Winter and spring tobacco seedling cultivation method

Abstract

The invention provides a winter-spring tobacco seedling cultivation method which comprises the steps that tobacco seedlings are sown according to weather forecast in the first ten-day period of December, the sowing time of the tobacco seedlings is 10-15 days earlier than the arrival time of cold air so that the tobacco seedlings can emerge before the cold air comes, and the highest temperature in a seedling raising shed is controlled through ventilation from the period from tobacco seedling sowing to seedling emergence. During the period from emergence of the tobacco seedlings to growth of fifth true leaves, heat preservation is conducted on the seedling raising shed, after the tobacco seedlings grow the fifth true leaves, the temperature in the seedling raising shed is reduced through ventilation, and growth of the tobacco seedlings is inhibited in combination with spraying of a growth inhibitor. According to the winter-spring tobacco seedling cultivation method, the cultivation cost of the tobacco seedlings can be reduced while the cultivation quality is guaranteed. The invention relates to the field of seedling raising.

Description

Technical Field

[0001] The present application relates to the field of seedling cultivation, and in particular to a method for cultivating tobacco seedlings in winter and spring. Background Art

[0002] At present, the tobacco varieties planted in the mountainous areas of Lingnan have a field growth period of about 120 days. In order to be able to harvest during the traditional harvest period (early July), spring tobacco is generally sown in mid-to-late December, seedlings are raised from December of the current year to March of the following year, and tobacco is transplanted from the seedbed to the field around early March. This cultivation method can achieve good seedling results in central and northern Hunan, but there are some obstacles when promoting it in the mountainous areas of Lingnan (including northern Guangdong and southern Hunan).

[0003] The reason is that the time period from sowing to germination of tobacco seedlings overlaps with the time period when cold air moves southward from these areas. With the struggle between cold and warm air, the temperature fluctuates greatly during this period, with sudden changes from warm to cold, resulting in uneven growth of the tobacco seedlings. If the cold air is stronger, the weak tobacco seedlings that have just emerged are prone to die under the influence of long-term low temperature, making it difficult to achieve the goal of "neat, strong, of appropriate age, and sufficient" seedling cultivation.

[0004] After transplanting into the field, the tobacco seedlings with thick stems grow fast, while those with small stems take a long time to grow. The distribution of large and small seedlings is obvious, and a lot of manpower and water and fertilizer are needed for "eccentric" management to achieve "balanced" growth of tobacco leaves in the field, which increases the cost of cultivation. In some related technologies, heaters are used to supplement heat for the seedling shed to keep the growth temperature of tobacco seedlings stable after sowing, which will also increase the cost of cultivation and affect the promotion and application of cultivation methods. Summary of the invention

[0005] The present application aims to solve at least one of the technical problems existing in the prior art. To this end, the present application proposes a winter-spring tobacco seedling cultivation method, which can reduce the cultivation cost of tobacco seedlings while ensuring the cultivation quality.

[0006] The winter and spring tobacco seedling cultivation method provided in the present application includes: sowing tobacco seedlings according to the weather forecast during early December, the sowing time of the tobacco seedlings is 10-15 days earlier than the arrival of cold air, so that the tobacco seedlings emerge before the arrival of the cold air; during the period from sowing the tobacco seedlings to emergence, the maximum temperature in the seedling shed is controlled by ventilation to avoid high temperature burns when the tobacco seedlings germinate; during the period from emergence of the tobacco seedlings to the growth of the fifth true leaf, the seedling shed is insulated; after the tobacco seedlings grow the fifth true leaf, the temperature in the seedling shed is lowered by ventilation, combined with spraying of growth inhibitors to inhibit the growth of the tobacco seedlings.

[0007] The winter-spring tobacco seedling cultivation method provided in this application has at least the following technical effects:

[0008] First, choosing to sow tobacco seedlings early before the arrival of cold air can prevent the emergence of tobacco seedlings from the period of sudden temperature drops and fluctuations, and avoid the death of seedlings under the influence of cold air. In addition, the temperature at this time (early December) is relatively high, so there is no need to supplement heat for the seedling shed, but ventilation and cooling are required. The cost of ventilation is much lower than the cost of supplementary heating, which can reduce the cost of cultivation.

