150 r.min^-1And culturing at the constant temperature of 28 ℃ for 12h until the bacteria content is O.D600 about 2.0, and mixing according to the volume ratio of 1:1 to obtain the microbial zymogen liquid.

Further, the composition of the LB medium is: tryptone 20g, yeast extract 5g, NaCl 5g, distilled water 1000mL, pH 7.2-7.4, sterilizing at 121 deg.C for 19min, and adding agar powder 10g into solid culture medium

Further, the cryptococcus rabbit is CGMCC2.5648, and the bacillus subtilis is CGMCC 1.14985.

Further, Cryptococcus rabbit (Cryptococcus cuniculus) of the present invention is purchased from China General Microbiological Culture Collection Center (CGMCC), and has the address: west road No. 1 hospital No. 3, north jing, chaoyang district, preservation date: 2016, 4/20/month, accession number: CGMCC 2.5648.

Further, Bacillus subtilis (CGMCC) of the present invention is purchased from China General Microbiological Culture Collection Center (CGMCC), and has the following address: west road No. 1 hospital No. 3, north jing, chaoyang district, preservation date: no. 12/10 in 2014, accession no: CGMCC 1.14985.

A preparation method of a chelated medium-trace element biological agent rich in selenium sugar alcohol comprises the following steps:

(1) the sugar alcohol and polyglutamic acid solution were mixed according to a ratio of 10 g: adding 100ml of the mixture into a container, heating to 50 ℃, stirring until the mixture is completely dissolved, and cooling to room temperature to obtain activated sugar alcohol;

(2) adding activated sugar alcohol and fulvic acid into water in sequence according to the weight parts, maintaining the temperature of the solution at 100 ℃, and stirring until the activated sugar alcohol and the fulvic acid are completely dissolved to obtain a mixture A;

(3) adding the secondary elements and the trace elements into the mixture A according to the parts by weight, maintaining the temperature of the solution at 100 ℃, and stirring at a constant speed for 30 minutes to obtain a mixture B;

(4) adding selenium salt into the mixture B according to the weight part, maintaining the temperature of the solution at 100 ℃, uniformly stirring for 30 minutes, and cooling to room temperature to obtain a mixture C;

(5) and finally adding the microbial fermentation bacteria liquid according to the weight parts, and uniformly stirring at room temperature to obtain a finished product.

Example 3

The chelating type medium and trace element biological microbial inoculum rich in selenium sugar alcohol is prepared from 0.3 part of selenium salt, 30 parts of activated sugar alcohol, 50 parts of medium element, 15 parts of fulvic acid, 8 parts of trace element, 5 parts of microbial fermentation liquor and 100 parts of water.

Further, the selenium salt is a mixture of potassium selenate and potassium selenite in a ratio of 1: 1.

Further, the preparation method of the activated sugar alcohol comprises the following steps: the sugar alcohol and polyglutamic acid solution were mixed according to a ratio of 10 g: adding 100ml into container, heating to 40-50 deg.C, stirring to dissolve completely, and cooling to room temperature to obtain activated sugar alcohol with polyglutamic acid solution mass concentration of 50%.

Further, the sugar alcohol is xylitol.

Further, the secondary elements are calcium nitrate and magnesium nitrate.

Further, the trace elements are ferrous sulfate, manganese sulfate, zinc sulfate, copper sulfate, boric acid and ammonium heptamolybdate.

Further, the preparation method of the microbial fermentation liquid comprises the following steps: respectively inoculating cryptococcus rabbit and bacillus subtilis on LB solid culture medium, culturing at 28 deg.C for 8 hr to obtain seed liquid, respectively inoculating the seed liquid in LB liquid culture medium according to 1% inoculum size, reciprocating shaking table 150 r.min^-1And culturing at the constant temperature of 28 ℃ for 12h until the bacteria content is O.D600 about 2.0, and mixing according to the volume ratio of 1:1 to obtain the microbial zymogen liquid.

Further, the composition of the LB medium is: tryptone 20g, yeast extract 5g, NaCl 5g, distilled water 1000mL, pH 7.2-7.4, sterilizing at 121 deg.C for 19min, and adding agar powder 10g into solid culture medium

Further, the cryptococcus rabbit is CGMCC2.5648, and the bacillus subtilis is CGMCC 1.14985.

