A biodegradable liquid mulch film for desertification control and its application
By compounding film-forming agents and sand-fixing degradation agents, combined with seed protectants and water-retaining regulators, the problems of liquid mulch affecting seed germination rate and contact have been solved, achieving efficient seed emergence and soil contact, adapting to drone operations, and suitable for desertification control.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- INNER MONGOLIA AGRICULTURAL UNIVERSITY
- Filing Date
- 2026-06-01
- Publication Date
- 2026-06-30
AI Technical Summary
Existing liquid mulch film affects seed germination rate, makes it difficult for seeds to contact the soil, and has low efficiency in drone operations.
Konjac glucomannan, sodium alginate, and starch were used as a film-forming agent, combined with a cross-linking agent to adjust viscosity. Maleic anhydride-grafted modified humic acid was used as a sand-fixing and degradation agent, along with activated weathered coal and chitosan. Seed protectants such as wood vinegar modified alfalfa powder were added to enhance biocompatibility and nutrient protection. The water-retaining regulator was a mixture of mineral materials and bentonite to ensure seed-soil contact and rapid film formation.
It achieves effective contact between seeds and soil, improves germination and emergence rates, reduces damage to seed radicles, adapts to windy and sandy environments, has good water retention, and is suitable for mechanized drone operations.
Smart Images
Figure CN122302384A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of agricultural production technology, and in particular to a biodegradable liquid mulch film for desertification control and its application. Background Technology
[0002] Mulch film is a polyethylene film used to cover the ground, mainly transparent or black. It functions to increase soil temperature and moisture, improve soil structure, and control pests and diseases. It is widely used for more than 40 kinds of crops, including grains, cotton, oilseeds, and vegetables, and can generally increase crop yields by 30-50%. With its widespread application, the coverage area exceeded 7 million hectares in 1996. However, long-term use has led to residual film pollution. To reduce pollution, thickened, high-strength mulch film recycling and fully biodegradable mulch film alternatives have been introduced. The latter, as an eco-friendly alternative technology, has been extensively studied. It uses natural polymers, humic acids, and polysaccharides as main raw materials. It can be sprayed onto the ground to form a film, producing the same effects as plastic mulch film. After spraying, it gradually degrades over 40-60 days and degrades into humic acid organic fertilizer within 2-3 months. It does not cause white pollution and has functions such as sand fixation, water retention, and biodegradability. It is suitable for mechanized operations using drones and is particularly suitable for large-scale ecological restoration in desertified areas.
[0003] However, current liquid mulch film technology still has many limitations. First, most liquid mulch film formulations contain herbicides, fungicides, or unmodified chemical additives, which can easily cause seed poisoning and damage to the radicle when directly mixed with seeds and sprayed, significantly reducing germination and seedling emergence rates. Second, most existing technologies adopt a two-step operation mode of sowing first and then covering with film. This requires drones to make many round trips and take a long time. If seeds and film liquid are mixed, the film-forming speed and permeability of liquid mulch film are difficult to match the needs of simultaneous sowing. After the seeds and film liquid are mixed and sprayed, the seeds often suspend on the surface of the film layer and cannot effectively contact the sandy soil, resulting in the seeds failing to germinate normally. Summary of the Invention
[0004] This application provides a biodegradable liquid mulch film for desertification control and its application, in order to solve the problems in related technologies where liquid mulch film affects seed germination rate and makes it difficult for seeds to come into contact with soil after mixed spraying.
[0005] Firstly, a biodegradable liquid mulch film for desertification control is provided, comprising, by weight parts: Film-forming agent 20-25 parts, sand-fixing and degradation agent 8-15 parts, water-retaining regulator 8-12 parts, seed protectant 3-6 parts, cross-linking agent 1-2 parts, water 120-150 parts; The preparation method of the biodegradable liquid mulch film for desertification control includes: S1. Heat water to 36~42℃, add film-forming agent under stirring, stir for 1.5~2h, add seed protectant, heat to 48~50℃, keep warm and stir for 1~1.5h to obtain pre-dispersion solution; S2. Add sand-fixing degradation agent to the pre-dispersed liquid, adjust pH to 6-6.5, heat to 60-65℃ and stir for 1-1.5 hours, and ultrasonically disperse once every 20 minutes during the process; cool to 52-55℃ and continue to add water-retaining regulator, stir and then add crosslinking agent to obtain membrane solution; S3. Cool the membrane liquid to 32~35℃, homogenize under high pressure, and then filter to obtain a biodegradable liquid mulch film for desertification control. The film-forming agent comprises konjac glucomannan, sodium alginate, and starch in a mass ratio of (3~4):3:3; The preparation method of the sand-fixing degradation agent includes the following steps: After dispersing humic acid in deionized water, the pH is adjusted to 4.5-5, maleic anhydride is added, and the mixture is stirred at 55-60℃ for 1.5-2 hours to obtain maleic anhydride-grafted modified humic acid. Then, activated weathered coal and 4-5 wt% chitosan acetic acid solution are added, and the mixture is stirred at 45-50℃ for 0.5-1 hours. After vacuum drying, a sand-fixing degradation agent is obtained. The seed protectant includes wood vinegar-modified alfalfa powder. The preparation method of wood vinegar-modified alfalfa powder includes: mixing alfalfa powder and wood vinegar at a mass ratio of 1:(2~3), stirring at a constant temperature of 50~55℃, and then drying to obtain wood vinegar-modified alfalfa powder.