[0009] Secondly, before the tobacco seedlings grow the fifth true leaf (early December to mid-January), the temperature is not too low. At this time, it is generally only necessary to reduce ventilation to achieve heat preservation in the seedling shed, and there is almost no need to add heat to the seedling shed, which can ensure the uniform growth of tobacco seedlings while reducing the cultivation cost;

[0010] Finally, considering the early sowing of tobacco seedlings, ventilation and cooling are used to inhibit the growth of tobacco seedlings after the fifth true leaf grows and the seedlings have a certain resistance to adversity. Growth inhibitors are then applied to avoid excessive growth of tobacco seedlings during transplanting. In addition, cooling can also inhibit the occurrence of diseases and insect pests, reducing the cost of cultivation.

[0011] In summary, the winter-spring tobacco seedling cultivation method can reduce the cultivation cost of tobacco seedlings while ensuring the cultivation quality.

[0012] According to some embodiments of the present application, after the tobacco seedling grows the fifth true leaf, the temperature for at least a portion of the period is kept lower than the normal growth temperature of the tobacco seedling.

[0013] According to some embodiments of the present application, after the tobacco seedlings grow the fifth true leaf, ventilation is used to lower the temperature in the seedling shed, including controlling the temperature in the seedling shed below 8° C. during the night period.

[0014] According to some embodiments of the present application, after the tobacco seedlings grow the fifth true leaf, ventilation is used to lower the temperature in the seedling shed, and the temperature in the seedling shed is controlled between 10°C and 15°C during the day.

[0015] According to some embodiments of the present application, after the tobacco seedlings grow the fifth true leaf, ventilation is used to control the relative humidity in the seedling shed to below 90%.

[0016] According to some embodiments of the present application, the growth inhibitor is sprayed when the maximum leaf width of 40-50% of the tobacco seedlings reaches 2 cm±10%.

[0017] According to some embodiments of the present application, during the period from sowing of tobacco seedlings to emergence, the maximum temperature in the seedling shed is controlled to not exceed 28°C.

[0018] According to some embodiments of the present application, during the period from the emergence of tobacco seedlings to the growth of the fifth true leaf, the temperature in the seedling shed is controlled between 10°C and 25°C.

[0019] According to some embodiments of the present application, during the period from sowing the tobacco seedlings to germination, the water level in the seedling nursery pool is controlled at 15 mm to 20 mm; after the tobacco seedlings grow the fifth true leaf to 7-10 days before transplanting the tobacco seedlings, the water level in the seedling nursery pool is controlled at 8 mm to 12 mm; from 7-10 days before transplanting the tobacco seedlings to the time of transplanting the tobacco seedlings, the water level in the seedling nursery pool is controlled at no more than 5 mm.

[0020] According to some embodiments of the present application, from the time the tobacco seedlings grow the fifth true leaf to 7-10 days before the tobacco seedlings are transplanted, water supply to the nursery pool is stopped when the water temperature is lower than 8°C, and water supply to the nursery pool is resumed after the water temperature is higher than 8°C. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The accompanying drawings are used to provide a further understanding of the technical solution disclosed in the present application and constitute a part of the specification. Together with the embodiments disclosed in the present application, they are used to explain the technical solution disclosed in the present application and do not constitute a limitation on the technical solution disclosed in the present application.

[0022] Figure 1 It is a schematic diagram of the process of the winter-spring tobacco seedling cultivation method of the embodiment of the present application;

[0023] Figure 2 The figure shows the effect of different cultivation methods on the uniformity of the maximum leaf width of tobacco seedlings when the fifth true leaf is visible;

[0024] Figure 3 The figure shows the effect of different sowing periods on the uniformity of the maximum leaf width of tobacco seedlings when the fifth true leaf is visible;

[0025] Figure 4 The figure shows the effect of different cultivation methods on the uniformity of stem diameter of tobacco seedlings when the 7th true leaf is visible;

[0026] Figure 5 The figure shows the effect of different sowing periods on the uniformity of stem diameter of tobacco seedlings when the seventh true leaf is visible. DETAILED DESCRIPTION

[0027] The embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application, and cannot be understood as limiting the present application.

