A disinfection method for sweet potato seedling greenhouses in the northern potato-growing area

Abstract

The present invention discloses a disinfection method for a sweet potato seedling-raising greenhouse in the northern potato-growing area, which includes: 1) Selecting the period from July 20th to August 20th, and using natural temperature and light conditions to disinfect the soil in the greenhouse; 2) After the supply of seedlings is completed, all the sweet potato tubers in the seedbed in the greenhouse are cleared out of the greenhouse; after the cleaning is completed, the nematicide fosthiazate and the fungicide thiophanate-methyl are applied to the seedbed; after the application of the agents, the bed soil is deeply plowed to make the bed soil stand upright; water is sprayed on the bed soil, and the surface of the bed soil is moist; 3) Cover the moist bed soil with a black plastic film and seal the edges with soil; close all the exits of the greenhouse and keep the greenhouse airtight for 20 days, and at least 7 days out of the 20 days should be cloudy or sunny; 4) After 20 days of keeping the greenhouse airtight, open or remove the greenhouse film to allow rainwater to naturally pour in; before the next use, apply microbial fertilizer and soil physical and chemical conditioner. The present invention greatly reduces the use cost of the seedling-raising greenhouse, can ensure the cleanliness of the bed soil, provides guarantee for the healthy output of sweet potato seedlings, and ensures the healthy development of the sweet potato industry.

Description

Technical Field

[0001] The invention relates to a disinfection method for a sweet potato seedling greenhouse in a northern potato region, and belongs to the technical field of sweet potato cultivation. Background Art

[0002] Sweet potatoes are the seventh largest food crop in the world, mainly distributed in Asia, Africa, Latin America and other regions, and China's planting area accounts for about 60% of the world's total. The planting methods of sweet potatoes in the north and south are different. Generally, they need to go through the growth period of seedling, field, harvest and storage. In the north, due to the lower temperature in February and March, greenhouse seedlings are mostly used. After two years of use, the seedling greenhouse is prone to disease accumulation and changes in soil physical and chemical properties. The greenhouse needs to be moved, but there are many problems with moving greenhouses, especially some relatively fixed greenhouses, which are difficult to move. If they are not moved, the soil needs to be replaced, and the cost of soil replacement is very high and difficult to operate. Therefore, the industry urgently needs a time-saving, labor-saving, and low-cost method for disinfecting sweet potato seedling greenhouses.

[0003] The main diseases in the northern potato areas are sweet potato root rot, sweet potato stem nematode disease and sweet potato black spot. Experimental analysis shows that the pathogens of these three diseases can die at 50℃ for 10 minutes or 55℃ for 5 minutes. Based on the lethal temperatures of the main diseases and pathogens in the northern potato areas, combined with greenhouse and climatic conditions, a series of experiments were carried out, and finally the disinfection method of sweet potato seedling greenhouses in the northern potato areas was determined. Summary of the invention

[0004] In view of the problems existing in the above-mentioned prior art, the present invention provides a method for disinfecting a sweet potato seedling greenhouse in the northern potato region.

[0005] In order to achieve the above object, the present invention adopts a method for disinfecting a sweet potato seedling greenhouse in a northern potato region, comprising the following steps:

[0006] 1) Selection of disinfection time

[0007] It was carried out between July 20 and August 20, using natural temperature and light conditions to disinfect the soil in the greenhouse;

[0008] 2) Treatment of soil in the sweet potato seedling greenhouse

[0009] Step a: After the seedlings are supplied, all the potato pieces in the seedbeds in the shed are removed from the shed;

[0010] Step b, after the cleaning is completed, applying nematicide thiamethoxam and fungicide thiophanate-methyl on the seedbed;

[0011] Step c: After applying the pesticide, deep plow the soil to make it stand upright;

[0012] Step d, spray water on the bed soil until the surface of the bed soil is moistened;

[0013] 3) Methods and timing of greenhouse covering

[0014] Step a: Cover the moist seedbed soil with black plastic film and seal the edges with soil;

[0015] Step b: Seal all the exits of the greenhouse, keep it airtight for 20 days, and there should be at least 7 cloudy or sunny days within these 20 days;

[0016] 4) Post - opening treatment methods

[0017] Step a: After 20 days of airtight treatment, open or remove the greenhouse film to allow rainwater to pour in naturally;

[0018] Step b: Before the next use, apply microbial fertilizer and soil physical and chemical conditioner.

