Application of soilless culture nutrient solution in eggplant cultivation

Abstract

The present invention relates to the preparation and application of a soilless culture nutrient solution, and more particularly, to its use in eggplant cultivation. By tailoring nutrient supply to eggplants according to their varying nutritional requirements at different growth stages, the present invention effectively addresses the problem of existing hydroponic nutrient solutions failing to tailor the configuration and supply of nutrients to the crop's varying nutritional needs at different growth stages. While increasing the yield of soilless hydroponic eggplant, the present invention can effectively reduce nitrate content, increase vitamin C, soluble sugar, and soluble solids content, and significantly improve the flavor and texture of the eggplant, thereby enhancing its quality.

Description

Technical Field

[0001] The invention relates to the preparation and application of a soilless culture nutrient solution, in particular to the application of the soilless culture nutrient solution in cultivating eggplant. Background Art

[0002] As a vital component of modern agriculture, protected agriculture, with its incomparable advantages over traditional agriculture, is rapidly developing and has become an effective means for farmers in many regions to increase their incomes and wealth. However, with its rapid growth, problems caused by continuous cropping, such as secondary salinization of protected soils and soil-borne diseases, have become increasingly serious. This not only reduces vegetable yield and quality but also pollutes the production environment. The availability of soil for agricultural use is decreasing year by year, hindering the sustainable development of protected agriculture. While water and fertilizer are key to improving vegetable yield and quality, the imbalance between protected vegetable yield, quality, and water and fertilizer efficiency is becoming increasingly serious. With China's rapid economic and social development and the acceleration of agricultural modernization, people's pursuit of agricultural products has expanded beyond simply high yield and quality. The concept of ecologically safe, green, pollution-free, and resource-efficient production has become deeply rooted in people's minds. my country currently leads the world in eggplant cultivation area and production, but a series of problems persist, including low yields, extensive water and fertilizer management, and low production efficiency. Traditional cultivation methods are hampered by continuous cropping problems, especially in greenhouses and sheds, where rotating eggplant crops is difficult. Soil-borne diseases are becoming increasingly prevalent, with incidence rates generally ranging from 20% to 30%, and in severe cases reaching 50%, even resulting in total crop failure. Currently, the primary method for controlling eggplant Verticillium wilt is grafting. However, grafting requires complex techniques, the grafting process is cumbersome, and can affect quality.

[0003] Soilless cultivation technology is an effective solution to various problems. It avoids the drawbacks of grafting and effectively circumvents soil salinization and soil-borne diseases caused by long-term continuous cropping in traditional soil cultivation. It improves crop utilization of water and nutrients, and is a high-tech agricultural technology for producing safe, high-quality, and high-yield agricultural products. It represents a new path to developing green and efficient agriculture. Soilless cultivation has numerous advantages and is gaining increasing attention. It frees crop production from the constraints of soil, greatly expanding the space available for agricultural production. It integrates multiple disciplines and technologies, contributing to the modernization of agricultural production.

[0004] The substrates used in soilless cultivation can be divided into organic and inorganic substrates based on their composition. Organic substrates are chemically unstable, and the nutrients they contain are not conducive to nutrient solution circulation cultivation. Inorganic substrates are chemically stable, contain virtually no nutrients, and have no impact on nutrient solution formulation and nutrient balance. They are currently the main substrate type used in nutrient solution circulation cultivation.

