Organic and inorganic fertilization method for tunnel watermelons

Abstract

The invention provides an organic-inorganic fertilization method for arched shed watermelons, and belongs to the technical field of watermelon planting.The organic-inorganic fertilization method comprises the steps that firstly, before the watermelons are transplanted, biogas slurry fertilizer, powder organic fertilizer, biological bacterial fertilizer, diammonium phosphate and A-type ternary compound fertilizer are sequentially applied, and then base fertilizer is formed; after the watermelons are transplanted, topdressing is conducted according to the growth stage of the watermelons, and in the vine extending stage, YM type compound microbial fertilizer and B type ternary compound fertilizer are sequentially applied to promote vine growth and expand the leaf area; in the young fruit stage, a YM type compound microbial fertilizer, a K type compound microbial fertilizer and a B type ternary compound fertilizer are sequentially applied, the root system absorption efficiency is enhanced, and sugar transportation is promoted; in the fruit swelling period, a YM type compound microbial fertilizer, an N type compound microbial fertilizer and a B type ternary compound fertilizer are sequentially applied to delay leaf senescence and guarantee continuous photosynthesis of leaves; wherein the YM type compound microbial fertilizer, the K type compound microbial fertilizer and the N type compound microbial fertilizer are biogas slurry fertilizers added with functional bacteria.

Description

Technical Field

[0001] This invention relates to the field of watermelon cultivation technology, and in particular to an organic-inorganic fertilization method for greenhouse watermelons. Background Technology

[0002] Watermelon is one of my country's important economic crops, with a wide planting area and large market demand. In recent years, with the rapid development of facility agriculture, the planting area of ​​greenhouse watermelons has been continuously expanding. Greenhouse cultivation can effectively utilize the greenhouse effect to create suitable temperature conditions for watermelon growth, significantly accelerating its growth and development process, achieving early maturity and market availability, and improving planting efficiency. However, in the process of greenhouse watermelon cultivation, farmers generally have problems with improper fertilization, mainly manifested in excessive application of chemical fertilizers. This not only leads to the deterioration of soil physical and chemical properties and reduced fertilizer utilization, but also directly causes a decline in the quality and yield of watermelon products. Summary of the Invention

[0003] In view of this, it is necessary to provide an organic-inorganic fertilization method for greenhouse watermelons to solve the technical problem of reduced watermelon quality and yield caused by excessive application of chemical fertilizers during greenhouse watermelon cultivation.

[0004] This invention provides a method for applying organic and inorganic fertilizers to watermelons grown in greenhouses, comprising the following steps: Step 1: Before transplanting watermelons, apply biogas slurry fertilizer, powdered organic fertilizer, bio-fertilizer, diammonium phosphate, and type A ternary compound fertilizer in sequence to form base fertilizer, so as to improve the physical and chemical properties of the soil. Step 2: After transplanting the watermelon, apply topdressing fertilizer according to the watermelon's growth stage. The specific topdressing fertilizer is as follows: S1: During the vine extension stage, apply YM type compound microbial fertilizer and B type ternary compound fertilizer in sequence to promote vine growth and expand leaf area; S2: During the young fruit stage, apply YM type compound microbial fertilizer, K type compound microbial fertilizer, and B type ternary compound fertilizer in sequence to enhance root absorption efficiency and promote sugar transport. S3: During the fruit expansion period, apply YM type compound microbial fertilizer, N type compound microbial fertilizer, and B type ternary compound fertilizer in sequence to delay leaf senescence and ensure continuous photosynthesis of leaves; Among them, the YM type compound microbial fertilizer, the K type compound microbial fertilizer, and the N type compound microbial fertilizer are all biogas slurry fertilizers with added functional bacteria.

[0005] Preferably, the YM type compound microbial fertilizer, the K type compound microbial fertilizer, and the N type compound microbial fertilizer are all biogas slurry fertilizers with added Bacillus subtilis and Bacillus beryl, with an effective viable count of 0.5-0.6 billion / mL, the mass ratio of Bacillus subtilis to Bacillus beryl is (1.9-2.1):(0.9-1.1), and the mass ratio of nitrogen, phosphorus, and potassium in the B type ternary compound fertilizer is (14-16):(4-6):(29-30).

