A tunnel type overwintering storage method for lily bulb of lilium davidii var. unicolor

Abstract

This invention provides a tunnel-type overwintering storage method for Lanzhou lily bulbs, belonging to the field of agricultural technology. The overwintering storage method for Lanzhou lily bulbs provided by this invention has the advantages of being suitable for large-scale production and low cost; the weight and moisture loss of the bulbs stored using this method is minimal, and the root system remains fresh and intact; the disease incidence is low at lower temperatures; it can effectively control rodent, bird, and low-temperature damage during overwintering in the field; and it can effectively utilize rural labor, reducing the labor and time pressure of harvesting and sowing, thus possessing excellent prospects for widespread application.

Description

Technical Field

[0001] This invention relates to the field of agricultural technology, and in particular to a method for overwintering Lanzhou lily bulbs in a tunnel system. Background Technology

[0002] Overwintering storage of Lanzhou lily (Lilium davidii var. unicolor) bulbs is a core aspect of large-scale production. Traditional storage methods mainly include cold storage, natural overwintering in seedbeds, and cellar storage, but all have significant limitations, as detailed below:

[0003] While cold storage can suppress diseases through low temperatures (-4℃±0.5℃), it has several drawbacks: high economic costs: the construction of a cold storage facility requires a one-time investment of 350,000-500,000 yuan (50-ton capacity), with a construction cost of 7,000-10,000 yuan per ton. Electricity consumption during operation accounts for 23.8% of the total storage cost (12,000 yuan / 13,000 kg bulbs); severe storage losses: after 6 months of storage, the fresh weight loss of seed bulbs reaches 15%-30%, and the germination rate of miniature seed bulbs drops from 100% to 91%. Furthermore, the high concentration of CO2 in the environment easily breeds Penicillium and Pythium, with a Penicillium disease incidence rate as high as 12.8%; low resource utilization: cold storage facilities can only operate for 6 months each year (November to April of the following year), remaining idle for the rest of the time, resulting in a utilization rate of less than 50%.

[0004] Naturally overwintered bulbs left in the seedbed without autumn harvesting, while exhibiting high root vitality (78.62 μg TTF / g·h), present the following problems: extremely high environmental dependence; fresh weight decreases by more than 45% without harvesting or winter watering, and bulb weight decreases by 8.13% when naturally overwintering and watered, with the loss directly related to soil type and climate fluctuations; severe biological stress: overwintering in open fields is susceptible to rodent and bird damage, with a germination rate of only 86%.

[0005] Traditional cellar storage uses sealed cellars, which is low-cost, but has poor ventilation and high humidity, which can easily lead to increased ethylene concentration and disease: In a closed environment, the concentration of ethylene released by the bulbs gradually increases, which can easily induce fungal and bacterial diseases and cause bulb rot; Operation is uncontrollable: It is difficult to precisely control the temperature and humidity inside the cellar, and the storage effect is significantly affected by the region and the operator's experience.

[0006] Furthermore, the time conflict between the harvesting and sowing of Lanzhou lily bulbs exacerbates the demand for storage: the spring harvesting window is short (2-3 weeks), labor is highly concentrated, and the problem of sprouting before harvesting is likely to occur; although there is ample time for autumn harvesting (October-November), autumn sowing has certain requirements for environmental conditions, and some high-altitude areas (above 2400 meters) cannot carry out autumn sowing. In addition, Lanzhou lilies require strict control of winter rodent and bird damage after autumn sowing. Winter rodent and bird damage is also the main reason for the reduced seedling emergence rate in the second spring after autumn sowing, further amplifying the shortcomings of existing technologies.

[0007] In summary, existing technologies struggle to balance economic efficiency, storage effectiveness, and adaptability to large-scale production, leading to decreased bulb quality, frequent disease outbreaks, and increased production costs. Therefore, there is an urgent need for a low-cost, highly controllable storage method suitable for large-scale implementation to address the issues of bulb quality degradation, biological stress, and labor shortages during winter. Summary of the Invention

[0008] The purpose of this invention is to provide a method for overwintering Lanzhou lily bulbs in a tunnel, which has excellent effects.

