High-altitude radish early harvest anti-ultraviolet special biodegradable mulching film and preparation method and application thereof

Abstract

The present application relates to the technical field of degradable mulching film, and particularly relates to a high-altitude early-harvesting anti-ultraviolet special biodegradable mulching film for radish, a preparation method and application thereof.According to mass fractions, the raw materials of the high-altitude early-harvesting anti-ultraviolet special biodegradable mulching film for radish include: 86-87 parts of polybutylene adipate terephthalate, 5 parts of polylactic acid, 5 parts of humic acid, 0.2-0.4 parts of ultraviolet absorber, 0.3 parts of antioxidant, 2.5-2.8 parts of carbon black and 0.5 parts of anti-hydrolysis agent.The raw material composition of the mulching film is simple, the raw materials are easy to obtain, and the cost is low.The preparation process is simple and easy to mass industrial production.The high-altitude early-harvesting anti-ultraviolet special biodegradable mulching film for radish prepared by the present application can be applied to high-altitude radish planting, can improve the growth of radish, promote early harvest of radish by 10-12 days, and increase the yield of radish.

Description

Technical Field

[0001] The invention relates to the technical field of degradable mulch films, in particular to a special ultraviolet-resistant biodegradable mulch film for early harvesting of radishes at high altitudes, and a preparation method and application thereof. Background Art

[0002] Radishes are root vegetables belonging to the genus Raphanus in the cruciferous family. They have been cultivated for thousands of years and are widely used in dietetics and traditional Chinese medicine. Radishes are widely cultivated in plateau regions, where temperatures are lower, ultraviolet radiation is higher, and sunshine duration is longer. Furthermore, high-intensity ultraviolet radiation can inhibit radish photosynthesis, causing green stems on the fleshy, aerial roots, and affecting the marketability of the radish. Mulching with mulch can effectively increase temperature and moisture retention, promote early maturity, improve the marketability of radishes, and increase soil porosity, thereby facilitating mechanized harvesting. However, the use of large amounts of non-degradable mulch can damage the ecological environment. Conventional biodegradable mulch, however, is not UV-resistant. When laid in areas with strong UV rays, it can tear and break prematurely due to exposure, prematurely losing its basic functionality. Therefore, providing a UV-resistant biodegradable mulch specifically designed for early harvesting of high-altitude radishes is of great significance for the green, mechanized production of high-altitude radishes. Summary of the Invention

[0003] Based on the above content, the present invention provides a special UV-resistant biodegradable mulch film for early harvesting of radishes at high altitudes, as well as a preparation method and application thereof.

[0004] To achieve the above object, the present invention provides the following solutions:

[0005] One of the technical solutions of the present invention is a special UV-resistant biodegradable mulch film for early harvesting of radishes at high altitudes. The raw materials, calculated by weight, include:

[0006] Polybutylene adipate / terephthalate (PBAT) 86-87 parts, polylactic acid (PLA) 5 parts, humic acid 5 parts, UV absorber 0.2-0.4 parts, antioxidant 0.3 parts, carbon black 2.5-2.8 parts and anti-hydrolysis agent 0.5 parts.

[0007] Furthermore, the raw materials also include 0.2 parts of aluminum powder.

[0008] A second technical solution of the present invention is a method for preparing the above-mentioned UV-resistant biodegradable mulch film for early harvesting of high-altitude radishes, comprising the following steps:

[0009] Polybutylene adipate / terephthalate is mixed with humic acid, an ultraviolet absorber, an antioxidant, an anti-hydrolysis agent and a binder in parts by mass, and then polylactic acid is added to mix, extruded and pelletized to obtain particles;

[0010] The particles are mixed with carbon black and film is blown to obtain the UV-resistant special biodegradable mulch film for early harvesting of high-altitude radishes (abbreviated as mulch film).

[0011] The third technical solution of the present invention is the application of the above-mentioned special UV-resistant biodegradable mulch film for early harvesting of high-altitude radishes in high-altitude radish cultivation.

[0012] A fourth technical solution of the present invention is a method for increasing the yield of high-altitude radish cultivation and early harvesting, which comprises covering the radish seedlings with the above-mentioned UV-resistant biodegradable mulch film specially used for early harvesting of high-altitude radishes.

[0013] The present invention discloses the following technical effects:

[0014] The raw material composition of the ground film of the present invention is simple, the raw materials are easily available and the cost is low.