[0006] Preferably, the pH value of the YM-type compound microbial fertilizer, the K-type compound microbial fertilizer, and the N-type compound microbial fertilizer is all 5.5-8.5; the YM-type compound microbial fertilizer contains 3%-3.2% nitrogen, 1.1%-1.3% phosphorus, and 1%-1.2% potassium; the K-type compound microbial fertilizer contains 1.9%-2.1% nitrogen, 2.8%-3% phosphorus, and 7.3%-7.5% potassium; and the N-type compound microbial fertilizer contains 9.4%-9.6% nitrogen, 3.6%-3.8% phosphorus, and 2.1%-2.3% potassium.

[0007] Preferably, in step S1, 21-23 kg of the YM type compound microbial fertilizer and 4-4.4 kg of the B type ternary compound fertilizer are applied per mu (unit of land area). In S2, 10-12 kg of the YM type compound microbial fertilizer, 10-12 kg of the K type compound microbial fertilizer, and 2-2.5 kg of the B type ternary compound fertilizer are applied per mu. In S3, 10-12 kg of the YM type compound microbial fertilizer, 10-12 kg of the N type compound microbial fertilizer, and 2-2.5 kg of the B type ternary compound fertilizer are applied per mu.

[0008] Preferably, the biogas slurry fertilizer is a concentrated biogas slurry fertilizer with chicken manure as the main raw material. The concentrated biogas slurry fertilizer contains water-soluble organic carbon, amino acids, phenolic substances, ester substances and aniline substances, and the nutrient content of the concentrated biogas slurry fertilizer is: nitrogen 0.9%-1.1%, phosphorus 0.3%-0.5% and potassium 0.3%-0.5%.

[0009] Preferably, the powdered organic fertilizer is made from chicken manure as the main raw material and chicken manure return feed as an auxiliary material. The total nutrients in the powdered organic fertilizer are 4%-6%, the organic matter is 30%-40%, and the moisture content is 25%-30%.

[0010] Preferably, the bio-fertilizer is made from laying hen manure as the main raw material, chicken offal and chicken blood enzymatic hydrolysate as auxiliary materials, and functional bacteria are added. The functional bacteria include Bacillus subtilis and Bacillus belyssus, and the mass ratio of Bacillus subtilis to Bacillus belyssus is (1.9-2.1):(0.9-1.1). The bio-fertilizer has an effective live bacteria count of 0.2-0.3 billion / g, an organic matter content of 40%-45%, and a total nutrient content of 8%-10%.

[0011] Preferably, the diammonium phosphate contains 17%-19% nitrogen and 45%-47% phosphorus.

[0012] Preferably, in step 1, 990-1010 kg of the biogas slurry fertilizer, 790-810 kg of the powdered organic fertilizer, 19-21 kg of the bio-fertilizer, 19-21 kg of the diammonium phosphate, and 19-21 kg of the type A ternary compound fertilizer are applied per mu, wherein the mass ratio of nitrogen, phosphorus, and potassium in the type A ternary compound fertilizer is (14-16):(14-16):(14-16).

[0013] Preferably, in step 1, the base fertilizer is applied by strip application of the biogas slurry fertilizer, the powdered organic fertilizer, the bio-fertilizer, the diammonium phosphate, and the type A ternary compound fertilizer; in step 2, the topdressing is applied by drip irrigation of the type YM compound microbial fertilizer, the type K compound microbial fertilizer, the type N compound microbial fertilizer, and the type B ternary compound fertilizer.

