A cultivation method for promoting early maturity of fresh corn

Abstract

This invention belongs to the field of crop cultivation, specifically relating to a cultivation method for promoting early maturity of sweet corn. It aims to address the technical shortcomings of existing early-maturing sweet corn cultivation techniques, such as low matching between sowing and harvesting periods, unstable heat preservation effects, low precision in accumulated temperature control, poor adaptability to mechanization, and a prominent contradiction between early maturity and quality. The cultivation method includes steps such as predictive sowing and seed treatment, construction of seedbeds, accumulated temperature control for seedling cultivation, construction of composite heat preservation facilities, post-transplant accumulated temperature control, water and fertilizer management, disease control, and harvesting. This invention shortens the growth period of sweet corn by 20-30 days and advances maturity by 10-20 days, while simultaneously balancing yield and quality, reducing cultivation costs, improving mechanization adaptability and regional universality, and meeting the needs of large-scale, green production.

Description

Technical Field

[0001] This invention belongs to the field of crop cultivation, specifically relating to a cultivation method for promoting early maturity of fresh corn. Background Technology

[0002] Sweet corn, with its sweet taste and rich nutrition, is highly favored by consumers. Early market entry can significantly improve the economic benefits of cultivation, making it one of the core requirements for the high-quality development of the sweet corn industry. Currently, existing technologies related to early market entry of sweet corn mainly focus on heat preservation and temperature increase, seedling transplanting, and staggered planting, achieving some early-maturing effects. However, many technical shortcomings remain, making it difficult to meet the comprehensive needs of the modern sweet corn industry for "early market entry, high quality, high efficiency, and green sustainability."

[0003] The main shortcomings of existing technologies are as follows: First, the insulation methods are either too simple or not complex enough. Existing technologies rely on single or multiple layers of plastic film for covering, which is mainly passive insulation and has low temperature control accuracy. In the event of severe weather such as late spring frosts or continuous rain, large temperature fluctuations can easily lead to chilling injury and weak seedlings in corn, resulting in poor yield stability. Secondly, the control of accumulated temperature lacks precision, failing to segment and manage the accumulated temperature requirements of fresh corn at different growth stages, resulting in limited effects in shortening the growth period and a contradiction between early maturity and reduced quality. Thirdly, the adaptability to mechanization is poor; traditional arched greenhouses are mostly fixed structures, making it difficult to integrate with mechanized operations such as sowing, transplanting, and plant protection, leading to high labor costs for large-scale planting. Fourthly, there is insufficient green sustainability, with a large reliance on ordinary mulch film, which is difficult to recycle and causes heavy pollution; the application of biodegradable mulch film is limited, and the resource utilization of agricultural waste such as straw is insufficient. Fifthly, the regional applicability is weak; most technologies are designed only for single ecological areas, requiring readjustment of technical parameters when promoted across regions, lacking standardized and replicable operating procedures. Sixthly, there is a disconnect between varieties and cultivation techniques; no specific early-maturing programs have been designed for the different growth characteristics of waxy corn, sweet corn, and sweet-waxy corn, resulting in poor adaptability.

[0004] Therefore, based on this, the technical solution of the present invention is proposed. Summary of the Invention

[0005] To address the problems of existing technologies, such as limited heat preservation methods, lack of precision in accumulated temperature control, poor adaptability to mechanization, insufficient green sustainability, weak regional applicability, and disconnect between varieties and cultivation techniques, this invention provides a cultivation method for promoting early maturity of sweet corn based on accumulated temperature control and composite heat preservation. Through systematic integration and innovation, it organically combines precise accumulated temperature control, efficient composite heat preservation, and simplified green cultivation. This significantly shortens the growth period of sweet corn, allows for earlier market entry, while ensuring yield and quality, reducing cultivation costs, improving mechanization adaptability and regional applicability, and meeting the needs of large-scale and green production.

[0006] The present invention provides a cultivation method for promoting early maturity of sweet corn, the cultivation method comprising the following steps:

[0007] (1) Predicting sowing and seed treatment: Establish a database of accumulated temperature for sweet corn, and use the target harvest time to calculate the seedling time of sweet corn. Then, pre-treat the sweet corn seeds by sun drying, hot water soaking and biological seed dressing to obtain pre-treated seeds. (2) Constructing seedbeds: Constructing composite seedbeds that include a straw fermentation layer, a nutrient substrate layer and an insulation layer to achieve biological warming and physical insulation during the cultivation of fresh corn; (3) Accumulated temperature regulation for seedling cultivation: The pretreated seeds are sown in seedling trays and placed in the composite structure seedling bed. Then, the accumulated temperature is regulated in stages according to the emergence period, seedling stage and early seedling stage to cultivate strong seedlings. (4) Construct composite insulation facilities: After deep plowing the selected site, apply base fertilizer and then ridge the site to construct composite insulation facilities including adjustable arched sheds, composite bubble film and biodegradable mulch film. (5) Accumulated temperature control after transplanting: The strong seedlings are transplanted to the composite heat preservation facility. After transplanting, the accumulated temperature is controlled and cultivated in stages according to the initial stage of transplanting, the seedling recovery period to the tasseling period, and the tasseling to the grain filling period. (6) Water and fertilizer management: During the cultivation of fresh corn, the amount of water and fertilizer should be adjusted according to the water and fertilizer requirements of fresh corn at different growth stages; (7) Disease control and harvesting: pests and diseases are controlled by a combination of agricultural and biological control. Fresh corn can be harvested with the husks intact during the milk stage.

[0008] Preferably, in step (1), the accumulated temperature dynamic prediction sowing technology can be closely combined with the warming effect of the composite heat preservation system, and can realize the transformation from "sowing according to the weather" to "sowing according to the accumulated temperature". First, a dedicated accumulated temperature database for fresh corn varieties is constructed, and the effective accumulated temperature required for the target variety from sowing to maturity is determined to lay the foundation for dynamic prediction of accumulated temperature. The type of fresh corn variety to be tested (waxy corn, sweet corn, sweet-waxy corn) is identified, and early-maturing, low-temperature resistant special varieties of the corresponding type are selected (through multi-year multi-point experiments, the basic effective accumulated temperature requirements of each variety are determined: sweet corn is 1150-1350℃, waxy corn is 1250-1450℃, and sweet-waxy corn is 1200-1400℃). The above data are sorted and archived to establish a variety accumulated temperature database, and the accumulated temperature thresholds of different varieties are identified to provide basic parameters for subsequent prediction. Secondly, the temperature increase equivalent correction under composite insulation conditions is carried out to improve the accuracy of accumulated temperature prediction. Under the composite insulation system of this invention (composite insulation system of straw fermentation heating, mulch film, composite bubble film and adjustable arched shed), the average daily temperature inside the shed / under the ridge can increase by 2.5-4.5℃. The temperature increase equivalent compensation correction is carried out on the accumulated temperature. Through the correction, the accumulated temperature can be completed 15-30 days earlier. Finally, the sowing and seedling time is deduced by working backward from the target harvest time (marketing period) to determine the target harvest date. The local meteorological data of the same period in the past 10 years is consulted. Combined with the medium and long-term temperature forecast of the year, the average daily temperature during the growth period is predicted, the theoretical number of days required is calculated, and the optimal seedling sowing date is deduced.

