A fertilizer for increasing sugar content of watermelon and a method of applying the same

Abstract

The application discloses a fertilizer for increasing sugar content of watermelons and a fertilization method thereof, and relates to the technical field of watermelon planting, which comprises a base fertilizer component and a seed treatment component.The base fertilizer component comprises roasted soybeans and potassium-containing compound fertilizer; through the organic-inorganic synergistic fertilization of the roasted soybeans and the potassium-containing compound fertilizer in the base fertilizer, slow-release carbon sources and readily available potassium are provided for the whole growth period of the watermelons, and the synthesis and transportation of sucrose in the fruits are significantly promoted; in the seed treatment stage, the seeds are soaked in a variable-temperature water at different times in combination with streptomycin and penicillin, pathogenic bacteria are efficiently killed and the systemic acquired resistance is induced without damaging the seed embryos, the disease incidence of seedlings is reduced by more than 50%, and meanwhile, the uniformity of seedling emergence is improved; the gauze is hung and laid flat to be stored and the germination is actively avoided, so that the root early decline and weak root phenomenon caused by the traditional germination are effectively prevented, and the environmental adaptability after transplanting is improved.

Description

Technical Field

[0001] This invention relates to the field of watermelon cultivation technology, specifically to a fertilizer for increasing the sugar content of watermelons and its application method. Background Technology

[0002] Watermelon is an important economic fruit crop widely cultivated in my country and globally. Its sugar content is a core indicator for measuring quality grade, determining market price, and consumer acceptance. For a long time, how to effectively increase watermelon sugar content without reducing yield has been a research hotspot and technical challenge in watermelon cultivation. Existing techniques for increasing watermelon sugar content mainly focus on the following aspects: First, breeding high-sugar varieties, but the promotion of superior varieties is limited by seed costs and regional adaptability; second, applying potassium fertilizer (such as potassium sulfate and potassium dihydrogen phosphate) during the fruit enlargement period, however, single or multiple applications of potassium fertilizer are easily absorbed and fixed by the soil or leached away with water, resulting in low fertilizer utilization; third, adopting pre-harvest water control measures, but excessive or improper water control can easily lead to hindered fruit enlargement, fruit cracking, or a significant decrease in yield. Furthermore, conventional cultivation often neglects the regulatory role of seed treatment on the plant's later stress resistance and nutrient absorption capacity, and lacks a systematic integrated plan from base fertilizer application and seed germination to water and fertilizer management throughout the entire growth period. Therefore, existing single technical methods generally face a core technical problem: under the premise of ensuring normal watermelon yield and normal fruit expansion, it is difficult to stably, significantly and repeatedly increase the sugar content in the center of the fruit. The sugar content increase is limited (usually less than 1 percentage point), and there are large differences in sugar content between different planting batches and different plots, which cannot meet the needs of large-scale and standardized production of high-quality watermelons. Summary of the Invention

[0003] To address the shortcomings of existing technologies, this invention provides a fertilizer for increasing the sugar content of watermelons and its application method, thus solving the technical problems mentioned in the background section.

[0004] To achieve the above objectives, the present invention provides the following technical solution: a fertilizer for increasing the sugar content of watermelons, comprising a base fertilizer component and a seed treatment component: The base fertilizer components include: roasted soybeans and potassium-containing compound fertilizer; the potassium-containing compound fertilizer is selected from one or more of potassium sulfate or nitrogen-phosphorus-potassium compound fertilizer. The seed treatment components include streptomycin and penicillin; the streptomycin and penicillin are used to soak watermelon seeds.

[0005] In some embodiments, when the potassium-containing compound fertilizer is a nitrogen-phosphorus-potassium compound fertilizer, its total nutrient mass fraction is ≥45%.

[0006] In some embodiments, the streptomycin is 72% agricultural streptomycin sulfate soluble powder, and the penicillin is 98% penicillin industrial salt soluble powder.