[0009] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0010] This invention provides a method for overwintering Lanzhou lily bulbs in a tunnel system, including the construction of storage tanks, environmental control, bulb treatment, tank filling, and storage management, specifically including the following steps:

[0011] a. Excavate 2 to 6 east-west oriented storage trenches with a width of 1 to 1.5 meters and a depth of 0.2 to 0.4 meters inside the solar energy-saving greenhouse, and lay an isolation layer on the bottom and perimeter of the trenches;

[0012] b. Cover the greenhouse with insulation blankets at all times and use ventilation to regulate the ambient temperature;

[0013] c. The bulbs are treated with a fungicide powder;

[0014] d. Lay the seed bulbs in a layer no more than 20cm thick and install a ventilation system;

[0015] e. Cover with an 8-12cm layer of dry soil and implement dynamic control in conjunction with temperature monitoring.

[0016] Preferably, the storage tanks are constructed to meet the following requirements: the tank spacing maintains a walkway of 0.4~0.6m;

[0017] A 0.8-1.2m protection zone should be maintained between the greenhouse's rear wall and the front roof enclosure structure.

[0018] A 40cm x 40cm water-blocking ditch is installed on the south side of the greenhouse.

[0019] Preferably, the environmental control includes maintaining the temperature in the range of -5°C to 5°C;

[0020] Rodent traps should be installed every 3-4 meters around the storage tank;

[0021] Place rodent traps at intervals of 3-4 meters on the surface of the covering.

[0022] Preferably, the insulating layer comprises a shade net and / or a layer of dried crop straw.

[0023] Preferably, the bactericide is selected from one or more of carbendazim, methyl isothion, or methyl thiophanate wettable powder.

[0024] Preferably, the ventilation system includes a bundle of straw arranged longitudinally along the central axis of the trough.

[0025] Preferably, the temperature monitoring includes maintaining the temperature within the range of 0 to -5°C during the freezing period.

[0026] Preferably, the dynamic control includes the following operations:

[0027] Leave the top and bottom vents open during the initial storage period until freezing;

[0028] Add moist insulation blankets to the storage tanks as the thawing period approaches;

[0029] Storage should be terminated when the covering soil thaws and the central buds of the seed bulbs become active.

[0030] Preferably, the total storage period of the overwintering storage method is controlled to be 150-180 days.

[0031] Preferably, the seed bulbs are spread out and sorted before being treated with fungicide dry powder.

[0032] The beneficial effects of this invention are:

[0033] The storage and overwintering method for Lanzhou lily bulbs provided by this invention is a novel, large-scale, and low-cost storage method. The stored bulbs show minimal weight and moisture loss, and the root system remains fresh and intact. The disease incidence is low at lower temperatures. It can effectively control rodent, bird, and low-temperature damage during overwintering in the field. It can effectively utilize rural labor, reducing the labor and time pressure of harvesting and sowing, and has excellent prospects for promotion. Attached Figure Description

[0034] Figure 1 This is a greenhouse plan view used in an embodiment of the present invention. Detailed Implementation

[0035] In different regions of Qinghai, the effective growing period for lilies in open fields is generally from May to August. Seedlings emerge in May, and the above-ground parts wither and die in mid-to-late August. In some areas, they can be harvested as early as late August. The growing period is generally 90-120 days. Large-scale, factory-style bulb nursery cultivation (starting from the scales) generally requires 2 years (3 years for direct seeding of scales in open fields), and it takes 3 years (2 years in Northeast China) for them to reach the harvestable size and become commercial bulbs. Miniature bulbs can be harvested in autumn or spring. Generally, spring harvesting yields better quality bulbs. However, the spring harvesting season is very short, only 2 to 3 weeks. In large-scale production, both harvesting and sowing require a lot of labor, which can easily lead to unharvested bulbs sprouting and emerging in the nursery. Autumn harvesting offers greater mobility and a longer harvesting period from October to November, allowing for autumn sowing. However, autumn-harvested microbulbs are unsuitable for autumn sowing in certain areas, such as high-altitude regions (most areas above 2400 meters) and the Yuzhong Beishan area in Gansu Province. These regions often practice autumn harvesting and spring sowing. Therefore, the storage of microbulbs has become a technical challenge for many enterprises and farmers. Improper storage can lead to a large number of bulbs rotting, failing to germinate, or exhibiting severe disease after germination. Some enterprises, when harvesting commercial bulbs in autumn, often store non-commercial bulbs in cold storage for sale as seeds the following spring. However, after a winter of storage, the bulbs lose a significant amount of nutrients and moisture, resulting in low germination rates, severe disease, and poor growth after sowing. To fully utilize the advantages of abundant labor resources and a long harvesting season in autumn, while overcoming the problem of reduced microbulb quality due to storage, this invention provides an economical and effective tunnel-type on-site storage method in autumn 2019, achieving excellent results. See the following examples for details.

