CN114751784A - Composite biological selenium-rich foliar fertilizer and preparation method thereof - Google Patents

Abstract

The invention provides a compound biological selenium-rich foliar fertilizer and a preparation method thereof, wherein the selenium-rich foliar fertilizer is prepared from the following raw materials in parts by weight: 10-20 parts of yeast extract powder, 30-40 parts of mushroom residue, 10-30 parts of selenium-rich photosynthetic bacteria fermentation liquor, 5-10 parts of bacillus fermentation liquor, 2-5 parts of potassium fulvate, 0.5-1 part of shell powder, 2-5 parts of polyethylene glycol and 2-5 parts of sodium bentonite. The invention uses the yeast extract powder and the mushroom residue fermentation product as nutrient sources to promote the further fermentation of the selenium-rich photosynthetic bacteria fermentation liquor and the bacillus fermentation liquor, so that the selenium-rich foliar fertilizer has comprehensive nutrition, and improves the absorption rate of plants to selenium, silicon and other nutrient elements while promoting the photosynthetic efficiency of the plants. The photosynthetic efficiency of the plant can be promoted by the matching of the biological organic selenium and the biological organic silicon. And the nitrogen-fixing rhodobacter has good nitrogen-fixing effect, and can promote the growth and development of plants together with the bacillus and improve the crop yield.

Description

Composite biological selenium-rich foliar fertilizer and preparation method thereof

Technical Field

The invention relates to the technical field of biological fertilizers, in particular to a compound biological selenium-rich foliar fertilizer and a preparation method thereof.

Background

Selenium is a trace element necessary for people, and has the functions of resisting oxidation, enhancing immunity, eliminating free radicals, protecting a biological membrane, preventing division and growth of cancer cells and the like. Selenium in human bodies needs to be supplemented by means of dietary intake, and the insufficient intake of selenium easily influences the physical health of people. At present, selenium element existing in nature mainly comprises chemical selenium and biological selenium, and the chemical selenium has strong toxicity and low human body absorption rate. Biological selenium is formed by combining selenium and organic substances in organisms through biotransformation, so that the biological selenium is safer and has relatively high absorption rate. Therefore, the acquisition of biological selenium is an important subject of research.

At present, a plant transformation method is a safe and effective means for obtaining biological selenium, but in the plant transformation process, inorganic selenium fertilizer or chemically synthesized organic selenide is sprayed outside roots, so that the utilization rate of selenium is low, the transformation rate of organic selenium is low, the finally obtained selenium-rich agricultural products have low organic selenium content which is not enough to meet the requirements of human bodies, and the inorganic selenium or chemically synthesized organic selenide easily causes irreversible damage to plants and pollution to soil and water quality.

In addition, the existing selenium-rich foliar fertilizer cannot promote the absorption and transformation of plants to selenium and cannot effectively prevent diseases.

Disclosure of Invention

In order to solve the technical problems, the invention aims to provide a compound biological selenium-rich foliar fertilizer and a preparation method thereof.

In order to achieve the above object, the technical scheme of the invention is as follows.

The compound biological selenium-rich foliar fertilizer consists of the following raw materials in parts by weight:

10-20 parts of yeast extract powder, 30-40 parts of mushroom residue, 10-30 parts of selenium-rich photosynthetic bacteria fermentation liquor, 5-10 parts of bacillus fermentation liquor, 2-5 parts of potassium fulvate, 0.5-1 part of shell powder, 2-5 parts of polyethylene glycol and 2-5 parts of sodium bentonite.

Further, the selenium-rich photosynthetic bacteria fermentation broth is prepared as follows:

adding sodium selenite into the RCVBN culture medium to obtain a selenium-rich liquid culture medium;

inoculating azotobacter in a selenium-rich liquid culture medium, and culturing for 2-5 days at the temperature of 20-35 ℃ under natural illumination conditions to obtain the azotobacter; wherein the inoculation amount of the azotobacter is 5-20% (volume fraction).

Furthermore, the amount of sodium selenite added is 0.5-2.0 g per 1L of RCVBN culture medium.

Furthermore, the nitrogen-fixing red bacteria are cultured under the micro-aerobic condition with the dissolved oxygen concentration of 0.2-1.0 mg/L.