[0028] In the description of the present application, it should be understood that descriptions involving orientation, such as up, down, front, back, left, right, etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0029] In the description of this application, "several" means one or more, "more" means more than two, "greater than", "less than", "exceed", etc. are understood to exclude the number itself, and "above", "below", "within", etc. are understood to include the number itself. If there is a description of "first" or "second", it is only used for the purpose of distinguishing technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0030] In the description of this application, unless otherwise clearly defined, terms such as setting, installing, connecting, etc. should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in this application based on the specific content of the technical solution.

[0031] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0032] The spring tobacco seedling period in Lingnan region (including northern Guangdong and southern Hunan) is mostly from mid-to-late December of the current year to early March of the following year. Affected by the southward movement of cold air, the temperature during this period is suddenly warm and cold. Before the tobacco seedlings have 5 true leaves, it is very easy for the temperature to be below 5°C for a long time in the seedling shed, resulting in the tobacco seedlings freezing to death, yellowing, abnormal leaf shape, growth shrinkage and other hazards, and the tobacco seedlings grow unevenly. After 5 true leaves, the seedling shed is prone to high temperatures of 28°C-32°C, causing serious leg growth of the tobacco seedlings, forming tall and weak seedlings, or high temperatures above 35°C, burning or wilting the tobacco seedlings, etc., making it extremely difficult to achieve the goal of "neat, strong, age-appropriate, and sufficient" seedling cultivation.

[0033] To solve these difficulties, some related technologies use biological fermentation heating, electric heating, coal furnace heating, etc. to supplement heat in the seedling shed, and some related technologies use a large shed inside a small shed for insulation. However, these methods are not widely promoted to meet the needs of production due to high material costs or large labor workload.

[0034] To this end, the present application provides a winter-spring tobacco seedling cultivation method that can reduce the tobacco seedling cultivation cost while ensuring the cultivation quality.

[0035] Reference Figure 1 The winter-spring tobacco seedling cultivation method provided in this application includes the following steps.

[0036] Step S110: During early December, tobacco seedlings are sown according to the weather forecast. The sowing time of tobacco seedlings is 10-15 days earlier than the arrival of cold air, so that the tobacco seedlings can emerge before the arrival of cold air.

[0037] It is understandable that in the Lingnan mountainous areas, the temperature gradually begins to drop in December. Due to the confrontation between cold and warm air, the temperature continues to fluctuate. When the warm air dominates, the maximum temperature can often reach above 20°C. When the cold air dominates, the temperature is likely to drop sharply to around 10°C due to the rainy weather it brings.

[0038] By paying close attention to weather forecasts or strengthening communication with the meteorological department, and sowing in early December before the arrival of cold air according to the weather forecast, you can effectively utilize the relatively high temperatures at this time and conveniently maintain the temperature in the seedling shed at a temperature suitable for the growth of tobacco seedlings, reduce or even eliminate the need for supplemental heating, and save the cost of cultivating tobacco seedlings.

[0039] Under ideal temperature conditions, it takes about 7-8 days for tobacco seedlings to germinate (with two cotyledons appearing) from sowing. For this reason, a lead time of 10-15 days is specially selected to allow a certain amount of growth time to avoid the emergence of tobacco seedlings coinciding with the strong cold air moving south.

[0040] It should be pointed out that the choice of advance period can be adjusted according to the weather conditions of the season. If the interval between two rounds of cold air is short, the advance period can be appropriately shortened within the range. If the interval between two rounds of cold air is long, the advance period can be appropriately extended within the range. Try to ensure that sowing is carried out on a date when the previous round of cold air has receded and the temperature is higher, so that the seedling shed can take advantage of the high temperature of the external environment.

[0041] Step S120: During the period from sowing the tobacco seedlings to germination, ventilation is used to control the maximum temperature in the seedling raising shed to prevent the tobacco seedlings from being burned by high temperatures when germinating.

[0042] Obviously, when warm air dominates, in extreme cases, the maximum temperature may exceed 25°C. If no treatment is taken, the maximum temperature in the seedling shed will obviously be higher, and may even burn or kill the tobacco seedlings. Therefore, by strengthening the ventilation inside and outside the seedling shed, the maximum temperature in the seedling shed can be reduced to prevent the tobacco seedlings from being burned by high temperatures when germinating.