[0019] Furthermore, the northern sweet potato growing areas refer to the sweet potato growing areas in northern Anhui, northern Jiangsu, Shandong, Henan, Hebei, Shaanxi, and Shanxi.

[0020] Furthermore, the application dosage and method of fosthiazate and thiophanate - methyl are as follows:

[0021] Spray the 30% fosthiazate emulsifiable concentrate at 80 - 120 ml per mu by diluting it with 50 - 75 kg of water, and spray the 50% thiophanate - methyl wettable powder at 100 - 125 ml per mu by diluting it with water or at a 1000 - 1500 - fold dilution.

[0022] Compared with the prior art, the disinfection method of the sweet potato seedling - raising greenhouse in the northern sweet potato growing areas of the present invention solves the problems of continuous cropping such as many diseases and soil compaction that occur in the sweet potato seedling - raising greenhouses in the northern sweet potato growing areas of our country after continuous years of seedling raising, greatly reduces the use cost of the seedling - raising greenhouse, can ensure the cleanliness of the seedbed soil, provides guarantee for the healthy output of sweet potato seedlings, and ensures the healthy development of the sweet potato industry. Detailed implementation manners

[0023] To make the objectives, technical solutions, and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below. However, it should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the scope of the present invention.

[0024] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which the present invention belongs. The terms used in the description of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0025] A disinfection method for sweet potato seedling - raising greenhouses in the northern sweet potato growing areas, mainly used in sweet potato growing areas such as northern Anhui, northern Jiangsu, Shandong, Henan, Hebei, Shaanxi, and Shanxi, specifically includes the following steps:

[0026] 1) Disinfection time selection

[0027] It was carried out between July 20 and August 20, using natural temperature and light conditions to disinfect the soil in the greenhouse;

[0028] 2) Treatment of soil in the sweet potato seedling greenhouse:

[0029] Step a: After the seedlings are supplied, all the potato pieces in the seedbeds in the shed are removed from the shed;

[0030] Step b, after the cleaning is completed, apply a nematicide (thiazothiazide) and a fungicide (thiophanate-methyl) on the seedbed;

[0031] The application dosage is: 30% thiophanate emulsifiable concentrate is sprayed at 80-120ml / mu with 50-75kg of water, and 50% thiophanate methyl wettable powder is sprayed at 100-125ml / mu with water or 1000-1500 times of dilution.

[0032] Step c, after applying the pesticide, deep plow the bed soil manually or mechanically to make the bed soil upright;

[0033] Step d, spray water on the bed soil to make the surface of the bed soil moist;

[0034] 3) Sealing method and time:

[0035] Step a, covering the moist bed soil with black mulch and sealing the edges with soil;

[0036] Step b, then close all the exits of the greenhouse and keep it sealed for 20 days, during which at least 7 days must be cloudy or sunny;

[0037] 4) Post-treatment methods of stuffy greenhouse

[0038] Step a: After 20 days of keeping the greenhouse sealed, open or remove the greenhouse film to allow rainwater to flow in naturally;

[0039] Step b. Before the next use, apply bacterial fertilizer (Jun Chongfeng (microbial agent produced by Shandong Agricultural University Fertilizer Technology Co., Ltd.) 1000g / mu) and soil physical and chemical conditioner (Qiangxing Soil Conditioner (Beihai Qiangxing Biotechnology Co., Ltd.) 200g / mu, diluted with water at a ratio of 1:5000) per mu.

[0040] Example 1

[0041] In 2020 and 2021, the seedling greenhouse disinfection test was carried out in Xuzhou Jiawang for two consecutive years. The greenhouse disinfection was carried out according to the above method:

[0042] All sweet potato tubers in the greenhouse seedbed are cleared out → Nematicide (fluthiamide) and fungicide (thiophanate-methyl) are applied on the seedbed → The bed soil is turned up and stood upright, and the micro-sprinkler switch is turned on to water → Black plastic film is covered and sealed with soil at the edges → All exits of the greenhouse are closed, and the greenhouse is fumigated at high temperature for 20 days → Microbial fertilizer and soil physical and chemical conditioner are applied.