[0014] Compared with existing technologies, the beneficial effects of this invention are as follows: This invention, through the synergistic application of organic fertilizers (biogas slurry fertilizer, powdered organic fertilizer) and inorganic fertilizers (diammonium phosphate, type A ternary compound fertilizer) in the base fertilizer, combined with the microecological regulation effect of bio-fertilizer, can effectively improve the physical and chemical properties of the soil, increase the soil's organic matter content and water and fertilizer retention capacity, laying a good soil foundation for watermelon growth. Based on this, different topdressing measures composed of YM-type compound microbial fertilizer, K-type compound microbial fertilizer, N-type compound microbial fertilizer, and B-type ternary compound fertilizer are designed for different growth stages of watermelon: vine extension stage, young fruit stage, and fruit expansion stage, achieving the combined application of organic fertilizer, chemical fertilizer, and functional bacteria. Specifically, the YM-type compound microbial fertilizer can continuously provide beneficial microorganisms and organic nutrients, maintaining root vitality and rhizosphere microecological stability; the K-type compound microbial fertilizer can promote sugar transport and fruit expansion during the young fruit stage; and the N-type compound microbial fertilizer can delay leaf senescence during the fruit expansion stage, ensuring continuous photosynthesis. This not only improved the quality of watermelons but also effectively increased yields, while reducing fertilizer use and improving soil physical and chemical properties. Attached Figure Description

[0015] To more clearly illustrate the technical solution of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without any creative effort.

[0016] Figure 1 Comparative photographs of the blades in the examples and comparative examples.

[0017] Figure 2 These are comparative photographs of single fruits used in the examples and comparative examples. Detailed Implementation

[0018] To further understand the present invention, preferred embodiments of the present invention are described below in conjunction with examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, and not for limiting the scope of the claims of the present invention.

[0019] This invention provides a method for applying organic and inorganic fertilizers to watermelons grown in greenhouses, comprising the following steps: Step 1: Before transplanting watermelons, apply biogas slurry fertilizer, powdered organic fertilizer, bio-fertilizer, diammonium phosphate, and type A ternary compound fertilizer in sequence to form base fertilizer, so as to improve the physical and chemical properties of the soil. Step 2: After transplanting the watermelon, apply topdressing fertilizer according to the watermelon's growth stage. The specific topdressing fertilizer is as follows: S1: During the vine extension stage, apply YM type compound microbial fertilizer and B type ternary compound fertilizer in sequence to promote vine growth and expand leaf area; S2: During the young fruit stage, apply YM type compound microbial fertilizer, K type compound microbial fertilizer, and B type ternary compound fertilizer in sequence to enhance root absorption efficiency and promote sugar transport. S3: During the fruit expansion period, apply YM type compound microbial fertilizer, N type compound microbial fertilizer, and B type ternary compound fertilizer in sequence to delay leaf senescence and ensure continuous photosynthesis of leaves; Among them, the YM type compound microbial fertilizer, the K type compound microbial fertilizer, and the N type compound microbial fertilizer are all biogas slurry fertilizers with added functional bacteria.

[0020] Compared with existing technologies, the beneficial effects of this invention are as follows: This invention, through the synergistic application of organic fertilizers (biogas slurry fertilizer, powdered organic fertilizer) and inorganic fertilizers (diammonium phosphate, type A ternary compound fertilizer) in the base fertilizer, combined with the microecological regulation effect of bio-fertilizer, can effectively improve the physical and chemical properties of the soil, increase the soil's organic matter content and water and fertilizer retention capacity, laying a good soil foundation for watermelon growth. Based on this, different topdressing measures composed of YM-type compound microbial fertilizer, K-type compound microbial fertilizer, N-type compound microbial fertilizer, and B-type ternary compound fertilizer are designed for different growth stages of watermelon: vine extension stage, young fruit stage, and fruit expansion stage, achieving the combined application of organic fertilizer, chemical fertilizer, and functional bacteria. Specifically, the YM-type compound microbial fertilizer can continuously provide beneficial microorganisms and organic nutrients, maintaining root vitality and rhizosphere microecological stability; the K-type compound microbial fertilizer can promote sugar transport and fruit expansion during the young fruit stage; and the N-type compound microbial fertilizer can delay leaf senescence during the fruit expansion stage, ensuring continuous photosynthesis. This not only improved the quality of watermelons but also effectively increased yields, while reducing fertilizer use and improving soil physical and chemical properties.