[0009] Seed pretreatment consists of three steps: (i) Sun-drying: On a sunny day, spread the seeds flat in a cool, ventilated place to sun-dry for 2-3 days, 4-6 hours each day, avoiding direct sunlight to improve germination rate; (ii) Warm water soaking: Place the sun-dried seeds in warm water at 55-60℃, stirring constantly, and soak at a constant temperature for 15-20 minutes. Then allow them to cool naturally to room temperature and continue soaking for 6-8 hours to kill pathogens on the seed surface and promote water absorption and germination; (iii) Biological seed dressing: After soaking, drain the seeds and apply a compound microbial agent (containing Bacillus subtilis and phosphate-solubilizing bacteria, with an effective viable count ≥2.0×10⁻⁶). 9 Treat seeds with a microbial agent (cfu / g) at a rate of 0.3-0.5% of the seed weight. After mixing, air dry for 1-2 hours to enhance seed resistance and promote robust seedling growth.

[0010] Preferably, in step (2), the seedbed is selected from a flat, well-drained, and well-lit plot, and adopts a three-layer composite structure of straw fermentation layer, nutrient substrate layer and heat preservation layer, which takes into account both biological heating and heat preservation effects, and realizes the resource utilization of straw.

[0011] (i) Construction of straw fermentation layer: Crush corn stalks into small pieces of 5-10cm, mix them evenly with well-rotted livestock and poultry manure and compound fermentation agent at a mass ratio of 6:3:1, spread them at the bottom of the seedbed, spread them to a thickness of 15-20cm, water them to a moisture content of 60-65%, cover them with plastic film and seal them for fermentation for 5-7 days. During the fermentation process, control the temperature at 50-60℃ to kill pathogens and insect eggs in the fermentation material, and at the same time release biological heat to provide a continuous and stable soil temperature for seedling cultivation. After fermentation, loosen and level the soil to ensure that the fermentation material is uniform and loose.

[0012] (ii) Nutrient substrate layer laying: Mix garden soil, leaf mold, perlite and slow-release fertilizer (N:P:K=15:15:15) evenly in a mass ratio of 5:3:1:1, sieve and lay it on top of the straw fermentation layer, with a thickness of 10-12cm, level and compact it to ensure that the substrate layer is loose and breathable and has sufficient nutrients to meet the growth needs of seedlings.

[0013] (iii) Installation of insulation layer: Cover the nutrient substrate layer with biodegradable insulation film, and at the same time lay heating wires on both sides of the seedling bed to assist in heating. The spacing between the heating wires is 15-20cm, and the power is 50-80W / m. 2 The heating wire is connected to the temperature control device to achieve precise temperature control and avoid damage to seedlings caused by low or high temperatures.

[0014] Preferably, in step (3), the pretreated seeds are sown into the seedling tray (1 seed per hole) at a depth of 2-3 cm. Then, the seedling tray is placed on the nutrient substrate layer of the seedling bed, covered with a thin layer of soil (1-2 cm thick), watered until the soil moisture content is 70-75%, covered with a biodegradable heat-insulating film, and the intelligent temperature control equipment is activated to carry out segmented temperature accumulation regulation to ensure the healthy growth of seedlings and shorten the seedling cycle.

[0015] Temperature accumulation regulation is divided into three stages: (i) Emergence period (from sowing to emergence): The core objective is to promote rapid seed germination. The daytime temperature is controlled at 25-28℃, the nighttime temperature is controlled at 15-18℃, and the cumulative temperature is controlled at 120-150℃. Generally, seedlings will emerge in 3-5 days. (ii) Seedling stage (from emergence to 3 leaves and 1 heart): The core goal is to cultivate strong seedlings and enhance their resistance to adverse conditions. The daytime temperature should be controlled at 22-25℃, the nighttime temperature at 12-15℃, and the cumulative temperature at 350-400℃. During this stage, timely ventilation should be provided to harden the seedlings and prevent them from growing too tall. (iii) Early seedling stage (3 leaves and 1 heart to 5 leaves and 1 heart): The core objective is to promote the growth of seedling roots and lay the foundation for transplanting and recovery. The daytime temperature is controlled at 20-22℃, the nighttime temperature is controlled at 10-12℃, and the cumulative temperature is controlled at 280-320℃. The accumulated temperature during the entire seedling stage is controlled at 750-870℃, shortening the seedling cycle to 20-25 days, which is 10-15 days shorter than traditional seedling methods. The seedlings also exhibit high uniformity and strong resistance. This process utilizes intelligent temperature control equipment, which includes a temperature sensor, controller, heating module (heating wire), and ventilation module (ventilation fan). The temperature sensor (SW-AEM17(T500N) wireless low-power soil three-in-one sensor) collects real-time temperature data from the seedbed and transmits it to the controller. The controller automatically activates the heating or ventilation module based on a preset temperature threshold, achieving a temperature control accuracy of ±0.5℃ and enabling precise control of accumulated temperature.

[0016] Preferably, in step (4), the planting field is deeply plowed to 25-30cm in advance, leveled and harrowed, and sufficient base fertilizer is applied (corn stalks, decomposed manure and fermentation agent are mixed in a ratio of 6:3:1, spread to a thickness of 15-20cm, with 2000-2500kg / mu of straw fermented organic fertilizer and 30-40kg / mu of ternary slow-release fertilizer), and the planting is carried out on ridges with a ridge width of 120cm, double rows on the large ridges, a ridge height of 15-20cm, and a ridge spacing of 40-60cm.