[0006] Preferably, it further includes 1 to 2 parts by weight of a degradation regulator, wherein the preparation method of the degradation regulator includes the following steps: after dehydrating the biogas residue, it is mixed with povidone at a mass ratio of 3:(1.5 to 2) and stirred for 10 to 15 minutes to obtain the degradation regulator; In the preparation method of the biodegradable liquid mulch film for desertification control, the degradation regulator is added before the crosslinking agent.
[0007] Preferably, the method for preparing activated weathered coal is as follows: the pulverized weathered coal is immersed in a 4-5 wt% hydrochloric acid solution, refluxed at 75-80°C for 1.5-2 hours, filtered and washed until neutral, to obtain activated weathered coal.
[0008] Preferably, the method for preparing the water-retaining regulator includes: pulverizing and drying mineral materials and bentonite, mixing them at a mass ratio of 1:(0.4~0.5), adding quercetin, and continuing to mix for 20~25 minutes to obtain the water-retaining regulator.
[0009] Preferably, the mineral material is selected from at least one of vermiculite and diatomaceous earth, and the amount of quercetin added is 1.5 to 2% of the sum of the mass of the mineral material and the bentonite.
[0010] Preferably, the mineral material comprises vermiculite and diatomaceous earth in a mass ratio of 1:1.
[0011] Preferably, in the sand-fixing degradation agent, the mass ratio of humic acid to deionized water is 1:(5~6), and the amount of maleic anhydride added is 2~4% of the mass of humic acid; The mass ratio of the maleic anhydride-grafted modified humic acid, activated weathered coal, and chitosan acetic acid solution is 2:(0.8~1):1.
[0012] Preferably, the seed protectant further includes sophorolipids, and the amount of sophorolipids added is 6-10% of the mass of the wood vinegar-modified alfalfa powder; The method for preparing the seed protectant includes: Sophorolipids were mixed with deionized water at a mass-to-volume ratio of 1:5, stirred and dissolved at 40-45°C, and then mixed with alfalfa powder modified with wood vinegar. After spray drying, a powdered seed protectant was obtained.
[0013] Preferably, the spray drying conditions are: inlet air temperature 115~120℃ and outlet air temperature 55~60℃.
[0014] Secondly, an application of the biodegradable liquid mulch film for desertification control as described above in the integrated application of seeds and mulch is provided.
[0015] The beneficial effects of the technical solution provided in this application include: This application provides a biodegradable liquid mulch film for desertification control and its application. A film-forming agent is a compound of konjac glucomannan, sodium alginate, and starch, balancing spray flowability and surface film formation. A cross-linking agent is used to adjust the viscosity of the liquid mulch film, enabling rapid formation of a continuous and flexible film layer on the sand surface, adapting to wind-blown sand environments. The sand-fixing degradation agent uses maleic anhydride-grafted modified humic acid to improve its water solubility and biocompatibility. The combination of activated weathered coal, chitosan, and maleic anhydride-grafted modified humic acid contains no free toxic substances, significantly reducing damage to seed radicles and plumules. A seed protectant, wood vinegar-modified alfalfa powder, provides nutrients, achieving the technical effect of direct mixing of the film liquid with seeds without inhibiting germination. The water-retaining regulator is a compound of mineral materials and bentonite, with quercetin introduced to enhance the stability of the film structure, achieving good water retention. Attached Figure Description
[0016] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0017] Figure 1 A flowchart illustrating the preparation method of the biodegradable liquid mulch film for desertification control provided in this application; Figure 2 A statistical diagram illustrating the number of seedlings produced for this application. Detailed Implementation
[0018] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.
[0019] See Figures 1-2 As shown, this application provides a biodegradable liquid mulch film for desertification control and its application.
