CN114557237B - Method for promoting cultivation of early spring pine cauliflowers by using full-biodegradable film - Google Patents

Abstract

The invention discloses a method for promoting early spring broccoli cultivation by using a fully biodegradable film, comprising the following steps: 1.1, variety selection; 1.2, sowing in late September to late December; 1.3, seedling raising; 1.4, land preparation and fertilization; 1.5, covering the ridge with a film, transplanting and planting; 1.6, field management; 1.7, binding leaves and protecting flowers; 1.8, pest control; 1.9, timely harvesting, in step 1.5, 1m wide and 6-10μm thick white or black fully biodegradable film is selected to cover the ridge surface 1 to 2 days before broccoli planting. The method can increase temperature and retain moisture in the early stage of broccoli cultivation by using a fully biodegradable film in the cultivation of broccoli, without affecting the normal growth and yield of broccoli, and can naturally decompose in the later stage of broccoli growth, reduce soil pollution, and can also reduce the workflow of artificial film covering and film uncovering, and reduce the cost of artificial film covering and film uncovering treatment.

Description

A method for promoting early spring broccoli cultivation using fully biodegradable film

Technical Field

The invention relates to the field of broccoli cultivation, and in particular to a method for promoting early spring broccoli cultivation by using a fully biodegradable film.

Background technique

Songhua cauliflower, also known as loose-flowered cauliflower, is a type of variant cauliflower of the Brassica oleracea species of the cruciferous family. It is named because of its long buds, thin flower layers, and loose shape of the flower heads when fully expanded, compared with ordinary cauliflower. At present, it is widely cultivated in Fujian, Guangdong, Guangxi, Zhejiang, Sichuan and other provinces and regions in my country and the suburbs of major cities. Compared with general compact cauliflower varieties, Songhua cauliflower has two significant characteristics: first, it has good boiling resistance and delicious taste. The vitamin C and soluble sugar content of Songhua cauliflower is significantly higher than that of compact flower head cauliflower, which is very popular with consumers; second, early and medium-maturing varieties have strong heat resistance and wider adaptability, which broadens the time for cauliflower production and listing. The price is more than double that of compact cauliflower, which increases economic benefits.

In southern regions, broccoli is mostly grown in greenhouses for seedling raising, open-field planting and cultivation. Although broccoli is a cold-loving and semi-cold-resistant vegetable crop, it is still necessary to lay ground film to keep warm and increase moisture during planting in winter and spring. At present, when planting broccoli, PE ground film is mostly used for covering to keep warm and increase moisture. However, PE ground film is not easy to decompose, and it takes a lot of labor to recycle it. It is also not easy to clean it up, causing soil compaction and damage to the soil structure, affecting the yield and quality of the next crop. The recycled ground film is often piled on the ridges of the fields, and there is no subsequent treatment method, which blocks ditches and causes environmental pollution. There is an urgent need on the market for a method of using fully biodegradable film to promote early spring broccoli cultivation, which can reduce the workflow of artificial covering and peeling, reduce labor, and protect the soil environment without affecting the yield and quality of broccoli.

Summary of the invention

In order to solve the above-mentioned technical problems, the purpose of the present invention is to provide a method for promoting the cultivation of early spring broccoli using a fully biodegradable film. The method utilizes a fully biodegradable film in the cultivation of broccoli, which can not only increase temperature and retain moisture in the early stage of broccoli cultivation without affecting the normal growth and yield of broccoli, but also decompose naturally in the later stage of broccoli growth to reduce soil pollution. It can also reduce the workflow of artificial film covering and removing, and there is no need to apply granular fertilizer.

Embodiment 1:

In order to achieve the above-mentioned purpose, the present invention adopts the following technical solutions:

A method for promoting early spring broccoli cultivation using a fully biodegradable film comprises the following steps:

1.1. Variety selection: Choose varieties that are sown in autumn and winter and harvested more than 65 days after planting;

1.2. Sowing time: choose from late September to late December;

1.3. Seedling cultivation:

1.3.1. Preparation of seedling raising site and substrate: Seedlings are raised in a plastic greenhouse with a flat bed surface and a layer of plastic film on it; the shed frame is covered with agricultural film; the seedling raising substrate is made of garden soil, silt, farmyard manure, coal slag and rice husk ash fermented and decomposed, or the seedling raising substrate is made of peat and vermiculite in a ratio of 1 to 4: 1 to 2, and 0.8 kg to 1.5 kg of compound fertilizer and 2 kg to 4 kg of superphosphate are added to each cubic meter of substrate, mixed evenly and set aside;

