A soil conditioner, its preparation method and application

Abstract

The present invention provides a soil conditioner, a preparation method thereof and an application, belonging to the technical field of the prevention and control of Spodoptera frugiperda. The preparation method comprises the following steps: exposing crops grown for 6-7 days to cis-3-Hexenyl acetate; (2) after the crops continue to grow for 5-10 days, removing the crops and collecting the soil in which the crops grow; (3) collecting the nematode community in the soil in step (2) to obtain the soil conditioner. The soil conditioner contains a soil nematode community. After adding the soil conditioner to the crop soil, it can improve the resistance of the crops to Spodoptera frugiperda, inhibit the growth of Spodoptera frugiperda, and reduce the feeding ability of Spodoptera frugiperda on corn leaves.

Description

Technical Field

[0001] The present invention belongs to the technical field of the prevention and control of Spodoptera frugiperda, and particularly relates to a soil conditioner, a preparation method thereof and an application thereof. Background Art

[0002] Spodoptera frugiperda, also known as fall armyworm, fall armyworm, and grassland armyworm, is a moth of the genus Spodoptera in the family Noctuidae. It is native to the tropical and subtropical regions of the Americas. Its larvae mainly feed on corn and rice. It is an important agricultural pest with strong adaptability, migratory ability and polyphagy, and can pose a threat to the production of crops.

[0003] In recent years, researchers have adopted an integrated prevention and control technology system mainly based on chemical control, physical control, biological control and agricultural control to solve the problem of damage caused by Spodoptera frugiperda. Among them, chemical control is still the main means. Although chemical control can significantly reduce the infection and occurrence of Spodoptera frugiperda, due to the large-scale use of chemical agents such as pesticides, Spodoptera frugiperda has developed drug resistance, and the residues of chemical pesticides also have great side effects on the environment. Therefore, it is particularly important to find a green and environmentally friendly control method.

[0004] Nematodes are the main components of the soil community and can be used as indicator organisms of soil health. It has been found that different groups of nematodes can have positive or negative effects on plant health. Nematode-microbe interactions can change soil nutrients and thus affect plant growth, and nematodes can also inhibit the invasion of plant pathogens by shaping the indigenous microbial community, etc. From the patent CN104969753A "A cultivation method for preventing and controlling banana plant pathogenic nematode disease by crop rotation", after one round of crop rotation, the reproduction of banana plant pathogenic nematodes in the soil can be inhibited, and the soil nematode community structure can be improved, thereby promoting the growth and development of bananas. Thus, it can be seen that the change of nematode community structure can affect the growth and defense of plants.

[0005] cis-3-Hexenyl acetate is a major green leaf volatile that is released in large amounts when plants are subjected to biotic and abiotic stresses. It can be used as a warning to enhance the defense responses of itself and neighboring plants. For example, in the patent CN114831116A "Application of cis-3-Hexenyl Acetate in Controlling Meloidogyne incognita", after exposing maize plants to cis-3-hexenyl acetate, the contents of defense hormones jasmonic acid, jasmonoyl-isoleucine conjugate, and abscisic acid in the plants can be increased, thereby effectively inhibiting the infectivity and fecundity of Meloidogyne incognita; in addition, in the patent CN116897931A "Application of cis-3-Hexenyl Acetate in Improving Crop Resistance, Yield and Promoting Crop Growth", cis-3-hexenyl acetate can not only improve crop resistance and inhibit the invasion of Spodoptera frugiperda, but also significantly increase the biomass and yield of crops. Thus, cis-3-hexenyl acetate is not only beneficial to the growth of maize, but also can enhance the resistance to plant pathogenic nematodes (root-knot nematodes) and Spodoptera frugiperda.

[0006] At present, the research on cis-3-hexenyl acetate mainly focuses on the fields of plant protection and prevention of continuous cropping obstacles, and there is no report on its use to improve the soil nematode community structure and thus enhance crop resistance to control Spodoptera frugiperda. Summary of the Invention

[0007] In view of this, the purpose of the present invention is to provide a soil conditioner, its preparation method and application. The soil conditioner can improve the resistance of crops to Spodoptera frugiperda, inhibit the growth of Spodoptera frugiperda, and reduce the feeding ability of Spodoptera frugiperda on maize leaves.