[0017] A three-layer composite insulation system consisting of an adjustable arched shed, composite bubble film, and biodegradable mulch film is constructed to balance insulation performance with mechanization compatibility, as detailed below: (i) Adjustable arched greenhouse: It adopts insertable arch rods, the arch rods are made of fiberglass, with a diameter of 8-10mm, a length of 2.5-3.0m, an insertion depth of 20-25cm into the soil, an arch rod spacing of 1.5-2.0m, and an arched greenhouse width of 1.2-1.5m. Adjustable buckles are installed at the top of the arch rods. The height of the arched greenhouse can be adjusted to 50-120cm according to the plant height of fresh corn at different growth stages, which is suitable for the growth needs of seedlings and mature plants, and is also convenient for mechanized operations.

[0018] (ii) Composite bubble film: Covered on adjustable arched sheds, it adopts a double-layer air insulation structure. The outer layer is a UV-resistant PE film with a thickness of 0.08-0.10mm, and the inner layer is a heat-insulating bubble film with a thickness of 0.12-0.15mm. The light transmittance is ≥85%, and the heat preservation effect is 30-40% higher than that of ordinary greenhouse film. It can effectively reduce heat loss at night and resist low temperature weather such as late spring cold.

[0019] (iii) Biodegradable mulch film: Cover the surface of the planting row with fully biodegradable material (polylactic acid base), with a width of 120-150cm and a thickness of 0.015-0.02mm. When covering, the film should be close to the ground and the edges should be compacted to reduce soil moisture evaporation and increase soil temperature. At the same time, it avoids environmental pollution caused by ordinary mulch film residue. After covering, holes should be punched in the film to facilitate subsequent transplanting.

[0020] Preferably, in step (5), when the seedlings grow to 5 leaves and 1 heart, transplanting is carried out on a sunny morning. Mechanized transplanting mode is adopted, with the transplanter adapted to the width of the adjustable arched shed and the transplanting depth of 5-6cm, to ensure that the seedling roots are in close contact with the soil. Watering is carried out in time after transplanting to thoroughly settle the roots and improve the survival rate of transplanting.

[0021] Planting density is adjusted according to variety type: 3500-4000 plants / mu for waxy corn, 2500-3000 plants / mu for sweet corn, and 3000-3500 plants / mu for sweet and waxy corn. After planting, the temperature inside the greenhouse is monitored by intelligent temperature control equipment (shared with the seedling stage and can be moved and installed) to carry out segmented accumulated temperature control, shorten the growth period, and ensure the healthy growth of seedlings.

[0022] Post-planting accumulated temperature regulation is divided into three stages: (i) Early stage of transplanting (1-7 days after transplanting): The core goal is to promote seedling establishment. The daytime temperature is controlled at 22-25℃, the nighttime temperature is controlled at 12-15℃, and the cumulative temperature is controlled at 180-220℃. During this stage, the ventilation openings are closed, and the humidity inside the greenhouse is kept at 70-75% to prevent seedlings from losing water. (ii) From seedling establishment to tasseling stage: The core objective is to promote the vegetative growth of plants. The daytime temperature should be controlled at 20-23℃, the nighttime temperature at 10-13℃, and the cumulative temperature at 800-900℃. During this stage, ventilation should be provided as needed according to the temperature to reduce humidity in the greenhouse and prevent disease. (iii) From tasseling to grain filling: The core objective is to promote ear development and improve fruit quality. Daytime temperature should be controlled at 23-26℃, nighttime temperature at 13-16℃, and cumulative temperature at 650-750℃. After transplanting, the cumulative temperature is controlled at 1630-1870℃, which shortens the growth period by 20-30 days compared with traditional cultivation methods and brings the market time forward by 10-20 days.

[0023] Preferably, in step (6), a drip irrigation system is used for integrated water and fertilizer management, which takes into account water conservation, labor saving and green environmental protection. According to the water and fertilizer requirements of fresh corn at different growth stages, the amount of water and fertilizer is precisely controlled to avoid nutrient waste and environmental pollution.

[0024] (i) Water management: After transplanting until seedling establishment, maintain soil moisture content at 70-75%; after seedling establishment until tasseling, maintain soil moisture content at 65-70%; from tasseling to grain filling, maintain soil moisture content at 60-65%; in the later stage of grain filling, appropriately control watering and maintain soil moisture content at 55-60% to promote fruit ripening and improve taste. Drip irrigation should be used to avoid flooding and reduce soil compaction.

[0025] (ii) Fertilizer regulation: In addition to applying sufficient base fertilizer before transplanting, apply topdressing twice and foliar spray once: After the seedlings have recovered (10-12 days after transplanting), apply nitrogen fertilizer (urea) at 10-15 kg / mu, and apply it evenly through the drip irrigation system to promote the growth of plant stems and leaves; before tasseling (30-35 days after transplanting), apply compound fertilizer of nitrogen, phosphorus and potassium (N:P:K=15:15:15) at 15-20 kg / mu to promote ear differentiation and floret development; during the grain filling period (15-20 days after tasseling), spray foliar fertilizer, which is 0.2% potassium dihydrogen phosphate and 35% slow-release liquid nitrogen fertilizer (Green Speed), at 30-40 kg / mu, to improve the sweetness and glutinousness of the ears and increase the yield.

[0026] (iii) Optimization of pollination microenvironment: During the early stage of male ear emergence, a micro drone (DJIMini 4 Pro) is used to fly at a height of 2m from 10:00 to 12:00 every day to assist in pollination. During the pollination period, the humidity in the greenhouse is maintained at 60-65% and the temperature at 25-28℃.

[0027] Preferably, in step (7), a green control model combining agricultural control and biological control is adopted, and no highly toxic and persistent pesticides are used throughout the process to ensure the safety of fresh corn.

[0028] (i) Agricultural control: Clean up the field before planting, remove the residues of the previous crop and weeds to reduce the overwintering base of pests and diseases; implement crop rotation and avoid continuous cropping to reduce the risk of soil-borne diseases; plant at a reasonable density to improve ventilation and light conditions in the field and reduce the breeding of diseases; promptly remove diseased and weak plants and take them out of the field for deep burial or burning to prevent the spread of pests and diseases.

[0029] (ii) Biological control: For corn borers, hang pheromone traps in the field, 15-20 per mu, to attract and kill male moths and reduce egg laying; for aphids, release natural enemy insects such as ladybugs and lacewings, 500-800 per mu; for diseases such as sheath blight and large leaf spot, spray biological pesticides (Jinggangmycin, Bacillus subtilis), 30-40 kg per mu, once every 7-10 days, for 2-3 consecutive times.