Further, Cryptococcus rabbit (Cryptococcus cuniculus) of the present invention is purchased from China General Microbiological Culture Collection Center (CGMCC), and has the address: west road No. 1 hospital No. 3, north jing, chaoyang district, preservation date: 2016, 4/20/month, accession number: CGMCC 2.5648.

Further, Bacillus subtilis (CGMCC) of the present invention is purchased from China General Microbiological Culture Collection Center (CGMCC), and has the following address: west road No. 1 hospital No. 3, north jing, chaoyang district, preservation date: no. 12/10 in 2014, accession no: CGMCC 1.14985.

A preparation method of a chelated medium-trace element biological agent rich in selenium sugar alcohol comprises the following steps:

(1) the sugar alcohol and polyglutamic acid solution were mixed according to a ratio of 10 g: adding 100ml of the mixture into a container, heating to 50 ℃, stirring until the mixture is completely dissolved, and cooling to room temperature to obtain activated sugar alcohol;

(2) adding activated sugar alcohol and fulvic acid into water in sequence according to the weight parts, maintaining the temperature of the solution at 100 ℃, and stirring until the activated sugar alcohol and the fulvic acid are completely dissolved to obtain a mixture A;

(3) adding the secondary elements and the trace elements into the mixture A according to the parts by weight, maintaining the temperature of the solution at 100 ℃, and stirring at a constant speed for 30 minutes to obtain a mixture B;

(4) adding selenium salt into the mixture B according to the weight part, maintaining the temperature of the solution at 100 ℃, uniformly stirring for 30 minutes, and cooling to room temperature to obtain a mixture C;

(5) and finally adding the microbial fermentation bacteria liquid according to the weight parts, and uniformly stirring at room temperature to obtain a finished product.

Comparative example 1

A selenium-rich sugar alcohol chelate type medium-trace element biological agent is prepared from selenium salt 0.3 parts, sugar alcohol 30 parts, medium element 50 parts, fulvic acid 15 parts, trace element 8 parts, microbial fermentation liquid 5 parts and water 100 parts.

Further, the selenium salt is a mixture of potassium selenate and potassium selenite in a ratio of 1: 1.

Further, the sugar alcohol is one or more of mannitol, sorbitol, xylitol and maltitol.

Further, the secondary elements are calcium nitrate and magnesium nitrate.

Further, the trace elements are ferrous sulfate, manganese sulfate, zinc sulfate, copper sulfate, boric acid and ammonium heptamolybdate.

Further, the preparation method of the microbial fermentation liquid comprises the following steps: respectively inoculating cryptococcus rabbit and bacillus subtilis on LB solid culture medium, culturing at 28 deg.C for 8 hr to obtain seed liquid, respectively inoculating the seed liquid in LB liquid culture medium according to 1% inoculum size, reciprocating shaking table 150 r.min^-1And culturing at the constant temperature of 28 ℃ for 12h until the bacteria content is O.D600 about 2.0, and mixing according to the volume ratio of 1:1 to obtain the microbial zymogen liquid.

Further, the composition of the LB medium is: tryptone 20g, yeast extract 5g, NaCl 5g, distilled water 1000mL, pH 7.2-7.4, sterilizing at 121 deg.C for 19min, and adding agar powder 10g into solid culture medium

Further, the cryptococcus rabbit is CGMCC2.5648, and the bacillus subtilis is CGMCC 1.14985.

Further, this comparative example, Cryptococcus rabbit (Cryptococcus cuniculus), purchased from China General Microbiological Culture Collection Center (CGMCC), address: west road No. 1 hospital No. 3, north jing, chaoyang district, preservation date: 2016, 4/20/month, accession number: CGMCC 2.5648.

Further, this comparative example was Bacillus subtilis (CGMCC), available from China General Microbiological Culture Collection Center (CGMCC), having the following address: west road No. 1 hospital No. 3, north jing, chaoyang district, preservation date: no. 12/10 in 2014, accession no: CGMCC 1.14985.