[0007] A method for increasing the sugar content of watermelons using the fertilizer described above, characterized by comprising the following steps: Step S1, application of base fertilizer: Before watermelon planting, the base fertilizer components are applied to the planting site, wherein the roasted soybeans and the potassium-containing compound fertilizer are applied simultaneously or sequentially, the amount of potassium-containing compound fertilizer applied is 50-100 kg per mu, and the amount of roasted soybeans applied is 120 kg per mu. Step S2, Seed Treatment: The watermelon seeds are soaked and disinfected using the seed treatment components, specifically including: Step S21: Use hot water at 70 degrees Celsius to scald the seeds and stir continuously during the scalding process; Step S22: After the water temperature has naturally cooled to 55 degrees Celsius, continue soaking the seeds for 15 minutes. Step S23: Let the soaking solution stand until the water temperature naturally drops to 30 degrees Celsius; Step S24: Add the streptomycin to the soaking solution, wherein the dosage of streptomycin is 1 million units per 2000 watermelon seeds; Step S25: Four hours after adding streptomycin, add the penicillin to the soaking solution. The dosage of the penicillin is 500,000 to 1,000,000 units per 2,000 watermelon seeds. Step S26: After adding penicillin, soak the seeds for 10-12 hours, then rinse them with clean water at least twice. Step S3, Seed germination treatment: Wrap the rinsed seeds in breathable gauze and store them by hanging, keeping the seeds flat and not actively stimulating the radicle; Step S4, Transplanting and Water and Fertilizer Management: Step S41: Transplant the treated seeds to the planting site. Seven days after transplanting, apply an aqueous solution containing diammonium phosphate as the first top dressing, accompanied by the first watering. The ratio of the first watering amount to the second watering amount is 4:1. Step S42: After the first watering is completed, water the second time after an interval of 1-2 hours. The amount of water for the second watering is 1 / 4 of the amount of water for the first watering. Step S43: Starting from the 7th day after transplanting, water with clean water every 7 days, or alternate with other functional aqueous solutions. Step S44: During the watermelon fruit enlargement and ripening period, irrigate once every two days.

[0008] In some embodiments, before the rinsing operation in step S26, the method further includes soaking the seeds for 30 minutes using a seed protection agent containing a plant growth regulator; the seed protection agent is an agent that can repair the physiological stress suffered by the seeds during high-temperature scalding and chemical disinfection.

[0009] In some embodiments, the environmental conditions for hanging storage in step S3 are: the ambient temperature is controlled at 25-30 degrees Celsius, the relative humidity is controlled at 60%-75%, and ventilation and light protection are maintained.

[0010] In some embodiments, the mass concentration of diammonium phosphate in the aqueous solution containing diammonium phosphate in step S41 is 0.2%-0.5%.

[0011] In some embodiments, after the first watering in step S42, the second watering is carried out after the surface water has completely infiltrated to a soil depth of 15-20 cm, and the amount of water for the second watering is 0.2-0.3 times that of the first watering.

[0012] In some embodiments, the other functional aqueous solution mentioned in step S43 is selected from one or more of humic acid water-soluble fertilizer, amino acid water-soluble fertilizer, or microbial inoculant aqueous solution.

[0013] In some embodiments, the irrigation method described in step S44, which involves irrigating every two days, involves an irrigation volume of 15-20 cubic meters per acre each time, and the irrigation water temperature is controlled at 20-25 degrees Celsius.

[0014] This invention provides a fertilizer for increasing the sugar content of watermelons and its application method, which has the following beneficial effects: By combining roasted soybeans and potassium-containing compound fertilizer in the base fertilizer, a synergistic organic-inorganic fertilization process was used to provide slow-release carbon sources and readily available potassium throughout the watermelon's entire growth period, significantly promoting the synthesis and translocation of sucrose in the fruit. During seed treatment, variable-temperature scalding combined with streakblastine and penicillin soaking at different times effectively killed pathogens and induced acquired resistance without damaging the embryo, reducing seedling disease incidence by more than 50% and improving seedling uniformity. Hanging and laying the seedlings flat with gauze and actively avoiding germination effectively prevented premature root aging and weak roots caused by traditional germination methods, enhancing post-transplant environmental adaptability. The strategy of initial 80% and secondary 20% irrigation after transplanting, combined with precise diammonium phosphate topdressing, optimized water infiltration and nutrient spatial distribution, promoting deep root development. Moderate stress management with irrigation every two days during the fruit enlargement period ensured normal fruit enlargement and improved the conversion efficiency of photosynthetic products into sugars. The entire method is simple to operate, saves water and fertilizer, requires no complicated equipment, and can steadily increase the sugar content of the center of watermelon by 1.5-3.0 percentage points. It also results in a sweeter taste and higher marketability of the fruit, making it suitable for large-scale promotion under different soil conditions and cultivation models. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the application method of the present invention. Detailed Implementation

[0016] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0017] This invention provides a fertilizer technology solution for improving the sugar content of watermelons, comprising a base fertilizer component and a seed treatment component. The base fertilizer component includes roasted soybeans and potassium-containing compound fertilizer; the potassium-containing compound fertilizer is selected from one or more of potassium sulfate or nitrogen-phosphorus-potassium compound fertilizer. The seed treatment component includes streptomycin and penicillin; the streptomycin and penicillin are used to soak watermelon seeds.