[0015] The preparation process of the invention is simple and easy to be industrialized on a large scale.

[0016] The high-altitude radish early harvesting anti-ultraviolet special biodegradable mulch film prepared by the present invention is applied to high-altitude radish planting, which can improve the growth of radish, harvest it in advance, and increase the yield of radish. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0018] Figure 1 The surface conditions of the mulch films prepared in Examples 1-5 were 60 days after covering.

[0019] Figure 2 These are the soil temperature and humidity of different treatment groups in the effect verification example; in the figure, A is soil temperature and B is soil humidity.

[0020] Figure 3 The figures show the degree of spread and number of leaves of radish in different treatment groups in the effect verification example; in the figure, A is the degree of spread and B is the number of leaves.

[0021] Figure 4 The root diameter and length of radish in different treatment groups in the effect verification example; in the figure, A is the root diameter; B is the root length.

[0022] Figure 5 The figures show the gross weight and net weight of radish per plant in different treatment groups in the effect verification example. In the figure, A is the gross weight of per plant; B is the net weight of per plant.

[0023] Figure 6 These are the gross weight and net weight per mu of radish in different treatment groups in the effect verification example; in the figure, A is the gross weight per mu; B is the net weight per mu.

[0024] Figure 7 These are photos of radish harvest from different treatment groups in the effect verification example. DETAILED DESCRIPTION

[0025] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0026] It should be understood that the terms described herein are intended only to describe particular embodiments and are not intended to limit the present invention. In addition, for numerical ranges herein, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. The intermediate value within any stated value or stated range, and each smaller range between any other stated value or intermediate value within the stated range, is also encompassed within the present invention. The upper and lower limits of these smaller ranges may be independently included or excluded within the scope.

[0027] Unless otherwise indicated, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art. Although only preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein may also be used in the practice or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of any conflict with any incorporated document, the contents of this specification shall prevail.

[0028] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments described herein without departing from the scope or spirit of the invention. Other embodiments will be apparent to those skilled in the art from the description of the invention. The description and examples are intended to be exemplary only.

[0029] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0030] A first aspect of the present invention provides a special UV-resistant biodegradable mulch film for early harvesting of radishes at high altitudes, the raw materials of which include, by weight:

[0031] Polybutylene adipate / terephthalate (PBAT) 86-87 parts, polylactic acid (PLA) 5 parts, humic acid 5 parts, UV absorber 0.2-0.4 parts, antioxidant 0.3 parts, carbon black 2.5-2.8 parts and anti-hydrolysis agent 0.5 parts.

[0032] When PBAT is added in excess, its high viscosity can easily clog the screw, making it difficult to blow a bubble. However, when PBAT is added in insufficient amounts, the amount of PLA must be increased. However, due to the rigidity of PLA, the bubble easily becomes brittle and breaks, making blown film difficult. In other words, adding too much or too little PBAT will result in difficulty in producing ground film.

[0033] PLA and PBAT are just the opposite. If the amount of PLA added is too little, it is difficult to blow bubbles; if the amount of PLA added is too much, the bubbles will easily become brittle and break, making it difficult to blow the film. Therefore, the present invention preferably limits the amount of PLA and PBAT to the above parameters.

[0034] In the present invention, the addition of 5 parts of humic acid is enough to meet its function in the mulch film; if the addition of humic acid is too much, it will cause the mulch film to degrade too quickly and increase the cost of the mulch film; if the addition of humic acid is too little, the humic acid mulch film cannot play its function of promoting early harvesting of radishes.

[0035] In a preferred embodiment of the present invention, the raw materials further include 0.2 parts of aluminum powder.

[0036] In the present invention, aluminum powder is used as a silver masterbatch material. As a metal material, aluminum powder has a natural metallic reflective effect, which is stronger than the reflective effect of polymer silver, thereby achieving an insect repellent effect (after the polymer silver material is dispersed on the film surface, it turns gray and the reflective effect is not obvious).

[0037] In a preferred embodiment of the present invention, the ultraviolet absorber is a mixture of UV326 and UV944 in a mass ratio of 1:1.

[0038] The present invention does not impose any particular limitation on the source of the raw materials, and any commercially available product known to those skilled in the art or any material prepared by existing methods may be used.