1.3.2, traying and sowing: After the substrate is trayed, the hole surface is scraped flat with a scraper and watered thoroughly with a watering can; the holes of the tray with the substrate are pressed with tools or fingers to a depth of 0.4cm to 0.6cm, so that the sowing depth is 0.5cm to 1cm; sow one seed in each hole; after sowing, cover the substrate and scrape it flat with a scraper, cover the seeds with water, and then cover with mulch;

1.3.3. Management after sowing: Remove the mulch after sowing and germination, and pay attention to ventilation, light transmission, heat preservation and humidity reduction in the greenhouse; generally water twice a day in the morning and evening, water evenly and thoroughly each time, and transplant seedlings in time to fill the gap when two cotyledons unfold;

1.4. Land preparation and fertilization: One week before transplanting, deep plowing should be carried out to remove the previous crop, stones, etc. remaining in the soil to avoid premature damage during film covering. After deep plowing and before rotary tillage, 50kg/mu of triple compound fertilizer or 500kg-800kg of commercial organic fertilizer should be applied. After rotary tillage and before leveling, 50kg/mu of triple compound fertilizer should be applied. The fertilizer should be fully mixed with the soil to avoid direct contact between the fertilizer and the fully biodegradable film, thereby preventing the fully biodegradable film from degrading prematurely.

1.5. Make ridges, cover with film, and transplant and plant: After the land is leveled, make ridges in a turtle-back shape; transplant and plant when the pine cauliflower seedlings grow 4 leaves, one plant per ridge, with a plant spacing of 50cm to 60cm, and 2,000 to 2,200 plants per mu. Water the holes sufficiently before planting, and the planting depth should be level with the cotyledons. Plant large and small seedlings separately. Cover the ridge surface with a 1m wide and 6μm to 10μm thick white or black fully biodegradable film 1 to 2 days before planting;

1.6 Field management:

1.6.1 Reasonable topdressing: Since the base fertilizer is applied sufficiently, there is no need to break the film manually to spread granular fertilizer. Topdressing is done once in the early stage of rosette leaf formation, the late stage of rosette leaf formation, and when buds appear. The foliar fertilizer is a fertilizer containing one or more trace elements of magnesium, boron, and molybdenum. When the foliar fertilizer does not contain boron, it is necessary to spray 0.3% borax solution; topdressing on the bed is prohibited to prevent premature degradation of the fully biodegradable film; topdressing can be combined with pest and disease control; no fertilizer shall be applied within 20 days before the harvest of broccoli products;

1.6.2. Water management: drip irrigation is strictly prohibited on the bed surface; the soil should be kept moist in the early stage, and dried after the flower balls are formed to avoid root rot; in drought, watering and watering are used, and flooding is prohibited; drainage should be carried out in time after rain, and water accumulation in the field is prohibited;

1.7. Bundle leaves to protect flowers: When the flower ball grows to the size of a fist, pull the 4 to 5 large alternate leaves close to the flower ball together and overlap them without breaking them. Then use 1 to 2 small bamboo sticks with a thickness of 2mm to 3mm and a length of 7cm to 10cm as fixing objects, pierce the overlapping leaf tips and weave them together to fix them at the main vein. The fixed leaves are bundled up in a lantern shape to cover the entire flower ball, thereby protecting the flower ball from direct sunlight during the subsequent growth process and leaving enough space for development and expansion.

1.8. Pest and disease control: Use yellow boards to kill aphids: Use 100cm×20cm yellow boards, at a density of 30-40 pieces/mu, and hang them between rows or plants, higher than the top of the plants, to kill aphids; During the bud and ball stages, spray with 10g of 15% indoxacarb, 60g/L spinetoram SC and 2000 times OD of 10% cyantraniliprole; In the middle and late stages of cauliflower growth, it is forbidden to use dimethoate;

1.9. Timely harvesting: When the flower head is fully expanded and the surrounding area begins to loosen, it is the appropriate harvesting period for broccoli. Leave 3 to 5 leaves to protect the flower head during harvesting.

Preferably, in step 1.5, the fully biodegradable film is Hongrui fully biodegradable film.

Preferably, in step 1.5, a black or white fully biodegradable film with a width of 1 m and a thickness of 6 μm is selected for covering.

The present invention has the following beneficial effects due to the adoption of the above technical solution:

1. By using fully biodegradable film in the cultivation of broccoli, it can not only increase temperature and retain moisture in the early spring broccoli cultivation period, and will not affect the normal growth and yield of broccoli when planted in the open field, but also decompose naturally in the later growth period of broccoli, reduce soil pollution, lighten the workflow of artificial mulching, and reduce the cost of artificial mulching and film removal.