[0018] By precisely combining roasted soybeans with potassium-containing compound fertilizer in the base fertilizer components, a synergistic effect of organic and inorganic nutrients is achieved. When roasted soybeans are applied to the soil at a rate of 120 kg per acre, their rich protein, oil, and organic matter are gradually decomposed and released under the action of soil microorganisms, forming a stable slow-release nitrogen source and carbon skeleton. This not only avoids the excessive vegetative growth problem easily caused by fast-acting nitrogen fertilizers but also continuously supplies organic nutrients throughout the watermelon's growth period, promoting root development and leaf photosynthesis. Simultaneously, 50-100 kg per acre of potassium sulfate or NPK compound fertilizer provides a high concentration of fast-acting potassium. Potassium ions, as a key activator of sugar transport and accumulation in fruit, can significantly increase the activity of sucrose phosphate synthase and sucrose synthase, accelerating the transfer of photosynthetic products to the fruit. This "slow-release and fast-release" combination of organic nitrogen source and potassium ensures both the continuity of nutrient supply and meets the explosive demand for potassium during the fruit expansion period.

[0019] The streptomycin and penicillin in the seed treatment components are precisely formulated with a ratio of 1 million units of streptomycin and 500,000 to 1 million units of penicillin per 2,000 seeds, exerting a dual effect of highly effective sterilization and physiological induction during the variable-temperature soaking treatment. Streptomycin has a specific killing effect on bacterial fruit spot pathogens carried by watermelon seeds, while penicillin can inhibit various fungal seed-borne diseases. The synergistic use of the two can significantly reduce the incidence of seedling damping-off and mature plant wilt. More importantly, the sub-inhibitory concentration of antibiotics can activate the seed's own defense response mechanism, inducing the pre-expression of pathogenesis-related proteins such as chitinase and β-1,3-glucanase, giving seedlings stronger systemic acquired resistance after transplanting. Combined with a gradient variable-temperature process of 70℃ seed scalding, 55℃ warm bath, and 30℃ constant-temperature soaking, the softening of the seed coat and the penetration of the drug solution are optimally balanced, effectively avoiding heat shock damage to the embryo caused by high temperatures, while ensuring uniform absorption of the agent.

[0020] In some embodiments, when the potassium-containing compound fertilizer is a nitrogen-phosphorus-potassium compound fertilizer, its total nutrient mass fraction is ≥45%.

[0021] The combined use of high-concentration potassium fertilizer can continuously supply carbon skeleton and potassium ions during the fruit enlargement period, significantly promoting sucrose synthesis and transport.

[0022] In some embodiments, streptomycin is 72% agricultural streptomycin sulfate soluble powder, and penicillin is 98% penicillin industrial salt soluble powder.

[0023] Treating seeds with the above-mentioned antibiotics can effectively kill fungal and bacterial pathogens on the seed surface, reduce the occurrence of seedling diseases, and at the same time, low-concentration antibiotic stimulation can induce the seeds to develop systemic acquired resistance, enhancing the plant's resistance to stress in the later stages.

[0024] like Figure 1 As shown, a method for increasing the sugar content of watermelons using the above-mentioned fertilizer is characterized by comprising the following steps: Step S1, application of base fertilizer: Before watermelon planting, the base fertilizer components are applied to the planting site, wherein the roasted soybeans and the potassium-containing compound fertilizer are applied simultaneously or sequentially, the amount of potassium-containing compound fertilizer applied is 50-100 kg per mu, and the amount of roasted soybeans applied is 120 kg per mu. Step S2, Seed Treatment: The watermelon seeds are soaked and disinfected using the seed treatment components, specifically including: Step S21: Use hot water at 70 degrees Celsius to scald the seeds and stir continuously during the scalding process; Step S22: After the water temperature has naturally cooled to 55 degrees Celsius, continue soaking the seeds for 15 minutes. Step S23: Let the soaking solution stand until the water temperature naturally drops to 30 degrees Celsius; Step S24: Add the streptomycin to the soaking solution, wherein the dosage of streptomycin is 1 million units per 2000 watermelon seeds; Step S25: Four hours after adding streptomycin, add the penicillin to the soaking solution. The dosage of the penicillin is 500,000 to 1,000,000 units per 2,000 watermelon seeds. Step S26: After adding penicillin, soak the seeds for 10-12 hours, then rinse them with clean water at least twice. Step S3, Seed germination treatment: Wrap the rinsed seeds in breathable gauze and store them by hanging, keeping the seeds flat and not actively stimulating the radicle; Step S4, Transplanting and Water and Fertilizer Management: Step S41: Transplant the treated seeds to the planting site. Seven days after transplanting, apply an aqueous solution containing diammonium phosphate as the first top dressing, accompanied by the first watering. The ratio of the first watering amount to the second watering amount is 4:1. Step S42: After the first watering is completed, water the second time after an interval of 1-2 hours. The amount of water for the second watering is 1 / 4 of the amount of water for the first watering. Step S43: Starting from the 7th day after transplanting, water with clean water every 7 days, or alternate with other functional aqueous solutions. Step S44: During the watermelon fruit enlargement and ripening period, irrigate once every two days.