[0005] Inorganic substrate cultivation uses rockwool, vermiculite, sand, perlite, and other materials as a fixed support for crop growth. A nutrient solution provides the water, fertilizer, oxygen, and environment necessary for growth. Nutrient solution preparation is not only a core technology for the normal growth of vegetables cultivated in inorganic substrates, but also the foundation and key to soilless cultivation. The success of substrate cultivation depends largely on parameters such as the nutrient solution formulation, concentration, the ratio of various nutrients, pH, and temperature, as well as whether nutrient solution management during plant growth meets the requirements of each growth stage. Only by adopting the correct nutrient solution formulation and using appropriate methods to prepare and manage the nutrient solution, ensuring that plants are in an optimal nutrient solution environment at all stages of growth and development, can rapid, high-yield, and high-quality cultivation be achieved. Because the nutrient solution plays a decisive role in substrate cultivation, a scientific and rational irrigation pattern is crucial. Nutrient solution irrigation volume and frequency, as key indicators of a scientific and rational irrigation pattern, have primarily impacted the growth and development of vegetables, primarily tomatoes, cucumbers, and potatoes. However, their impact on eggplant growth under inorganic substrate cultivation has been less well-documented.

[0006] Eggplant (Solanum melongena L.) is a major Solanaceae vegetable crop worldwide, second only to potato (S. tuberosum) and tomato (S. lycopersicum). In 2018, global eggplant production reached 53.6 million tons, of which my country produced 34.1 million tons, accounting for 63.62% of the global total. China has become the world's largest producer and consumer of eggplant. Eggplant is a fertilizer-loving crop with a long growing season and high fertilizer requirements. Nutrient requirements increase gradually from planting to harvest. Nutrient absorption during the peak to late fruiting period accounts for over 90% of the total nutrient intake during the entire growing period, with peak fruiting accounting for two-thirds. To produce 1,000 kilograms of eggplant, 2.6–3.3 kilograms of nitrogen, 0.6–1.0 kilograms of phosphorus (P₂O₅), and 4.7–5.6 kilograms of potassium (K₂O) are required. From planting to harvest, eggplant's nitrogen absorption increases linearly, reaching its highest level during peak growth. Adequate nitrogen supply ensures adequate leaf area. Phosphorus affects flower bud differentiation, so ensuring adequate phosphorus supply is crucial during early growth. Potassium absorption remains comparable to nitrogen until mid-growth, then increases significantly. During peak fruiting, both nitrogen and potassium absorption increase.

[0007] The concentration of eggplant nutrient solution (EC value) varies at different growth stages. A scientifically and rationally formulated nutrient solution not only promotes balanced plant growth but also improves fertilizer utilization efficiency. Currently, most nutrient solutions are based on Japanese garden-tested and Yamazaki nutrient solution formulas, which are difficult to adapt to the diverse needs of different regions, vegetable types, and cultivation seasons. Furthermore, there is no comprehensive production technology system for nutrient solution configuration, supply method, frequency, volume, and EC value at different stages of nutrient solution cultivation. Only an optimal nutrient solution formula and a scientifically and rationally formulated irrigation frequency and volume can effectively regulate the ratio of air, water, and fertilizer in the substrate, promote plant growth and development, and improve fruit quality.

[0008] The patent documents retrieved by the applicant include:

[0009] Patent document with application number 201610735929.8 discloses a nutrient solution formula for eggplant, which includes, by dosage, 310-382 mg / L of calcium nitrate, 601-687 mg / L of potassium sulfate, 72-103 mg / L of ammonium dihydrogen phosphate, 219-258 mg / L of magnesium sulfate, 2.1-3.2 mg / L of boric acid, 10-22 mg / L of ferrous sulfate, 1.5-3.2 mg / L of zinc sulfate, 0.9-1.7 mg / L of copper nitrate, 0.25-0.6 mg / L of ammonium nitrate, and 0.1-0.39 mg / L of calcium sulfate. The formula of the invention is reasonable, and calcium nitrate, potassium sulfate, ammonium dihydrogen phosphate, magnesium sulfate, boric acid, ferrous sulfate, zinc sulfate, copper nitrate, ammonium nitrate and calcium sulfate are comprehensively utilized to improve the utilization of nutrient solution components, and the nutrients in the formula are fully coordinated to be suitable for the growth of eggplants. The mutual coordination of the various components in the formula satisfies the nutritional requirements for the growth of the eggplants, and the proportions of the various components in the nutrient solution are adjusted to well meet the growth requirements of the eggplants, thereby well cooperating with the growth of the eggplants.