[0039] A second aspect of the present invention provides a method for preparing the above-mentioned UV-resistant biodegradable mulch film for early harvesting of high-altitude radishes, comprising the following steps:

[0040] Polybutylene adipate / terephthalate is mixed with humic acid, an ultraviolet absorber, an antioxidant, an anti-hydrolysis agent and a binder in parts by mass, and then polylactic acid is added to mix, extruded and pelletized to obtain particles;

[0041] The particles are mixed with carbon black, blown into a film, and processed into the UV-resistant special biodegradable mulch film for early harvesting of high-altitude radishes (hereinafter referred to as mulch film) according to required sizes.

[0042] In a preferred embodiment of the present invention, the binder is white oil.

[0043] The added amount of the white oil is 0.01% of the total mass of the ground film raw materials.

[0044] White oil plays the role of a binder in the present invention, which can make the powder and granular materials in the raw materials fully mixed. If the addition of white oil is omitted, the powder and granular materials will be separated, which is not conducive to the performance of the blend.

[0045] In a preferred embodiment of the present invention, the uniform mixing is specifically stirring at 60° C. for 20 minutes.

[0046] If the mixing temperature is too high, the PLA material will become sticky and lose the uniform mixing effect. If the mixing temperature is too low, the optimal bonding effect will not be achieved, the powdered material in the additive will sink to the bottom, and the uniform mixing effect will not be achieved. Therefore, the mixing temperature of the present invention is preferably limited to the above parameters.

[0047] In a preferred embodiment of the present invention, the mixing time is 10 minutes.

[0048] In a preferred embodiment of the present invention, a twin-screw extruder is used for extrusion, and the temperature of each zone is set in the range of 150-180°C.

[0049] In a preferred embodiment of the present invention, the film blowing is specifically carried out on a three-layer co-extrusion film blowing machine, the screw temperature of each zone is 165-180°C, the film gap is set between 0.15-0.2mm, and the blow-up ratio is set between 4.5-6.

[0050] In some specific embodiments of the present invention, the temperature of the feed port is 165°C, the temperature of zone 1 is 170°C, the temperature of zone 2 is 170°C, the temperature of zone 3 is 180°C, and the temperature of the discharge port is 170°C.

[0051] If the screw temperature in each zone exceeds the temperature range recorded above, either the material does not melt and cannot be pushed out from the screw for film blowing by the die head, or the temperature is too high and the material melts too much, and the material becomes thin in the screw and flows out of the screw in a water-like state, making film blowing impossible.

[0052] In a preferred embodiment of the present invention, when the raw materials also include aluminum powder, polybutylene adipate / terephthalate is uniformly mixed with humic acid, ultraviolet absorber, antioxidant, aluminum powder, anti-hydrolysis agent and adhesive in parts by mass, and then polylactic acid is added to mix, extruded, and pelletized to obtain particles.

[0053] A third aspect of the present invention provides the use of the above-mentioned special UV-resistant biodegradable mulch film for early harvesting of high-altitude radishes in high-altitude radish cultivation.

[0054] A fourth aspect of the present invention provides a method for increasing the yield of high-altitude radish cultivation and early harvesting, wherein the radish seedlings are planted and covered with the above-mentioned high-altitude radish cultivation special UV-resistant biodegradable mulch film.

[0055] The molecular weight of the polylactic acid (PLA) used in the embodiment of the present invention is 45000; the particle size of the aluminum powder used is 3000 mesh; the model of the white oil used is No. 50

[0056] The present invention is further described below by way of examples.

[0057] Example 1

[0058] Calculated by mass percentage, the raw materials of the ground film are composed of the following components: PBAT 91.5%, PLA 5%, UV absorber UV 3260.15%, UV absorber UV9440.15%, antioxidant 10100.3%, carbon black 2.4% and anti-hydrolysis agent 0.5%.

[0059] The preparation method of the above-mentioned ground film comprises the following steps:

[0060] Step 1: Dry PLA until the moisture content is less than 50PPM;

[0061] Step 2: After mixing PBAT with ultraviolet absorber UV 326, ultraviolet absorber UV944, antioxidant 1010, and anti-hydrolysis agent, 0.01% of white oil based on the total mass of the film raw materials was added, and the mixture was stirred in a mixing box at 60° C. for 20 minutes to obtain a mixture A;

[0062] Step 3: Mixture A is taken out and mixed with PLA in another mixing box for 10 minutes to obtain mixture B;