[0025] This method, through the coordinated operation of steps S1 to S44, achieves precise nutrient supply and water regulation throughout the entire growth period of watermelon: the combination of roasted soybeans and potassium-containing compound fertilizer in the base fertilizer provides long-lasting organic matter and fast-acting potassium, laying the material foundation for sugar synthesis; the variable-temperature seed scalding and timed soaking with streptomycin and penicillin during the seed treatment stage effectively kill pathogens and induce systemic resistance in seeds, resulting in uniform and robust seedling emergence; the hanging storage germination method avoids the weak root phenomenon caused by artificial germination and enhances the adaptability of seedlings; the coupling of multiple waterings (80%+20%) and diammonium phosphate topdressing after transplanting promotes deep root development and nutrient absorption; the irrigation pattern every two days during the fruit enlargement period meets the fruit's water requirements while creating moderate stress, accelerating the conversion of photosynthetic products into sugars. Ultimately, this method can increase the core sugar content of watermelons by 1.5-3.0 percentage points compared to conventional planting methods, and the fruits have a sweet taste, rich flavor, and significantly improved marketability.

[0026] In some embodiments, before the rinsing operation in step S26, the method further includes soaking the seeds for 30 minutes using a seed protection agent containing a plant growth regulator; the seed protection agent is an agent that can repair the physiological stress suffered by the seeds during high-temperature scalding and chemical disinfection.

[0027] This seed protection agent is an aqueous solution containing a composition of plant growth regulators. Its active ingredients are selected from one or more of brassinolide, aminoethyl esters, sodium nitrophenolate, or gibberellic acid, with a mass concentration of 0.01%-0.05%. This agent effectively removes excess reactive oxygen species generated during high-temperature seed treatment and antibiotic treatment by regulating the level of endogenous hormones in seeds and activating antioxidant enzyme systems such as superoxide dismutase (SOD) and peroxidase (POD). It also repairs cell membrane damage and restores seed vigor. After soaking in this agent for 30 minutes, seed germination rate can be increased by 15%-20%, seedling root vigor is enhanced, and post-transplant stress resistance is significantly improved.

[0028] This remediation treatment can reduce oxidative damage caused by high temperatures and antibiotics, improve seed vigor index, advance germination time by 1-2 days, and increase seedling chlorophyll content by more than 15%.

[0029] In some embodiments, the environmental conditions for hanging storage in step S3 are as follows: the ambient temperature is controlled at 25-30 degrees Celsius, the relative humidity is controlled at 60%-75%, and ventilation and light protection are maintained; the gauze wrapping is in the form of single or multiple layers of gauze wrapping, and the hanging method is to ensure that each seed is in a flat and non-overlapping state.

[0030] These environmental parameters simulate the optimal microclimate for natural seed germination, avoiding the growth of mold induced by high temperature and humidity. The flat, non-overlapping state ensures that each seed receives a uniform oxygen supply, increasing the germination rate to over 95%.

[0031] In some embodiments, the mass concentration of diammonium phosphate in the aqueous solution containing diammonium phosphate in step S41 is 0.2%-0.5%; it is prepared according to the planting area ratio during application so that the water-soluble diammonium phosphate is evenly applied to the root area of ​​the plant.

[0032] This concentration range of diammonium phosphate provides sufficient phosphorus to promote root development while avoiding the risk of burning seedlings due to excessive concentration. Uniform application ensures balanced nutrition for each seedling, laying the foundation for later sugar accumulation.

[0033] In some embodiments, after the first watering in step S42, the surface water is completely infiltrated to a soil depth of 15-20 cm before the second watering is carried out, and the amount of water for the second watering is 0.2-0.3 times that of the first watering.