A preparation method of a chelated medium-trace element biological agent rich in selenium sugar alcohol comprises the following steps:

(1) adding sugar alcohol and fulvic acid into water in sequence according to the weight part, maintaining the temperature of the solution at 100 ℃, and stirring until the sugar alcohol and the fulvic acid are completely dissolved to obtain a mixture A;

(2) adding the secondary elements and the trace elements into the mixture A according to the parts by weight, maintaining the temperature of the solution at 100 ℃, and stirring at a constant speed for 30 minutes to obtain a mixture B;

(3) adding selenium salt into the mixture B according to the weight part, maintaining the temperature of the solution at 100 ℃, uniformly stirring for 30 minutes, and cooling to room temperature to obtain a mixture C;

(4) and finally adding the microbial fermentation bacteria liquid according to the weight parts, and uniformly stirring at room temperature to obtain a finished product.

This comparative example was the same as example 3 except that activation of the sugar alcohol was not performed.

Comparative example 2

The chelating type medium and trace element biological microbial inoculum rich in selenium sugar alcohol is prepared from 0.3 part of selenium salt, 30 parts of activated sugar alcohol, 50 parts of medium element, 15 parts of fulvic acid, 8 parts of trace element, 5 parts of microbial fermentation liquor and 100 parts of water.

Further, the selenium salt is a mixture of potassium selenate and potassium selenite in a ratio of 1: 1.

Further, the preparation method of the activated sugar alcohol comprises the following steps: the sugar alcohol and polyglutamic acid solution were mixed according to a ratio of 10 g: adding 100ml into container, heating to 40-50 deg.C, stirring to dissolve completely, and cooling to room temperature to obtain activated sugar alcohol with polyglutamic acid solution mass concentration of 50%.

Further, the sugar alcohol is xylitol.

Further, the secondary elements are calcium nitrate and magnesium nitrate.

Further, the trace elements are ferrous sulfate, manganese sulfate, zinc sulfate, copper sulfate, boric acid and ammonium heptamolybdate.

Further, the preparation method of the microbial fermentation liquid comprises the following steps: inoculating Bacillus subtilis to LB solid culture medium, culturing at 28 deg.C for 8 hr to obtain seed solution, inoculating the seed solution to LB liquid culture medium according to 1% inoculum size, and reciprocating shaking table for 150 r.min^-1And culturing at the constant temperature of 28 ℃ for 12h until the bacterium content is O.D600 about 2.0 to obtain the microbial zymogen liquid.

Further, the composition of the LB medium is: tryptone 20g, yeast extract 5g, NaCl 5g, distilled water 1000mL, pH 7.2-7.4, sterilizing at 121 deg.C for 19min, and adding agar powder 10g into solid culture medium

Further, this comparative example was Bacillus subtilis (CGMCC), available from China General Microbiological Culture Collection Center (CGMCC), having the following address: west road No. 1 hospital No. 3, north jing, chaoyang district, preservation date: no. 12/10 in 2014, accession no: CGMCC 1.14985.

A preparation method of a chelated medium-trace element biological agent rich in selenium sugar alcohol comprises the following steps:

(1) the sugar alcohol and polyglutamic acid solution were mixed according to a ratio of 10 g: adding 100ml of the mixture into a container, heating to 50 ℃, stirring until the mixture is completely dissolved, and cooling to room temperature to obtain activated sugar alcohol;

(2) adding activated sugar alcohol and fulvic acid into water in sequence according to the weight parts, maintaining the temperature of the solution at 100 ℃, and stirring until the activated sugar alcohol and the fulvic acid are completely dissolved to obtain a mixture A;

(3) adding the secondary elements and the trace elements into the mixture A according to the parts by weight, maintaining the temperature of the solution at 100 ℃, and stirring at a constant speed for 30 minutes to obtain a mixture B;

(4) adding selenium salt into the mixture B according to the weight part, maintaining the temperature of the solution at 100 ℃, uniformly stirring for 30 minutes, and cooling to room temperature to obtain a mixture C;

(5) and finally adding the microbial fermentation bacteria liquid according to the weight parts, and uniformly stirring at room temperature to obtain a finished product.