[0063] Step 4: After taking out the mixed material B, pour it into a twin-screw extruder for extrusion, and set the temperature of each zone to 150-180°C (the temperature of the feed port is 150°C, the temperature of the first zone is 165°C, the temperature of the second zone is 170°C, the temperature of the third zone is 165°C, and the temperature of the discharge port is 150°C), followed by air cooling and pelletizing to obtain particles;

[0064] Step 5: After blending the above particles with carbon black, the film is blown on a three-layer co-extrusion film blowing machine. The feed port temperature is 165°C, the temperature of zone 1 is 170°C, the temperature of zone 2 is 170°C, the temperature of zone 3 is 180°C, the discharge port temperature is 170°C, the film port gap is set to 0.2 mm (between 0.15-0.2 mm), and the blowing ratio is set to 4.2 (between 4.5-6); a ground film (marked as PT8) is obtained.

[0065] Example 2

[0066] Calculated by mass percentage, the raw materials of the ground film are composed of the following components: PBAT 91%, PLA 5%, UV absorber UV 3260.2%, UV absorber UV9440.2%, antioxidant 10100.3%, carbon black 2.8% and anti-hydrolysis agent 0.5%.

[0067] The preparation method of the above-mentioned ground film is the same as the preparation method of the ground film in Example 1, and the obtained ground film is marked as PT6.

[0068] Example 3

[0069] Calculated by mass percentage, the raw materials of the ground film are composed of the following components: PBAT 86%, PLA 5%, humic acid 5%, UV absorber UV3260.2%, UV absorber UV 9440.2%, antioxidant 10100.3%, carbon black 2.8%, and anti-hydrolysis agent 0.5%.

[0070] The above-mentioned method for preparing a mulch film differs from the method for preparing a mulch film in Example 1 only in that, in step 2, PBAT is mixed with humic acid, ultraviolet absorber UV 326, ultraviolet absorber UV944, antioxidant 1010, and anti-hydrolysis agent, and then 0.01% of white oil is added to the total mass of the mulch film raw materials. The mixture is stirred in a mixing box at 60° C. for 20 minutes to obtain a mixture A. The remaining steps and parameters are the same as in Example 1. The mulch film prepared in this example is marked FZS6 and has a thickness of 6 μm.

[0071] Example 4

[0072] Calculated by mass percentage, the raw materials of the ground film are composed of the following components: PBAT 86%, PLA 5%, humic acid 5%, UV absorber UV3260.2%, UV absorber UV 9440.2%, antioxidant 10100.3%, carbon black 2.8%, and anti-hydrolysis agent 0.5%.

[0073] The preparation method of the above-mentioned ground film is the same as the preparation method of the ground film in Example 3; the ground film prepared in this example is marked as FZS8, with a thickness of 8 μm.

[0074] Example 5

[0075] Calculated by mass percentage, the raw materials of the ground film are composed of the following components: PBAT 86.3%, PLA 5%, humic acid 5%, UV absorber UV3260.1%, UV absorber UV 9440.1%, antioxidant 10100.3%, carbon black 2.5%, aluminum powder 0.2%, and anti-hydrolysis agent 0.5%.

[0076] The above-mentioned method for preparing a mulch film differs from the method for preparing a mulch film in Example 1 only in that, in step 2, PBAT is mixed with humic acid, ultraviolet absorber UV 326, ultraviolet absorber UV944, antioxidant 1010, aluminum powder, and an anti-hydrolysis agent, and then 0.01% of white oil is added to the total mass of the mulch film raw materials. The mixture is stirred in a mixing box at 60° C. for 20 minutes to obtain a mixture A. The remaining steps and parameters are the same as in Example 1. The mulch film prepared in this example is labeled FZS12.

[0077] Effect Verification Example 1

[0078] The performance tests of the mulch films prepared in Examples 1-5 were conducted as follows:

[0079] 1.1 Test materials and experimental design

[0080] The experiment was conducted in the open field in Litang County, Sichuan Province, from July to August 2023. Radish varieties were tested, including the "Xia Shuai 335" variety. Ridge dimensions were: length × width × height = 20 m × 0.5 m × 0.2 m. 222 plants were planted per ridge, with a planting density of 14,807 plants per mu. Six treatments were set up in the experiment, as shown in Table 1: the unmulched group (CK), and the mulched groups (PT6, PT8, FZS6, FZS8, and FZS12). Five replicates were performed. (The mulched group was mulched on the day of planting. The mulching method is conventional in the art and is not the focus of patent protection for this invention, so it will not be described here.)