[0036] 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 scope of protection of the present invention.

[0037] Example

[0038] 1) Miniature bulb tunnel storage design

[0039] Utilizing a solar-powered energy-saving greenhouse, an east-west trench is dug inside. A 1.5-meter buffer zone is left on the north side (from the rear wall) and the south side (from the front roof enclosure structure) as protected areas. For a typical 9.0-meter-wide solar-powered energy-saving greenhouse, three trenches are evenly dug along the greenhouse's length, each 1.2 meters wide and 0.3 meters deep, with a 0.5-meter walkway. The greenhouse plan used in this example is shown in [reference needed]. Figure 1Lay a layer of shade netting at the bottom and around the perimeter of the planting trench to prevent direct contact between the microbulbs and the soil. Use imported or local peat moss (for planting) as the substrate. Basic requirements: Before placing the microbulbs, thoroughly dry the trench, ensuring no water enters. Then lay the shade netting, followed by a 5.0 cm thick layer of sterilized peat moss (50% carbendazim, 50% thiophanate-methyl, or 75% methyl thiophanate, 30 grams per cubic meter of peat moss, with a relative moisture content of 40%-50%). Next, place the sterilized microbulbs (directly treated with a similar concentration to the peat moss) on top of the peat moss, approximately 20 cm thick. Cover the microbulbs with another 5.0 cm layer of peat moss, and then cover with shade netting or straw matting to prevent strong sunlight exposure. When temperatures are high, open the top and bottom vents until the soil is completely frozen. In early spring, a thick insulating blanket is laid on the surface of the trough, fully moistened with water and kept frozen day and night. The greenhouse is closed during the day and opened at night through the vents. After entering spring, temperature changes and the germination of the microbulbs are monitored at all times to ensure that the covering substrate is frozen. When the covering substrate begins to thaw and the central buds of the microbulbs begin to move, they are removed from the trough and planted as soon as possible.

[0040] 2) Comparison of overwintering effects of autumn harvesting and non-harvesting of miniature bulbs

[0041] Bulbs left unwatered and unharvested during winter experience significant water loss (autumn of 2018 and spring of 2019), with the degree of loss closely related to the substrate type. Without winter watering, the fresh weight of overwintered microbulbs decreases significantly, ranging from 6.5% to 48.08%, with only a slight increase observed in A4 substrate. Natural soil has a relatively small impact on the weight of overwintered bulbs. Using sheep manure as a substrate, the weight loss of bulbs without winter watering is substantial, averaging over 45.0%, therefore sheep manure is unsuitable as a storage or overwintering substrate. Although cold storage can be standardized with environmental control (generally -4.0℃ ± 0.5℃), high CO2 concentrations can easily form, leading to the growth of pathogens such as Penicillium and Pythium, causing rot of the basal plate, roots, and some external scales. Furthermore, cold storage easily causes microbulbs to lose moisture; severe CO2 poisoning and water loss in the cold storage often result in central bud rot after sowing, leading to failure to germinate. Therefore, choosing a suitable storage method for miniature bulbs is crucial for Lanzhou lilies. In the autumn of 2019, the research team designed and adopted a tunnel-style in-situ storage method, achieving a Penicillium spore incidence rate of less than 5.0% (3.4%), and a germination rate of 100% after sowing in 2020. Weight loss data shows that without harvesting and naturally overwintering (with winter watering), the miniature bulbs lost 8.13% of their weight, while those stored in tunnels only lost 2.93%, indicating better overall quality. Tunnel-style storage of miniature bulbs resulted in a smaller weight loss, lower disease incidence, and effective control of rodent and bird damage during overwintering, while also reducing labor and time constraints during harvesting. However, tunnel storage also has its weaknesses: firstly, it requires advanced tunnel design and bulb disinfection techniques; secondly, it demands strict control over environmental factors such as substrate and bulb moisture content, and autumn and early spring temperature management, otherwise the losses could be incalculable.