[0021] Furthermore, the YM type compound microbial fertilizer, the K type compound microbial fertilizer, and the N type compound microbial fertilizer are all biogas slurry fertilizers with added Bacillus subtilis and Bacillus beryl, and their effective viable bacteria count is 0.5-0.6 billion / mL. The mass ratio of Bacillus subtilis to Bacillus beryl is (1.9-2.1):(0.9-1.1). The combination of Bacillus subtilis and Bacillus beryl improves nutrient utilization through phosphorus and potassium solubilization, reduces fertilizer loss, quickly meets the needs of fruit enlargement, and makes up for the slow release of organic nutrients. The mass ratio of nitrogen, phosphorus, and potassium in the B type ternary compound fertilizer is (14-16):(4-6):(29-30).

[0022] Furthermore, the pH values ​​of the YM-type compound microbial fertilizer, the K-type compound microbial fertilizer, and the N-type compound microbial fertilizer are all 5.5-8.5, ensuring good compatibility with the soil environment after application. Simultaneously, this pH range is also suitable for the growth and reproduction of *Bacillus subtilis* and *Bacillus vesalis*, ensuring their rapid colonization and biological activity after application. The YM-type compound microbial fertilizer contains 3%-3.2% nitrogen, 1.1%-1.3% phosphorus, and 1%-1.2% potassium, thereby maintaining root vitality without causing nutrient overload or the risk of seedling burn. The K-type compound microbial fertilizer contains... The nitrogen content is 1.9%-2.1%, the phosphorus content is 2.8%-3%, and the potassium content is 7.3%-7.5%, thus meeting the large potassium demand of watermelon during the young fruit stage. Potassium promotes the transport of sugar to the fruit and accelerates the expansion of fruit cells. The N-type compound microbial fertilizer contains 9.4%-9.6% nitrogen, 3.6%-3.8% phosphorus, and 2.1%-2.3% potassium to delay leaf senescence, maintain continuous photosynthesis, and provide sufficient carbon source for fruit expansion.

[0023] Furthermore, as the growth process progresses, the proportion of chemical fertilizers is reduced and the proportion of organic fertilizers is increased, so as to gradually replace chemical fertilizers with organic fertilizers. In S1, 21-23 kg of YM-type compound microbial fertilizer and 4-4.4 kg of B-type ternary compound fertilizer are applied per mu. YM-type compound microbial fertilizer serves as the main fertilizer to provide organic nutrients and beneficial microorganisms to promote stem and leaf growth. B-type ternary compound fertilizer serves as an auxiliary fertilizer to meet the immediate needs of the vine extension period with fast-acting nutrients. This not only ensures the rapid expansion of vine length and leaf area, but also avoids the risk of seedling burn caused by the single application of chemical fertilizers. In S2, 10-12 kg of YM-type compound microbial fertilizer, 10-12 kg of K-type compound microbial fertilizer, and 2-2.5 kg of B-type ternary compound fertilizer are applied per mu. The YM-type compound microbial fertilizer and the K-type compound microbial fertilizer are applied in equal amounts. On the basis of maintaining root vitality and microecological stability with the YM-type compound microbial fertilizer, the K-type compound microbial fertilizer is used to enhance potassium supply and promote sugar transport to the fruit, while the B-type ternary compound fertilizer is only used as an auxiliary supplement. Similarly, in S3, 10-12 kg of the YM type compound microbial fertilizer, 10-12 kg of the N type compound microbial fertilizer, and 2-2.5 kg of the B type ternary compound fertilizer are applied per mu.

[0024] Furthermore, the biogas slurry fertilizer is made from chicken manure as the main raw material, and is produced through existing anaerobic fermentation, solid-liquid separation, multi-stage membrane concentration, and ultraviolet sterilization processes to increase the nutrient content per unit volume. The concentrated biogas slurry fertilizer contains water-soluble organic carbon, amino acids, phenolic substances, esters, and aniline substances, thereby promoting the rapid reproduction of Bacillus subtilis and Bacillus belye, and inhibiting the growth of pathogens in the soil. Specifically, the content of each component in the concentrated biogas slurry fertilizer is shown in Table 1. Preferably, the concentrated biogas slurry fertilizer is 5 times the concentration shown in Table 1, and the nutrient content in the concentrated biogas slurry fertilizer is: nitrogen 0.9%-1.1%, phosphorus 0.3%-0.5%, and potassium 0.3%-0.5%.