In this comparative example, the procedure of example 3 was repeated except that the microbial fermentation broth contained no cryptococcus rabbit.

Comparative example 3

The chelating type medium and trace element biological microbial inoculum rich in selenium sugar alcohol is prepared from 0.3 part of selenium salt, 30 parts of activated sugar alcohol, 50 parts of medium element, 15 parts of fulvic acid, 8 parts of trace element, 5 parts of microbial fermentation liquor and 100 parts of water.

Further, the selenium salt is a mixture of potassium selenate and potassium selenite in a ratio of 1: 1.

Further, the preparation method of the activated sugar alcohol comprises the following steps: the sugar alcohol and polyglutamic acid solution were mixed according to a ratio of 10 g: adding 100ml into container, heating to 40-50 deg.C, stirring to dissolve completely, and cooling to room temperature to obtain activated sugar alcohol with polyglutamic acid solution mass concentration of 50%.

Further, the sugar alcohol is xylitol.

Further, the secondary elements are calcium nitrate and magnesium nitrate.

Further, the trace elements are ferrous sulfate, manganese sulfate, zinc sulfate, copper sulfate, boric acid and ammonium heptamolybdate.

Further, the preparation method of the microbial fermentation liquid comprises the following steps: inoculating Cryptococcus rabbit on LB solid culture medium, culturing at 28 deg.C for 8 hr to obtain seed liquid, inoculating the seed liquid in LB liquid culture medium according to 1% inoculum size, and reciprocating shaking table150r·min^-1And culturing at the constant temperature of 28 ℃ for 12h until the bacterium content is O.D600 about 2.0 to obtain the microbial zymogen liquid.

Further, the composition of the LB medium is: tryptone 20g, yeast extract 5g, NaCl 5g, distilled water 1000mL, pH 7.2-7.4, sterilizing at 121 deg.C for 19min, and adding agar powder 10g into solid culture medium

Further, the cryptococcus rabbit is CGMCC 2.5648.

Further, this comparative example, Cryptococcus rabbit (Cryptococcus cuniculus), purchased from China General Microbiological Culture Collection Center (CGMCC), address: west road No. 1 hospital No. 3, north jing, chaoyang district, preservation date: 2016, 4/20/month, accession number: CGMCC 2.5648.

A preparation method of a chelated medium-trace element biological agent rich in selenium sugar alcohol comprises the following steps:

(1) the sugar alcohol and polyglutamic acid solution were mixed according to a ratio of 10 g: adding 100ml of the mixture into a container, heating to 50 ℃, stirring until the mixture is completely dissolved, and cooling to room temperature to obtain activated sugar alcohol;

(2) adding activated sugar alcohol and fulvic acid into water in sequence according to the weight parts, maintaining the temperature of the solution at 100 ℃, and stirring until the activated sugar alcohol and the fulvic acid are completely dissolved to obtain a mixture A;

(3) adding the secondary elements and the trace elements into the mixture A according to the parts by weight, maintaining the temperature of the solution at 100 ℃, and stirring at a constant speed for 30 minutes to obtain a mixture B;

(4) adding selenium salt into the mixture B according to the weight part, maintaining the temperature of the solution at 100 ℃, uniformly stirring for 30 minutes, and cooling to room temperature to obtain a mixture C;

(5) and finally adding the microbial fermentation bacteria liquid according to the weight parts, and uniformly stirring at room temperature to obtain a finished product.

This comparative example is the same as example 3 except that the microbial fermentation broth does not contain Bacillus subtilis.

Fertilizer efficiency test

Test site: in a modern agriculture demonstration garden in Lin Shu city, Shandong province, the physicochemical properties of the soil to be tested are shown in Table 1.