[0008] To achieve the above purpose, the present invention provides the following technical solutions:

[0009] The present invention provides a preparation method of a soil conditioner, comprising the following steps:

[0010] (1) Exposing and treating crops that have grown for 6-7 days with cis-3-hexenyl acetate;

[0011] (2) After the crops continue to grow for 5-10 days, removing the crops and collecting the soil in which the crops have grown;

[0012] (3) Collecting the nematode community in the soil described in step (2) to obtain the soil conditioner.

[0013] Preferably, the dosage of the active ingredient of cis-3-hexenyl acetate in step (1) is 60-80 ng / (h·plant); the exposure treatment time is 1-2 h / (d·time), and the number of exposure treatments is 5-6 times.

[0014] Preferably, when removing in step (2), both the above-ground part and the underground part of the crops are removed; when collecting, the surface soil of 5-15 cm is collected.

[0015] Preferably, the method for collecting in step (3) includes the shallow dish method and the Baermann funnel method.

[0016] Preferably, the dosage form of the soil conditioner includes a solution; the crops include corn.

[0017] The present invention also provides a soil conditioner obtained by the preparation method described above.

[0018] The present invention also provides the application of the soil conditioner in improving the resistance of crops to Spodoptera frugiperda.

[0019] The present invention also provides the application of the soil conditioner in increasing the contents of jasmonic acid and 12-oxo-phytodienoic acid in crops.

[0020] Preferably, the soil conditioner is added to the soil where crops are planted.

[0021] Preferably, the crops include corn.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] The present invention for the first time discovers that after exposing and treating contemporary crops with cis-3-Hexenyl acetate, the structure of the nematode community in its soil can be improved, and after removing the contemporary crops, the nematode community in the contemporary exposed soil is collected to obtain a soil conditioner, and when it is added to the soil for planting a new generation of crops, it is found that the soil conditioner can improve the resistance of crops to Spodoptera frugiperda, and can inhibit the growth of Spodoptera frugiperda and reduce the feeding ability of Spodoptera frugiperda on corn leaves.

[0024] In addition, cis-3-Hexenyl acetate used in the present invention has the characteristics of being safe, environmentally friendly, non-toxic, and having a relatively low cost, and using it to treat crops will not bring negative impacts to the growth of the soil and crops. Description of the Drawings

[0025] Figure 1 It is a schematic diagram of a cis-3-Hexenyl acetate slow-release device;

[0026] Figure 2 It is a schematic diagram of exposing and treating a corn plant with cis-3-Hexenyl acetate;

[0027] Figure 3 It is a device diagram for collecting the nematode community solution in contemporary soil by the shallow dish method;

[0028] Figure 4 It is a device diagram for collecting the nematode community solution in contemporary soil by the Baermann funnel method;

[0029] Figure 5The weight gain results of Spodoptera frugiperda on new generation maize plants and the results of maize leaf damage in different treatments were measured, where "*" indicates P < 0.05;

[0030] Figure 6 The contents of maize leaf defense hormones in different treatments were measured, where "*" indicates P < 0.05. Specific implementation manner

[0031] The present invention provides a preparation method of a soil conditioner, which comprises the following steps:

[0032] (1) Exposing crops grown for 6 - 7 days with cis-3-Hexenyl acetate;

[0033] (2) After the crops continue to grow for 5 - 10 days, removing the crops and collecting the soil where the crops grow;

[0034] (3) Collecting the nematode community in the soil described in step (2) to obtain the soil conditioner.

[0035] In the present invention, crops grown for 6 - 7 days are exposed with cis-3-Hexenyl acetate.

[0036] In the present invention, the dosage of the active ingredient of cis-3-Hexenyl acetate is preferably 60 - 80 ng / (h·plant), more preferably 65 - 75 ng / (h·plant), and even more preferably 70 ng / (h·plant); the exposure time is preferably 1 - 2 h / (d·time), more preferably 1.2 - 1.8 h / (d·time), even more preferably 1.4 - 1.6 h / (d·time), and still more preferably 1.5 h / (d·time); the number of exposure times is preferably 5 - 6 times; when exposing, a slow-release device containing cis-3-Hexenyl acetate is preferably placed beside the crops.

[0037] In the present invention, after the crops continue to grow for 5 - 10 days, the crops are removed and the soil where the crops grow is collected.