The RCVBN culture medium comprises the following components: 4g/L of D, L-malic acid, 1g/L of ammonium sulfate, 0.9g/L of dipotassium phosphate, 0.6g/L of monopotassium phosphate, 0.12g/L of magnesium sulfate heptahydrate, 0.075g/L of calcium chloride and 0.012g/L, Na of ferrous sulfate heptahydrate₂EDTA 0.02g/L, boric acid 2.8X 10^-3g/L, manganese sulfate 41.6X 10^-3g/L, 2.4X 10 zinc sulfate heptahydrate^-4g/L, sodium molybdate dihydrate 7.52X 10^-4g/L, calcium nitrate trihydrate 4X 10^-5g/L, thiamine hydrochloride 1X 10^-3g/L, biotin 1.5X 10^-5g/L, 1X 10 nicotinic acid^-3g/L, 1X 10 of p-aminobenzoic acid^-3g/L，pH6.8。

Further, the bacillus fermentation broth is prepared as follows:

adding sodium silicate into the liquid culture medium B, and adjusting the pH to 6.5-7.2; and inoculating 5-10% of the inoculum size into the activated bacillus subtilis microbial inoculum, and culturing for 2-6 days at 30-40 ℃ to obtain the bacillus subtilis microbial inoculum.

Further, the sodium silicate is added in an amount of 0.5 to 2.0g per 1L of the liquid medium B.

Further, the formula of the liquid medium B is as follows:

3.5g of glucose, 5g of yeast extract, 10g of peptone, 3g of magnesium sulfate, 0.025g of manganese sulfate, 0.4g of potassium dihydrogen phosphate and 0.6g of dipotassium hydrogen phosphate were added to 1L of sterile water, and the pH was 7.2.

A preparation method of a compound biological selenium-rich foliar fertilizer comprises the following steps:

S1, weighing the components according to the weight part ratio of claim 1; mixing the crushed mushroom residues with the yeast extract powder, fermenting at the humidity of 60-65%, adding sodium bentonite after fermentation is finished, and fully and uniformly mixing to obtain a nutrient source;

s2, dividing the nutrient source of S1 into two parts, respectively adding the two parts into the selenium-rich photosynthetic bacterium fermentation liquid and the bacillus fermentation liquid, introducing sterile air, stirring and fermenting at 30-40 ℃, filtering after fermentation is completed, and combining the two parts of filtrate to obtain the selenium-rich biological agent;

s3, uniformly mixing the potassium fulvate, the shell powder and the polyethylene glycol, then adding the selenium-enriched biological agent of S2, and fully and uniformly mixing to obtain the compound biological selenium-enriched foliar fertilizer.

The invention has the beneficial effects that:

1. the invention promotes selenium to be converted into biological organic selenium by nitrogen-fixing red bacteria to obtain selenium-rich photosynthetic bacteria fermentation liquor; promoting the silicon to be converted into biological organic silicon by using bacillus to obtain silicon-rich bacillus fermentation liquor; the yeast extract powder and the mushroom residue fermentation product are used as nutrient sources to promote further fermentation of the selenium-rich photosynthetic bacteria fermentation liquor and the bacillus fermentation liquor so as to obtain nutrient elements which can be absorbed and utilized by plants, so that the selenium-rich foliar fertilizer is comprehensive in nutrition, and the absorption rate of the plants to selenium, silicon and other nutrient elements is improved while the plant photosynthetic efficiency is promoted.

2. The invention can promote the photosynthetic efficiency of plants by matching the biological organic selenium and the biological organic silicon. And the nitrogen-fixing rhodobacter has good nitrogen-fixing effect, and can promote the growth and development of plants together with the bacillus and improve the crop yield.

3. The bacillus of the invention can also exert the biological control effect of plant diseases, thereby reducing the application of pesticides and reducing the pesticide residue of agricultural products.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail with reference to the following embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Azotobacteria, Shanghai plain Biotech, Inc.

Bacillus subtilis microbial inoculum, Weifang Yihao biotechnology Limited.

The experimental methods described in the following examples are all conventional methods unless otherwise specified; the reagents and materials are commercially available, unless otherwise specified.