2. The present invention combines deep plowing one week before transplanting to remove the previous crop, stones, etc. remaining in the soil, thereby avoiding premature damage of the fully biodegradable film during the film covering, and applies fertilizer after deep plowing and before rotary tillage to fully mix the fertilizer with the soil, avoiding direct contact between the fertilizer and the fully biodegradable film, and preventing the fully biodegradable film from degrading prematurely.

3. During the production of broccoli, the present invention prohibits topdressing on the bed surface or artificially breaking the film to spread chemical fertilizers. 50kg/mu of ternary compound fertilizer or 500kg-800kg of commercial organic fertilizer is applied before rotary tillage after deep plowing, 50kg/mu of ternary compound fertilizer is applied before leveling, sufficient base fertilizer is applied, and foliar fertilizer is applied outside the roots in the later stage. In addition, drip irrigation is strictly prohibited on the bed surface during the production of broccoli, so that the degradation time of the fully biodegradable film is compatible with the time required for heat preservation and entropy increase in the production process of broccoli, thereby ensuring the normal growth of crops.

4. In the cultivation of early spring broccoli, the present invention adopts a 1m wide and 6μm to 10μm thick white or black fully biodegradable film to cover the bed surface, so that the degradation time of the fully biodegradable film is adapted to the time required for heat preservation and entropy increase of the broccoli during the production process, thereby meeting the actual growth needs of the broccoli. Among them, 6μm black fully biodegradable film and 6μm white fully biodegradable film are preferably used, which have low cost and are economical and applicable. The broccoli grown with 6μm black fully biodegradable film has good commercial quality.

Detailed ways

The embodiments of the present invention are described in detail below. It should be understood that the following embodiments are only provided to explain the present invention and cannot be construed as limiting the scope of the present invention.

1. A method for promoting early spring broccoli cultivation using a fully biodegradable film, comprising the following contents:

1.1 Variety selection

The broccoli that is sown in winter and harvested in spring is generally selected from varieties that are sown in winter and picked more than 65 days after planting. Early-maturing varieties with a short growth period sown in late September bloom early and are prone to early flowering; varieties with a long growth period are harvested late, and the flower head formation is affected by high temperatures, and often have poor commercial quality. Therefore, broccoli varieties with a long growth period are selected for early sowing, and broccoli varieties with a short growth period are selected for late sowing. As a preferred choice, broccoli varieties with a growth period of 65 to 150 days are selected.

1.2. Sowing time

Choose to sow in late September to late December.

1.3. Seedling cultivation

1.3.1. Preparation of seedling raising site and substrate: Generally, seedlings are raised in plastic greenhouses with a flat bed surface and a thick plastic film on top to prevent roots from burrowing into the soil and facilitate rooting of seedlings. The shed racks are covered with agricultural film and sunshade nets to prevent wind, rain and temperature. The seedling raising substrate can be made of garden soil, silt, farmyard manure, coal slag and rice husk ash that have been fermented and decomposed and piled in advance. The seedling raising substrate for factory-based seedling raising can also be made of peat and vermiculite in a ratio of about 1 to 4: 1 to 2. Add 0.8 kg to 1.5 kg of compound fertilizer and 2 kg to 4 kg of superphosphate to each cubic meter of substrate, mix well and set aside.

1.3.2, tray loading and sowing:

After the substrate is placed on the tray, the hole surface is scraped flat with a scraper and water is sprayed with a watering can. The holes of the tray with the substrate are pressed with tools or fingers to a depth of 0.4cm to 0.6cm, and the sowing depth is 0.5cm to 1cm to prevent the seedlings from falling over during watering. Sow one seed in each hole, and sow 1 to 2 more trays of spare seedlings to fill the gap. After sowing, cover the substrate and scrape it with a scraper. After the seeds are covered, water them thoroughly, and then cover them with mulch to retain water and ensure uniform seedling emergence.

1.3.3 Post-sowing management

Generally, seedlings will emerge 3 days after sowing. Remove the mulch film in time after sowing and pay attention to ventilation, light transmission, heat preservation and humidity reduction in the shed. Water shortage in the substrate can easily cause the seedlings to wilt and become old seedlings, so water should be added when the substrate on the hole surface turns white. Generally, water twice in the morning and evening. The seedling raising time is in autumn, when the temperature is high at noon. Avoid watering during high temperatures at noon to hurt the seedlings. Water evenly and thoroughly each time to help the seedlings take root and form root lumps. When the two cotyledons unfold, transplant the seedlings in time to fill the gap. The seedling period of plug tray seedlings is relatively short. Generally, the seedling age of 128-hole plug trays is 35 to 45 days, and that of 72-hole plug trays is about 40 to 50 days. After the seedlings are established, they should be transplanted in time to avoid aging of the seedlings.