[0020] The konjac glucomannan and sodium alginate used in the following examples and comparative examples are food-grade, wherein the konjac glucomannan has a purity ≥90% and a viscosity of 40000 mPa·s (1% aqueous solution, 25℃), and the sodium alginate has a viscosity of 400 mPa·s (1% aqueous solution); the starch is industrial-grade corn starch with a fineness ≥120 mesh; the humic acid is agricultural-grade powdered humic acid with a fineness of 200 mesh; the weathered coal is agricultural-grade weathered coal powder with a total humic acid content ≥45% and a fineness ≥200 mesh; the chitosan is food-grade deacetylated chitosan with a degree of deacetylation ≥90% and a viscosity of 100 mPa·s (1% acetic acid solution); the vermiculite is expanded vermiculite powder with a mesh size of 200 mesh, an expansion ratio of 8~12 times, and a porosity ≥70%; and the diatomaceous earth is filter aid grade diatomaceous earth with a fineness of 325 mesh, SiO2 ≥85%, and a specific surface area ≥30 m². 2 / g; Bentonite is sodium-based bentonite, with a blue absorption capacity ≥30 g / 100 g and an expansion capacity ≥30 mL / g; Alfalfa meal is feed-grade alfalfa meal, with a fineness ≥100 mesh and crude protein ≥16%; Wood vinegar is agricultural-grade refined wood vinegar, pH=4.5, organic matter ≥30%, and tar-free; Sophorolipid is biological-grade sophorolipid; Povidone is PVP K-30, with a molecular weight of approximately 45,000~55,000; Quercetin is plant-extracted grade, with a purity ≥95%; Dehydrated biogas residue is well-rotted dehydrated biogas residue, with organic matter ≥45% and humic acid ≥15%.
[0021] Example 1 The biodegradable liquid mulch film for desertification control provided in this embodiment consists of: 220g film-forming agent, 100g sand-fixing degradation agent, 100g water-retention regulator, 45g seed protectant, 15g xanthan gum, 10g degradation regulator, and 1300g water.
[0022] The preparation method of biodegradable liquid mulch film for desertification control is as follows: S101. After heating water to 40℃, add 88g konjac glucomannan, 66g sodium alginate and 66g starch sequentially under stirring at 800r / min (addition interval 15min), stir for 1.5h, add seed protectant, heat to 50℃, keep warm and stir for 1h to obtain pre-dispersion liquid. S102. Add sand-fixing degradation agent to the pre-dispersion liquid, adjust pH to 6.5, heat to 60℃ and stir for 1 hour, and ultrasonically disperse once every 20 minutes (power 200W, 5 minutes each time); cool down to 52℃ and continue to add water-retaining regulator and stir for 30 minutes, then add degradation regulator and stir for 10 minutes, and finally add crosslinking agent xanthan gum (food grade, 80 mesh) and stir for 30 minutes to obtain the membrane solution; S103. Cool the membrane solution to 35℃, homogenize it twice using a high-pressure homogenizer (pressure 20MPa), and filter it with a filter screen with a pore size of 100μm to remove impurities, thus obtaining a biodegradable liquid mulch film for desertification control.
[0023] The preparation method of the sand-fixing degradation agent is as follows: After dispersing 60g of humic acid into 300g of deionized water, the pH was adjusted to 4.5 with 0.1mol / L dilute hydrochloric acid, and 1.8g of maleic anhydride was added. The mixture was stirred and mixed at 55℃ for 2h to obtain maleic anhydride-grafted modified humic acid. Take 54g of maleic anhydride-grafted modified humic acid, add 27g of activated weathered coal and 27g of 5wt% chitosan acetic acid solution (chitosan is dissolved in 2wt% acetic acid solution, ultrasonically dispersed at 300W, solid-liquid ratio 1g:20mL), stir at 50℃ for 0.5h, vacuum dry (vacuum degree -0.08MPa, temperature 50℃), and then pulverize to a particle size ≤0.1mm to obtain sand-fixing degradation agent; The method for preparing activated weathered coal is as follows: weathered coal pulverized to a particle size ≤0.075mm is impregnated in a 5wt% hydrochloric acid solution, refluxed at 80℃ for 1.5h, filtered and washed until neutral, to obtain activated weathered coal.
[0024] The preparation method of the water-retaining regulator is as follows: 35g vermiculite, 35g diatomaceous earth, and 35g bentonite were pulverized to a particle size ≤0.05mm and dried at 110℃. After adding 2.1g quercetin, the mixture was further mixed in a high-speed mixer at a speed of 1500r / min for 25min to obtain a water-retaining regulator.