[0043] Optionally, in some embodiments, during the period from sowing of tobacco seedlings to emergence, the maximum temperature in the seedling shed can be controlled to be no more than 30°C, preferably no more than 28°C.

[0044] For example, when the sensor detects that the temperature in the seedling shed reaches 26°C (2°C to 3°C away from the maximum temperature), the fan can be started for ventilation, and the temperature of the external environment can be used to cool down the seedling shed, thereby leaving a certain safety margin.

[0045] Step S130: During the period from when the tobacco seedlings emerge to when the fifth true leaf grows, the seedling raising shed is kept warm.

[0046] Through insulation, the temperature of the seedling shed can be stabilized at a temperature suitable for the growth of tobacco seedlings. On the one hand, it ensures the normal germination and growth of the tobacco seedlings, and on the other hand, it avoids low temperature damage that causes differences in the growth of the tobacco seedlings.

[0047] It is understandable that it takes about 30 days from the emergence of tobacco seedlings to the growth of the fifth true leaf (cross stage). Therefore, after early sowing, the fifth true leaf will grow around mid-January or mid-to-late January. Due to early sowing, during most of the time between the emergence of seedlings and the growth of the fifth true leaf, although the cold air has moved south, the temperature has not dropped to a low point. On many dates, the temperature can still be maintained at around 10℃ to 20℃. Therefore, the temperature of the external environment can be conveniently used to achieve heat preservation in the seedling shed. Generally speaking, it is only necessary to reduce the number of ventilation inside and outside the seedling shed, or cancel the ventilation inside and outside, to maintain the temperature at a suitable growth temperature, basically without the need for supplementary heating, saving the cost of tobacco seedling cultivation.

[0048] Optionally, in some embodiments, during the period from when the tobacco seedlings emerge to when the fifth true leaf grows, the temperature in the seedling shed can be controlled between 10°C and 25°C.

[0049] Step S140: After the tobacco seedlings grow the fifth true leaf, ventilation is used to lower the temperature in the seedling shed, and growth inhibitors are sprayed to inhibit the growth of the tobacco seedlings.

[0050] It is understandable that due to early sowing, the time from sowing to transplanting of tobacco seedlings is lengthened. If the tobacco seedlings are allowed to grow at a suitable temperature, they will grow too tall, which is not conducive to subsequent field cultivation.

[0051] Taking into account that after the fifth true leaf, the synthetic capacity of the tobacco seedlings has been improved, the main root has been significantly thickened, a large number of primary lateral roots have occurred, and secondary or tertiary lateral roots have grown successively, which has a certain ability to resist adversity. This application specifically chooses to inhibit the growth of the tobacco seedlings after the tobacco seedlings grow the fifth true leaf, thereby avoiding excessive growth of the tobacco seedlings during transplanting. In addition, cooling can also inhibit the occurrence of diseases and pests and reduce cultivation costs.

[0052] Optionally, in order to fully utilize the stress resistance of tobacco seedlings and inhibit their growth, the temperature in at least a portion of the time period can be lowered to a temperature at which tobacco seedlings are difficult to grow, such as below 10°C.

[0053] Specifically, during the period from the fifth true leaf to the seventh true leaf (cat's ear period), which is from mid-to-late January to mid-February, the night temperature can often drop below 10°C, and in extreme cases can even reach around 0°C. Based on this, in some embodiments, during the night period, the temperature in the seedling shed can be controlled below 8°C.

[0054] In addition, in some embodiments, during the daytime, the temperature in the seedling shed is controlled between 10° C. and 15° C. Although tobacco seedlings can grow at this temperature, this temperature is significantly lower than the suitable temperature for tobacco seedling growth, and thus can also have a good inhibitory effect.

[0055] It should be pointed out that ventilation and cooling can also reduce the relative humidity in the seedling shed, which can also play a role in inhibiting the growth of tobacco seedlings.

[0056] Optionally, in some embodiments, after the tobacco seedlings grow the fifth true leaf, ventilation is used to control the relative humidity in the seedling shed to below 90%.

[0057] Optionally, in some embodiments, the growth inhibitor is sprayed when the maximum leaf width of 40-50% of the tobacco seedlings reaches about 2 cm.