Example 1

The compound biological selenium-rich foliar fertilizer consists of the following raw materials in parts by weight:

12 parts of yeast extract powder, 35 parts of mushroom residue, 22 parts of selenium-rich photosynthetic bacteria fermentation liquor, 8 parts of bacillus fermentation liquor, 3 parts of potassium fulvate, 0.6 part of shell powder, 3 parts of polyethylene glycol and 3 parts of sodium bentonite.

The preparation method of the compound biological selenium-rich foliar fertilizer comprises the following steps:

s1 preparation of selenium-rich photosynthetic bacteria fermentation liquor

Adding sodium selenite into RCVBN culture medium, and adding 1.0g of sodium selenite into each 1L of RCVBN culture medium to obtain selenium-rich liquid culture medium;

the RCVBN culture medium comprises the following components: 4g/L of D, L-malic acid, 1g/L of ammonium sulfate, 0.9g/L of dipotassium phosphate, 0.6g/L of monopotassium phosphate, 0.12g/L of magnesium sulfate heptahydrate, 0.075g/L of calcium chloride and 0.012g/L, Na of ferrous sulfate heptahydrate₂EDTA 0.02g/L, boric acid 2.8X 10^-3g/L, manganese sulfate 41.6X 10^-3g/L, 2.4X 10 zinc sulfate heptahydrate^-4g/L, sodium molybdate dihydrate 7.52X 10^-4g/L, calcium nitrate trihydrate 4X 10^-5g/L, thiamine hydrochloride 1X 10^-3g/L, biotin 1.5X 10^-5g/L, 1X 10 nicotinic acid^-3g/L, 1X 10 of p-aminobenzoic acid^-3g/L，pH6.8。

Inoculating azotobacteria in selenium-rich liquid culture medium, and culturing at 30 deg.C under natural illumination for 4 days; wherein the inoculation amount of the azotobacter is 10 percent (volume). The nitrogen-fixing rhodobacter is cultured under the micro-aerobic condition with the dissolved oxygen concentration of 0.5 mg/L. The thallus concentration in the selenium-rich photosynthetic bacteria fermentation liquor is 1.62 multiplied by 10 ⁸cfu/mL。

S2 preparation of Bacillus fermentation liquor

Sodium silicate was added to liquid medium B at a ratio of 1.0g per 1L of liquid medium B. Adjusting the pH to 7.2; then inoculating the activated bacillus subtilis microbial inoculum with the inoculation amount of 8 percent, and culturing for 5 days at the temperature of 38 ℃ to obtain the bacillus subtilis microbial inoculum. The thallus concentration in the bacillus fermentation liquor is 2.13 multiplied by 10⁷cfu/mL。

The formula of the liquid culture medium B is as follows: 3.5g of glucose, 5g of yeast extract, 10g of peptone, 3g of magnesium sulfate, 0.025g of manganese sulfate, 0.4g of potassium dihydrogen phosphate and 0.6g of dipotassium hydrogen phosphate were added to 1L of sterile water, and the pH was 7.2.

S3, mixing the crushed mushroom residues with yeast extract powder, fermenting at 60% humidity, adding sodium bentonite after fermentation, and fully and uniformly mixing to obtain a nutrient source;

s4, dividing the nutrient source of S3 into two parts, respectively adding the two parts into the selenium-rich photosynthetic bacteria fermentation liquor of S1 and the bacillus fermentation liquor of S2, introducing sterile air, stirring and fermenting for 7 days at 38 ℃, filtering after fermentation is finished, and combining the two parts of filtrate to obtain the selenium-rich biological agent;

s5, uniformly mixing the potassium fulvate, the shell powder and the polyethylene glycol, then adding the selenium-rich biological agent of S4, and fully and uniformly mixing to obtain the compound biological selenium-rich foliar fertilizer.

Example 2

The compound biological selenium-rich foliar fertilizer consists of the following raw materials in parts by weight:

20 parts of yeast extract powder, 40 parts of mushroom residue, 30 parts of selenium-rich photosynthetic bacteria fermentation liquor, 10 parts of bacillus fermentation liquor, 5 parts of potassium fulvate, 1 part of shell powder, 5 parts of polyethylene glycol and 5 parts of sodium bentonite.