[0025] The preparation method of seed protectant is as follows: 3.7g of sophorolipid was mixed with 18.5g of deionized water and stirred at 45℃ to dissolve. Then it was mixed with 46g of wood vinegar-modified alfalfa powder and spray-dried (inlet air temperature 120℃, outlet air temperature 60℃) to obtain a powdered seed protectant. The preparation method of wood vinegar modified alfalfa powder is as follows: 50g of alfalfa powder (particle size ≤0.05mm) is mixed with 100g of wood vinegar, stirred at a constant temperature of 55℃ and then dried to obtain wood vinegar modified alfalfa powder.
[0026] The degradation regulator is prepared by: dewatering the biogas residue, mixing 7g of dewatered biogas residue with 3.5g of povidone and stirring for 10min to obtain the degradation regulator.
[0027] Example 2 The biodegradable liquid mulch film for desertification control provided in this embodiment consists of: 220g film-forming agent, 100g sand-fixing degradation agent, 100g water-retaining regulator, 45g seed protectant, 15g xanthan gum, and 1300g water.
[0028] In addition, unlike Example 1, the seed protectant in this example does not contain sophorolipid; the preparation method of the biodegradable liquid mulch film for desertification control is the same as in Example 1.
[0029] Example 3 The difference between this embodiment and Embodiment 1 is that the biodegradable liquid mulch film provided in this embodiment consists of: 220g film-forming agent, 150g sand-fixing degradation agent, 120g water-retaining regulator, 45g seed protectant, 15g xanthan gum, 10g degradation regulator, and 1300g water.
[0030] Apart from that, the preparation method of the biodegradable liquid mulch film for desertification control is the same as in Example 1.
[0031] Example 4 The biodegradable liquid mulch film for desertification control provided in this embodiment consists of: 200g film-forming agent, 80g sand-fixing degradation agent, 80g water-retaining regulator, 30g seed protectant, 10g guar gum, 10g degradation regulator, and 1200g water.
[0032] The preparation method of biodegradable liquid mulch film for desertification control is as follows: S401. After heating water to 36℃, add 66.7g konjac glucomannan, 66.6g sodium alginate and 66.7g starch sequentially under stirring at 800r / min (addition interval 15min), stir for 1.5h, add seed protectant, heat to 48℃, keep warm and stir for 1h to obtain pre-dispersion liquid. S402. Add sand-fixing degradation agent to the pre-dispersion liquid, adjust pH to 6, heat to 60℃ and stir for 1.5h, and ultrasonically disperse once every 20min (power 200W, 5min each time); cool to 52℃ and continue to add water-retaining regulator and stir for 30min, then add degradation regulator and stir for 10min, and finally add crosslinking agent guar gum (industrial grade guar gum) and stir for 30min to obtain membrane solution; S403. Cool the membrane solution to 32℃, homogenize it twice using a high-pressure homogenizer (pressure 20MPa), and filter it with a filter screen with a pore size of 100μm to remove impurities, thus obtaining a biodegradable liquid mulch film for desertification control.
[0033] The preparation method of the sand-fixing degradation agent is as follows: After dispersing 55g of humic acid into 350g of deionized water, the pH was adjusted to 5 using 0.1mol / L dilute hydrochloric acid, and 1.1g of maleic anhydride was added. The mixture was stirred and mixed at 55℃ for 2h to obtain maleic anhydride-grafted modified humic acid. Take 50g of maleic anhydride-grafted modified humic acid, add 20g of activated weathered coal and 25g of 4wt% chitosan acetic acid solution (chitosan is dissolved in 2wt% acetic acid solution, ultrasonically dispersed at 300W, solid-liquid ratio 1g:25mL), stir at 45℃ for 0.5h, vacuum dry (vacuum degree -0.08MPa, temperature 50℃), and then pulverize to a particle size ≤0.1mm to obtain sand-fixing degradation agent; The method for preparing activated weathered coal is as follows: weathered coal pulverized to a particle size ≤0.075mm is immersed in a 4wt% hydrochloric acid solution, refluxed at 75℃ for 2h, filtered and washed until neutral, to obtain activated weathered coal.
[0034] The preparation method of the water-retaining regulator is as follows: 60g of vermiculite and 24g of bentonite were pulverized to a particle size ≤0.05mm and dried at 110℃. 1.26g of quercetin was added and the mixture was then mixed in a high-speed mixer at a speed of 1500r / min for 20min to obtain a water-retaining regulator.