[0058] For example, the growth inhibitor can use a product with paclobutrazol as the main component, thereby bringing about certain sterilization and improving stress resistance. Of course, products with chlormequat or other ingredients as the main components can also be used, and this application does not limit this.

[0059] In summary, first of all, the present application chooses to sow tobacco seedlings early before the arrival of cold air, so that the emergence period of tobacco seedlings can avoid the period of sudden temperature drop and fluctuation, and avoid the death of seedlings under the influence of cold air. In addition, the temperature is relatively high at this time (early December), so there is no need to supplement heat for the seedling shed, but ventilation and cooling are required. The cost of ventilation is much lower than the cost of supplementary heating, thereby reducing the cultivation cost;

[0060] Secondly, before the tobacco seedlings grow the fifth true leaf (early December to mid-January), the temperature is not too low. At this time, it is generally only necessary to reduce ventilation to achieve heat preservation in the seedling shed, and there is almost no need to add heat to the seedling shed, which can ensure the uniform growth of tobacco seedlings while reducing the cultivation cost;

[0061] Finally, considering the early sowing of tobacco seedlings, the present application specifically selects ventilation and cooling to inhibit the growth of tobacco seedlings after the tobacco seedlings grow the fifth true leaf and have a certain resistance to adversity, and then combines the application of growth inhibitors to avoid excessive growth of tobacco seedlings during transplanting, which is conducive to reducing manual labor and the number of leaf cutting. In addition, cooling can also inhibit the occurrence of diseases and insect pests and reduce the cultivation cost;

[0062] Therefore, the winter-spring tobacco seedling cultivation method can reduce the cultivation cost of tobacco seedlings while ensuring the cultivation quality. This application is different from the general winter-spring seedling cultivation method that focuses on heat preservation and promotes the rapid growth of tobacco seedlings. It focuses on making full use of natural factors and adopting "physical ventilation + chemical inhibition" means to greatly reduce manual work and control the hidden dangers of man-made pests and diseases, so as to achieve the purpose of "reducing labor and costs, improving quality and increasing efficiency" and cultivate "uniform, strong, suitable and sufficient" tobacco seedlings. Among them, "winter-spring tobacco seedlings" means that the tobacco seedling sowing time of this application is slightly earlier than the conventional spring tobacco sowing time.

[0063] Optionally, the winter-spring tobacco seedling cultivation method can also control the water level.

[0064] Illustratively, in some embodiments, during the period from sowing the tobacco seedlings to germination, the water level in the seedling nursery pool is controlled at 15 mm to 20 mm; after the tobacco seedlings grow the fifth true leaf to 7-10 days before transplanting the tobacco seedlings, the water level in the seedling nursery pool is controlled at 8 mm to 12 mm; from 7-10 days before transplanting the tobacco seedlings to the time of transplanting the tobacco seedlings, the water level in the seedling nursery pool is controlled at no more than 5 mm.

[0065] In some embodiments, in order to prevent the underground part of the tobacco seedlings from being damaged by low temperature, water supply to the nursery pool is stopped when the water temperature is below 8°C after the tobacco seedlings grow the fifth true leaf and 7-10 days before the tobacco seedlings are transplanted, and water supply to the nursery pool is resumed after the water temperature is above 8°C.

[0066] In order to ensure reliable ventilation, optionally, in some embodiments, for a seedling shed that is more than 50 meters long, a cylindrical axial flow fan is provided in the shed and a negative pressure fan is provided at each end of the shed, for a total of three fans. If the shed is about 40 meters long, a negative pressure fan is provided at each end of the shed; the fans at both ends are connected to the outside of the shed, the fan power is about 100W-150W, the wind direction of the fans is in the same direction, and the wind is guided to the top of the shed by wind guide plates to avoid direct blowing on the seedlings.

[0067] In addition, in order to promote air circulation around the tobacco seedlings, optionally, in some embodiments, the bottom of the seedling pool is higher than the ground of the seedling shed, so that the water in the pool can be easily drained out of the seedling pool, and the tobacco seedling growth environment is higher than the ground, which is convenient for ventilation of the tobacco seedlings. Preferably, the surroundings of the seedling pool are about 0.03m-0.04m higher than the ground.