[0043] A control was set up in the experiment, and the temperature of the 20CM soil layer and the isolation and identification of soil nematodes were measured under different treatments.

[0044] The disinfection method of the sweet potato seedling greenhouse of the present invention can complete the sterilization and disinfection of the soil in the greenhouse without moving the greenhouse soil, providing guarantee for the next year's greenhouse seeding.

[0045] The specific scheme and results are as follows:

[0046] 1. Materials and Methods

[0047] 1) Greenhouse preparation

[0048] Four sweet potato seedling greenhouses with intact plastic films were selected, and the sweet potato tubers and seedlings in the greenhouses were cleaned up in mid-July.

[0049] 2) Chemical preparation

[0050] 30% fluthiamide EC: 80 - 120 ml / mu, diluted with 50 - 75 kg of water and sprayed;

[0051] 50% thiophanate-methyl wettable powder: 100 - 125 ml / mu, diluted with water and sprayed, or sprayed with 1000 - 1500 times solution;

[0052] Junchongfeng (microbial inoculant produced by Shandong Agricultural University Fertilizer Technology Co., Ltd.): 1000 g / mu;

[0053] Qiangxing soil loosening agent (Beihai Qiangxing Biotechnology Co., Ltd.): 200 g / mu, diluted with water at a ratio of 1:5000 and applied;

[0054] 3) Specific steps

[0055] Cleaning: The sweet potato seedlings and tubers in the greenhouse were cleared out on July 20 - 25;

[0056] Pesticide application: 30% fluthiamide EC (80 - 120 ml / mu, diluted with 50 - 75 kg of water and sprayed) and 50% thiophanate-methyl wettable powder (sprayed with 1000 - 1500 times solution) were applied on the cleared bed soil;

[0057] Turning the soil and watering: The bed soil was turned up and stood upright with a small tractor, and the micro-sprinkler switch was turned on to water;

[0058] Covering the film and sealing the greenhouse: Covered with black plastic film and sealed with soil at the edges, all exits of the greenhouse were closed, and the greenhouse was fumigated at high temperature for 20 days;

[0059] Temperature measurement: During the greenhouse soil steaming period, use a thermometer to record the maximum and minimum temperatures inside the greenhouse, and the temperature at a depth of 20 cm in the soil layer from July 20th to August 20th.

[0060] Pathogen determination: Divide 2400 isolated potato rot nematodes into 12 10ML centrifuge tubes with water. Put 200 nematodes in each centrifuge tube. Insert the nematode centrifuge tubes into the soil layer at a depth of 20 CM under the black film in the test greenhouse. Place 4 tubes in each greenhouse. After the greenhouse soil steaming ends, take out the centrifuge tubes and determine the number of surviving nematodes in each tube.

[0061] Open the greenhouse: From August 20th to 30th, open the greenhouse, mainly by removing (or rolling up) the greenhouse film to allow the greenhouse soil to receive 1 - 2 rainfalls.

[0062] Before the next use, apply 1000 g / acre of bacterial fertilizer (microbial inoculant produced by Shandong Agricultural University Fertilizer Technology Co., Ltd., Jun Chongfeng) and 200 g / acre of soil physical and chemical conditioner (Qiangxing Loosening Soil Essence produced by Beihai Qiangxing Biotechnology Co., Ltd., diluted with water at a ratio of 1:5000) per mu.

[0063] 2. Results and analysis

[0064] 1) Greenhouse temperature measurement

[0065] In 2021 and 2022, the high-temperature greenhouse soil steaming temperature of the seeding greenhouse was measured. After the seeding greenhouse finished supplying seedlings, follow the steps below:

[0066] Remove all potato tubers from the seedbed - Apply nematocide (fluthiamide) and fungicide (thiophanate-methyl) on the bed soil - Turn up the bed soil vertically, turn on the micro-sprinkler switch to water - Cover with black plastic film and seal the edges with soil - Seal all exits of the greenhouse for treatment, and record the temperature inside the greenhouse and the temperature at a depth of 20 CM in the soil layer at each time.