[0035] The preparation method of seed protectant is as follows: 2.1g of sophorolipid was mixed with 10.5g of deionized water and stirred at 40℃ to dissolve. Then it was mixed with 35g of wood vinegar-modified alfalfa powder and spray-dried (inlet air temperature 115℃, outlet air temperature 55℃) to obtain a powdered seed protectant. The preparation method of wood vinegar modified alfalfa powder is as follows: 40g of alfalfa powder (particle size ≤0.05mm) is mixed with 120g of wood vinegar, stirred at a constant temperature of 50℃ and then dried to obtain wood vinegar modified alfalfa powder.
[0036] The degradation regulator is prepared by dewatering the biogas residue, mixing 6g of dewatered biogas residue with 4g of povidone and stirring for 10min to obtain the degradation regulator.
[0037] Example 5 The biodegradable liquid mulch film for desertification control provided in this embodiment consists of: 250g film-forming agent, 150g sand-fixing degradation agent, 120g water-retention regulator, 60g seed protectant, 20g xanthan gum, 20g degradation regulator, and 1500g water.
[0038] The preparation method of biodegradable liquid mulch film for desertification control is as follows: S501. After heating water to 42℃, add 100g konjac glucomannan, 75g sodium alginate and 75g starch sequentially under stirring at 800r / min (addition interval 15min), stir for 2h, add seed protectant, heat to 50℃, keep warm and stir for 1.5h to obtain pre-dispersion liquid. S502. Add sand-fixing degradation agent to the pre-dispersion liquid, adjust pH to 6.5, heat to 65℃ and stir for 1 hour, and ultrasonically disperse once every 20 minutes (power 200W, 5 minutes each time); cool down to 55℃ and continue to add water-retaining regulator and stir for 30 minutes, then add degradation regulator and stir for 10 minutes, and finally add crosslinking agent xanthan gum (food grade, 80 mesh) and stir for 30 minutes to obtain the membrane solution; S503. Cool the membrane solution to 35℃, homogenize it twice using a high-pressure homogenizer (pressure 20MPa), and filter it with a filter screen with a pore size of 100μm to remove impurities, thus obtaining a biodegradable liquid mulch film for desertification control.
[0039] The preparation method of the sand-fixing degradation agent is as follows: After dispersing 85g of humic acid into 430g of deionized water, the pH was adjusted to 4.5 with 0.1mol / L dilute hydrochloric acid, and 3.44g of maleic anhydride was added. The mixture was stirred and mixed at 60℃ for 1.5h to obtain maleic anhydride-grafted modified humic acid. Take 80g of maleic anhydride-grafted modified humic acid, add 40g of activated weathered coal and 40g of 5wt% chitosan acetic acid solution (chitosan is dissolved in 2wt% acetic acid solution, ultrasonically dispersed at 300W, solid-liquid ratio 1g:20mL), stir at 50℃ for 1h, vacuum dry (vacuum degree -0.08MPa, temperature 50℃), and then pulverize to a particle size ≤0.1mm to obtain sand-fixing degradation agent; The method for preparing activated weathered coal is the same as in Example 1.
[0040] The preparation method of the water-retaining regulator is as follows: 82g of diatomaceous earth and 41g of bentonite were pulverized to a particle size ≤0.05mm and dried at 110℃. After adding 2.46g of quercetin, the mixture was further mixed in a high-speed mixer at a speed of 1500r / min for 25min to obtain a water-retaining regulator.
[0041] The preparation method of seed protectant is as follows: Mix 6.5g of sophorolipid with 32.5g of deionized water, stir and dissolve at 45℃, then mix with 65g of wood vinegar-modified alfalfa powder, spray dry (inlet air temperature 120℃, outlet air temperature 60℃) to obtain a powdered seed protectant. The preparation method of wood vinegar modified alfalfa powder is as follows: 70g of alfalfa powder (particle size ≤0.05mm) is mixed with 140g of wood vinegar, stirred at a constant temperature of 55℃ and then dried to obtain wood vinegar modified alfalfa powder.
[0042] The degradation regulator is prepared by: after dehydrating the biogas residue, mixing 15g of dehydrated biogas residue with 7.5g of povidone and stirring for 15min to obtain the degradation regulator.
[0043] Comparative Example 1 The difference between this comparative example and Example 1 is that no water-retaining regulator is added to the components of the biodegradable liquid mulch film for desertification control in this comparative example.
[0044] Comparative Example 2 The difference between this comparative example and Example 1 is that the sand-fixing degradation agent is replaced with an equal amount of humic acid in this comparative example.
[0045] Comparative Example 3 The difference between this comparative example and Example 1 is that the film-forming agent in this comparative example is replaced with an equal amount of starch.
[0046] Comparative Example 4 The difference between this comparative example and Example 1 is that no water-retaining regulator or seed protectant is added in this comparative example.