[0025] Table 1. Content of each component in concentrated biogas slurry fertilizer Furthermore, the powdered organic fertilizer is made primarily from chicken manure, which is naturally rich in calcium. When applied, it can enhance the hardness and toughness of watermelon rinds. Chicken manure return material is used as an auxiliary material to make the powder. The total nutrients in the powdered organic fertilizer are 4%-6%, organic matter is 30%-40%, and moisture is 25%-30%.

[0026] Furthermore, the bio-fertilizer is made primarily from laying hen manure, supplemented with chicken viscera and chicken blood enzymatic hydrolysate, and contains added functional bacteria. These functional bacteria include Bacillus subtilis and Bacillus belyssus, with a mass ratio of (1.9-2.1):(0.9-1.1). The bio-fertilizer contains 0.2-0.3 billion viable bacteria per gram, 40%-45% organic matter, and 8%-10% total nutrients. This promotes soil aggregate formation, improves soil aeration and water and fertilizer retention capacity, alleviates soil compaction caused by long-term application of chemical fertilizers, and lays a good soil foundation for watermelon growth.

[0027] Furthermore, the diammonium phosphate contains 17%-19% nitrogen and 45%-47% phosphorus.

[0028] Furthermore, in step 1, 990-1010 kg of the biogas slurry fertilizer, 790-810 kg of the powdered organic fertilizer, 19-21 kg of the bio-fertilizer, 19-21 kg of the diammonium phosphate, and 19-21 kg of the type A ternary compound fertilizer are applied per mu (unit of land area). The mass ratio of nitrogen, phosphorus, and potassium in the type A ternary compound fertilizer is (14-16):(14-16):(14-16). The organic fertilizer (the biogas slurry fertilizer and the powdered organic fertilizer) is the main component, playing a role in improving the soil and providing long-term fertilization. The chemical fertilizer (the diammonium phosphate and the type A ternary compound fertilizer) is the auxiliary component, meeting the immediate needs of watermelon seedlings for fast-acting nutrients after transplanting. Combined with the bio-fertilizer, the soil nutrients are activated. In this way, the amount of chemical fertilizer used is significantly reduced, the risk of nitrogen and phosphorus loss is reduced, and the pollution of the soil by chemical fertilizer is effectively mitigated.

[0029] Furthermore, in step 1, the base fertilizer is applied by strip application of the biogas slurry fertilizer, the powdered organic fertilizer, the bio-fertilizer, the diammonium phosphate, and the type A ternary compound fertilizer; in step 2, the topdressing is applied by drip irrigation of the type YM compound microbial fertilizer, the type K compound microbial fertilizer, the type N compound microbial fertilizer, and the type B ternary compound fertilizer.

[0030] To further understand the present invention, the following examples and comparative examples demonstrate the organic and inorganic fertilization method for greenhouse watermelons, as well as the quality and yield of the watermelon products.

[0031] The greenhouse watermelon planting site is located in an agricultural industrial park. The site is flat, with uniform soil fertility and good drainage and irrigation conditions.

[0032] The selected watermelon variety is the disease-resistant Ruilong, a fresh-eating hybrid variety belonging to the Cucurbitaceae family and the Citrus genus. It is a mid-to-late maturing variety with a total growth period of approximately 108 days and a fruit development period of approximately 35 days. The plant exhibits robust and vigorous growth, with the first female flower appearing around the 11th node, and female flowers spaced 5-7 nodes apart, resulting in easy fruit setting. The rind is 1.1 cm thick, firm, and does not crack. Individual fruits weigh 6-8 kg and are suitable for storage and transportation.

[0033] On April 1, 2025, the seedlings were transplanted and planted in the arched greenhouses of the agricultural industrial park. The greenhouses were 55 meters long and 7.2 meters wide, with each greenhouse covering an area of ​​0.6 mu (400 square meters). The seedlings were planted on raised beds with a height of 10 cm and a width of 120 cm. The planting density was 1600 plants per mu, with a plant spacing of 55 cm and a row spacing of 120 cm.