The preparation method of the compound biological selenium-rich foliar fertilizer comprises the following steps:

s1 preparation of selenium-rich photosynthetic bacteria fermentation liquor

Adding sodium selenite into RCVBN culture medium, and adding 2.0g of sodium selenite into each 1L of RCVBN culture medium to obtain selenium-rich liquid culture medium;

inoculating azotobacteria into selenium-rich liquid culture medium, and culturing at 35 deg.C under natural illumination for 2 days; wherein the inoculation amount of the azotobacteria is 20% (volume). The culture of the azotobacter is carried out under the micro-aerobic condition with the dissolved oxygen concentration of 1.0 mg/L. The thallus concentration in the selenium-rich photosynthetic bacteria fermentation liquor is 1.36 multiplied by 10⁸cfu/mL。

S2 preparation of Bacillus fermentation liquor

Sodium silicate was added to the liquid medium B in an amount of 2.0g per 1L of the liquid medium B. Adjusting the pH to 7.0; then inoculating the activated bacillus subtilis microbial inoculum with the inoculation amount of 10 percent, and culturing for 6 days at the temperature of 40 ℃ to obtain the bacillus subtilis microbial inoculum. The thallus concentration in the bacillus fermentation liquor is 1.71 multiplied by 10 ⁷cfu/mL。

The formula of the liquid culture medium B is as follows: 3.5g of glucose, 5g of yeast extract, 10g of peptone, 3g of magnesium sulfate, 0.025g of manganese sulfate, 0.4g of monopotassium phosphate and 0.6g of dipotassium phosphate are added into 1L of sterile water, and the pH value is 7.2.

S3, mixing the crushed mushroom residues with yeast extract powder, fermenting at 65% humidity, adding sodium bentonite after fermentation is finished, and fully and uniformly mixing to obtain a nutrient source;

s4, dividing the nutrient source of S3 into two parts, respectively adding the two parts into the selenium-rich photosynthetic bacteria fermentation liquor of S1 and the bacillus fermentation liquor of S2, introducing sterile air, stirring and fermenting for 10 days at 40 ℃, filtering after the fermentation is finished, and combining the two parts of filtrate to obtain the selenium-rich biological agent;

s5, uniformly mixing the potassium fulvate, the shell powder and the polyethylene glycol, then adding the selenium-rich biological agent of S4, and fully and uniformly mixing to obtain the compound biological selenium-rich foliar fertilizer.

Example 3

The compound biological selenium-rich foliar fertilizer consists of the following raw materials in parts by weight:

10 parts of yeast extract powder, 30 parts of mushroom residue, 10 parts of selenium-rich photosynthetic bacteria fermentation liquor, 5 parts of bacillus fermentation liquor, 2 parts of potassium fulvate, 0.5 part of shell powder, 2 parts of polyethylene glycol and 2 parts of sodium bentonite.

The preparation method of the compound biological selenium-rich foliar fertilizer comprises the following steps:

S1 preparation of selenium-rich photosynthetic bacteria fermentation liquor

Adding sodium selenite into RCVBN culture medium, and adding 0.5g of sodium selenite into each 1L of RCVBN culture medium to obtain selenium-rich liquid culture medium;

inoculating azotobacteria into selenium-rich liquid culture medium, and culturing at 20 deg.C under natural illumination for 5 days; wherein the inoculation amount of the azotobacteria is 5% (volume). The culture of the azotobacter is carried out under the micro-aerobic condition with the dissolved oxygen concentration of 0.2 mg/L. The thallus concentration in the selenium-rich photosynthetic bacteria fermentation liquor is 2.35 multiplied by 10⁸cfu/mL。

S2 preparation of Bacillus fermentation liquor

Sodium silicate was added to the liquid medium B in an amount of 0.5g per 1L of the liquid medium B. Adjusting the pH to 6.5; then inoculating the activated bacillus subtilis microbial inoculum with the inoculation amount of 5 percent, and culturing for 2 days at the temperature of 30 ℃ to obtain the bacillus subtilis microbial inoculum. The thallus concentration in the bacillus fermentation liquor is 1.94 multiplied by 10⁷cfu/mL。

The formula of the liquid culture medium B is as follows: 3.5g of glucose, 5g of yeast extract, 10g of peptone, 3g of magnesium sulfate, 0.025g of manganese sulfate, 0.4g of potassium dihydrogen phosphate and 0.6g of dipotassium hydrogen phosphate were added to 1L of sterile water, and the pH was 7.2.