[0047] Experiments were conducted on the biodegradable liquid mulch film for desertification control (hereinafter referred to as "liquid mulch film") prepared in the examples and comparisons.
[0048] Pumpkin seeds (8-15mm in diameter, germination rate ≥90%) were selected, with 50 seeds per group. The dried pumpkin seeds and the prepared liquid mulch were mixed at a mass-to-volume ratio of 0.5kg:10L to obtain a seed-mulch mixture. After standing at 25℃ for 30 minutes, the mixed seeds were removed and evenly spread in a germination box, covered with three layers of moist filter paper, maintaining a humidity of 75%. The box was then placed in an artificial climate chamber (temperature 25℃, light 14h / d, humidity 80%) as the treatment group. Germination rate was recorded on day 7, and seed viability retention rate was calculated. Germination retention rate (%) = (germination rate of treatment group / germination rate of control group) × 100% The control group consisted of seeds soaked in water, with germination conditions identical to those of the treatment group.
[0049] Further testing was conducted in test fields with sandy soil, a top 5cm moisture content of 7%, and a diurnal temperature range of 15°C. For each embodiment and comparative example, four 2m × 2m plots were set up in each group. The experimental groups (including experimental group 1 and experimental group 2) were sprayed with the above-mentioned seed-mulch mixture, while the control groups (including control group 1 and control group 2) were sprayed with only seeds and water. The field emergence rate was recorded on day 10, and the seedling retention rate was calculated, with the average value taken. Seedling emergence and retention rate (%) = (Experimental group seedling emergence rate / Control group seedling emergence rate) × 100% The control group consisted of dried pumpkin seeds that were sprayed with water but not mixed with liquid mulch. The results are shown in Table 1.
[0050] Table 1 The seed protectants in Examples 1, 3, and 5 were mixtures of wood vinegar-modified alfalfa powder and sophorolipids. The liquid mulch contained no free harmful components, and both seed viability retention and germination rate retention were at a high level. In Example 2, the lack of sophorolipids as a surfactant reduced the compatibility between the liquid mulch and the seeds, causing some seeds to be tightly encased in the mulch and hindering respiration, resulting in a lower viability retention rate compared to Example 1. In Example 5, the ratio of sophorolipids to wood vinegar-modified alfalfa powder was increased to 10%, which also improved the seed viability retention rate compared to Examples 1 (8%) and 4 (6%). This indicates that sophorolipids can reduce seed damage by lowering the surface tension of the mulch, while the wood vinegar-modified alfalfa powder provides nutritional protection, further maintaining a good germination rate retention.
[0051] See appendix for further details. Figure 2As shown, based on the results of a ten-day experiment, a statistical chart of the number of seedlings in the experimental and control groups in Example 1 is presented. It is clear that spraying liquid mulch has a significant promoting effect on pumpkin seed germination. The difference in germination began to appear on the third day after sowing. In the two experimental groups sprayed with liquid mulch, experimental group 1 had 22 seedlings, and experimental group 2 had 34 seedlings, for a total of 56 seedlings in the experimental groups. In contrast, in the two control groups that were not sprayed with liquid mulch, control group 1 had 18 seedlings, and control group 2 had 22 seedlings, for a total of 40 seedlings in the control group. It can be seen that on the third day, the number of seedlings in the sprayed groups was significantly higher than that in the control groups, especially in experimental group 2, which reached 34 seedlings, 12 more than the highest number of 22 seedlings in the control group. By the seventh day after sowing, the difference had widened further. In the experimental group 1, which was sprayed with liquid mulch, the number of seedlings increased to 38, and in the experimental group 2, it reached 41, for a total of 79. In contrast, the two control groups, which were not sprayed with liquid mulch, had 29 and 22 seedlings respectively, for a total of 51. At this point, the average number of seedlings in the sprayed groups was 39.5, while the average in the control groups was 25.5, meaning the sprayed groups had approximately 55% more seedlings than the control groups. The tenth day was the final statistical endpoint. At this point, the experimental group 1 with liquid mulch had 45 seedlings, and the experimental group 2 had 54 seedlings, for a total of 99. The control groups without spraying had 32 seedlings, and the control groups had 39 seedlings, for a total of 71. The highest number of seedlings in the sprayed groups reached 54, while the highest number in the control groups was only 39, a difference of 15. Based on the final total number of seedlings, the average seedling emergence rate of the two trays of pumpkin seeds sprayed with liquid mulch was 77%, while the average seedling emergence rate of the two trays without liquid mulch was only 55%, a difference of 22 percentage points. The seedling emergence rate of the sprayed group was about 40% higher than that of the control group.