[0010] The above-mentioned existing technologies all use a single formula during the eggplant growth period, and do not provide the optimal EC value of the nutrient solution in different growth periods and the supporting technology for closed-circulation cultivation of inorganic matrix nutrient solution, especially the intelligent and simplified cultivation technology, and do not mention whether the nutrient solution formula can improve the quality of eggplant on the basis of high yield. Summary of the Invention

[0011] The purpose of the present invention is to disclose the application of soilless culture nutrient solution in the cultivation of eggplant, especially targeting the characteristics of eggplant root system such as weak adventitious rooting ability, easy lignification, and poor drought resistance, and combining the different nutritional needs of eggplant in different growth stages such as seedling stage, early fruiting stage and peak fruiting stage to provide targeted nutrition supply, and combining with intelligent management, while increasing the yield of hydroponic eggplant, the nitrate content in the eggplant can be effectively reduced, the soluble sugar, vitamin C and soluble solids content can be increased, the quality of the eggplant is improved, and an intelligent and simplified nutrient solution cultivation and management technology system for eggplant is realized.

[0012] The overall technical concept of the present invention is:

[0013] The application of soilless culture nutrient solution in eggplant cultivation includes the following process steps:

[0014] A. First stage: Adjust the pH of the first nutrient solution to 5.5-6.5, the EC of the first nutrient solution to 1.5-1.8 ds / m, and supply 1.0 L of solution per plant once a day. The first stage is from planting to the appearance of buds in the eggplants.

[0015] B. Second stage: Adjust the pH of the first nutrient solution to 6.5-6.8, the EC of the first nutrient solution to 1.8-2.5 ds / m, and supply 1.0 L of solution per plant, twice a day. The second stage is the flowering and fruiting period, from flowering to the early stage of fruit expansion.

[0016] C. The third stage: Adjust the pH of the second nutrient solution to 6.5-6.8, the EC of the second nutrient solution to 2.5-3.0 ds / m, and supply 1.5 L of solution per plant, twice a day. The third stage is the fruiting period, from the expansion of the eggplant fruit to the completion of the fruit harvest.

[0017] The liquid supply in steps A, B, and C is carried out by drip irrigation;

[0018] The first nutrient solution is composed of the following raw materials:

[0019] Ca(N03)2·4H2O: 400mg / L~410mg / L; NH4H2PO4: 40mg / L~50mg / L; KNO3: 280mg / L~290mg / L; MgSO4·7H2O: 150mg / L~160mg / L; Fe-EDTA: 20mg / L~25mg / L; MnSO4·4H2O: 2.1mg / L~2.2mg / L; H3BO3: 2.80mg / L~2.90mg / L; ZnSO4·7H2O: 0.20mg / L~0.25mg / L; CuSO4·5H2O: 0.08mg / L~0.1mg / L; (NH4)2MoO4·4H2O: 0.02mg / L~0.03mg / L; the balance is water; pH = 5.5~6.8; EC = 1.5~2.5ds / m;

[0020] The second nutrient solution is composed of the following raw materials:

[0021] Ca(N03)2·4H2O: 400mg / L~410mg / L; NH4H2PO4: 40mg / L~50mg / L; KNO3: 400mg / L~410mg / L; MgSO4·7H2O: 150mg / L~160mg / L; Fe-EDTA: 20mg / L~25mg / L; MnSO4·4H2O: 2.1mg / L~2.2mg / L; H3BO3: 2.80mg / L~2.90mg / L; ZnSO4·7H2O: 0.20mg / L~0.25mg / L; CuSO4·5H2O: 0.08mg / L~0.1mg / L; (NH4)2MoO4·4H2O: 0.02mg / L~0.03mg / L; the balance is water; pH=6.5~6.8; EC=2.5~3.0ds / m.