S3, mixing the crushed mushroom residues with yeast extract powder, fermenting at 60% humidity, adding sodium bentonite after fermentation, and fully and uniformly mixing to obtain a nutrient source;

S4, dividing the nutrient source of S3 into two parts, respectively adding the two parts into the selenium-rich photosynthetic bacterium fermentation liquor of S1 and the bacillus fermentation liquor of S2, introducing sterile air, stirring and fermenting for 5 days at 30 ℃, filtering after the fermentation is finished, and combining the two parts of filtrate to obtain the selenium-rich biological agent;

s5, uniformly mixing the potassium fulvate, the shell powder and the polyethylene glycol, then adding the selenium-enriched biological agent of S4, and fully and uniformly mixing to obtain the compound biological selenium-enriched foliar fertilizer.

Comparative example 1

The biological selenium-rich foliar fertilizer consists of the following raw materials in parts by weight:

12 parts of yeast extract powder, 35 parts of mushroom residue, 22 parts of selenium-rich photosynthetic bacteria fermentation liquor, 3 parts of potassium fulvate, 0.6 part of shell powder, 3 parts of polyethylene glycol and 3 parts of sodium bentonite.

The preparation method of the biological selenium-rich foliar fertilizer comprises the following steps:

s1 preparation of selenium-rich photosynthetic bacteria fermentation liquor

Adding sodium selenite into RCVBN culture medium, and adding 1.0g of sodium selenite into each 1L of RCVBN culture medium to obtain selenium-rich liquid culture medium;

inoculating azotobacteria in selenium-rich liquid culture medium, and culturing at 30 deg.C under natural illumination for 4 days; wherein the inoculation amount of the azotobacteria is 10% (volume). The nitrogen-fixing rhodobacter is cultured under the micro-aerobic condition with the dissolved oxygen concentration of 0.5 mg/L. The thallus concentration in the selenium-rich photosynthetic bacteria fermentation liquor is 1.17 multiplied by 10 ⁸cfu/mL。

S2, mixing the crushed mushroom residues with yeast extract powder, fermenting at 60% humidity, adding sodium bentonite after fermentation, and fully and uniformly mixing to obtain a nutrient source;

s3, adding the nutrient source of S2 into the selenium-rich photosynthetic bacterium fermentation liquor of S1, introducing sterile air, stirring and fermenting for 7 days at 38 ℃, filtering after fermentation is finished, and combining the two filtrates to obtain the selenium-rich biological agent;

s4, uniformly mixing the potassium fulvate, the shell powder and the polyethylene glycol, then adding the selenium-enriched biological agent of S3, and fully and uniformly mixing to obtain the compound biological selenium-enriched foliar fertilizer.

The selenium-enriched foliar fertilizers of the embodiments 1 to 3 and the comparative example 1 are sprayed on a field where rice is planted, so as to verify the effect of the selenium-enriched foliar fertilizer.

The field for planting rice is divided into 5 test areas, which are respectively marked as a test area A, a test area B, a test area C, a test area D and a test area E. And (4) performing normal field management on the rice during planting.

Spraying foliar fertilizer to 5 test areas respectively in the full heading period of the rice, wherein the foliar fertilizer of the embodiment 1 is sprayed to the test area A; the foliar fertilizer of the embodiment 2 is sprayed in the test area B; the foliar fertilizer of the embodiment 3 is sprayed in the test C area; spraying the foliar fertilizer of the comparative example 1 in the test D area; test zone E was sprayed with water as a control.

In the fertilization process, foliar fertilizer is diluted by 800 times and is sprayed once after a week interval.

And in the rice harvesting period, harvesting the rice in each test area, drying in the air, removing the hulls, weighing the harvested hulled rice, and calculating the yield increase rate.