[0052] Fill a transparent culture box with the aforementioned sandy soil and compact it until the surface is level. Take 100 dried pumpkin seeds and mix them with the prepared liquid mulch film according to the above ratio to obtain a seed-mulch film mixture. Spray this mixture onto the sandy soil in the transparent culture box. 24 hours after spraying (when the liquid mulch film has formed), observe the seed positions along the cross-section of the culture box and count the proportion of seeds embedded in the soil. Percentage of seeds buried in soil (%) = (Number of seeds located in the top 0-8mm of soil / Total number of seeds) × 100% Further testing was conducted on the degradation rate.
[0053] Take 5g of liquid mulch film from each group to prepare a film (0.2mm thick), and place it in a composting environment (temperature 30℃, humidity 60%, microbial content 10). 6 The remaining mass of the samples (CFU / g) was measured at 30, 60, and 90 days, and the degradation rate of the mulch film was calculated. Plastic film degradation rate (%) = [(initial mass - remaining mass) / initial mass] × 100% The proportion of seeds planted in the soil and the degradation rate of the plastic film are shown in Table 2.
[0054] Table 2 The film-forming agent ratio, water-retaining regulator, and overall viscosity affect the seed penetration effect. The film-forming agent in the examples combines good fluidity with slow film formation, and the water-retaining regulator further enhances the permeability of the liquid mulch, increasing the seed penetration rate. The seed protectant in Example 2 lacks sophorolipids, resulting in high surface tension and slow penetration. Some seeds are encapsulated by the film liquid and float on the surface, slightly reducing the seed penetration rate. In Comparative Example 1, no water-retaining regulator was added, resulting in poor film liquid permeability and a decreased seed penetration rate. Comparative Example 3 used pure starch as the film-forming agent, resulting in excessively fast film formation and a thick film layer. Comparative Example 4 lacked both water-retaining regulator and seed protectant, leading to poor adhesion between the film liquid and the soil and insufficient penetration depth. Both examples showed a significant decrease in the seed penetration rate.
[0055] Furthermore, considering the degradation rates at 30 days, 60 days, and 90 days, the degradation rate of the examples remained stable, with a degradation rate exceeding 85% at 90 days. Examples 1 and 3-5 used a combination of dehydrated biogas residue and povidone as a degradation regulator. The biogas residue is rich in biodegradable components, and povidone has good film-forming and dispersing properties. Combined with a sand-fixing degradation agent, the mulch film achieved gradual degradation within 30-90 days.
[0056] Meanwhile, this application tested the water retention performance of the liquid mulch film prepared in Example 1 after 7 days of spraying: The above-mentioned sandy soil was placed in a transparent culture box, compacted until the surface was flat, and the initial moisture content was measured. Liquid mulch film was sprayed at a dosage of 20L per acre, serving as the treatment group, while the control group was not sprayed; the mixture was placed in an artificial climate chamber (temperature 25℃, humidity 50%, wind speed 2m / s). On the 7th day, the moisture content of the top 0-5cm soil and the deep 5-15cm soil were measured using a soil moisture meter, and the water retention rate was calculated; simulated rainfall (spraying 10mm of clean water, measured with a high-precision rain gauge), and the time it took for rainwater to penetrate to a depth of 15cm was recorded as the infiltration time.
[0057] Water retention rate (%) = (Moisture content of the treatment group / Initial moisture content) × 100% The processing group in the formula is the same as that in Example 1. The results are shown in Table 3.
[0058] Table 3 As can be seen, Example 1 has good water retention performance.
[0059] The specific application of the biodegradable liquid mulch film for desertification control prepared in this application embodiment is as follows: after initial screening of seeds, the seeds and biodegradable liquid mulch film for desertification control are mixed at a mass-volume ratio of 0.5 kg: 10 L to obtain a seed-mulch film mixture. The mixture is then placed in a container equipped with a stirring rod and sprayed under stirring conditions to prevent the seeds from settling to the bottom. This allows for simultaneous liquid mulch film laying and seed sowing, achieving the basic functions of mulch film such as soil heat preservation, water retention, evaporation prevention, and improved plant germination speed, as well as degradability and sand reduction. At the same time, it enables mulch film laying and seed sowing to be carried out simultaneously, reducing the working time of drones.
[0060] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.