[0022] The hydroponic nutrient solution of the present invention is used for hydroponics of eggplant in combination with its nutritional requirements and growth characteristics during its growth stage:

[0023] From planting to fruiting, eggplant seedlings have a small nutrient area and require less fertilizer. Therefore, the first nutrient solution is used in the first and second stages. From fruiting to harvest, large quantities of fruit are produced, requiring greater fertilizer. Potassium, in particular, is crucial for effectively improving eggplant yield and quality. Therefore, the second nutrient solution is used in the third stage. The pH and EC values ​​of the nutrient solution are adjusted according to the characteristics of each growth stage.

[0024] The process conditions of each process step are as follows:

[0025] In order to ensure the nutrient supply of eggplant at each growth stage, the preferred technical solution is that the liquid supply time in steps A, B and C is 8:00 to 18:00.

[0026] The pH in steps A, B and C is adjusted using boric acid.

[0027] In order to achieve better drip irrigation and nutrient supply effects, the preferred technical implementation means starts with laying four drip irrigation belts in each cultivation trough in steps A, B, and C for drip irrigation.

[0028] To facilitate the preparation of the hydroponic nutrient solution, the preferred technical solution is that the first nutrient solution and the second nutrient solution are prepared according to the following steps:

[0029] a. Calcium nitrate and potassium nitrate are placed in a liquid storage tank, mixed and dissolved, and water is added to the volume according to the concentration multiple of the raw material content and stirred to prepare a first mother liquor;

[0030] b. Place ammonium dihydrogen phosphate, magnesium sulfate, chelated iron, manganese sulfate, boric acid, zinc sulfate, copper sulfate, and ammonium molybdate in a liquid storage tank, mix and dissolve them, add water to the volume according to the concentration multiple of the raw material content, and stir evenly to prepare a second mother liquor;

[0031] c. When using, mix the first mother liquor and the second mother liquor in a volume ratio of 1:1, dilute with water, adjust the pH and EC value, and prepare the first nutrient solution or the second nutrient solution respectively.

[0032] The main functions of the various components in the soilless culture nutrient solution of the present invention are as follows:

[0033] The main functions of each nutrient are as follows:

[0034] The eggplant nutrient solution contains macroelements and trace elements required for plant growth, wherein the macroelements include N, P, Ca, Mg, K and the like, and the trace elements include Fe, B, Mn, Zn, Mo, Cu and the like.

[0035] Calcium nitrate tetrahydrate primarily provides the calcium and nitrogen elements necessary for plant growth. It provides calcium ions, improves the selective absorption capacity of root cell membranes, enhances resistance to environmental stress, and promotes normal plant growth. It also provides nitrogen, meeting plant growth requirements and promoting leaf development.

[0036] Ammonium dihydrogen phosphate mainly promotes the growth of plant roots and improves the quality and yield of fruits. It provides the phosphorus and nitrogen elements required for plant growth.

[0037] Potassium nitrate primarily provides the potassium and nitrogen elements necessary for plant growth. Roots absorb potassium ions, which alter their absorption of water and oxygen from the external environment, effectively regulating the root system's oxygen absorption rate and preventing root rot due to oxygen deficiency during plant growth. It also promotes fruit development.

[0038] Magnesium sulfate heptahydrate is primarily used to provide the magnesium element required for plant growth. By directly supplying magnesium ions to the solution, it satisfies the plant's need for magnesium ions, promoting plant photosynthesis and protein synthesis during photosynthesis.

[0039] Manganese sulfate tetrahydrate mainly provides the manganese element required for plant growth.

[0040] Fe-EDTA mainly provides the iron required for plant growth. At the same time, sodium iron acts as a plant growth regulator, further regulating the plant's absorption rate of external nutritional factors during growth.

[0041] Boric acid mainly provides the boron element required for plant growth. Its main function is to promote the normal operation of carbohydrates. It can also promote the production of auxin, thereby promoting faster growth of plants.

[0042] Ammonium molybdate mainly provides the molybdenum element required for plant growth.