[0042] As can be seen from the above embodiments, the tunnel-type in-situ storage provided by the present invention is a novel large-scale, low-cost storage method. The stored micro-bulbs exhibit minimal weight loss and a low disease incidence rate, effectively controlling rodent and bird damage during winter and reducing labor and time constraints during harvesting. From late October 2019 to mid-April 2020, the present invention successfully stored over 5000 kg (approximately 1.12 million bulbs) of micro-bulbs in a 270㎡ solar-powered greenhouse, with storage moisture and dry matter loss of less than 3.0% and a disease incidence rate of less than 6.0%.

[0043] This invention provides a novel, large-scale, low-cost storage method with the following superior advantages:

[0044] Storage capacity is flexible and adjustable: Solar-powered greenhouses are abundant in the Lanzhou lily-producing area, with a current vacancy rate exceeding 40%, representing surplus resources owned by farmers. A standard solar greenhouse (50 meters long and 9 meters wide) can store 13,000-14,000 kilograms of seed bulbs, equivalent to a 20,000 kilogram cold storage unit. Farmers cannot meet the needs of building their own cold storage units due to limitations in terms of space, investment, and utilization rate.

[0045] Low construction cost: By utilizing idle solar-powered greenhouses, farmers do not need to incur additional construction costs. Cold storage facilities require a minimum construction volume of 50 tons, with each ton costing at least 7,000 to 10,000 yuan. The one-time construction cost of 350,000 to 500,000 yuan is difficult for farmers to invest.

[0046] It can improve the utilization rate of solar greenhouses: Many simple solar greenhouses are idle because their heat preservation cannot meet the needs of vegetable production in winter and spring. Using them for lily bulb storage increases the utilization rate by 40-50%. Cold storage is idle for about 6 months except for November to April of the following year, with a utilization rate of only 50%.

[0047] Low operating costs:

[0048] Cost of sun-dried energy-saving greenhouse tunnel burial = Labor + Infrastructure + Disinfection = 18,000 yuan + 3,000 yuan + 3,000 yuan = 21,300 yuan (calculated based on 13,000 kg of bulbs)

[0049] Cold storage cost = Labor + Cold storage depreciation (based on storing 13,000 kg of bulbs) + Disinfection + Electricity = 18,000 yuan + Depreciation 20,000 yuan + 300 yuan + 12,000 yuan = 50,300 yuan (based on 13,000 kg of bulbs)

[0050] Based on a 6-month storage period, the storage cost per kilogram of seed bulbs stored in a sun-dry greenhouse tunnel is 1.64 yuan, while the storage cost in a cold storage is 3.87 yuan. The cost of tunnel burial is only 42.3% of the cost of cold storage, which is 89.0% lower than the cost of cold storage.

[0051] The storage effect is better than that of cold storage.

[0052] The stored seed bulbs showed minimal weight and moisture loss, and their root systems remained fresh and intact; the disease incidence was low when stored at lower temperatures.

[0053] Low weight and moisture loss

[0054] Bulb storage is a crucial technique for minimizing the loss of substances and water within the bulbs and breaking dormancy. Lanzhou lily bulbs can be harvested in autumn and stored for overwintering, or left to overwinter outdoors without harvesting in autumn. The effects of storage and open-field overwintering differ significantly. Bulbs left in the seedbed without autumn harvesting and winter watering suffer substantial water loss, the degree of which is closely related to soil type. Weight loss data shows that unharvested bulbs that overwinter naturally (with winter watering, in black calcareous soil) lose 8.13% of their weight, while those stored in tunnels lose only 2.93%, a mere 36.0% of the weight loss from unharvested bulbs. Cold storage for 6 months results in a weight loss of approximately 15% or more, sometimes exceeding 30%, which is 6-7 times the loss from tunnel storage.

[0055] Root vigor is better than that of cold storage, and second only to that of not harvesting.

[0056] Root activity of bulbs stored in cold storage, buried in tunnels, and not harvested was measured simultaneously at the end of storage in early April. The root activity of bulbs stored in cold storage was 58.62 μg TTF / g·h, that of bulbs buried in tunnels was 70.82 μg TTF / g·h, and that of bulbs not harvested was 78.62 μg TTF / g·h. This shows that the root activity of bulbs buried in tunnels was higher than that of bulbs stored in cold storage, but lower than that of bulbs not harvested.

[0057] The incidence rate is lower than that of cold storage.