[0034] The two irrigations within a short interval mimic the "wetting followed by infiltration" process in natural rainfall, allowing water to fully infiltrate into the deep roots while controlling the field water holding capacity between 65% and 75%. This ensures both water supply and soil aeration, which is beneficial for the expression of genes related to sugar accumulation.

[0035] In some embodiments, the other functional aqueous solution in step S43 is selected from one or more of humic acid water-soluble fertilizer, amino acid water-soluble fertilizer, or microbial inoculant aqueous solution.

[0036] Humic acid can chelate trace elements in the soil and stimulate root growth, amino acid water-soluble fertilizer directly replenishes organic nitrogen sources, and microbial agents improve the rhizosphere microecology. The alternating use of these functional aqueous solutions and purified water continuously improves soil fertility and plant stress resistance.

[0037] In some embodiments, the irrigation method in step S44, which involves irrigating every two days, involves an irrigation volume of 15-20 cubic meters per acre each time, and the irrigation water temperature is controlled at 20-25 degrees Celsius.

[0038] The overall results validate the synergistic effect of each step of the method, with a significant increase in sugar content, and the fruit has a sweet taste, rich flavor, and greatly improved marketability.

[0039] It is worth noting that all standard parts used in this invention can be purchased from the market, and irregularly shaped parts can be customized according to the description and drawings. The specific connection methods of each part all adopt conventional methods such as bolts, rivets, and welding that are mature in the prior art. The models of electrical structure equipment involved can be selected according to the user's needs, as long as they meet the requirements of this application. In addition, the circuit connection adopts conventional connection methods in the prior art. The supporting electrical structures such as the control, current detection, position feedback, predictive voltage synchronization, and parameter adjustment of the electrical equipment are all existing technologies, such as PLC controllers and module structures, so they will not be described in detail here.

[0040] A specific embodiment of this application is described below with reference to the accompanying drawings: Example 1 (Standard Parameter Combination) Step S1, application of base fertilizer: Fifteen days before watermelon planting, the planting area should be deeply plowed and prepared. Roasted soybeans should be applied as organic base fertilizer at a rate of 240 catties per mu (approximately 16.7 hectares), spread evenly, and then rotary tilled into the soil. At the same time, potassium sulfate (containing 50% K2O) should be applied as potassium fertilizer at a rate of 150 kg per mu (approximately 75 catties per hectare), applied in strips at the bottom of the planting rows and mixed evenly with the soil.

[0041] Step S2, Seed treatment: Select 2000 plump, disease-free watermelon seeds. First, perform a seed scalding treatment: place the seeds in 70°C hot water and stir continuously and rapidly to avoid localized overheating and scalding the embryo. When the water temperature naturally drops to 55°C, continue soaking the seeds for 15 minutes. Then, allow the soaking solution to cool naturally to 30°C. Add 1.6 million units of streptomycin sulfate to the soaking solution and stir well. Four hours after adding the streptomycin, add 1.2 million units of sodium penicillin and continue soaking. The total soaking time, starting from the addition of streptomycin, is 12 hours. After soaking, rinse the seeds twice with clean water, each rinse lasting at least 3 minutes, to thoroughly remove any residual chemicals.

[0042] Step S3, Seed germination treatment: Wrap the rinsed seeds in double-layered breathable gauze, 30-50 seeds per package, keeping them flat and not overlapping. Hang the gauze packages in a well-ventilated, shaded environment, maintaining a temperature of 28±2 degrees Celsius and a relative humidity of 65%-70%. Do not actively water or spray water during the hanging storage period, and do not perform any artificial germination treatment. Keep the seeds in a natural state for about 48 hours, at which point the seed coat will soften but not yet show white.

[0043] Step S4, Transplanting and Water and Fertilizer Management: Transplant the treated seeds to the planting area at a spacing of 40 cm between plants and 2 meters between rows, planting approximately 800 plants per acre. Seven days after transplanting, apply a 0.3% diammonium phosphate solution as the first top dressing, applied with irrigation water. The amount applied should be calculated based on the planting area, ensuring the diammonium phosphate is evenly distributed around the plant roots. Water the plant for the first time along with the top dressing, using 80% of the total irrigation volume. One hour after the first watering, water a second time, using 20% ​​of the total irrigation volume, to achieve a field water holding capacity of 70%. From the seventh day after transplanting, irrigate with clean water (well water with residual chlorine removed) every seven days. Once the watermelon fruit enlargement stage (15-20 days after fruit set), irrigate every two days, keeping the soil moist but not waterlogged, until seven days before fruit maturity.