[0043] Zinc sulfate heptahydrate mainly provides the zinc element required for plant growth, promotes the hydrolysis of substances in plants and the progress of photosynthesis.

[0044] Copper sulfate pentahydrate mainly provides the copper trace element required for plant growth, which can improve the stability of chlorophyll, prevent chlorophyll from being destroyed prematurely, and promote crop absorption.

[0045] Among the above ingredients, copper sulfate pentahydrate, manganese sulfate tetrahydrate, calcium nitrate tetrahydrate, magnesium sulfate heptahydrate, and zinc sulfate heptahydrate may also be replaced by their corresponding anhydrous compounds, which can be converted according to the dosage. Nitrogen, phosphorus, and potassium nutrients may also be replaced by other forms of soluble salts, and the dosages may be verified through experiments. Such changes do not deviate from the essence of the present invention.

[0046] The applicant should clarify that the concentration management of nutrient solutions for the same crop species requires changes based on the growth stage and climatic conditions. Lower concentrations can be used during the seedling and early growth stages, while higher concentrations should be used during peak flowering and fruiting stages. Because most crop roots grow in the nutrient solution and absorb water, nutrients, and oxygen, its concentration, composition, pH, and dissolved oxygen levels constantly change. This absorption by the crop roots changes the quantity and ratio of various compounds and ions in the nutrient solution, which in turn changes the concentration, pH, and dissolved oxygen content of the nutrient solution. Furthermore, the metabolic processes of the roots secrete organic matter, and the shedding, death, and even aging and death of some root epidermal cells leave the nutrient solution, allowing microorganisms to multiply in the nutrient solution, thereby altering its properties to varying degrees. Changes in the environmental climate can also affect the temperature of the nutrient solution. Furthermore, plants have different requirements for nutrient solution concentration and other factors at different growth stages. Therefore, to meet the requirements for optimal crop growth, the concentration and pH of the nutrient solution must be rationally regulated. More importantly, the concentration and pH of the nutrient solution will change with changes in temperature, which is something that those skilled in the art should know and understand, and the above changes do not affect the use of the nutrient solution and the growth of the plants.

[0047] The substantial features and significant technical advancements achieved by the present invention are:

[0048] 1. The raw materials of the soilless culture nutrient solution involved in the present invention are easily available and the preparation process is simple.

[0049] 2. After eggplant was cultivated with the soilless culture nutrient solution of the present invention, various biological indicators were significantly better than those of the control.

[0050] 3. According to the existing national standard for determining nitrate in vegetables, the applicant determined the nitrate content in the eggplants cultured in the soilless culture nutrient solution provided by the present invention, and the nitrate content was in compliance with the national standard (≤440 mg / kg).

[0051] 4. The applicants tested the soilless culture nutrient solution of the present invention on eggplants and found that the yield of different eggplant types significantly increased after application of the hydroponic nutrient solution. The yield per mu of the Knight (long eggplant) and the Qieyou No. 1 (round eggplant) reached 5,320 to 6,452 kg / mu and 5,982 to 6,744 kg / mu, respectively, representing relative yield increases of 16.67% to 41.49% and 11.44% to 25.63%, respectively.