[0081] Table 1 Experimental design

[0082]

[0083] 1.2 Measurement items and methods

[0084] 1.2.1 Degradation of mulch film

[0085] Film degradation was observed every 10 days after mulching, and film damage (whether cracks or fissures appeared, and the degree of fragmentation) was recorded for each treatment. Film degradation was graded as follows: Grade 0: No cracks; Grade 1: Beginning to develop cracks; Grade 2: 25% of the films in the field had fine cracks; Grade 3: 2-2.5 cm cracks; Grade 4: Uniform network-like cracks appeared in the film, with no large film fragments; Grade 5: The film was reduced to fragments smaller than 4 x 4 cm.

[0086] 1.2.2 Determination of tensile properties of ground film

[0087] According to GB / T1040.1-2006, a long strip specimen with a width of 10-25mm and a length of not less than 150mm is selected. Two parallel lines with an interval of 50mm are marked in the middle of the specimen. The test speed is 500mm / min and the test is carried out until the specimen breaks. The results are averaged from 5 parallel tests to record the tensile strength and elongation of the film.

[0088] 1.2.3 Determination of light transmittance / haze of ground film

[0089] According to GB / T2410-2008, the light transmittance and haze of the film were measured using an integrating sphere light transmittance / haze meter. All ground film samples were cut into 40×40 mm dimensions and measured three times in parallel, with the average value taken.

[0090] 1.2.4 Determination of moisture retention performance of ground film

[0091] The moisture retention performance of the ground film was tested using the water vapor transmission rate test method. The equipment used was a PERMEW3 / 060 water vapor transmission rate tester with a test accuracy of 0.01g / (m 2 24 hours), with three replicates per sample and six cycles per replicate. The stable value is used as the moisture permeability of the mulch film. The test principle is to create a specific humidity difference on both sides of the sample at a certain temperature. Water vapor passes through the sample into the dry side. By measuring the weight loss of the moisture permeable cup over time, the water vapor transmission rate and other parameters of the sample are calculated.

[0092] 1.2.5 Soil temperature and humidity measurement

[0093] An HLY-B03 soil temperature and humidity meter (Wuhan Hanlinyuan Technology Co., Ltd.) was used. The probe was inserted to a depth of 10 cm. Measurements were taken at three locations per treatment, repeated three times. The soil temperature and humidity were read 10 cm below the soil surface between 9:30 and 10:00 am. The effects of the different treatments on soil temperature and humidity were compared.

[0094] 1.2.6 Determination of soil physical and chemical properties

[0095] Determination of pH and EC (electrical conductivity): naturally air-dried soil was mixed with deionized water at a volume ratio of 1:5, with 100 cm soil 3 , 500 mL of deionized water, stir thoroughly for 30 minutes, seal with plastic wrap, let stand for 10 hours, filter, and measure with a pH meter and conductivity meter.

[0096] Determination of bulk density and porosity: Take a core cutter with a volume of 100 mL, weigh it (W1), use the core cutter to take soil at a depth of 0 - 10 cm for each treatment, repeat 4 times, number and package it, and then bring it back to the laboratory for determination. Weigh to obtain the total weight of the fresh soil and the core cutter (W2), use a three-phase instrument (model from Japan) to measure the volume of the fresh soil (V1), then place the core cutter with the soil at the end with a mesh sieve in a tray filled with clear water and let it stand for 24 hours, then weigh again (W3), and measure the volume (V2). Then place the core cutter with the soil in an oven at 80 °C and dry it to a constant weight, weigh again (W4), and measure the volume of the dried soil (V3).

[0097] Bulk density = (W4 - W1) / 100 (1)

[0098] Total porosity = (100 - V3) / 100 × 100% (2)

[0099] Water-holding porosity = (V2 - V3) / 100 × 100% (3)

[0100] Aeration porosity = (100 - V2) / 100 × 100% (4)

[0101] 1.2.7 Determination of radish growth indicators, number of leaves and plant spread, economic traits, and yield

[0102] Count the number of leaves and the spread on July 2, July 12, July 22, August 2, August 12, and August 22; After the radishes are mature, harvest them uniformly. Randomly select 6 radishes for each treatment, and measure the root length, root diameter, gross weight per plant, and net weight per plant of the radishes respectively. Calculate the yield per mu according to 11,000 plants / 667 m 2 Convert to yield per mu.