[0068] The nursery pond can be constructed with cement mortar and brick hardening. Furthermore, if the nursery pond is set on the ground instead of suspended in the air, the four sides of the pond can be simply built with small wooden stakes and film. Compared with the nursery pond constructed of concrete, it is more in line with the needs of reducing labor and costs, green and low carbon, and land protection.

[0069] The present application tests the winter-spring tobacco seedling cultivation method provided by the present application through the following experiments.

[0070] Experimental conditions:

[0071] Experimental group: Using the winter-spring tobacco seedling cultivation method embodiment provided by the present application, ventilation and growth inhibitors were used to inhibit the growth of tobacco seedlings. Before the tobacco seedlings had 5 true leaves, when the maximum leaf width was about 2 cm, 25% paclobutrazol dwarfing agent plant chlormequat was sprayed once, the general application concentration was 5000 times, and 50% chlormequat aqueous solution was sprayed, the application concentration was 1250 times (the concentrations were lower than the concentrations recommended by the product).

[0072] Control group: The method of supplementary heat + greenhouse inside a small greenhouse was used for insulation. Control group 1 (CK1) was sown in early December, at the same time as the experimental group (i.e. early sowing), control group 2 (CK2) was sown in mid-December (i.e. normal sowing), and control group 3 (CK3) was sown in late December (i.e. late sowing).

[0073] Experimental results:

[0074] The growth of tobacco seedlings cultivated based on different methods was statistically analyzed, and the results are shown in the following table.

[0075]

[0076]

[0077] The calculation formula of the coefficient of variation is:

[0078]

[0079] Among them, SD is the standard deviation, x i is the maximum leaf width / stem diameter data of the i-th plant; is the sample mean.

[0080] The calculation method of labor cost for thinning and filling seedlings is:

[0081] Labor usage = total labor usage (days) / (number of tobacco seedling trays for thinning and reseeding * 162 holes / 1100 plants).

[0082] The disease index is calculated as follows:

[0083] Disease index = [Σ(number of diseased leaves at each level * representative value at each level) / (total number of leaves surveyed * highest representative value)]*100%;

[0084] Among them, the number of diseased leaves at each level is the number of diseased leaves in each disease severity level, the representative value at each level is the value corresponding to each level, the total number of leaves surveyed is the total number of leaves surveyed, and the highest representative value is the value corresponding to the highest level of disease severity.

[0085] The calculation method of the average effective leaves in the field after transplanting is:

[0086] Average number of effective leaves = Σeffective leaves / number of investigated plants;

[0087] Among them, 10-15 days after the tobacco plants are toppled, the leaves at the bottom and top that are expected to have low economic value are optimally removed. When 80% of the tobacco plants have formed a round top, 30-50 tobacco plants in the field are randomly selected, and the leaves of each plant are counted as effective leaves and accumulated.

[0088] This application analyzes the impact of different cultivation methods and sowing periods based on the data in the table.

[0089] Reference Figure 2 , Figure 2 The cultivation method of the present application (i.e., the new method in the figure) and the cultivation method of the control group 1 (i.e., the traditional method in the figure) were compared in terms of the uniformity of the maximum leaf width (see the 5th true leaf). It can be seen that the cultivation method of the present application is not inferior to the cultivation method of the control group 1 in terms of effect, but the cultivation method of the present application has obvious advantages in implementation cost.

[0090] Reference Figure 3 , Figure 3 The differences in the uniformity of maximum leaf width among the cultivation methods of the control group were compared, and it was found that early sowing had a significant advantage in the uniformity of maximum leaf width.

[0091] Reference Figure 4 , Figure 4 By comparing the differences in stem thickness uniformity between the cultivation method of the present application (i.e., the new method in the figure) and the cultivation method of the control group 1 (i.e., the traditional method in the figure) (after 7 true leaves), it can be seen that the cultivation method of the present application is superior to the cultivation method of the control group 1 in effect, and the cultivation method of the present application has obvious advantages in implementation cost.

[0092] Reference Figure 5 , Figure 5 The differences in stem thickness uniformity among the cultivation methods of the control group were compared, and it was found that early sowing had a clear advantage in stem thickness uniformity.