[0044] The watermelons produced in this embodiment have an average sugar content of 12.6% at the center, which is about 2.1 percentage points higher than that of conventional planting methods.

[0045] Example 2 (Dosage of high-potassium penicillin) Step S1, application of base fertilizer: Ten days before planting, apply 240 catties of roasted soybeans per mu (approximately 0.067 hectares), along with 180 catties of NPK compound fertilizer (N-P2O5-K2O ratio 15-15-15) per mu. After spreading the roasted soybeans, till the soil. Apply the compound fertilizer in furrows before sowing, to a depth of about 15 cm, avoiding direct contact with the seeds.

[0046] Step S2, Seed treatment: Select 2000 watermelon seeds. The seed scalding process is the same as in Example 1: heat in 70°C water, stir and cool, then soak at 55°C for 15 minutes, and allow to cool to 30°C. Add 1.6 million units of streptomycin. After 4 hours, add 1.6 million units of penicillin (high dose, suitable for fields with heavily pathogenic seeds or significant continuous cropping obstacles). The total soaking time is controlled to 10 hours to shorten the treatment cycle. After soaking, rinse three times with clean water, changing the water each time to ensure no residue remains.

[0047] Step S3, Seed germination treatment: Wrap the seeds in a single layer of gauze and hang them in a dark room at a temperature of 30±1℃ and a relative humidity of 60%-65%, keeping them flat and not overlapping. Maintain a quiet and well-ventilated environment during storage, and do not induce germination. Transplant the seeds after approximately 36 hours when the seed coat softens.

[0048] Step S4, Transplanting and Water and Fertilizer Management: On the 7th day after transplanting, apply a 0.5% diammonium phosphate solution (high concentration) to promote seedling root development. The first watering should be 80% of the total irrigation volume, and the second watering should be 20%, with a 30-minute interval between the two waterings. Thereafter, water thoroughly every 7 days. During the watermelon fruit enlargement period, water every 2 days, and simultaneously spray the leaves with a 0.2% potassium dihydrogen phosphate solution every other watering to promote sugar accumulation. Stop watering 10 days before harvest.

[0049] The watermelons produced in this embodiment have an average sugar content of 13.1% in the center, which is about 2.6 percentage points higher than that of conventional planting methods.

[0050] Example 3 (Low potassium, low penicillin, prolonged soaking) Step S1, application of base fertilizer: Twenty days before planting, apply 240 catties of roasted soybeans per mu (approximately 0.067 hectares) and 100 catties of potassium sulfate per mu (approximately 0.067 hectares) (low potassium dosage, suitable for sandy loam soils with high available potassium content). After applying the base fertilizer, plow to a depth of 30 cm to ensure the fertilizer is thoroughly mixed with the soil.

[0051] Step S2, Seed treatment: 2000 watermelon seeds. Seed scalding: Stir in 70°C hot water, cool to 55°C, and soak for 15 minutes. Let cool naturally to 30°C. Add 1.6 million units of streptomycin. After 4 hours, add 800,000 units of penicillin (low dose). The total soaking time, starting from the addition of streptomycin, is extended to 14 hours to accommodate some watermelon varieties with thicker seed coats. After soaking, rinse twice with clean water, soaking the seeds in clean water for 5 minutes each time and gently rubbing them, then change the water and soak again for 5 minutes to ensure complete removal of the pesticide solution.

[0052] Step S3, Seed germination treatment: Wrap the seeds in three layers of gauze (to increase moisture retention) and hang them in an environment with a temperature of 25±1℃ and a relative humidity of 70%-75%, keeping the seeds flat and not overlapping. During storage, check the moisture content of the gauze; if the gauze becomes too dry, lightly spray it once (just keep the gauze moist, do not soak the seeds), but this example does not actively induce radicle development. The seeds are ready for transplanting after about 60 hours.

[0053] Step S4, Transplanting and Water and Fertilizer Management: Seven days after transplanting, apply a 0.2% diammonium phosphate solution (low concentration, suitable for weak seedlings or during the cold spring season). Water 80% of the soil the first time, and 20% the second time, with a 2-hour interval. Afterward, alternate watering with clean water and humic acid water-soluble fertilizer (diluted 500 times) every 7 days to increase soil organic matter content. Once the fruit begins to enlarge, water every 2 days, reducing the amount of water each time (approximately 70% of the usual amount) to avoid diluting the sugar content due to excessive moisture. Stop watering 7 days before harvest.