[0103] Use a PLA-BX丨ACID F5 type sugar-acid ratio detector to measure the sugar-acid ratio of each radish; Use the anthrone colorimetric method to measure the soluble sugar content in the fruit; Use the fast blue salt colorimetric method to measure the vitamin C content; Use the colorimetric method to measure the cellulose content; Use the anthrone colorimetric method to measure the starch content; Use high performance liquid chromatography (HPLC) to measure the content of raphanusin.

[0104] 2 Results and analysis

[0105] 2.1 Properties of different plastic films

[0106] The mechanical properties of the plastic films prepared in Examples 1 - 5 are shown in Table 2.

[0107] Table 2 Mechanical properties of plastic films

[0108]

[0109] Note: Different lowercase letters in the same column indicate significant differences among treatments (n=3, p<0.05). Time is shown before and after use.

[0110] Table 2 shows that before use, there were no significant differences in tensile load, tensile strength, or nominal strain at break between PT6 and FZS6, or between PT8 and FZS8. The mechanical properties of FZS6 were significantly lower than those of FZS8, and those of FZS8 were significantly lower than those of FZS12. After use, the mechanical properties of each membrane were significantly lower than before use. FZS12 was significantly higher than PT6 and FZS6 in all three mechanical properties, and significantly higher than PT8 and FZS8 in tensile load, but showed no significant differences in tensile strength or nominal strain at break compared to PT8 and FZS8.

[0111] 2.2 Degradation of different mulch films

[0112] Mulch film PT6 showed no cracks during the early growth period of radish. However, minor cracks appeared 30 days after mulching, reaching degradation level 1. Minor cracks appeared 50 days after mulching, reaching degradation level 2. Mulch film PT8 developed minor cracks 30 days after mulching, reaching degradation level 1. Mulch film FZS6 developed minor cracks 20 days after mulching, reaching degradation level 1. Minor cracks appeared 40 days after mulching, reaching degradation level 2. Major cracks appeared 50 days after mulching, reaching degradation level 3. Mulch film FZS8 developed minor cracks 40 days after mulching, reaching degradation level 1. Degradation accelerated in the later stages of mulching, with minor cracks appearing and toughness deteriorating 50 days after mulching, reaching degradation level 2. Mulch film FZS12 developed minor cracks 50 days after mulching, reaching degradation level 1. Details are shown in Table 3.

[0113] Table 3 Degradation of mulch film during radish growth

[0114]

[0115] Note: 0-5 represents the grading index of mulch film degradation. The larger the value, the higher the degree of mulch film degradation (n=4).

[0116] The surface condition of the ground film prepared in Example 1-5 after 60 days of covering is as follows: Figure 1 As shown. Figure 1 It can be seen that the field fragments and holes in the FZS6 treatment were significantly more than those in the other treatments, the degradation degrees of FZS8 and PT6 were relatively consistent, and the degradation degrees of FZS12 and PT8 treatments were lighter.

[0117] 2.3 Effects of different mulch films on soil temperature and humidity

[0118] Figure 2 The soil temperature and humidity of different treatment groups are shown in the figure. In the figure, A is the soil temperature and B is the soil humidity. Figure 2As shown in center A, on July 22, the soil temperatures of the PT6, PT8, FZS6, FZS8, and FZS12 mulch treatments were 14.8°C, 15.6°C, 18.1°C, 19.3°C, and 18.8°C, respectively, which were significantly higher than those of the CK by 0.20°C, 1.00°C, 3.50°C, 4.70°C, and 4.20°C, respectively (p < 0.05). On August 2, the soil temperatures of the five mulch treatments were all higher than those of the unmulched treatment, but there was no significant difference in soil temperature among the biodegradable mulch treatments. As the ambient temperature in the open-field greenhouse decreased, significant changes occurred among the treatments. On August 12, the average soil temperature of the FZS6 treatment was the highest, at 25.8°C, which was higher than those of the CK, PT6, PT8, FZS6, FZS8, and FZS12, by 1.4°C, 2.8°C, 2.8°C, 1°C, and 7.4°C, respectively. The mulching film can increase the soil temperature. The mulch film of the present invention has the same good heat preservation property as the polyethylene mulch film.