1.4. Land preparation and fertilization

One week before transplanting, deep plowing should be carried out to remove residual previous crops, stones, etc. in the soil to avoid premature damage to the film. After deep plowing and before rotary tillage, 50kg/mu of triple compound fertilizer or 500kg-800kg of commercial organic fertilizer should be applied. After rotary tillage and before leveling, 50kg/mu of triple compound fertilizer should be applied. The fertilizer should be fully mixed with the soil to avoid direct contact between the fertilizer and the fully biodegradable film to prevent premature degradation of the fully biodegradable film.

1.5. Making ridge covering film and transplanting and planting

After the ground is leveled, the furrows are made, with a furrow width of 1.3m, a furrow width of 30cm, a furrow depth of 30cm, and a turtle-back shape. When the pine cauliflower seedlings grow about 4 leaves, they are transplanted and planted, one plant per furrow, with a plant spacing of about 50cm to 60cm, and 2,000 to 2,200 plants per mu. Before planting, the holes are watered enough, and the planting depth is level with the cotyledons. Large and small seedlings are planted separately. The day before planting, a 1m wide, 6μm to 10μm thick white or black fully biodegradable film is used to cover the furrow surface. Preferably, a 1m wide, 6μm thick black or white fully biodegradable film is selected to cover the furrow surface, and the fully biodegradable film is a Hongrui fully biodegradable film.

1.6 Field management

1.6.1. Reasonable topdressing

Since the base fertilizer is sufficient, there is no need to break the film to apply granular fertilizer during this period. Topdressing is done once in the early stage of rosette leaf formation, the late stage of rosette leaf formation, and when buds appear. Foliar topdressing can be combined with pest and disease control. The foliar fertilizer is a fertilizer containing one or more trace elements of magnesium, boron, and molybdenum; among them, boron has a significant effect on the yield and quality of flower balls, especially in the flower ball expansion period. Therefore, when the foliar fertilizer does not contain boron, it should be sprayed with 0.3% borax solution during the flowering period to promote the expansion and whitening of the flower balls. In the middle and late stage of topdressing, refuse to use ammonium carbonate or fertilizers containing ammonium carbonate to avoid hairy flowers on the flower balls. No chemical fertilizers shall be applied within 20 days before the harvest of broccoli products.

1.6.2 Water Management

Songhua cauliflower has many thin leaves, which can reach 17 to 23 leaves in the middle and late stages of growth, 6 to 8 more than ordinary cauliflower varieties. It has a large transpiration volume, and wilting often occurs in the field due to water loss, especially when it suddenly clears up after continuous rain. The wilting phenomenon is particularly obvious. Therefore, the soil in the vegetable field where Songhua cauliflower is planted should not be too wet to cause root rot, nor too dry to cause water shortage. Generally, the soil should be kept moist in the early stage, and after the flower ball is formed, it should be dried to avoid root rot. In production, methods and measures such as clearing ditches and draining, timely watering, soil cultivation, mowing and covering, and mulching are adopted to timely adjust the soil moisture status, strive to balance the water supply, and keep the soil moist and loose. In drought, irrigate and water, and prohibit flooding; drain in time after rain, prohibit water accumulation in the field, and strictly prohibit the use of drip irrigation on the ridge surface to prevent premature degradation of the fully biodegradable film.

1.7. Bundle leaves and protect flowers

The flower heads will turn yellow when exposed to sunlight, and the color will become darker under strong light conditions in summer and autumn. This change not only affects the appearance of the product, but also affects the freshness and tenderness of the flower heads. Therefore, flower head care is an important part of the production process of Songhua cauliflower. Unlike the flower head care of ordinary cauliflowers, Songhua cauliflower mostly uses leaf bundles to protect the flowers instead of folding leaves to cover the flowers. This is especially true in the production process of sparse planting and cultivating large bulbs, because the flower heads are fluffy and large, the inner leaves have poor embracing ability, and the flower head development and leaf growth are simultaneous. Folding leaves to cover the flowers are often moved by the expansion of the flower head and the growth of the inner leaves, and the shading effect is not good.