[0052] 5. This formula can effectively reduce the nitrate content in eggplant while increasing yield, while also increasing the content of vitamin C, total soluble sugars, and soluble solids, effectively improving the quality of the eggplant fruit. The nitrate content of Knight (long eggplant) and Qieyou No. 1 (round eggplant) hydroponically cultured in nutrient solution with an inorganic substrate was lower than that of the control, by 13.02% to 18.89% and 22.49% to 48.38%, respectively. The total soluble sugar content of Knight (long eggplant) and Qieyou No. 1 (round eggplant) hydroponically cultured in nutrient solution with an inorganic substrate was 35.55 mg / kg to 38.30 mg / kg and 31.65 mg / kg to 36.28 mg / kg, respectively, representing increases of 3.67% to 11.69% and 4.59% to 19.89%, respectively, compared to the control. The vitamin C contents of Knight (long eggplant) and Qieyou No. 1 (round eggplant) hydroponically cultured in nutrient solution with an inorganic matrix ranged from 1.86mg / 100g to 2.29mg / 100g and 1.13mg / 100g to 1.34mg / 100g, respectively, representing increases of 20.78% to 48.70% and 34.52% to 59.52%, respectively, compared to the control. The soluble solids contents of Knight (long eggplant) and Qieyou No. 1 (round eggplant) hydroponically cultured in nutrient solution with an inorganic matrix were 4.50% to 4.9% and 3.9% to 4.0%, respectively, representing increases of 2.63% to 5.26%, compared to the control. DETAILED DESCRIPTION

[0053] The present invention is further described below in conjunction with examples, but should not be construed as limiting the present invention. The scope of protection of the present invention is subject to the contents described in the claims, and any replacement of equivalent technical means made according to the description does not depart from the scope of protection of the present invention.

[0054] Example 1

[0055] The application of soilless culture nutrient solution in eggplant cultivation includes the following process steps:

[0056] A. Phase I: Adjust the pH of the first nutrient solution to 5.5-6.5, the EC of the first nutrient solution to 1.5 ds / m, and supply 1.0 L of solution per plant once a day. The first phase is from planting to the appearance of buds in the eggplants.

[0057] B. Second stage: Adjust the pH of the first nutrient solution to 6.5-6.8, the EC of the first nutrient solution to 1.8 ds / m, and supply 1.0 L of solution per plant, twice a day. The second stage is the flowering and fruiting period, from flowering to the early stage of fruit expansion.

[0058] C. The third stage: Adjust the pH of the second nutrient solution to 6.5-6.8, the EC of the second nutrient solution to 2.5 ds / m, and supply 1.5 L of solution per plant, twice a day. The third stage is the fruiting period, from the expansion of the eggplant fruit to the completion of the fruit harvest.

[0059] In steps A, B, and C, four drip irrigation tapes are laid in each cultivation trough for drip irrigation.

[0060] The first nutrient solution consists of the following raw materials:

[0061] Ca(N03)2·4H2O: 400mg / L; NH4H2PO4: 40mg / L; KNO3: 280mg / L; MgSO4·7H2O: 150mg / L; Fe-EDTA: 20mg / L; MnSO4·4H2O: 2.1mg / L; H3BO3: 2.80mg / L; ZnSO4·7H2O: 0.20mg / L; CuSO4·5H2O: 0.08mg / L; (NH4)2MoO4·4H2O: 0.02mg / L; the balance is water; pH = 5.5~6.8; EC = 1.5~1.8ds / m.

[0062] The second nutrient solution consists of the following raw materials:

[0063] Ca(N03)2·4H2O: 400mg / L; NH4H2PO4: 40mg / L; KNO3: 400mg / L; MgSO4·7H2O: 150mg / L; Fe-EDTA: 20mg / L; MnSO4·4H2O: 2.1mg / L; H3BO3: 2.80mg / L; ZnSO4·7H2O: 0.20mg / L; CuSO4·5H2O: 0.08mg / L; (NH4)2MoO4·4H2O: 0.02mg / L; the balance is water; pH = 6.5~6.8; EC = 2.5ds / m.

[0064] The liquid supply time in steps A, B, and C is 8:00 to 18:00.

[0065] The pH in steps A, B and C is adjusted using boric acid.