[0030] Harvesting at maturity: Based on the characteristics of the variety and market demand, fresh corn is harvested during the milk stage. Waxy corn is harvested 20-25 days after pollination, sweet corn is harvested 18-22 days after pollination, and sweet-waxy corn is harvested 21-26 days after pollination. Harvest with the husks on to avoid damaging the ears. Market the corn promptly after harvesting to ensure the taste and quality of fresh corn.

[0031] The beneficial effects of this invention are as follows: (1) Precise accumulated temperature control, resulting in significant early growth: This invention uses intelligent temperature control equipment, combined with the accumulated temperature requirements of fresh corn at different growth stages (seedling stage, after transplanting), to precisely supply effective accumulated temperature according to the growth stage, preventing excessive growth, low temperature, and premature aging, so that corn matures in the fastest and most robust way. Segmented precise accumulated temperature control, with temperature control accuracy of ±0.5℃, and controllable accumulated temperature throughout the process, effectively shortens the growth period by 20-30 days and advances the market time by 10-20 days. Compared with the existing single heat preservation technology, the early growth effect is improved by 20-50%, and the seedlings are more uniform and vigorous, avoiding low temperature damage.

[0032] (2) High efficiency of composite insulation, suitable for different regions: It integrates four layers of composite insulation structure: straw fermentation biological heating, adjustable arched shed, composite bubble film and biodegradable mulch film. It forms an all-round closed insulation system from underground, above ground, inside the shed and air layer. It takes into account both biological heating and physical insulation. The insulation effect is 30-40% higher than the existing technology. It can effectively resist the cold spring and continuous rainy weather. At the same time, it is suitable for different ecological regions such as northern regions, Yangtze River Basin, and Huang-Huai-Hai region. The number of insulation layers and accumulated temperature parameters can be adjusted according to regional climate differences, which has strong universality.

[0033] (3) Strong adaptability to mechanization and reduced labor costs: The adjustable insertion arched greenhouse is designed so that the height of the arched greenhouse can be adjusted according to the growth height of the plants. It is suitable for mechanized transplanting, plant protection, harvesting and other operations, greatly reducing manual operation. The labor cost is reduced by 30-40% when planting on a large scale, solving the problem of poor adaptability to mechanization of existing technologies.

[0034] (4) Green and sustainable, taking into account both quality and environmental protection: straw fermentation is used to make agricultural waste into treasure, and biodegradable mulch film is used to reduce residual pollution; biological seed dressing, biological control and green water and fertilizer integration technology are used to ensure the safety of fresh corn food by not using highly toxic and high-residue pesticides throughout the process, while improving the soil and increasing soil fertility to achieve green and sustainable production; drone pollination is used to replace traditional manual pollination, which increases the efficiency of operation by 10 times and the uniformity of pollen distribution by 42.8% (obtained by pollen sedimentation slide detection method).

[0035] (5) Precise variety matching, early maturity and quality synergy: Special early-maturing varieties are selected based on the different growth characteristics of waxy corn, sweet corn and sweet-waxy corn. With targeted accumulated temperature control and cultivation management programs, the problems of existing technology, variety and cultivation being disconnected and the contradiction between early maturity and quality are solved. While bringing the corn to market earlier, the sweetness, waxiness and yield of fresh corn are guaranteed. The yield is increased by 5-10% and the quality compliance rate is increased by 15-20% compared with traditional cultivation methods.

[0036] (6) Simplified and standardized, easy to promote and apply: The entire cultivation method process is clear, and each link has clear operating parameters and standards, forming a standardized operating procedure (SOP). At the same time, it takes into account both low cost and high efficiency. It can be applied by ordinary farmers and large-scale bases, and has broad prospects for promotion. Detailed Implementation

[0037] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be described in detail below. Obviously, the described embodiments are merely some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other implementation methods obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0038] Example 1: Application in Northern China (Zhangjiakou City, Hebei Province) This embodiment provides a cultivation method for promoting early maturity of sweet corn (specifically for northern regions characterized by low spring temperatures and frequent late spring frosts). The cultivation method includes the following steps: (1) Predicting sowing and seed treatment A dedicated accumulated temperature database for fresh corn varieties was constructed, and the basic effective accumulated temperature requirement of the tested low-temperature resistant early-maturing waxy corn variety Jingke Nuo 2000 (80-day growth period) was determined to be 1300℃. Based on the warming effect of the composite insulation system of this invention (straw fermentation warming, mulch film, composite bubble film, and adjustable arched greenhouse), an equivalent compensation correction for accumulated temperature increase was made based on an average daily temperature increase of 3.5℃ inside the greenhouse. The target market launch date was set as June 10th. Meteorological data from Zhangjiakou City for the same period over the past 10 years was consulted, and combined with the medium- and long-term temperature forecasts for the year, the average daily temperature during the growth period was predicted, leading to the deduction that the optimal seedling sowing date was March 12th.

[0039] Seed pretreatment: On a sunny day, spread the seeds out in a cool, well-ventilated place to dry for 3 days, 5 hours each day, avoiding direct sunlight; then, place the dried seeds in 58℃ warm water, stirring constantly, and soak at this constant temperature for 18 minutes. After naturally cooling to room temperature, continue soaking for 7 hours to kill pathogens on the seed surface; finally, remove the soaked seeds and drain them, then treat them with a solution containing Bacillus subtilis and phosphate-solubilizing bacteria with an effective viable count ≥2.0×10⁻⁶. 9 Treat seeds with a compound microbial inoculant at a concentration of CFU / g, using 0.4% of the seed weight. After mixing, air dry for 1.5 hours to enhance seed resistance.

[0040] (2) Constructing seedbeds Choose a flat, well-drained, and sunny site to build the seedbed. Use a three-layer composite structure consisting of a straw fermentation layer, a nutrient substrate layer, and an insulation layer to combine biological warming and physical insulation. (i) Straw fermentation layer: Crush corn stalks into 5-10cm pieces, mix them evenly with well-rotted cow manure and compound fermentation agent at a mass ratio of 6:3:1, spread them at the bottom of the seedbed to a thickness of 18cm, water them until the moisture content is 62%, cover them with plastic film and seal them for fermentation for 6 days. During the fermentation process, control the temperature at around 55℃ to kill pathogens and insect eggs in the fermentation material, and at the same time release biological heat to provide a continuous and stable ground temperature. After fermentation, loosen and level the material to ensure that the fermentation material is uniform and loose.

[0041] (ii) Nutrient substrate layer: Mix garden soil, leaf mold, perlite and slow-release fertilizer (N:P:K=15:15:15) evenly in a mass ratio of 5:3:1:1, sieve and spread it on top of the straw fermentation layer, with a thickness of 11cm, level and compact it to ensure that the substrate layer is loose, breathable and nutrient-rich.