The specific method is as follows: When the flower ball grows to the size of a fist, pull the 4 to 5 large alternate leaves close to the flower ball together and overlap them without breaking them. Then use 1 to 2 small bamboo sticks with a thickness of 2mm to 3mm and a length of 7cm to 10cm as fixing objects to pierce the overlapping leaf tips and string them together to fix them at the main vein. The fixed leaves are tied up in a lantern shape to cover the entire flower ball, so that the flower ball is protected from direct sunlight during the subsequent growth process, and there is enough space for development and expansion. The stricter the sunshade and flower protection, the better. Tight leaf binding can completely prevent sunlight from shining on the flower ball, and even in the midsummer environment, the entire flower ball can still remain white and tender. Compared with the usual method of folding leaves to cover flowers, the leaf binding and flower protection is completed in one go, eliminating the trouble of folding leaves to cover flowers many times, saving labor and time, and achieving better results.

1.8. Pest and disease control

1.8.1. The main insect pests of broccoli in early spring are aphids, cabbage loopers, diamondback moths, leaf miners, etc.

Prevention and control should implement the plant protection policy of "prevention first, integrated control", give priority to agricultural control, physical control, and biological control, use chemical control in a scientific and coordinated manner, strictly control the number of medications, observe the safe interval period, control pests and diseases below the allowable economic threshold, and control pesticide residues within the national green food standards to achieve the goals of safety, quality, and harmlessness.

Specific prevention and control settings are divided into physical prevention and chemical prevention:

Physical control: Yellow board to kill aphids: Use 100cm×20cm yellow board, at a density of 30-40 pieces/mu, to hang between rows or plants, higher than the top of the plant, to kill aphids. Large-scale bases can use sex attractants installed in the field to kill pests.

Chemical control: Spray 10g of 15% indoxacarb, 60g/L ethyl spinetoram SC, and 2000 times OD of 10% cyantraniliprole during the bud and ball stages. Do not use dimethoate in the middle and late stages of the growth of broccoli to prevent the production of red and green hairy flowers in the ball. Various pest control should also be based on prevention and control as early as possible.

1.8.2. The main diseases of broccoli in early spring are black rot and anthracnose. In the early stage of the disease, spray 20% zinc thiazole SC 500 times solution or 8% Ningnanmycin AS 800-1000 times solution to prevent the disease.

1.9. Harvest at the right time and dispose of the residual leaves in time

Generally, the harvest period for broccoli is about 20 days after the broccoli bulbs appear. When the broccoli bulbs are fully expanded and the surrounding area begins to loosen, it is the appropriate harvest period for broccoli bulbs. When harvesting, 3 to 5 leaves can be left to protect the broccoli bulbs and avoid mechanical damage or contamination during storage and transportation. After harvesting, sell them as soon as possible or put them in a cold storage at about 4°C for pre-cooling and preservation. After harvesting the broccoli bulbs, promptly dispose of the remaining rhizomes and leaves in the field and carry out harmless treatment to reduce the occurrence of diseases and pests. Its rhizomes and leaves can be used as excellent feed for sheep and rabbits.

2. A comparative test was conducted between the method for cultivating broccoli using a fully biodegradable film provided by the present invention and the method for cultivating broccoli using a conventional PE mulch film, and the effects of different fully biodegradable film thicknesses on broccoli in early spring were explored:

2.1. Test location: The test is located at a base in Nanyang Street, Xiaoshan District.

2.2. Test crops: Songhua cauliflower, variety: Songhua cauliflower variety is Alishan 105 days;

2.3. Test method: The field test adopts randomized block test, with 4 treatments and conventional PE mulch film as control treatment. Each treatment is repeated 4 times. The treatment area is 39m ² and 123 plants are used.

Treatment 1: The fully biodegradable film is a 10 μm thick white fully biodegradable film with a width of 1 m;

Treatment 2: The fully biodegradable film was a 1m wide, 8μm thick white fully biodegradable film;

Treatment 3: The fully biodegradable film is a 6 μm thick white fully biodegradable film with a width of 1 m;

Treatment 4: The fully biodegradable film is a 6 μm thick black fully biodegradable film with a width of 1 m;

Control (CK): The PE mulch was a 1m wide, 10μm thick white PE mulch.

2.4 Experimental Methods

The broccoli seedlings were raised in December 2018, transplanted on January 14, 2019, and covered with film the day before transplanting.

Investigation on the degradation of fully biodegradable film: check the degradation of the fully biodegradable film every 2 weeks after 1 month of film coating, and check the degradation of the fully biodegradable film every week after 2 months of film coating.