[0034] The optimal temperature range for the entire growth period of the disease-resistant Ruilong watermelon variety is 15-35℃, with an optimal temperature range of 15-30℃ from the seedling stage to flowering and fruit setting. During the fruit expansion stage, a diurnal temperature range of 8-10℃ is required. Local temperatures are low and fluctuate significantly during April and May; therefore, temperature control through opening and closing the greenhouse film is necessary. The greenhouse should be removed 40-50 days after transplanting, when the temperature is relatively stable during the watermelon fruit expansion stage.

[0035] Before transplanting watermelons, both the example and the comparative examples followed the same step 1, applying base fertilizer, as shown in Table 2: Table 2. Base fertilizer application rate in step 1 Among them: biogas slurry fertilizer contains 1% nitrogen, 0.4% phosphorus, and 0.4% potassium; powdered organic fertilizer contains 6% total nutrients, 30% organic matter, and 25% moisture; bio-fertilizer contains Bacillus subtilis to Bacillus vesiculosus in a mass ratio of 2:1, 0.2-0.3 billion / g of effective live bacteria, 45% organic matter, and 8% total nutrients; diammonium phosphate contains 18% nitrogen and 46% phosphorus; and type A ternary compound fertilizer contains nitrogen, phosphorus, and potassium in a mass ratio of 15:15:15.

[0036] After watermelon transplanting, the examples and comparative examples used different steps in step 2. Based on step 1 above, topdressing was applied using drip irrigation according to the growth stage of the watermelon, as shown in Table 3: Table 3. Topdressing dosage in step 2 Among them, the mass ratio of Bacillus subtilis to Bacillus vesiculosus in YM-type, K-type, and N-type compound microbial fertilizers is 2:1, and the effective viable count is 0.5-0.6 billion / mL. The nitrogen content of YM-type compound microbial fertilizer is 3.1%, the phosphorus content is 1.2%, and the potassium content is 1.1%; the nitrogen content of K-type compound microbial fertilizer is 2%, the phosphorus content is 2%, and the potassium content is 7.4%; the nitrogen content of N-type compound microbial fertilizer is 9.5%, the phosphorus content is 3.7%, and the potassium content is 2.2%. The mass ratio of nitrogen, phosphorus, and potassium in B-type ternary compound fertilizer is 15:5:30, the mass ratio of nitrogen, phosphorus, and potassium in C-type ternary compound fertilizer is 18:18:18, and the mass ratio of nitrogen, phosphorus, and potassium in D-type ternary compound fertilizer is 28:5:7.

[0037] 1. Growth index measurement During the fruit expansion period of watermelon, 30 watermelon plants were randomly selected from the arched greenhouses in the examples and comparative examples, respectively. The vine length, chlorophyll content, and fruit circumference were measured using a measuring tape, and the average values ​​of the watermelon growth indicators were calculated, as shown in Table 4.

[0038] 2. Yield Measurement After the watermelons matured, 30 watermelons were randomly selected from the greenhouses in both the example and the comparative examples, and the yield indicators such as the single fruit weight were statistically analyzed, as shown in Table 5.

[0039] 3. Quality Measurement Thirty mature watermelons were randomly selected from the greenhouses in both the example and comparative examples. The soluble solids content, vitamin C content, and firmness of the fruits were measured, as shown in Table 6. Soluble solids content was determined using a handheld refractometer; vitamin C content was determined using the 2,6-dichlorophenolindophenol titration method; and firmness was determined using a fruit firmness tester.

[0040] Results and Analysis: Table 4. Measurement of Watermelon Growth Indicators During Fruit Enlargement Period Figure 1 Comparative photographs of the blades in the examples and comparative examples.

[0041] From Table 4 and Figure 1 It can be seen that during the fruit expansion period, the SPAD value of the comparative example was higher than that of the control example, while the leaf area, vine length, fruit circumference, and fruit setting position were higher in the control example than in the comparative example. The SPAD value of the control example was lower than that of the control example, by 3.14%, but the difference was not significant. The leaf area, vine length, and fruit circumference of the control example were 13.52%, 20.25%, and 8.70% higher than those of the control example, respectively, indicating that the topdressing of the control example was more conducive to promoting the longitudinal growth of watermelon plants and the accumulation of photosynthetic products. Moreover, the fruit setting position of 9.1 in the control example was two positions further back than that of 7.1 in the control example, which was more conducive to the accumulation of substances in the plant and subsequent fruit expansion.