[0042] (iii) Insulation layer and auxiliary heating: A biodegradable insulation film is placed on top of the nutrient substrate layer, and electric heating wires are laid on both sides of the seedling bed to assist in heating. The spacing between the heating wires is 18cm and the power is 60W / m. 2 The heating wire is connected to an intelligent temperature control device to achieve precise temperature regulation.

[0043] (3) Seedling cultivation by accumulating temperature regulation Sow the pretreated seeds into seedling trays, one seed per hole, at a depth of 2.5cm. Then place the seedling trays on the nutrient substrate layer of the seedbed, cover with a 1.5cm layer of soil, and water until the soil moisture content reaches 72%. Cover again with a biodegradable insulation film and activate the intelligent temperature control equipment (composed of a temperature sensor, controller, heating module, and ventilation module, with a temperature control accuracy of ±0.5℃) to perform segmented accumulated temperature control according to the growth stage. (i) Emergence period (from sowing to emergence, 3-4 days): The core objective is to promote rapid seed germination, control daytime temperature at 26-27℃, nighttime temperature at 16-17℃, and accumulate a total temperature of 135℃. (ii) Seedling stage (from emergence to 3 leaves and 1 heart, 10-12 days): The core objective is to cultivate strong seedlings and enhance their resistance to adverse conditions. Control the daytime temperature to 23-24℃ and the nighttime temperature to 13-14℃, with a cumulative temperature of 375℃. During this stage, timely ventilation and hardening of the seedlings are necessary to prevent them from growing too tall. (iii) Early seedling stage (3 leaves and 1 heart to 5 leaves and 1 heart, 8-10 days): The core objective is to promote root growth and lay the foundation for transplanting and seedling recovery. Control the daytime temperature to 21-22℃ and the nighttime temperature to 11-12℃, with a cumulative temperature of 300℃.

[0044] The cumulative temperature during the entire seedling period was 810℃, and the seedling cycle was 28 days. The seedlings were robust and uniform, without excessive growth or low-temperature damage.

[0045] (4) Construct composite insulation facilities Before planting, the field should be deeply plowed to 28cm, leveled and harrowed, and sufficient base fertilizer should be applied: mix corn stalks, well-rotted manure and fermentation agent in a ratio of 6:3:1, spread to a thickness of 18cm, and apply 2200kg / mu of fermented organic fertilizer and 35kg / mu of slow-release fertilizer. Then, ridges should be made for planting, using a double-row ridge pattern with a ridge width of 65cm, a ridge height of 18cm, and a ridge spacing of 85cm.

[0046] A three-layer composite insulation system consisting of an adjustable arched shed, composite bubble film, and biodegradable mulch film is constructed to balance insulation performance with mechanization adaptability. (i) Adjustable arched greenhouse: It adopts fiberglass insert arch rods with a diameter of 8-10mm and a length of 2.5-3.0m. The insertion depth into the soil is 20-25cm and the spacing between adjacent arch rods is 1.8m. Adjustable buckles are installed at the top of the arch rods. The initial height of the arched greenhouse is set at 60cm, and it can be adjusted within the range of 50-120cm according to the growth height of the plants. It is suitable for mechanized transplanting and plant protection operations. (ii) Composite bubble film: Covered on adjustable arched greenhouse, it adopts a double-layer air insulation structure. The outer layer is a UV-resistant PE film with a thickness of 0.08-0.10mm, and the inner layer is a heat-insulating bubble film with a thickness of 0.12-0.15mm. The light transmittance is ≥85%, and the heat preservation effect is 30-40% higher than that of ordinary greenhouse film, which can effectively resist the cold in spring. (iii) Biodegradable mulch film: made of polylactic acid-based fully biodegradable material, 90cm wide and 0.015-0.02mm thick, covering the surface of the planting row. When covering, the film should be close to the ground and the edges should be compacted to reduce soil moisture evaporation and weed growth. After covering, holes should be punched in the film according to the planting density to facilitate subsequent transplanting.

[0047] (5) Regulation of accumulated temperature after transplanting When the seedlings have grown to 5 leaves and 1 heart, choose a sunny morning for mechanized transplanting. The transplanter should be adapted to the width of the adjustable arched greenhouse, and the transplanting depth should be 5.5cm to ensure that the seedling roots are in close contact with the soil. Water thoroughly immediately after transplanting to improve the survival rate. The planting density is 3,500 plants / acre, which meets the planting requirements of waxy corn varieties.

[0048] After transplanting, a portable intelligent temperature control device, used in conjunction with the seedling stage, is used to monitor the temperature inside the greenhouse, and segmented accumulated temperature management is implemented according to the growth stage: (i) Early stage of transplanting (1-7 days after transplanting): The core goal is to promote seedling establishment. Control the daytime temperature to 23-24℃ and the nighttime temperature to 13-14℃, with a cumulative temperature of 200℃. During this stage, close the ventilation openings and maintain the humidity in the greenhouse at 70-75% to prevent seedlings from losing water. (ii) From seedling establishment to tasseling stage (8-32 days after transplanting, a total of 25 days): The core objective is to promote the vegetative growth of the plants. Control the daytime temperature to 21-22℃ and the nighttime temperature to 11-12℃, with a cumulative temperature of 850℃. During this stage, ventilate as needed according to the temperature to reduce humidity in the greenhouse and prevent disease. (iii) From tasseling to grain filling stage (33-54 days after transplanting, a total of 22 days): The core objective is to promote ear development and improve fruit quality. The daytime temperature is controlled at 24-25℃ and the nighttime temperature at 14-15℃, with a cumulative temperature of 700℃.

[0049] The cumulative temperature after transplanting is 1750℃, which shortens the growth period by 32 days compared to traditional cultivation methods.

[0050] In the early stage of tassel emergence (about 30 days after transplanting), use a miniature drone for assisted pollination from 10:00 to 12:00 every day, with a flight altitude of 2m. During the pollination period, maintain the humidity in the greenhouse at 60-65% and the temperature at 25-28℃ to improve the pollination and seed setting rate.

[0051] (6) Water and fertilizer management Using a drip irrigation system for integrated water and fertilizer management avoids excessive irrigation and soil compaction, and allows for precise control of water and fertilizer requirements based on different growth stages of sweet corn. (i) Water control: After transplanting and before seedling establishment, maintain soil moisture content at 72%; after seedling establishment and before tasseling, maintain soil moisture content at 68%; from tasseling to grain filling, maintain soil moisture content at 63%; in the later stage of grain filling, control water appropriately and maintain soil moisture content at 58% to promote fruit ripening and improve taste.