Cauliflower growth and yield determination. Starting from the beginning of March, the number of leaves of cauliflowers with different treatments was investigated weekly. The cauliflowers were harvested and measured on May 8. The plant height, spread, number of outer leaves, maximum leaf length, maximum leaf width, flower head height, flower head width, heart column height, heart column width, looseness, single head weight, diseases and insect pests and other indicators were measured. Among them, the looseness was the highest at 10, tight at 10, relatively tight at 8, relatively loose at 6, and loose at 4.

2.5 Data Analysis

Microsoft Office Excel 2010 was used for data processing; DPS v7.05 software was used for statistical analysis, and the LSD method was used for multiple comparisons. * or different lowercase letters indicate significant differences at the p ≤ 0.05 level;

3. Test results and analysis

3.1 Questionnaire for different degradation membrane conditions

The degradation of biodegradable films and PE mulch films of different thicknesses are shown in Tables 1 and 2. On March 14, 2019, about 60 days after filming, the 6μm black biodegradable film and the 6μm white biodegradable film had several natural cracks or holes less than 2cm, which can be regarded as the induction period, and the other mulch films had not yet shown natural cracks. By March 22, the 8μm and 10μm white biodegradable films had also reached the induction period, while the 6μm black biodegradable film and the 6μm white biodegradable film had multiple cracks greater than 2cm, and had reached the cracking period, while the 8μm and 10μm white biodegradable films did not reach the cracking period until April 1. By April 11, the 8μm and 10μm white biodegradable films entered the large cracking period, while the 6μm black biodegradable film and the 6μm white biodegradable film had begun to break and entered the fragmentation period. The performance of the ordinary PE mulch was relatively stable during this period, and some cracks of 0 to 20 cm appeared on April 11, which can be regarded as being in the induction period. The broccoli was harvested on May 8, and the land was plowed on May 15.

Table 1 Degradation of fully biodegradable films and PE mulch films of different thicknesses

Table 2 Survey on degradation status of fully biodegradable films and PE mulch films of different thicknesses

In the present invention, the induction period is the time from film covering to the appearance of more than 3 natural cracks or holes no larger than 2 cm for every 1 m of extension from film covering to the bed surface; the cracking period is the time when natural cracks or holes (diameter) larger than 2 cm but smaller than 20 cm appear on the bed surface film; the large crack period is the time when natural cracks no smaller than 20 cm appear on the bed surface film; the fragmentation period is the time when the bed surface film fragments and the maximum area of the film debris is no larger than 16 square centimeters; and the film-free period is the time when basically no film debris is seen on the bed surface.

3.2 Effects of different thicknesses of fully biodegradable films and PE films on the growth and yield of broccoli

Table 3 Effects of different thicknesses of fully biodegradable films and PE mulch on the number of broccoli leaves

The effects of fully biodegradable films and PE mulches of different thicknesses on the number of broccoli leaves can be seen from Table 3. In each growth period, the number of broccoli leaves with ordinary PE mulches is the largest, because ordinary PE mulches are relatively intact throughout the growth period of broccoli and can better achieve the effect of heat preservation and moisture increase. However, there is no significant difference in the number of broccoli leaves in treatments 1 to 4 compared with that in the control group, indicating that the use of fully biodegradable films has no effect on the growth and development of broccoli.

Table 4 Effects of different thicknesses of fully biodegradable films and PE mulch on the growth of broccoli

The effects of different thicknesses of fully biodegradable films and PE mulch on the mature plants of pine cauliflower are shown in Table 4. The plant heights of treatment groups 1 to 4 were all lower than those of the control group, but there was no significant difference between the treatment groups and the control group. Compared with the plant height, the control group had the least number of outer leaves, and treatment 2 had the most outer leaves, which was 24.3% higher than the control group. There were no significant differences in the spread, maximum leaf length, and maximum leaf width among the experimental groups. In terms of leaf disease incidence, the leaf disease incidence of treatments 1 and 3 was lower, significantly lower than that of treatments 2 and 4, but there was no significant difference compared with the control group.

Table 5 Effects of different thicknesses of fully biodegradable films and PE mulch on cauliflower bulbs and yield

As can be seen from Table 5, there is no significant difference in yield among the five groups. The yields of the five treatment groups vary, but the spacing between rows and plants is equal, indicating that there are certain differences in the weight of a single flower head. Since there are no significant differences in the height and width of the flower head, this indicates that there are differences in the density of the flower heads. The density difference is generally manifested as a difference in looseness. From the looseness, we can also find that the flower heads in the control group are more compact, while the flower heads in treatments 1-4 are looser and more commercial.