Claims
1. A degradable sand control liquid mulch, characterized in that, According to parts by weight, it includes: Film-forming agent 20-25 parts, sand-fixing and degradation agent 8-15 parts, water-retaining regulator 8-12 parts, seed protectant 3-6 parts, cross-linking agent 1-2 parts, water 120-150 parts; The preparation method of the biodegradable liquid mulch film for desertification control includes: S1. Heat water to 36~42℃, add film-forming agent under stirring, stir for 1.5~2h, add seed protectant, heat to 48~50℃, keep warm and stir for 1~1.5h to obtain pre-dispersion solution; S2. Add sand-fixing degradation agent to the pre-dispersed liquid, adjust pH to 6-6.5, heat to 60-65℃ and stir for 1-1.5 hours, and ultrasonically disperse once every 20 minutes during the process; cool to 52-55℃ and continue to add water-retaining regulator, stir and then add crosslinking agent to obtain membrane solution; S3. Cool the membrane liquid to 32~35℃, homogenize under high pressure, and then filter to obtain a biodegradable liquid mulch film for desertification control. The film-forming agent comprises konjac glucomannan, sodium alginate, and starch in a mass ratio of (3~4):3:3; The preparation method of the sand-fixing degradation agent includes the following steps: After dispersing humic acid in deionized water, the pH is adjusted to 4.5-5, maleic anhydride is added, and the mixture is stirred at 55-60℃ for 1.5-2 hours to obtain maleic anhydride-grafted modified humic acid. Then, activated weathered coal and 4-5 wt% chitosan acetic acid solution are added, and the mixture is stirred at 45-50℃ for 0.5-1 hours. After vacuum drying, a sand-fixing degradation agent is obtained. The seed protectant includes wood vinegar-modified alfalfa powder. The preparation method of wood vinegar-modified alfalfa powder includes: mixing alfalfa powder and wood vinegar at a mass ratio of 1:(2~3), stirring at a constant temperature of 50~55℃, and then drying to obtain wood vinegar-modified alfalfa powder.
2. The biodegradable liquid mulch film for desertification control as described in claim 1, characterized in that: It also includes a degradation regulator in parts by weight of 1 to 2 parts. The preparation method of the degradation regulator includes the following steps: after dehydrating the biogas residue, it is mixed with povidone in a mass ratio of 3:(1.5 to 2) and stirred for 10 to 15 minutes to obtain the degradation regulator. In the preparation method of the biodegradable liquid mulch film for desertification control, the degradation regulator is added before the crosslinking agent.
3. The biodegradable liquid mulch film for desertification control as described in claim 1, characterized in that: The method for preparing activated weathered coal is as follows: the pulverized weathered coal is immersed in a 4-5 wt% hydrochloric acid solution, refluxed at 75-80℃ for 1.5-2 hours, filtered and washed until neutral, to obtain activated weathered coal.
4. The biodegradable liquid mulch film for desertification control as described in claim 1, characterized in that: The method for preparing the water-retaining regulator includes: pulverizing and drying mineral materials and bentonite, mixing them at a mass ratio of 1:(0.4~0.5), adding quercetin, and continuing to mix for 20~25 minutes to obtain the water-retaining regulator.
5. The biodegradable liquid mulch film for desertification control as described in claim 4, characterized in that: The mineral material is selected from at least one of vermiculite and diatomaceous earth, and the amount of quercetin added is 1.5 to 2% of the sum of the mass of the mineral material and the bentonite.
6. The biodegradable liquid mulch film for desertification control as described in claim 5, characterized in that: The mineral material comprises vermiculite and diatomaceous earth in a mass ratio of 1:
1.
7. The biodegradable liquid mulch film for desertification control as described in claim 1, characterized in that: In the sand-fixing and degradation agent, the mass ratio of humic acid to deionized water is 1:(5~6), and the amount of maleic anhydride added is 2~4% of the mass of humic acid; The mass ratio of the maleic anhydride-grafted modified humic acid, activated weathered coal, and chitosan acetic acid solution is 2:(0.8~1):
1.
8. The biodegradable liquid mulch film for desertification control as described in claim 1, characterized in that: The seed protectant also includes sophorolipids, and the amount of sophorolipids added is 6-10% of the mass of the wood vinegar-modified alfalfa powder; The method for preparing the seed protectant includes: Sophorolipids were mixed with deionized water at a mass-to-volume ratio of 1:5, stirred and dissolved at 40-45°C, and then mixed with alfalfa powder modified with wood vinegar. After spray drying, a powdered seed protectant was obtained.
9. The biodegradable liquid mulch film for desertification control as described in claim 8, characterized in that: The spray drying conditions are: inlet air temperature 115~120℃ and outlet air temperature 55~60℃.
10. The application of the biodegradable liquid mulch film for desertification control as described in any one of claims 1 to 9 in the integrated application of seeds and mulch film.