[0052] (ii) Fertilizer regulation: In addition to applying sufficient base fertilizer before transplanting, topdressing is carried out three times: After the seedlings have recovered (11 days after transplanting), apply 12 kg / mu of urea through the drip irrigation system to promote the growth of plant stems and leaves; before tasseling (32 days after transplanting), apply 18 kg / mu of NPK compound fertilizer (N:P:K=15:15:15) to promote ear differentiation and floret development; during the grain filling period (18 days after tasseling), spray foliar fertilizer (0.2% potassium dihydrogen phosphate, 35% slow-release liquid nitrogen fertilizer (Green Speed)) at 35 kg / mu to improve the glutinousness and sweetness of the ears.

[0053] (7) Disease control and harvesting A green control model combining agricultural and biological control is adopted, without the use of highly toxic and persistent pesticides throughout the entire process. (i) Agricultural control: Thoroughly clean the field before transplanting, remove the residue of the previous soybean crop and weeds in the field to reduce the overwintering base of pests and diseases; implement crop rotation to reduce the risk of soil-borne diseases; plant at a reasonable density to improve ventilation and light conditions in the field; promptly remove diseased and weak plants and take them out of the field for deep burial to prevent the spread of pests and diseases.

[0054] (ii) Biological control: For corn borers, hang 18 corn borer pheromone traps per mu to attract and kill male moths and reduce egg laying; for aphids, release 600 ladybugs per mu for biological control; for sheath blight, spray 35 kg of Jinggangmycin biological pesticide per mu, spray once every 7 days, for 2 consecutive times.

[0055] Harvesting at maturity: Based on the characteristics of the Jingke Nuo 2000 variety and market demand, harvesting is carried out 23 days after pollination (late milk stage) with the husks intact to avoid damaging the ears. Harvesting is done promptly to ensure fresh taste and quality. This embodiment results in a market launch 28 days earlier than traditional cultivation methods, an 8% increase in yield, and fuller ears with good glutinousness and suitable sweetness.

[0056] Example 2: Application in the Yangtze River Basin (Wuhu City, Anhui Province) This embodiment provides a cultivation method to promote early maturity of sweet corn (specifically for the Yangtze River basin, characterized by abundant rainfall and large temperature fluctuations in spring). The cultivation method is largely the same as in Embodiment 1, and includes the following briefly described steps: (1) Predicted sowing and seed treatment: The early-maturing sweet and waxy corn variety "Australian Sweet Waxy 75" (75-day growth period) was selected. Seed pretreatment: sun-drying for 2 days, 4 hours a day; soaking in 55℃ warm water for 15 minutes, then soaking for 6 hours after natural cooling; using compound microbial agent (effective viable count 2.0×10⁻⁶) 9 Seed treatment with CFU / g inoculant at a rate of 0.3% of seed weight, followed by air drying for 1 hour.

[0057] (2) Constructing the seedbed: Select a well-drained and well-lit plot for the seedbed. The straw fermentation layer is made by mixing corn stalks, well-rotted chicken manure, and compound fermentation agent in a ratio of 6:3:1, spreading it to a thickness of 15cm, watering it to a moisture content of 60%, covering it with film for fermentation for 5 days, and controlling the fermentation temperature at around 50℃. The nutrient substrate layer is made by mixing garden soil, leaf mold, perlite, and slow-release fertilizer in a mass ratio of 5:3:1:1, spreading it to a thickness of 10cm. Cover it with a biodegradable heat-insulating film and lay heating wires (15cm spacing, 50W / m). 2 ), connect to intelligent temperature control equipment.

[0058] (3) Accumulated temperature regulation for seedling raising: Sow the seeds into the seedling tray, place them in the seedling bed, cover with a thin layer of soil 1cm, water until the soil moisture content is 70%, cover with biodegradable heat-insulating film, and regulate the accumulated temperature in stages: during the seedling stage (3 days), the daytime temperature is 25-26℃ and the nighttime temperature is 15-16℃, with an accumulated temperature of 120℃; during the seedling stage (9 days), the daytime temperature is 22-23℃ and the nighttime temperature is 12-13℃, with an accumulated temperature of 350℃; during the early seedling stage (8 days), the daytime temperature is 20-21℃ and the nighttime temperature is 10-11℃, with an accumulated temperature of 280℃; the entire seedling raising process takes 25 days, with a cumulative accumulated temperature of 750℃, resulting in high seedling uniformity.

[0059] (4) Construct composite insulation facilities: Deep plow the planting field to 25cm, apply sufficient base fertilizer (2000kg / mu of fermented straw organic fertilizer and 30kg / mu of ternary slow-release fertilizer), and plant on raised beds with a width of 60cm, a height of 15cm, and a spacing of 80cm between beds; construct adjustable arched sheds (arch spacing of 1.5m and initial height of 50cm), cover with composite bubble film, and cover the planting rows with biodegradable mulch film (width of 80cm), with holes punched in the film for later use.

[0060] (5) Accumulated temperature control after transplanting: When the seedlings grow to 5 leaves and 1 heart, they are transplanted by mechanization at a planting density of 3300 plants / mu and a transplanting depth of 5cm. They are then thoroughly watered. Accumulated temperature control in stages after transplanting: In the early stage of transplanting (6 days), the daytime temperature is 22-23℃ and the nighttime temperature is 12-13℃, with an accumulated temperature of 180℃. From the seedling establishment period to the tasseling period (22 days), the daytime temperature is 20-21℃ and the nighttime temperature is 10-11℃, with an accumulated temperature of 800℃. From the tasseling period to the grain filling period (20 days), the daytime temperature is 23-24℃ and the nighttime temperature is 13-14℃, with an accumulated temperature of 650℃. The cumulative accumulated temperature after transplanting is 1630℃, which shortens the growth period by 28 days.

[0061] (6) Water and fertilizer management: Drip irrigation system is used. Soil moisture content is 70% from transplanting to seedling establishment; 65% from seedling establishment to tasseling; 60% from tasseling to grain filling; and 55% in the later stage of grain filling. Topdressing: Apply 10 kg / mu of urea after seedling establishment, apply 15 kg / mu of NPK compound fertilizer before tasseling, and spray 30 kg / mu of 0.2% potassium dihydrogen phosphate and 35% slow-release liquid nitrogen fertilizer (Green Speed) during the grain filling period.