[0067] Table 1 Greenhouse soil steaming temperature table of sweet potato seedling greenhouses in different years

[0068]

[0069]

[0070] As can be seen from Table 1, when the weather is cloudy or sunny and the air temperature reaches above 30°C, the temperature inside the greenhouse can reach 55°C, and the temperature at a depth of 20 CM in the soil layer can reach 50°C. When the air temperature remains above 35°C continuously, the temperature inside the greenhouse can reach 67 - 70°C, and the temperature at a depth of 20 CM in the soil layer can reach above 55°C. According to the research on the lethal temperature of fungi, bacteria, and nematodes infecting sweet potatoes, the pathogens can be killed at 50°C for 10 minutes and 55°C for 5 minutes. Therefore, high-temperature greenhouse soil steaming can achieve the effect of killing pathogens.

[0071] 2) Soil turning and plastic film covering test

[0072] In order to make the temperature of the 20 - centimeter soil layer reach the lethal temperature of the pathogenic bacteria, temperature measurements were carried out on turning the soil or not, covering with plastic film or not.

[0073] It was set that: Treatment 1, digging the soil + covering with film; Treatment 2, digging the soil + not covering with film; Treatment 3, not digging the soil + covering with film; Treatment 4, not digging the soil + not covering with film, etc., a total of 4 treatments.

[0074] Table 2 Temperature of the 20 - centimeter soil layer under different treatments

[0075]

[0076] The results showed that: for the temperature of the 20 - centimeter soil layer, turning the soil and covering with plastic film increased the temperature by an average of 6.8 - 7.0 °C compared with not turning the soil and not covering with plastic film, by an average of 4.9 - 5.5 °C compared with turning the soil and not covering with plastic film, and by an average of 3.4 - 3.9 °C compared with not turning the soil and covering with plastic film. Therefore, only when turning the soil and covering with plastic film can the temperature of the 20 - centimeter soil layer be stabilized above 50 °C to achieve the sterilization effect.

[0077] 3) Determination of common pathogenic bacteria of sweet potatoes in the northern sweet potato planting area:

[0078] The main diseases in the northern sweet potato planting area are sweet potato root rot, stem nematode disease, and black spot disease. Sweet potato root rot is mainly soil - borne in the field, and the seedling - borne diseases are mainly stem nematode disease and black spot disease. Therefore, we carried out actual prevention and control measurements on two kinds of pathogenic bacteria. The data showed that the lethal temperature of the pathogen of sweet potato stem nematode disease, Ditylenchus destructor, is 48 - 49 °C for 10 minutes, and the lethal temperature of the pathogen of sweet potato black spot disease is 51 - 53 °C for 10 minutes. From the temperature measurement results, it can be seen that the greenhouse soil steaming can reach this temperature. For further verification, 2400 Ditylenchus destructor nematodes isolated were divided and packed into 12 10 - mL centrifuge tubes with water, with 200 nematodes in each centrifuge tube. The nematode - containing centrifuge tubes were inserted into the 20 - centimeter soil layer under the black film in the experimental greenhouse, with 4 tubes placed in each greenhouse. After the soil steaming ended, the centrifuge tubes were taken out and the number of surviving nematodes in each tube was measured.

[0079] Table 3 Determination of the pathogen of sweet potato stem nematode

[0080]

[0081] From the measurement results, it can be seen that most of the nematodes have died, indicating that the actual control effect of soil steaming on sweet potato stem nematode disease can reach more than 98%. Combined with pesticides, the purpose of completely killing the pathogenic nematodes can be achieved.

[0082] Table 4 Lethal temperature table of the main seedling - borne pathogenic bacteria of sweet potatoes in the northern sweet potato planting area

[0083] Disease name Lethal temperature and time Main transmission rules Sweet potato black rot The lethal temperature of the pathogen is 51-53°C for 10 minutes Seedling transmission and soil transmission Sweet potato stem nematode disease The lethal temperature of the pathogen is 48-49°C for 10 minutes Seedling transmission and soil transmission Sweet potato black dot disease The lethal temperature of the pathogen is 50°C for 10 minutes Seedling transmission and soil transmission Sweet potato purple root rot The lethal temperature of the pathogen is 50°C for 10 minutes Seedling transmission and soil transmission

[0084] 4) Effects of Bacterial Fertilizer and Soil Physical and Chemical Conditioner on Sweet Potato Seedlings