[0066] The first nutrient solution and the second nutrient solution are prepared according to the following steps:

[0067] a. Calcium nitrate and potassium nitrate are placed in a liquid storage tank, mixed and dissolved, and water is added to the volume according to the concentration multiple of the raw material content and stirred to prepare a first mother liquor;

[0068] b. Place ammonium dihydrogen phosphate, magnesium sulfate, chelated iron, manganese sulfate, boric acid, zinc sulfate, copper sulfate, and ammonium molybdate in a liquid storage tank, mix and dissolve them, add water to the volume according to the concentration multiple of the raw material content, and stir evenly to prepare a second mother liquor;

[0069] c. When using, mix the first mother liquor and the second mother liquor in a volume ratio of 1:1, dilute with water, adjust the pH and EC value, and prepare the first nutrient solution or the second nutrient solution respectively.

[0070] Example 2

[0071] The difference between this embodiment and embodiment 1 is that:

[0072] The first nutrient solution is composed of the following raw materials:

[0073] Ca(N03)2·4H2O: 410mg / L; NH4H2PO4: 50mg / L; KNO3: 290mg / L; MgSO4·7H2O: 160mg / L; Fe-EDTA: 25mg / L; MnSO4·4H2O: 2.2mg / L; H3BO3: 2.90mg / L; ZnSO4·7H2O: 0.25mg / L; CuSO4·5H2O: 0.1mg / L; (NH4)2MoO4·4H2O: 0.03mg / L; the balance is water; pH = 5.5-6.8; EC = 1.8-2.5ds / m;

[0074] The second nutrient solution is composed of the following raw materials:

[0075] Ca(N03)2·4H2O: 410mg / L; NH4H2PO4: 50mg / L; KNO3: 410mg / L; MgSO4·7H2O: 160mg / L; Fe-EDTA: 25mg / L; MnSO4·4H2O: 2.2mg / L; H3BO3: 2.90mg / L; ZnSO4·7H2O: 0.25mg / L; CuSO4·5H2O: 0.1mg / L; (NH4)2MoO4·4H2O: 0.03mg / L; the balance is water; pH = 6.5~6.8; EC = 3.0ds / m.

[0076] A. First stage: Adjust the pH of the first nutrient solution to 5.5-6.5, the EC of the first nutrient solution to 1.8 ds / m, and supply 1.0 L of solution per plant once a day. The first stage is from planting to the appearance of buds in the eggplants.

[0077] B. Second stage: Adjust the pH of the first nutrient solution to 6.5-6.8, the EC of the first nutrient solution to 2.5 ds / m, and supply 1.0 L of solution per plant twice a day. The second stage is the flowering and fruiting period, which is from flowering to the early stage of fruit expansion.

[0078] C. The third stage: adjust the pH of the second nutrient solution to 6.5-6.8, the EC of the second nutrient solution to 3.0ds / m, the liquid supply volume to 1.5L / each plant, and the liquid supply frequency to 2 times a day. The third stage is the fruiting period, that is, from the expansion of eggplant fruits to the completion of fruit harvesting.

[0079] The rest of the content is the same as in Example 1.

[0080] Example 3

[0081] The difference between this embodiment and embodiment 1 is that:

[0082] The first nutrient solution is composed of the following raw materials:

[0083] Ca(N03)2·4H2O: 403mg / L; NH4H2PO4: 43mg / L; KNO3: 282mg / L; MgSO4·7H2O: 153mg / L; Fe-EDTA: 22mg / L; MnSO4·4H2O: 2.12mg / L; H3BO3: 2.83mg / L; ZnSO4·7H2O: 0.22mg / L; CuSO4·5H2O: 0.085mg / L; (NH4)2MoO4·4H2O: 0.023mg / L; the balance is water; pH = 5.5-6.8; EC = 1.6-2.0ds / m;

[0084] The second nutrient solution is composed of the following raw materials:

[0085] Ca(N03)2·4H2O: 403mg / L; NH4H2PO4: 43mg / L; KNO3: 403mg / L; MgSO4·7H2O: 153mg / L; Fe-EDTA: 22mg / L; MnSO4·4H2O: 2.12mg / L; H3BO3: 2.83mg / L; ZnSO4·7H2O: 0.22mg / L; CuSO4·5H2O: 0.085mg / L; (NH4)2MoO4·4H2O: 0.023mg / L; the balance is water; pH = 6.5~6.8; EC = 2.6ds / m.