[0062] (7) Disease control and harvesting: Agricultural control: Clean the field, remove weeds, plant at a reasonable density, and drain water in time to prevent flooding; Biological control: Hang 15 corn borer pheromone traps per mu, release 500 lacewings per mu, and spray Bacillus subtilis to control large leaf spot disease, 30 kg per mu, spray twice. Harvest 20 days after pollination. The ears are sweet and have a good taste. It is on the market 25 days earlier than the traditional cultivation method, and the yield is increased by 6%.

[0063] Example 3: Application in the Huang-Huai-Hai region (Zhengzhou, Henan Province) This embodiment provides a cultivation method for bringing fresh corn to market earlier (specifically for the Huang-Huai-Hai region, characterized by rapid temperature rises and drought in spring). The cultivation method is largely the same as in Embodiment 1, including the following briefly described steps: (1) Predicted sowing and seed treatment: The sweet corn variety “Golden Crown 218” (77-day growth period) was selected. Seed pretreatment: sun-drying for 3 days, 6 hours a day; soaking in 60℃ warm water for 20 minutes, then soaking for 8 hours after natural cooling; using compound microbial agent (effective viable count 2.0×10⁻⁶) 9 Seed treatment with CFU / g inoculant at a rate of 0.5% of seed weight, followed by air drying for 2 hours.

[0064] (2) Constructing seedbeds: Select flat and easily irrigated plots for seedbed construction. The straw fermentation layer is made by mixing corn stalks, well-rotted sheep manure, and compound fermentation agents in a ratio of 6:3:1, laying a 20cm thick layer, watering to a moisture content of 65%, covering with film for fermentation for 7 days, and controlling the fermentation temperature at around 60℃. The nutrient substrate layer is made by mixing garden soil, leaf mold, perlite, and slow-release fertilizer in a mass ratio of 5:3:1:1, laying a 12cm thick layer. Cover with biodegradable heat-insulating film and lay heating wires (20cm spacing, 80W / m). 2 ), connect to intelligent temperature control equipment.

[0065] (3) Accumulated temperature regulation for seedling raising: Sow the seeds into the seedling tray, place them in the seedling bed, cover with a thin layer of soil 2cm, water until the soil moisture content is 75%, cover with biodegradable heat-insulating film, and regulate the accumulated temperature in stages: during the seedling stage (4 days), the daytime temperature is 27-28℃ and the nighttime temperature is 17-18℃, with an accumulated temperature of 150℃; during the seedling stage (12 days), the daytime temperature is 24-25℃ and the nighttime temperature is 14-15℃, with an accumulated temperature of 400℃; during the early seedling stage (10 days), the daytime temperature is 21-22℃ and the nighttime temperature is 11-12℃, with an accumulated temperature of 320℃; the entire seedling raising process takes 30 days, with a cumulative accumulated temperature of 870℃, and the seedlings have strong resistance to adverse conditions.

[0066] (4) Construct composite insulation facilities: Deeply cultivate the planting field to 30cm, apply sufficient base fertilizer (2500kg / mu of fermented straw organic fertilizer and 40kg / mu of ternary slow-release fertilizer), and plant on raised beds with a width of 70cm, a height of 20cm, and a spacing of 90cm between beds; construct adjustable arched sheds (arch spacing of 2.0m and initial height of 70cm), cover with composite bubble film, and cover the planting rows with biodegradable mulch film (100cm wide), with holes punched in the film for later use.

[0067] (5) Accumulated temperature control after transplanting: When the seedlings grow to 5 leaves and 1 heart, they are transplanted by mechanization at a planting density of 3600 plants / mu and a transplanting depth of 6cm. They are then thoroughly watered. Accumulated temperature control in stages after transplanting: In the early stage of transplanting (7 days), the daytime temperature is 24-25℃ and the nighttime temperature is 14-15℃, with an accumulated temperature of 220℃. From the seedling establishment period to the tasseling period (26 days), the daytime temperature is 22-23℃ and the nighttime temperature is 12-13℃, with an accumulated temperature of 900℃. From the tasseling period to the grain filling period (23 days), the daytime temperature is 25-26℃ and the nighttime temperature is 15-16℃, with an accumulated temperature of 750℃. The cumulative accumulated temperature after transplanting is 1870℃, which shortens the growth period by 35 days.

[0068] (6) Water and fertilizer management: Drip irrigation system is used. Soil moisture content is 75% from transplanting to seedling establishment; 70% from seedling establishment to tasseling; 65% from tasseling to grain filling; and 60% in the later stage of grain filling. Topdressing: Apply 15 kg / mu of urea after seedling establishment, apply 20 kg / mu of NPK compound fertilizer before tasseling, and spray 40 kg / mu of 0.2% potassium dihydrogen phosphate and 35% slow-release liquid nitrogen fertilizer (Green Speed) during the grain filling period.

[0069] (7) Disease control and harvesting: Agricultural control: Clean the field, rotate crops (previous crop is wheat), plant at a reasonable density, and irrigate in a timely manner; Biological control: Hang 20 corn borer pheromone traps per mu, release 800 ladybugs per mu, and spray jinggangmycin at 40 kg per mu to control sheath blight, spraying 3 times. Harvest 25 days after pollination. The ears have a sweet and glutinous taste, excellent quality, and are harvested 30 days earlier than traditional cultivation methods, with a 10% increase in yield.

[0070] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A cultivation method for promoting early maturity of sweet corn, characterized in that, The cultivation method includes the following steps: (1) Predicting sowing and seed treatment: Establish a database of accumulated temperature for sweet corn, and use the target harvest time to calculate the seedling time of sweet corn. Then, pre-treat the sweet corn seeds by sun drying, hot water soaking and biological seed dressing to obtain pre-treated seeds. (2) Constructing seedbeds: Constructing composite seedbeds that include a straw fermentation layer, a nutrient substrate layer and an insulation layer to achieve biological warming and physical insulation during the cultivation of fresh corn; (3) Accumulated temperature regulation for seedling cultivation: The pretreated seeds are sown in seedling trays and placed in the composite structure seedling bed. Then, the accumulated temperature is regulated in stages according to the emergence period, seedling stage and early seedling stage to cultivate strong seedlings. (4) Construct composite insulation facilities: After deep plowing the selected site, apply base fertilizer and then ridge the site to construct composite insulation facilities including adjustable arched sheds, composite bubble film and biodegradable mulch film. (5) Accumulated temperature control after transplanting: The strong seedlings are transplanted to the composite heat preservation facility. After transplanting, the accumulated temperature is controlled and cultivated in stages according to the initial stage of transplanting, the seedling recovery period to the tasseling period, and the tasseling to the grain filling period. (6) Water and fertilizer management: During the cultivation of fresh corn, the amount of water and fertilizer should be adjusted according to the water and fertilizer requirements of fresh corn at different growth stages; (7) Disease control and harvesting: pests and diseases are controlled by a combination of agricultural and biological control. Fresh corn can be harvested with the husks intact during the milk stage.