[0054] The watermelons produced in this embodiment have an average sugar content of 12.1% in the center, which is about 1.6 percentage points higher than that of conventional planting methods.

[0055] Example 4 (medium potassium, medium penicillin, and added microbial inoculant) Step S1, application of base fertilizer: Twelve days before planting, apply 240 catties of roasted soybeans per mu (approximately 0.067 hectares) and 125 catties of potassium sulfate per mu (approximately 0.87 hectares). Additionally, add Bacillus subtilis inoculant (2×10⁻⁶) to the base fertilizer. 10 Apply 2 kg of CFU / gram per acre, mixed with roasted soybeans, to improve the rhizosphere microecological environment.

[0056] Step S2, Seed treatment: 2000 watermelon seeds. Soaking: Stir in 70°C hot water, soak at 55°C for 15 minutes, then cool to 30°C. Add 1.6 million units of streptomycin. After 4 hours, add 1 million units of penicillin (moderate to low dose). Total soaking time: 11 hours. Rinsing: Rinse twice with clean water. Before each rinse, soak the seeds in clean water for 2 minutes, then change the water.

[0057] Step S3, Seed germination treatment: Wrap the seeds in double layers of gauze and hang them in an environment with a temperature of 27±2℃ and a relative humidity of 68%-72%, spreading them out flat without overlapping. Do not germinate the seeds during storage; keep them in their natural state for approximately 50 hours.

[0058] Step S4, Transplanting and Water and Fertilizer Management: On the 7th day after transplanting, apply a 0.35% diammonium phosphate solution through irrigation. Water 80% for the first time and 20% for the second, with an interval of 1 hour. Thereafter, water with clean water every 7 days. Starting from the 21st day after transplanting, apply Bacillus subtilis inoculant (diluted 300 times) with irrigation water every 14 days, for a total of 2 applications. During the fruit enlargement period, irrigate every 2 days, and lightly hoe the soil after each watering to maintain soil aeration.

[0059] The watermelons produced in this embodiment have an average sugar content of 12.8% in the center, which is about 2.3 percentage points higher than that of conventional planting methods.

[0060] Example 5 (Organic Potassium Substitute, High Penicillin Content, Short Soaking) Step S1, application of base fertilizer: Seven days before planting, apply 240 catties of roasted soybeans per mu. Instead of using chemical potassium fertilizer, apply 200 catties of wood ash (containing about 5%-8% K2O) per mu as a potassium source, while also supplementing trace elements. After mixing the roasted soybeans with the wood ash, spread the mixture and then lightly till to a depth of 15 cm.

[0061] Step S2, Seed treatment: 2000 watermelon seeds. Seed scalding: Stir in 70℃ hot water, soak at 55℃ for 15 minutes, then cool to 30℃. Add 1.6 million units of streptomycin. After 4 hours, add 1.4 million units of penicillin (medium-high dose). The total soaking time is shortened to 9 hours, suitable for early-maturing varieties with strong germination. Rinsing: Rinse three times with clean water, rinsing for 2 minutes each time under running water.

[0062] Step S3, Seed germination treatment: Wrap the seeds in a single layer of gauze and hang them in an environment with a temperature of 29±1℃ and a relative humidity of 65%-70%, keeping the seeds flat. Store for about 40 hours. Once the seed coat has softened, transplant directly without pre-germination.

[0063] Step S4, Transplanting and Water and Fertilizer Management: Seven days after transplanting, apply a 0.4% diammonium phosphate solution via irrigation. Water 80% of the soil for the first irrigation and 20% for the second, with a 45-minute interval. Thereafter, irrigate with clean water every 7 days. During the watermelon vine extension stage (20-25 days after transplanting) and the fruit setting stage (35-40 days after transplanting), apply an additional application of wood ash leachate (wood ash:water = 1:10, soak for 24 hours and then use the supernatant), with irrigation water. During the fruit enlargement stage, irrigate every 2 days, and stop watering 8 days before harvest.

[0064] The watermelons produced in this embodiment have an average sugar content of 12.9% in the center, which is about 2.4 percentage points higher than that of conventional planting methods. The fruits also have a sweet taste and rich flavor.

[0065] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, the phrase "comprising an element defined as..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0066] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A fertilizer for increasing the sugar content of watermelons, characterized in that, Includes base fertilizer components and seed treatment components: The base fertilizer components include: roasted soybeans and potassium-containing compound fertilizer; the potassium-containing compound fertilizer is selected from one or more of potassium sulfate or nitrogen-phosphorus-potassium compound fertilizer. The seed treatment components include streptomycin and penicillin; the streptomycin and penicillin are used to soak watermelon seeds.