Table 6 Comparative analysis of comprehensive costs of biodegradable films and PE mulch films of different thicknesses

Due to policy factors, the current market for ordinary PE mulch films only supplies 10μm and above. Compared with 10μm PE mulch films, the 6μm, 8μm and 10μm fully biodegradable films used in the present invention enter the fragmentation period in 180 days, and are easily broken when the land is plowed after harvesting broccoli. According to the comprehensive cost comparison analysis table of biodegradable films of different thicknesses and PE mulch films shown in Table 6, although the mulch cost of fully biodegradable films is higher than that of PE films, there is no film removal fee and disposal fee, and the total use cost is lower than that of PE films. In addition, since there is no significant difference in the yield of broccoli when using 6μm, 8μm, 10μm fully biodegradable films and ordinary PE films, the broccoli balls using fully biodegradable films are looser and have high commercial value. The smaller the thickness of the fully biodegradable film, the lower the cost. Therefore, in terms of cost performance, the use of 6μm fully biodegradable films has the lowest cost and is the most economical and applicable.

4. Discussion

There are differences in the degradation time of biodegradable films of different thicknesses and colors. The degradation speed of the 6μm black biodegradable film and the 6μm white biodegradable film is faster, and they begin to enter the induction period 59 days after laying, while the 8μm and 10μm white biodegradable films enter the induction period 68 days after laying. The 6μm-thick biodegradable film enters each period 7-14 days earlier than the 8μm and 10μm biodegradable films. By the time of the harvest, the four biodegradable films have reached the fragmentation stage and do not require manual recovery later. After the rotary tillage, almost no film fragments can be seen. The same 6μm biodegradable film, the black biodegradable film group of broccoli grew slower, but with fewer cracks or holes, while the white biodegradable film group of broccoli grew faster but with more holes. Although the black biodegradable film can absorb more visible light heat, it intercepts infrared rays, which will relatively reduce the temperature of the soil layer, while the white biodegradable film can transmit short-wave solar radiation and block long-wave ground radiation, which can preserve heat better than the black biodegradable film. Therefore, at the same thickness, the crops on the white biodegradable film in early spring grow faster than those on the black biodegradable film. In addition, the weeds under the black biodegradable film grow slower due to insufficient sunlight, while the weeds under the white biodegradable film grow faster and push out some holes, so the natural cracks of the black biodegradable film are less than those of the white biodegradable film.

From Table 4 and Table 5, we can see that the yield and flower head firmness of ordinary PE film are higher than those of the four fully biodegradable film groups. The use of fully biodegradable film is beneficial to reducing the firmness of broccoli and improving the commercial quality of broccoli, while there is no significant difference in yield. Therefore, fully biodegradable film has good promotion value. Laying mulch during early spring is beneficial to the growth of broccoli. Among them, ordinary PE mulch has the best insulation and moisture retention effect because it will not crack. The number of leaves of broccoli is always in the leading position during the growth and development period, but there is no significant difference in the number of leaves among the five experimental groups. According to Tables 4 and 5, we believe that 6-10μm fully biodegradable film can achieve the effect of heat preservation and moisture retention in the early growth period of early spring broccoli. In the later growth period, due to the increase in temperature, early spring broccoli does not need mulch covering for insulation and moisture retention. The 6μm black fully biodegradable film and the 6μm white fully biodegradable film are already in the fragmentation period when the film is artificially broken. The degradation time is adapted to the growth cycle of broccoli, and there is no need for artificial film breaking, which saves labor. As the preferred choice, the 6μm black fully biodegradable film and the 6μm white fully biodegradable film can meet the actual growth needs of broccoli. According to Table 6, in terms of cost performance, the 6μm black fully biodegradable film and the 6μm white fully biodegradable film have the lowest cost and are the most economical and applicable.

All features described in the description and the appended claims are essential features of the invention both individually and in any combination.

Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limiting the present invention. Ordinary technicians in the field can change, modify, replace, modify, delete some features, add features or re-combine features to form a technical solution in the above embodiments without departing from the principles and purpose of the present invention. Any simple modifications, equivalent changes and modifications made to the above embodiments based on the innovative principles of the present invention are still within the scope of the technical solution of the present invention.