TABLE 1 Effect of different foliar fertilizers on the already-produced amount of selenium in rice

	Selenium content (mg/kg)	Yield increase (%)
			Example 1	0.293	23.7
Example 2	0.252	20.8
			Example 3	0.285	22.6
Comparative example 1	0.176	15.4

As can be seen from the table 1, compared with the comparative example 1, the foliar fertilizer of the embodiments 1 to 3 of the invention can not only obviously increase the selenium content in rice, but also promote the yield increase. The biological organic selenium and the biological organic silicon are matched to promote the photosynthetic efficiency of plants, and the foliar fertilizer disclosed by the embodiment 1-3 of the invention utilizes the yeast extract powder and the mushroom residue fermentation product as nutrient sources to promote the further fermentation of the selenium-rich photosynthetic bacteria fermentation liquor and the bacillus fermentation liquor so as to obtain nutrient elements capable of being absorbed and utilized by the plants, so that the selenium-rich foliar fertilizer has comprehensive nutrition, the photosynthetic efficiency of the plants is promoted, the absorption rate of the plants to selenium, silicon and other nutrient elements is improved, and the crop yield is further improved.

The present invention is not limited to the above preferred embodiments, and any modifications, equivalents and improvements made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims (8)

1. The compound biological selenium-rich foliar fertilizer is characterized by comprising the following raw materials in parts by weight:

10-20 parts of yeast extract powder, 30-40 parts of mushroom residue, 10-30 parts of selenium-rich photosynthetic bacteria fermentation liquor, 5-10 parts of bacillus fermentation liquor, 2-5 parts of potassium fulvate, 0.5-1 part of shell powder, 2-5 parts of polyethylene glycol and 2-5 parts of sodium bentonite.

2. The compound biological selenium-enriched foliar fertilizer as claimed in claim 1, wherein the selenium-enriched photosynthetic bacteria fermentation liquor is prepared as follows:

adding sodium selenite into the RCVBN culture medium to obtain a selenium-rich liquid culture medium;

inoculating azotobacteria into a selenium-rich liquid culture medium, and culturing for 2-5 days at the temperature of 20-35 ℃ under the natural illumination condition to obtain the azotobacteria; wherein the inoculation amount of the azotobacteria is 5-20%.

3. The compound biological selenium-enriched foliar fertilizer of claim 2, wherein the addition amount of sodium selenite is 0.5-2.0 g per 1L of RCVBN culture medium.

4. The compound biological selenium-enriched foliar fertilizer as claimed in claim 2, wherein the culture of the azotobacter is under the micro-aerobic condition with dissolved oxygen concentration of 0.2-1.0 mg/L.

5. The compound biological selenium-rich foliar fertilizer of claim 1, wherein the preparation of the bacillus fermentation broth is as follows:

Adding sodium silicate into the liquid culture medium B, and adjusting the pH value to 6.5-7.2; then inoculating 5-10% of the inoculum size into the activated bacillus subtilis microbial inoculum, and culturing for 2-6 days at 30-40 ℃ to obtain the bacillus subtilis microbial inoculum.

6. The compound biological selenium-enriched foliar fertilizer for the foliage of claim 5, wherein the addition amount of the sodium silicate is 0.5-2.0 g per 1L of the liquid culture medium B.

7. The compound biological selenium-enriched foliar fertilizer as claimed in claim 5, wherein the formula of the liquid culture medium B is as follows:

3.5g of glucose, 5g of yeast extract, 10g of peptone, 3g of magnesium sulfate, 0.025g of manganese sulfate, 0.4g of monopotassium phosphate and 0.6g of dipotassium phosphate are added into 1L of sterile water, and the pH value is 7.2.

8. The preparation method of the compound biological selenium-enriched foliar fertilizer disclosed by claim 1 is characterized by comprising the following steps:

s1, weighing the components according to the weight part ratio of claim 1; mixing the crushed mushroom residues with the yeast extract powder, fermenting at the humidity of 60-65%, adding sodium bentonite after fermentation is finished, and fully and uniformly mixing to obtain a nutrient source;

s2, dividing the nutrient source of S1 into two parts, respectively adding the two parts into the selenium-rich photosynthetic bacterium fermentation liquid and the bacillus fermentation liquid, introducing sterile air, stirring and fermenting at 30-40 ℃, filtering after fermentation is completed, and combining the two parts of filtrate to obtain the selenium-rich biological agent;

S3, uniformly mixing the potassium fulvate, the shell powder and the polyethylene glycol, then adding the selenium-enriched biological agent of S2, and fully and uniformly mixing to obtain the compound biological selenium-enriched foliar fertilizer.