[0038] In the present invention, when removing, it is preferably to remove both the above-ground part and the underground part of the crops; when collecting, it is preferably to collect the surface soil of 5 - 15 cm, more preferably 6 - 12 cm, even more preferably 8 - 10 cm, and still more preferably 9 cm.

[0039] In the present invention, the nematode community in the soil is collected to obtain the soil conditioner.

[0040] In the present invention, the collection method preferably includes the shallow dish method and the Baermann funnel method; the dosage form of the soil conditioner preferably includes solution; the crops preferably include maize.

[0041] The present invention also provides a soil conditioner prepared by the described preparation method.

[0042] The present invention also provides the application of the described soil conditioner in improving the resistance of crops to Spodoptera frugiperda.

[0043] The present invention also provides the application of the described soil conditioner in increasing the contents of jasmonic acid and 12-oxo-phytodienoic acid in crops.

[0044] In the present invention, when applying, it is preferably to add the described soil conditioner to the soil for growing crops; when adding to the soil for growing crops, it is preferably added to the surface soil with a depth of 10 - 20 cm, more preferably 12 - 18 cm, still more preferably 14 - 16 cm, and even more preferably 15 cm; the volume mass ratio of the soil conditioner to the surface soil with a depth of 10 - 20 cm for growing crops is preferably 1:40 - 50, more preferably 1:42 - 48, still more preferably 1:44 - 46, and even more preferably 1:45; the crops preferably include corn; the crops are preferably a batch of newly planted crops with sterilized soil.

[0045] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the protection scope of the present invention.

[0046] Example 1 Preparation of the Sustained Release Device

[0047] Wind 2 mg of glass wool (purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.) into a small ball with moderate tightness and put it into a 2 mL screw - neck injection vial (purchased from Shanghai ANPEL Laboratory Technologies Inc.). Add 100 μL of a 98% purity solution of leaf acetate (purchased from Shanghai Macklin Biochemical Co., Ltd.). Insert a disposable micropipette (purchased from Hirschmann Laborgeräte GmbH) into the matching 9 mm - opening screw cap (purchased from Shanghai ANPEL Laboratory Technologies Inc.), wrap it tightly with parafilm sealing film, and wrap the bottle body with tin foil to avoid light, so that the release rate of leaf acetate reaches 70 ng / h. The obtained sustained release device is as Figure 1 shown.

[0048] Example 2 Preparation of the Soil Conditioner

[0049] Sow corn seeds in cultivation pots (600 g of soil per pot), place them in a greenhouse with a temperature of 26 °C, a humidity of 50%, and a CO2 concentration of 500 ppm, and water 15 mL per corn plant per day to ensure the normal growth of corn. After 6 days of vegetative growth of the first - generation corn plants, place a leaf acetate sustained release device prepared in Example 1 beside each corn plant for leaf acetate exposure treatment of the corn plants (as Figure 2As shown in the figure, the treatment time was 1.5 hours per day for 5 consecutive days. After the exposure ended, the corn was allowed to continue growing for 7 days. Then, the above-ground and underground parts of the contemporary corn plants after treatment were removed, and the soil in the contemporary cultivation pots was collected.

[0050] The soil conditioner was prepared by the shallow dish method and the Baermann funnel method successively. The specific operations are as follows:

[0051] Weigh 350 g of the above-collected contemporary soil and place it in a shallow dish device. Then add pure water to submerge the soil and let it stand for 24 hours. After 24 hours, the solutions collected from the shallow dishes were filtered through 100-mesh and 500-mesh sieves respectively. The nematodes on the 500-mesh sieve were rinsed into the Baermann funnel and left standing for 24 hours. Then, the valve of the Baermann funnel was opened to collect the nematode solution, and the soil conditioner was obtained.

[0052] Example 3 Planting of the new generation of corn plants

[0053] The seeds of the new generation of corn were sown in 350 g of sterilized soil (sterilized at 121 °C for 30 minutes, sterilized 3 times). When the corn grew to the 7th day, 5 ml of the soil conditioner prepared in Example 2 was applied to the sterilized soil, and the corn plants continued to grow for 7 days.

[0054] Comparative Example 1

[0055] The new generation of corn was planted according to the method in Example 3, with the only difference being that the soil conditioner prepared in Example 2 was not added.