2. The fertilizer for increasing the sugar content of watermelons according to claim 1, characterized in that, When the potassium-containing compound fertilizer is a nitrogen-phosphorus-potassium compound fertilizer, its total nutrient mass fraction is ≥45%.

3. The fertilizer for increasing the sugar content of watermelons according to claim 1, characterized in that, The streptomycin is 72% agricultural streptomycin sulfate soluble powder, and the penicillin is 98% penicillin industrial salt soluble powder.

4. A method for increasing the sugar content of watermelons using the fertilizer described in any one of claims 1 to 3, characterized in that, Includes the following steps: Step S1, application of base fertilizer: Before watermelon planting, the base fertilizer components are applied to the planting site, wherein the roasted soybeans and the potassium-containing compound fertilizer are applied simultaneously or sequentially, the amount of potassium-containing compound fertilizer applied is 50-100 kg per mu, and the amount of roasted soybeans applied is 120 kg per mu. Step S2, Seed Treatment: The watermelon seeds are soaked and disinfected using the seed treatment components, specifically including: Step S21: Use hot water at 70 degrees Celsius to scald the seeds, and stir continuously during the scalding process; Step S22: After the water temperature has naturally cooled to 55 degrees Celsius, continue soaking the seeds for 15 minutes. Step S23: Let the soaking solution stand until the water temperature naturally drops to 30 degrees Celsius; Step S24: Add the streptomycin to the soaking solution, wherein the dosage of streptomycin is 1 million units per 2000 watermelon seeds; Step S25: Four hours after adding streptomycin, add the penicillin to the soaking solution. The dosage of the penicillin is 500,000 to 1,000,000 units per 2,000 watermelon seeds. Step S26: After adding penicillin, soak the seeds for 10-12 hours, then rinse them with clean water at least twice. Step S3, Seed germination treatment: Wrap the rinsed seeds in breathable gauze and store them by hanging, keeping the seeds flat and not actively stimulating the radicle; Step S4, Transplanting and Water and Fertilizer Management: Step S41: Transplant the treated seeds to the planting site. Seven days after transplanting, apply an aqueous solution containing diammonium phosphate as the first top dressing, accompanied by the first watering. The ratio of the first watering amount to the second watering amount is 4:

1. Step S42: After the first watering is completed, water the second time after an interval of 1-2 hours. The amount of water for the second watering is 1 / 4 of the amount of water for the first watering. Step S43: Starting from the 7th day after transplanting, water with clean water every 7 days, or alternate with other functional aqueous solutions. Step S44: During the watermelon fruit enlargement and ripening period, irrigate once every two days.

5. The method for applying a fertilizer to increase the sugar content of watermelon according to claim 4, characterized in that, Before the rinsing operation described in step S26, the method further includes soaking the seeds for 30 minutes using a seed protection agent containing plant growth regulators; the seed protection agent is an agent that can repair the physiological stress suffered by the seeds during high-temperature scalding and chemical disinfection.

6. The method for applying a fertilizer to increase the sugar content of watermelon according to claim 4, characterized in that, The environmental conditions for hanging storage in step S3 are: ambient temperature controlled at 25-30 degrees Celsius, relative humidity controlled at 60%-75%, and ventilation and light protection maintained.

7. The method for applying a fertilizer to increase the sugar content of watermelon according to claim 4, characterized in that, In the aqueous solution containing diammonium phosphate described in step S41, the mass concentration of diammonium phosphate is 0.2%-0.5%.

8. The method for applying a fertilizer to increase the sugar content of watermelon according to claim 4, characterized in that, After the first watering in step S42, wait until the surface water has completely infiltrated to a soil depth of 15-20 cm before watering a second time, and the amount of water for the second watering is 0.2-0.3 times that of the first watering.

9. The method for applying a fertilizer to increase the sugar content of watermelon according to claim 4, characterized in that, The other functional aqueous solution mentioned in step S43 is selected from one or more of humic acid water-soluble fertilizer, amino acid water-soluble fertilizer, or microbial inoculant aqueous solution.

10. The method for applying a fertilizer to increase the sugar content of watermelon according to claim 4, characterized in that, The irrigation method described in step S44, which involves irrigating every two days, involves an irrigation volume of 15-20 cubic meters per acre each time, and the irrigation water temperature is controlled at 20-25 degrees Celsius.

Images