[0058] Traditional cellar storage involves sealing the cellar, resulting in high humidity and poor air circulation. This leads to a gradual increase in the concentration of ethylene released from the bulbs, making them susceptible to rot and other diseases. While cold storage allows for standardized environmental control (generally -4.0℃±0.5℃), it also generates high CO2 concentrations, promoting the growth of pathogens such as Penicillium and Pythium, causing rot of the basal plate, roots, and some external scales. Furthermore, cold storage easily leads to moisture loss in the microbulbs. Severe CO2 poisoning and moisture loss in the storage often result in central bud rot after sowing, preventing seedling emergence. Therefore, choosing a suitable storage method for microbulbs is crucial for Lanzhou lilies. In the autumn of 2019, the research group designed and adopted a tunnel-style in-situ storage method, achieving a Penicillium incidence rate below 5.0% (minimum 3.4%), approximately 8.0% lower than the incidence rate of cold storage (12.8%) during the same period, and slightly higher than the incidence rate of bulbs not harvested for overwintering. The germination rate reached 100% after sowing in 2020.

[0059] The bulbs exhibit better growth vigor than those stored in cold storage.

[0060] In 2019, field growth vigor measurements were conducted on seed bulbs stored without harvesting, in tunnels, and in cold storage in Yangqitai Village, Putai Township, Ledu District, Haidong City, Qinghai Province. The results showed that the average plant height at flowering time was 38 cm for tunnel-stored bulbs, a decrease of 1.2 cm compared to the average height of unharvested bulbs (39.2 cm), but an increase of 0.6 cm compared to the average height of cold-stored bulbs (37.4 cm). The germination rate of unharvested bulbs was only 86%, while the germination rate of tunnel-stored bulbs reached 100.0%, and the germination rate of cold-stored bulbs was 91.0%. This indicates that tunnel-stored bulbs are of better quality and exhibit superior growth vigor compared to other storage methods. This is consistent with previous findings that bulbs stored in cellars and cold storage showed poorer growth in the second year compared to those overwintered in open fields, but tunnel storage proved to be more effective than cellar storage.

[0061] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for overwintering storage of Lanzhou lily bulbs in a tunnel system, characterized in that, This includes the construction of storage tanks, environmental control, bulb treatment, tank filling, and storage management, specifically including the following steps: a. Excavate 2 to 6 east-west oriented storage trenches with a width of 1 to 1.5 meters and a depth of 0.2 to 0.4 meters inside the solar energy-saving greenhouse, and lay an isolation layer on the bottom and perimeter of the trenches; b. Cover the greenhouse with insulation blankets at all times and use ventilation to regulate the ambient temperature; c. The bulbs are treated with a fungicide powder; d. Lay the seed bulbs in a layer no more than 20cm thick and install a ventilation system; e. Cover with an 8-12cm layer of dry soil and implement dynamic control in conjunction with temperature monitoring; The environmental control includes maintaining the temperature in the range of -5℃ to 5℃; and maintaining the temperature in the range of -5℃ to 0℃ during the freezing period. The ventilation system includes straw bundles arranged longitudinally along the central axis of the trough; The dynamic control includes the following operations: Leave the top and bottom vents open during the initial storage period until freezing; Add moist insulation blankets to the storage tanks as the thawing period approaches; Storage should be terminated when the covering soil thaws and the central buds of the seed bulbs become active.

2. The overwintering storage method according to claim 1, characterized in that, The construction of the storage tanks meets the following requirements: the tank spacing maintains a walkway of 0.4~0.6m; A 0.8-1.2m protection zone should be maintained between the greenhouse's rear wall and the front roof enclosure structure. A 40cm x 40cm water-blocking ditch is installed on the south side of the greenhouse.

3. The overwintering storage method according to claim 1, characterized in that, Rat traps are installed every 3-4 meters around the storage tank; rat traps are also placed on the surface of the covering material at 3-4 meter intervals.

4. The overwintering storage method according to claim 1, characterized in that, The insulating layer includes a shade net and / or a layer of dried crop straw.

5. The overwintering storage method according to claim 1, characterized in that, The bactericide is selected from one or more of carbendazim, methyl isothion, or methyl thiophanate wettable powder.

6. The overwintering storage method according to claim 1, characterized in that, The total storage period for the winter storage method is controlled to be 150-180 days.

7. The overwintering storage method according to claim 1, characterized in that, Before the bulbs are treated with fungicide dry powder, they are spread out to dry and sorted.

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