[0042] Table 5. Watermelon Yield Indicators Measurement Table Figure 2 These are comparative photographs of single fruits used in the examples and comparative examples.

[0043] From Table 5 and Figure 2 It can be seen that the average single fruit weight of the example was 2.88 kg, which was higher than the 2.35 kg of the comparative example; the melon circumference of the example (53.20 cm) was higher than that of the comparative example (48.96 cm), representing an 8.7% increase; and in terms of yield per mu (a Chinese unit of area, approximately 0.067 hectares), the yield of the example was 4608 kg per mu, significantly higher than that of the comparative example (3760 kg per mu), with a yield increase of 22.55%. The results indicate that the example significantly promoted watermelon yield.

[0044] Table 6. Watermelon Quality Index Measurement Table As shown in Table 6, all watermelon quality indicators of the embodiment were superior to those of the comparative example. The watermelon rind firmness of the embodiment was 17.66 kgf, and the flesh firmness was 0.77 kgf, both higher than the comparative example. Higher rind and flesh firmness is more conducive to storage and transportation, and results in a crisper texture. The sugar content in the center and at the edge of the embodiment were 8.17% and 10.43% respectively, both higher than the comparative example, with a sugar content difference of 2.26%, indicating that the topdressing in the embodiment could improve the sweetness and uniformity of the watermelon fruit, thus improving fruit quality. Furthermore, the vitamin C content in the embodiment was 2.81 mg / 100g, higher than the 2.77 mg / 100g of the comparative example, indicating that the topdressing in the embodiment helped increase the accumulation of vitamin C in the watermelon fruit.

[0045] The above description discloses only preferred embodiments of the present invention and should not be construed as limiting the scope of the invention. Those skilled in the art will understand that implementing all or part of the above embodiments and making equivalent changes in accordance with the claims of the present invention are still within the scope of the invention.

Claims

1. A method for applying organic and inorganic fertilizers to watermelons grown in arched greenhouses, characterized in that, Includes the following steps: Step 1: Before transplanting watermelons, apply biogas slurry fertilizer, powdered organic fertilizer, bio-fertilizer, diammonium phosphate, and type A ternary compound fertilizer in sequence to form base fertilizer, so as to improve the physical and chemical properties of the soil. Step 2: After transplanting the watermelon, apply topdressing fertilizer according to the watermelon's growth stage. The specific topdressing fertilizer is as follows: S1: During the vine extension stage, apply YM type compound microbial fertilizer and B type ternary compound fertilizer in sequence to promote vine growth and expand leaf area; S2: During the young fruit stage, apply YM type compound microbial fertilizer, K type compound microbial fertilizer, and B type ternary compound fertilizer in sequence to enhance root absorption efficiency and promote sugar transport. S3: During the fruit expansion period, apply YM type compound microbial fertilizer, N type compound microbial fertilizer, and B type ternary compound fertilizer in sequence to delay leaf senescence and ensure continuous photosynthesis of leaves; Among them, the YM type compound microbial fertilizer, the K type compound microbial fertilizer, and the N type compound microbial fertilizer are all biogas slurry fertilizers with added functional bacteria.

2. The method for organic-inorganic fertilization of watermelons in arched greenhouses as described in claim 1, characterized in that, The YM type compound microbial fertilizer, the K type compound microbial fertilizer, and the N type compound microbial fertilizer are all biogas slurry fertilizers with added Bacillus subtilis and Bacillus vesiculus, with an effective viable count of 0.5-0.6 billion / mL. The mass ratio of Bacillus subtilis to Bacillus vesiculus is (1.9-2.1):(0.9-1.1). The mass ratio of nitrogen, phosphorus, and potassium in the B type ternary compound fertilizer is (14-16):(4-6):(29-30).