[0119] like Figure 2 As shown in B, the soil moisture ranged from 10% to 30% during the entire treatment period. On July 12, the soil moisture in the PT6, PT8, FZS6, FZS8 and FZS12 treatments was 20.24%, 20.16%, 19.08%, 19.12% and 20.36%, respectively, which was significantly increased by 2.2%, 1.94%, 0.86%, 0.92% and 2.14% compared with CK, respectively (p < 0.05); in the early stage, there was no obvious difference in soil moisture among the various mulching treatments; on August 12, in the late stage of the radish fleshy root swelling period, with the degradation of the biodegradable mulch, the soil moisture decreased and the water retention capacity of the mulch decreased.

[0120] 2.4 Effects of different mulching methods on radish growth indicators, leaf number and plant spread, economic traits, and yield

[0121] Figure 3 The figures show the degree of spread and number of leaves of radish in different treatment groups; in the figure, A is the degree of spread and B is the number of leaves.

[0122] Figure 4 The root diameter and length of radish in different treatment groups; in the figure, A is the root diameter; B is the root length.

[0123] Figure 5 The gross weight and net weight of radish per plant in different treatment groups; in the figure, A is the gross weight of per plant; B is the net weight of per plant.

[0124] Depend on Figure 3 、 Figure 4 and Figure 5It can be seen that compared with CK, mulching significantly increased the development of radish plants; on August 22, the development of radish in FZS12 treatment reached 57 cm, which was significantly higher than that of other treatments (p < 0.05), significantly increased by 21.28% compared with PT6 treatment, significantly increased by 29.55% compared with PT8 treatment, and significantly increased by 46.15% compared with FZS6 treatment; the root diameter of radish covered with mulch was significantly higher than that of CK treatment (p < 0.05); the root length of radish covered with biodegradable mulch FZS12 and FZS18 was significantly higher than that of CK treatment (p < 0.05); the gross weight and net weight of radish per plant covered with biodegradable mulch FZS12 were significantly higher than those of CK treatment (p < 0.05) and other treatment groups.

[0125] Figure 6 The following are the gross weight and net weight of radish per mu in different treatment groups; in the figure, A is the gross weight per mu; B is the net weight per mu. Figure 6 It can be seen that the radish yield of the FZS12 group was significantly higher than that of the other treatment groups.

[0126] Figure 7 Photos of radish harvest for different treatment groups. Figure 7 It can be seen that the radishes in the FZS12 group grew stronger, the fleshy roots were generally thicker and longer, and they grew evenly and were of the same size. The fleshy roots had no branches, the commercial shape was good, and the above-ground fleshy roots were longer, which was conducive to mechanical harvesting.

[0127] The embodiments described above are merely descriptions of preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Without departing from the spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by persons skilled in the art should fall within the scope of protection defined by the claims of the present invention.

Claims

1. A method for increasing the yield of high-altitude radish planting and early harvesting, characterized in that: After planting radish seedlings, cover with UV-resistant biodegradable mulch for early harvesting of high-altitude radishes; The raw materials of the high-altitude radish early harvesting special UV-resistant biodegradable mulch film are composed of 86-87 parts of polybutylene adipate / terephthalate, 5 parts of polylactic acid, 5 parts of humic acid, 0.2-0.4 parts of ultraviolet absorber, 0.3 parts of antioxidant, 0.2 parts of aluminum powder, 2.5-2.8 parts of carbon black, 0.5 parts of anti-hydrolysis agent and adhesive, calculated by weight. The ultraviolet absorber is a mixture of UV326 and UV944 in a mass ratio of 1:1; The method for preparing the UV-resistant biodegradable mulch film for early harvesting of radishes at high altitudes comprises the following steps: Polybutylene adipate / terephthalate is mixed with humic acid, ultraviolet absorber, antioxidant, aluminum powder, anti-hydrolysis agent and adhesive in parts by mass, and then polylactic acid is added to mix, extruded and pelletized to obtain particles; The particles are mixed with carbon black and blown into a film to obtain the UV-resistant biodegradable mulch film for early harvesting of high-altitude radishes; The adhesive is white oil; The mixing is specifically carried out by stirring at 60°C for 20 minutes; the mixing time is 10 minutes; The film blowing is specifically carried out on a three-layer co-extrusion film blowing machine, with a feed inlet temperature of 165°C, a zone 1 temperature of 170°C, a zone 2 temperature of 170°C, a zone 3 temperature of 180°C, a discharge port temperature of 170°C, a film gap set to between 0.15-0.2mm, and a blow-up ratio set to between 4.5-6; The thickness of the special UV-resistant biodegradable mulch film for early harvesting of radishes at high altitude is 12 μm.

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