TABLE 1 physicochemical Properties of the soil

Test work: tomato of the variety "Provence"

Experiment design: a total of 7 treatments were set for examples 1-3, comparative examples 1-3 and the blank

Base fertilizer (N: P)₂O₅︰K₂O15: 15: 15) the liquid microbial inoculum is applied once before planting, in the examples and the comparative examples, 55 percent, 30 percent and 15 percent are applied in the full-bloom stage and the total amount is 300L/hm according to the fertilizer requirement characteristics of tomatoes in the seedling stage of the tomatoes²。

Repeating each treatment for 3 times, randomly arranging in blocks, laying isolation membrane with depth of 1m between cells, area of 8 square meters, planting fructus Lycopersici Esculenti with membrane, 1 membrane, 2 tubes and 2 rows, plant spacing of 65cm, and theoretical number of plants of 5.2 × 10⁴Strain/hm². Total irrigation quantity 2700m³/hm²Irrigating for 8 times, treating the fungicide and fertilizing with water, wherein each treatment adopts a separate fertilizing tank, and other cultivation management measures refer to local fields.

Measurement items and methods

After the fruits are harvested, the edible parts of the tomato fruits are taken and washed by clear water and distilled water, and finally, the water is absorbed by absorbent paper for standby. Measuring the content of soluble solid in part of tomato fruits, and measuring the content of vitamin C and soluble sugar in another part of tomato fruits. Deactivating enzyme of the rest fructus Lycopersici Esculenti in oven at 105 deg.C for 30min, oven drying in oven at constant temperature of 60 deg.C to constant mass, pulverizing with pulverizer, sealing, and storing for determining content of each element in fruit.

The content of soluble solid is measured by a refractometer method; the content of vitamin C is determined by adopting a 2, 6-dichloroindophenol titration method; the content of soluble sugar is determined by anthrone colorimetry.

Ca. Measuring Mg, Fe, Mn, Cu, Zn, Mo and Se elements, weighing 0.15g of sample, adding 6mL of HNO₃1mL HF and 1mL H₂O₂Placing the mixture in a BHW-09A type constant temperature digestion instrument, carrying out pre-digestion at 120 ℃ for 30min, transferring the mixture into an ETHOSA type microwave digestion instrument for digestion at 160 ℃ for about 1h, then placing the mixture into the BHW-09A type constant temperature digestion instrument for digestion at 160 ℃, carrying out acid dispelling until the volume of digestion liquid is about 1mL, and carrying out constant volume to 45 mL; ca and Mg were measured by ICE3500 atomic absorption spectrometer, Fe, Mn, Cu, Zn, Mo and Se were measured by Nex ION350X inductively coupled plasma mass spectrometer.

The selenium enrichment capacity of the tomatoes, namely the capacity of the crops to absorb selenium element, is measured by a biological enrichment factor (BCF).

The calculation formula is as follows:

the biological enrichment factor (%) ═ concentration of elements in the organism/concentration of elements in the root soil × 100.

Tomato yield assay

Respectively weighing 1 st ear fruit to 3 rd ear fruit when fruit is mature, calculating average single plant yield and whole plant single plant yield of each ear fruit, and finally converting to 667m per ear fruit²And (4) yield.

TABLE 2 tomato planting Effect

As can be seen from the data in the table, the tomato fruit obtained in the embodiment of the invention has better quality indexes such as fruit VC, soluble sugar and the like, and better accumulation of mineral elements and selenium elements than the comparative example 1 which has less activation means and changes the comparative ratio 2-3 of microbial composition, which probably because the addition of the activated sugar alcohol and the fulvic acid jointly promote the chelation of medium and trace elements, and the addition of the microbial fermentation liquor can promote the absorption of selenium elements and trace elements in the chelation by crops, and the combination of carbohydrate substances generated by mass propagation in soil, plant mucus, mineral embryo bodies and the like can improve the granular structure of soil, decompose organic substances and minerals, release nutrient elements, simultaneously form humus, improve the soil fertility, promote the transportation of upward moisture of root systems and selenium elements and trace elements, forming a good system, thereby promoting the growth of the ground and the underground part and improving the mixing amount and the quality of the tomatoes on the whole. The raw materials of the invention cooperate with each other to realize the efficient absorption and utilization of selenium and medium and trace elements by crops.

It should be noted that the above-mentioned embodiments are only some of the preferred modes for implementing the invention, and not all of them. Obviously, all other embodiments obtained by persons of ordinary skill in the art based on the above-mentioned embodiments of the present invention without any creative effort shall fall within the protection scope of the present invention.