[0085] To enable the disinfected greenhouse to better restore its original vitality, bacterial fertilizer (1000 g / mu of Junchongfeng (microbial inoculant produced by Shandong Agricultural University Fertilizer Industry Co., Ltd.)) and soil physical and chemical conditioner (200 g / mu of Qiangxing Loosening Essence (Beihai Qiangxing Biotechnology Co., Ltd.), diluted with water at a ratio of 1:5000) were applied to the greenhouse that had undergone soil steaming disinfection. A comparison was made between the growth of sweet potato seedlings with and without the application. In the same greenhouse, 6 nursery beds of 1.2M * 4M were made. In 3 beds, Junchongfeng (1000 g / mu) and Qiangxing Loosening Essence (200 g / mu) were used at the optimal dosage, and in 3 beds, they were not applied. 3 sweet potato seedlings with leaf lengths of about 20 cm were planted at a density of 100 plants per square meter. The growth of sweet potato seedlings was investigated at 7d, 14d, 21d, 28d, and 35d. Each time, 10 sweet potato seedlings were taken from each bed to investigate the number of leaf nodes, root numbers, and branch numbers respectively.

[0086] The results showed that:

[0087] At 7d, the number of leaf nodes, root numbers, and branch numbers of the sweet potato seedlings with the application of bacterial fertilizer and soil conditioner were 3.83, 2.53, and 1.0 respectively, while those of the sweet potato seedlings without the application of bacterial fertilizer and soil conditioner were 3.7, 2.33, and 1.0 respectively. There was no significant difference between the application and non-application.

[0088] At 35d, the number of leaf nodes, root numbers, and branch numbers of the sweet potato seedlings with the application of bacterial fertilizer and soil conditioner were 10.07, 7.13, and 3.67 respectively, while those of the sweet potato seedlings without the application of bacterial fertilizer and soil conditioner were 8.3, 5.23, and 3.27 respectively. The growth potential of the sweet potato seedlings with the application of bacterial fertilizer and soil conditioner was significantly stronger than that without the application. It shows that the application of bacterial fertilizer and soil conditioner has no obvious effect on the growth of sweet potato seedlings in the early stage, while it has a certain promoting effect on the growth of sweet potato seedlings in the later stage.

[0089] Table 5 Growth of Sweet Potato Seedlings with the Application of Bacterial Fertilizer and Soil Conditioner

[0090]

[0091] Thus, it can be seen that by using the disinfection method of the sweet potato seedling greenhouse of the present invention, not only can harmful pathogenic bacteria be eliminated, but also the physical and chemical properties of the soil can be restored, and the growth of sweet potato seedlings can be promoted. Therefore, the present invention has a good effect on the reuse of sweet potato seedling greenhouses in the northern sweet potato planting areas.

[0092] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, or improvements made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims

1. A disinfection method for sweet potato seedling greenhouses in the northern potato-growing area, characterized in that, The northern potato region refers to the potato regions in northern Anhui, northern Jiangsu, Shandong, Henan, Hebei, Shaanxi and Shanxi, and includes the following steps: 1) Selection of disinfection time It was carried out between July 20 and August 20, using natural temperature and light conditions to disinfect the soil in the greenhouse; 2) Treatment of bed soil in sweet potato seedling greenhouse Step a: After the seedlings are supplied, all the potato pieces in the seedbeds in the shed are removed from the shed; Step b, after the cleaning is completed, apply nematicide thiamethoxam and fungicide thiophanate-methyl on the seedbed; the dosage and method of applying thiamethoxam and thiophanate-methyl are as follows: spray 30% thiamethoxam emulsifiable concentrate at 80-120 ml / mu with 50-75 kg of water, and spray 50% thiophanate-methyl wettable powder at 100-125 ml / mu with water or 1000-1500 times of liquid; Step c: After applying the pesticide, deep plow the soil to make it stand upright; Step d, spray water on the bed soil until the surface of the bed soil is moistened; 3) How and when to close the shed Step a, covering the moist bed soil with black mulch and sealing the edges with soil; Step b: Close all the exits of the greenhouse and keep it sealed for 20 days, with at least 7 days being cloudy or sunny; 4) Post-opening treatment methods Step a: After 20 days of keeping the greenhouse sealed, open or remove the greenhouse film to allow rainwater to flow in naturally; Step b: Apply bacterial fertilizer and soil physical and chemical conditioners before next use.

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