2. The cultivation method for promoting early maturity of fresh corn according to claim 1, characterized in that, In step (1), a database of accumulated temperature for fresh corn is established, and the basic effective accumulated temperature requirements are determined to be 1150-1350℃ for sweet corn, 1250-1450℃ for waxy corn, and 1200-1400℃ for sweet and waxy corn; and the accumulated temperature is compensated and corrected by an average daily temperature increase of 2.5-4.5℃. And / or, the pretreatment methods for seeds, including sun-drying, hot water soaking, and biological seed dressing, are as follows: sun-dry the seeds for 2-3 days under sunny, cool, and well-ventilated conditions, for 4-6 hours each day; then soak the seeds in hot water at a constant temperature of 55-60℃ for 15-20 minutes, and continue soaking for 6-8 hours after natural cooling; finally, treat the seeds with a solution containing Bacillus subtilis and phosphate-solubilizing bacteria with an effective viable count ≥2.0 × 10⁻⁶. 9 Treat seeds with a compound microbial inoculant at a concentration of CFU / g, using 0.3-0.5% of the seed weight. After treatment, allow the seeds to air dry for 1-2 hours.

3. The cultivation method for promoting early maturity of sweet corn according to claim 1, characterized in that, In step (2), a composite seedbed is constructed, comprising a straw fermentation layer, a nutrient substrate layer, and an insulation layer; wherein: The method for preparing the straw fermentation layer is as follows: corn straw, well-rotted livestock and poultry manure, and compound fermentation agent are mixed in a mass ratio of 6:3:1, and then sealed and fermented at 50-60℃ for 5-7 days to obtain a straw fermentation layer with a thickness of 15-20cm and a moisture content of 60-65%. And / or, the method for preparing the nutrient substrate layer is as follows: mix garden soil, leaf mold, perlite and slow-release fertilizer in a mass ratio of 5:3:1:1, level and compact to obtain the nutrient substrate layer; And / or, the insulation layer is a biodegradable insulation film covering the nutrient matrix layer.

4. The cultivation method for promoting early maturity of sweet corn according to claim 1, characterized in that, In step (3), the method of segmented temperature control according to the emergence period, seedling period, and early seedling stage is as follows: During the emergence period, the daytime temperature is controlled at 25-28℃ and the nighttime temperature at 15-18℃, with a cumulative temperature of 120-150℃; During the seedling period, the daytime temperature is controlled at 22-25℃ and the nighttime temperature at 12-15℃, with a cumulative temperature of 350-400℃; During the early seedling stage, the daytime temperature is controlled at 20-22℃ and the nighttime temperature at 10-12℃, with a cumulative temperature of 280-320℃. And / or, the cumulative accumulated temperature during the entire seedling period is 750-870℃, and the seedling cycle is 20-25 days.

5. The cultivation method for promoting early maturity of sweet corn according to claim 1, characterized in that, In step (4), after deep plowing the selected site, base fertilizer is applied, and then ridges are formed. A composite insulation facility is constructed, consisting of an adjustable arched shed, composite bubble film, and biodegradable mulch film; wherein: The composite insulation facility is constructed as follows: (i) Use insertable arch rods with a diameter of 8-10mm and a length of 2.5-3.0m, insert them into the soil to a depth of 20-25cm, and keep the spacing between adjacent arch rods at 1.5-2.0m. After construction, an adjustable arched shed is obtained. (ii) Cover the adjustable arched canopy with composite bubble film, wherein the composite bubble film is a double-layer air insulation structure, the outer layer is a UV-resistant PE film with a thickness of 0.08-0.10mm, and the inner layer is a heat-insulating bubble film with a thickness of 0.12-0.15mm, and the light transmittance is ≥85%; (iii) Simply cover the planting row with biodegradable mulch film; the biodegradable mulch film is a polylactic acid-based fully biodegradable material with a width of 120-150cm and a thickness of 0.015-0.02mm.

6. The cultivation method for promoting early maturity of sweet corn according to claim 1, characterized in that, In step (5), the strong seedlings are transplanted to the composite insulation facility, and the planting density is: 3500-4000 plants / mu for waxy corn, 2500-3000 plants / mu for sweet corn, and 3000-3500 plants / mu for sweet and waxy corn. And / or, the method of segmented accumulated temperature regulation and cultivation after transplanting is as follows: In the early stage of transplanting, the daytime temperature is controlled at 22-25℃ and the nighttime temperature at 12-15℃, with a cumulative accumulated temperature of 180-220℃; in the period from seedling establishment to tasseling, the daytime temperature is controlled at 20-23℃ and the nighttime temperature at 10-13℃, with a cumulative accumulated temperature of 800-900℃; in the period from tasseling to grain filling, the daytime temperature is controlled at 23-26℃ and the nighttime temperature at 13-16℃, with a cumulative accumulated temperature of 650-750℃; the cumulative accumulated temperature throughout the entire period after transplanting is 1630-1870℃.

7. The cultivation method for promoting early maturity of sweet corn according to claim 1, characterized in that, In step (6), a drip irrigation system is used to adjust the amount of water and fertilizer applied according to the water and fertilizer requirements of fresh corn at different growth stages; wherein: The methods for regulating irrigation are as follows: from transplanting to before seedling establishment, control the soil moisture content at 70-75%; from seedling establishment to before tasseling, control the soil moisture content at 65-70%; from tasseling to grain filling, control the soil moisture content at 60-65%; and in the later stage of grain filling, control the soil moisture content at 55-60%. And / or, the methods for regulating fertilization are as follows: after the seedlings have recovered, apply 10-15 kg / mu of urea; before the tasseling, apply 15-20 kg / mu of NPK compound fertilizer; and during the grain-filling period, spray 30-40 kg / mu of foliar fertilizer.

8. The cultivation method for promoting early maturity of sweet corn according to claim 1, characterized in that, In step (7), a combined approach of agricultural and biological control is adopted to prevent and control pests and diseases; wherein: The biological control method is as follows: hang 15-20 corn borer pheromone traps per acre and / or release 500-800 aphid natural enemy insects per acre.