Claims (2)

1. The method for promoting the cultivation of the early spring pine cauliflowers by using the full-biodegradable film is characterized by comprising the following steps of:

1.1, variety selection: selecting varieties picked more than 65 days after autumn and winter sowing and field planting;

1.2, sowing time: 12 months;

1.3, seedling raising:

1.3.1, seedling raising field and matrix preparation: seedling raising in a plastic greenhouse, wherein the bed surface is flat, and a layer of plastic film is paved on the bed surface; covering a shed frame of the greenhouse with an agricultural film; the seedling substrate is prepared from vegetable garden soil, silt, farmyard manure coal cinder and rice chaff ash through fermentation and decomposition, or the seedling substrate is prepared from turf and vermiculite 1-4: 1 to 2, each matrix is added with 0.8kg to 1.5kg of compound fertilizer and 2kg to 4kg of superphosphate, and the mixture is uniformly stirred for standby;

1.3.2, dishing and sowing: after the substrate is dished, the hole surface is scraped by a scraping plate, and water is sprayed by a watering can; pressing the holes of the hole tray with the matrix by using a tool or a finger, wherein the depth is 0.4 cm-0.6 cm, and the sowing depth is 0.5 cm-1 cm; 1 seed is sown in each hole; covering a matrix after sowing, scraping the matrix with a scraper, covering seeds, watering thoroughly, and covering a mulching film;

1.3.3 post-cast management: removing the mulching film after sowing and emergence, and paying attention to ventilation, light transmission, heat preservation and dehumidification in the greenhouse; watering is carried out twice in the morning and at night, each time, watering is carried out uniformly, and transplanting seedlings is carried out in time to supplement the defects when two cotyledons are unfolded;

1.4, soil preparation and fertilization: removing residual previous crops, stones and the like in soil after one week of transplanting in combination with deep ploughing, applying 50 kg/mu of ternary compound fertilizer or 500 kg-800 kg of commercial organic fertilizer before rotary tillage after deep ploughing, applying 50 kg/mu of ternary compound base fertilizer before leveling after rotary tillage, fully mixing the fertilizer with the soil, and avoiding direct contact of the fertilizer with a film;

1.5, ridging, covering a film, transplanting and field planting: making a furrow after land leveling, wherein the furrow is in a tortoiseshell shape; transplanting open field planting is carried out when 4 leaves grow out on the pine seedlings, one plant grows in each furrow, the plant spacing is 50 cm-60 cm, 2000-2200 plants are planted in each mu, enough water is poured into cavities before field planting, the field planting depth is level with cotyledons, large and small seedlings are separately planted, white or black full-biodegradable films with the width of 1m and the thickness of 6 mu m are selected to cover furrow surfaces 1-2 days before field planting;

1.6, field management:

1.6.1, rational topdressing: dressing foliar fertilizer for 1 time in the initial stage of rosette leaf formation, the later stage of rosette leaf formation and bud emergence, wherein the foliar fertilizer is fertilizer containing one or more trace elements of magnesium, boron and molybdenum, and when the foliar fertilizer does not contain boron, 0.3% borax solution is sprayed in a matching way; inhibiting additional fertilizer on the furrow surface; within 20 days before harvesting of the pine pollen product, no fertilizer must be applied;

1.6.2, moisture management: the drip irrigation is strictly forbidden on the furrow surface; the moisture is mainly kept moist in the early stage, and the flower bulbs are mainly dried after being formed, so that root rot is avoided; irrigation of horse race water and watering during drought, and forbidding flood irrigation; draining water in time after rain, and prohibiting field water accumulation;

1.7, leaf binding and flower protecting: when the flower ball grows to the size of a fist, 4-5 mutually grown large She Jiushi pieces close to the flower ball are folded and stacked without breaking, 1-2 small bamboo sticks with the thickness of 2-3 mm and the length of 7-10 cm are used as fixed connectors, the puncture and stacking blade tips are strung and fixed at a main vein, and the strung and fixed blades are strung in a lantern shape to cover the whole flower ball;

1.8, pest control: yellow plates were used to trap aphids: yellow plates with the density of 100cm multiplied by 20cm are hung between rows or plants according to the density of 30-40 blocks/mu, and are higher than the tops of the plants to trap and kill aphids; spraying 10g of 15% indoxacarb, 60g/L of spinetoram SC and 10% cyantraniliprole OD 2000-time liquid in the bud stage and the globoid stage, and prohibiting the use of the dimefon in the middle and later growth stages of the cauliflower;

1.9, timely harvesting: when the flower ball is fully expanded and the periphery is loose, the proper picking period of the pine pollen is obtained, and 3-5 leaves are reserved for protecting the flower ball during picking.

2. The method for promoting cultivation of early spring pine cauliflowers by using full-biodegradable film according to claim 1, wherein in step 1.5, the full-biodegradable film is a HongRui full-biodegradable film.