[0093] It can be seen that the winter-spring tobacco seedling cultivation method provided in this application can cultivate better tobacco seedlings, and because it eliminates the cost of supplementary heating and small sheds, it has obvious advantages in implementation costs and is more suitable for promotion and application.

[0094] In some selectable embodiments, the function / operation mentioned in the block diagram may not occur in the order mentioned in the operation diagram. For example, depending on the function / operation involved, the two boxes shown in succession can actually be executed substantially simultaneously or the boxes can sometimes be executed in reverse order. In addition, the embodiment presented and described in the flow chart of the application is provided by way of example, for the purpose of providing a more comprehensive understanding of technology. The disclosed method is not limited to the operation and logic flow presented herein. Selectable embodiments are expected, wherein the order of various operations is changed and the sub-operation of a part described as a larger operation is performed independently.

[0095] Although the embodiments of the present application have been shown and described, those skilled in the art will appreciate that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present application, and that the scope of the present application is defined by the claims and their equivalents.

Claims

1. A method for cultivating tobacco seedlings in winter and spring, characterized in that: include: In early December, tobacco seedlings are sown according to the weather forecast. The sowing time of tobacco seedlings is 10-15 days earlier than the arrival of cold air, so that the tobacco seedlings can emerge before the arrival of cold air. During the period from sowing to germination of tobacco seedlings, ventilation is used to control the maximum temperature in the seedling shed to prevent tobacco seedlings from being burned by high temperatures when germinating; During the period from the emergence of tobacco seedlings to the growth of the fifth true leaf, the seedling shed should be kept warm; After the tobacco seedlings grow the fifth true leaf, use ventilation to lower the temperature in the seedling shed, combined with spraying growth inhibitors to inhibit the growth of the tobacco seedlings.

2. The winter-spring tobacco seedling cultivation method according to claim 1, characterized in that: After the tobacco seedlings grow the fifth true leaf, the temperature is kept lower than the normal growth temperature of the tobacco seedlings for at least a portion of the period.

3. The method for cultivating winter-spring tobacco seedlings according to claim 2, characterized in that: After the tobacco seedlings grow the fifth true leaf, use ventilation to lower the temperature in the seedling shed, including controlling the temperature in the seedling shed below 8°C during the night.

4. The winter-spring tobacco seedling cultivation method according to claim 3, characterized in that: After the tobacco seedlings grow the fifth true leaf, ventilation is used to lower the temperature in the seedling shed. During the day, the temperature in the seedling shed is controlled between 10℃ and 15℃.

5. The winter-spring tobacco seedling cultivation method according to claim 1, characterized in that: After the tobacco seedlings grow the fifth true leaf, use ventilation to control the relative humidity in the seedling shed below 90%.

6. The winter-spring tobacco seedling cultivation method according to claim 1, characterized in that: When the maximum leaf width of 40-50% of the tobacco seedlings reaches 2 cm ± 10%, spray the growth inhibitor.

7. The method for cultivating winter-spring tobacco seedlings according to claim 1, characterized in that: During the period from tobacco seedling sowing to germination, the maximum temperature in the seedling shed is controlled at no more than 28℃.

8. The method for cultivating winter-spring tobacco seedlings according to claim 1, characterized in that: From the time the tobacco seedlings emerge to the time the fifth true leaf grows, the temperature in the seedling shed is controlled between 10℃ and 25℃.

9. The method for cultivating winter-spring tobacco seedlings according to claim 1, characterized in that: During the period from sowing to germination of tobacco seedlings, the water level in the seedling nursery pool is controlled at 15mm to 20mm; from the growth of the fifth true leaf of the tobacco seedlings to 7-10 days before transplanting, the water level in the seedling nursery pool is controlled at 8mm to 12mm; from 7-10 days before transplanting to transplanting, the water level in the seedling nursery pool is controlled at no more than 5mm.

10. The winter-spring tobacco seedling cultivation method according to claim 9, characterized in that: From the time the tobacco seedlings grow the fifth true leaf to 7-10 days before transplanting the tobacco seedlings, stop supplying water to the nursery pond when the water temperature is below 8°C, and resume supplying water to the nursery pond after the water temperature is above 8°C.

Images