[0056] Test Example 1

[0057] When the new generation of corn in Example 3 and Comparative Example 1 grew to the 14th day after sowing, one second-instar larva of Spodoptera frugiperda was placed on the third fully expanded leaf of each of them. A cotton piece (round, with a diameter of 3.5 cm and a thickness of 0.5 cm) and a wire mesh cage (cylindrical, with a diameter of 2 cm and a height of 1 cm) were used to fix the larva, and it was ensured that the larva could move freely in the cage. In the first 3 days after inoculation, the corn leaves eaten by Spodoptera frugiperda were collected every 24 hours, pasted on A4 paper, scanned, and the damaged area was measured. After 3 days of inoculation, the Spodoptera frugiperda larvae were collected and weighed to obtain the index of the larval weight gain after Spodoptera frugiperda ate the corn leaves and its damage degree to the corn leaves. The measurement results are as Figure 5 shown.

[0058] The method for measuring the larval weight gain was as follows: Record the weights of the larvae at the beginning and end of the inoculation stage, calculate the relative weight gain of the larvae and divide it by the number of days of inoculation. The specific calculation formula is shown in formula (1).

[0059]

[0060] The method for measuring the damage degree of corn leaves is as follows: Scan the leaves remaining after the fall armyworm feeds, and use the analysis software Digimizer 4.6.1 to quantitatively calculate the damaged leaf area.

[0061] It can be seen from Figure 5 that the soil conditioner containing nematode communities can improve the resistance of the new generation of corn and inhibit the pest damage of the fall armyworm. Compared with the control group (Comparative Example 1), the growth of the fall armyworm in the corn treated with the soil conditioner was significantly inhibited, including a significant decrease in the feeding area of the corn leaves and the self-weight gain of the fall armyworm.

[0062] Test Example 2

[0063] The corn leaves of the new generation in Example 3 and Comparative Example 1, which grew to the 14th day after sowing, were frozen in liquid nitrogen and then ground into fine powder. 0.1 g of the leaf powder sample was weighed, and 12-oxo-phytodienoic acid and jasmonic acid in the corn leaf powder were extracted with an isotope-labeled product (1 ng d6-JA) (purchased from Beijing Solarbio Science & Technology Co., Ltd.), and analyzed by ultra-high performance liquid chromatography-tandem quadrupole mass spectrometry (UHPLC-MS / MS) to obtain the content of defensive sex hormones contained in the new generation of corn leaves. The measurement results are as Figure 6 shown.

[0064] It can be seen from Figure 6 that the soil conditioner containing nematode communities can inhibit the pest damage of the fall armyworm by promoting the synthesis of defensive sex hormones in the new generation of corn leaves. Compared with the control group (Comparative Example 1), the soil conditioner containing nematode communities significantly increased the contents of the defensive sex hormones jasmonic acid and 12-oxo-phytodienoic acid, the precursor of jasmonic acid synthesis, in the corn leaves, indicating that the soil conditioner containing nematode communities can inhibit the invasion of the fall armyworm by increasing the content of defensive sex hormones in the corn leaves.

[0065] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A method for preparing a soil conditioner, characterized in that: The steps include: (1) Exposure of corn plants grown for 6-7 days using phytol acetate; (2) After the crops continue to grow for 5 to 10 days, remove the crops and collect the soil where the corn crops grew; (3) collecting the nematode community in the soil described in step (2) using the shallow plate method and the Baermann funnel method to obtain a soil conditioner; The dosage of the active ingredient of the phytol acetate in step (1) is 70 ng / (h·plant); the exposure treatment time is 1.5 h / (d·time), and the number of exposure treatments is 5 to 6 times; In step (2), the above-ground and underground parts of the crop are removed during the removing process; and the surface soil of 5 to 15 cm is collected during the collecting process; The exposure treatment is to place a slow-release device containing phytol acetate next to the crops.

2. The soil conditioner prepared by the preparation method according to claim 1.

3. Use of the soil conditioner according to claim 2 in improving the resistance of crops to fall armyworm.

4. Use of the soil conditioner according to claim 2 in increasing the content of jasmonic acid and 12-oxo-phytodienoic acid in crops.

5. The use according to claim 3 or 4, characterized in that: The soil conditioner is added to the soil where crops are planted.

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