3. The method for organic-inorganic fertilization of watermelons in arched greenhouses as described in claim 2, characterized in that, The pH values ​​of the YM-type compound microbial fertilizer, the K-type compound microbial fertilizer, and the N-type compound microbial fertilizer are all 5.5-8.5; the YM-type compound microbial fertilizer contains 3%-3.2% nitrogen, 1.1%-1.3% phosphorus, and 1%-1.2% potassium; the K-type compound microbial fertilizer contains 1.9%-2.1% nitrogen, 2.8%-3% phosphorus, and 7.3%-7.5% potassium; and the N-type compound microbial fertilizer contains 9.4%-9.6% nitrogen, 3.6%-3.8% phosphorus, and 2.1%-2.3% potassium.

4. The method for organic-inorganic fertilization of watermelons in arched greenhouses as described in claim 3, characterized in that, In S1, 21-23 kg of the YM type compound microbial fertilizer and 4-4.4 kg of the B type ternary compound fertilizer are applied per mu; In S2, 10-12 kg of the YM type compound microbial fertilizer, 10-12 kg of the K type compound microbial fertilizer, and 2-2.5 kg of the B type ternary compound fertilizer are applied per mu. In S3, 10-12 kg of the YM type compound microbial fertilizer, 10-12 kg of the N type compound microbial fertilizer, and 2-2.5 kg of the B type ternary compound fertilizer are applied per mu.

5. The method for organic-inorganic fertilization of watermelons in arched greenhouses as described in claim 1, characterized in that, The biogas slurry fertilizer is a concentrated biogas slurry fertilizer with chicken manure as the main raw material. The concentrated biogas slurry fertilizer contains water-soluble organic carbon, amino acids, phenolic substances, esters and aniline substances, and the nutrient content of the concentrated biogas slurry fertilizer is: nitrogen 0.9%-1.1%, phosphorus 0.3%-0.5% and potassium 0.3%-0.5%.

6. The method for organic-inorganic fertilization of watermelons in arched greenhouses as described in claim 5, characterized in that, The powdered organic fertilizer is made from chicken manure as the main raw material and chicken manure return feed as an auxiliary material. The total nutrients in the powdered organic fertilizer are 4%-6%, the organic matter is 30%-40%, and the moisture is 25%-30%.

7. The method for applying organic and inorganic fertilizers to watermelons in greenhouses as described in claim 6, characterized in that, The bio-fertilizer is made from laying hen manure as the main raw material, chicken offal and chicken blood enzymatic hydrolysate as auxiliary materials, and functional bacteria are added. The functional bacteria include Bacillus subtilis and Bacillus belyssus, and the mass ratio of Bacillus subtilis to Bacillus belyssus is (1.9-2.1):(0.9-1.1). The bio-fertilizer has an effective live bacteria count of 0.2-0.3 billion / g, an organic matter content of 40%-45%, and a total nutrient content of 8%-10%.

8. The method for organic-inorganic fertilization of watermelons in arched greenhouses as described in claim 7, characterized in that, The diammonium phosphate contains 17%-19% nitrogen and 45%-47% phosphorus.

9. The method for applying organic and inorganic fertilizers to watermelons in arched greenhouses as described in claim 8, characterized in that, In step 1, 990-1010 kg of biogas slurry fertilizer, 790-810 kg of powdered organic fertilizer, 19-21 kg of bio-fertilizer, 19-21 kg of diammonium phosphate, and 19-21 kg of type A ternary compound fertilizer are applied per mu. The mass ratio of nitrogen, phosphorus, and potassium in the type A ternary compound fertilizer is (14-16):(14-16):(14-16).

10. The method for organic-inorganic fertilization of watermelons in arched greenhouses as described in claim 1, characterized in that, In step 1, the base fertilizer is applied by strip application of the biogas slurry fertilizer, the powdered organic fertilizer, the bio-fertilizer, the diammonium phosphate, and the type A ternary compound fertilizer; In step 2, the topdressing is applied by drip irrigation using the YM type compound microbial fertilizer, the K type compound microbial fertilizer, the N type compound microbial fertilizer, and the B type ternary compound fertilizer.

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