[0086] A. Phase I: Adjust the pH of the first nutrient solution to 5.5-6.5, the EC of the first nutrient solution to 1.6 ds / m, and supply 1.0 L of solution per plant once a day. The first phase is from planting to the appearance of buds in the eggplants.

[0087] B. Second stage: Adjust the pH of the first nutrient solution to 6.5-6.8, the EC of the first nutrient solution to 2.0 ds / m, and supply 1.0 L of solution per plant, twice a day. The second stage is the flowering and fruiting period, from flowering to the early stage of fruit expansion.

[0088] C. The third stage: adjust the pH of the second nutrient solution to 6.5-6.8, the EC of the second nutrient solution to 2.6ds / m, the liquid supply volume to 1.5L / plant, and the liquid supply frequency to 2 times a day. The third stage is the fruiting period, that is, from the expansion of eggplant fruits to the completion of fruit harvesting.

[0089] The rest of the content is the same as in Example 1.

[0090] Example 4

[0091] The difference between this embodiment and embodiment 1 is that:

[0092] The first nutrient solution is composed of the following raw materials:

[0093] Ca(N03)2·4H2O: 408mg / L; NH4H2PO4: 47mg / L; KNO3: 288mg / L; MgSO4·7H2O: 157mg / L; Fe-EDTA: 24mg / L; MnSO4·4H2O: 2.18mg / L; H3BO3: 2.87mg / L; ZnSO4·7H2O: 0.24mg / L; CuSO4·5H2O: 0.095mg / L; (NH4)2MoO4·4H2O: 0.028mg / L; the balance is water; pH = 5.5-6.8; EC = 1.7-2.3ds / m;

[0094] The second nutrient solution is composed of the following raw materials:

[0095] Ca(N03)2·4H2O: 408mg / L; NH4H2PO4: 47mg / L; KNO3: 408mg / L; MgSO4·7H2O: 157mg / L; Fe-EDTA: 24mg / L; MnSO4·4H2O: 2.18mg / L; H3BO3: 2.87mg / L; ZnSO4·7H2O: 0.24mg / L; CuSO4·5H2O: 0.095mg / L; (NH4)2MoO4·4H2O: 0.028mg / L; the balance is water; pH = 6.5~6.8; EC = 2.8ds / m.

[0096] A. Phase I: Adjust the pH of the first nutrient solution to 5.5-6.5, the EC of the first nutrient solution to 1.7 ds / m, and supply 1.0 L of solution per plant once a day. The first phase is from planting to bud formation.

[0097] B. Second stage: Adjust the pH of the first nutrient solution to 6.5-6.8, the EC of the first nutrient solution to 2.3 ds / m, and supply 1.0 L of solution per plant, twice a day. The second stage is the flowering and fruiting period, from flowering to the early stage of fruit expansion.

[0098] C. The third stage: Adjust the pH of the second nutrient solution to 6.5-6.8, the EC of the second nutrient solution to 2.8 ds / m, and supply 1.5 L of solution per plant, twice a day. The third stage is the fruiting period, from the expansion of the eggplant fruit to the completion of the fruit harvest.

[0099] The rest of the content is the same as in Example 1.

[0100] To verify the effect of the above embodiment, the applicant conducted the following experiments:

[0101] 1. Test Materials and Experimental Design

[0102] Experimental time and location: The experiment will be conducted in the multi-span smart greenhouse of Hebei Modern Agricultural Experimental Park from 2022 to 2023.

[0103] Test materials: Qieyou No. 1 (round eggplant) and Knight (long eggplant).

[0104] Hydroponic technology: uses a closed inorganic matrix nutrient solution circulation timed and quantitative intelligent control system for cultivation. Vermiculite is used as the soilless cultivation medium.

[0105] 2. Experimental Design

[0106] After germination, seeds were sown in 72-well trays with a V (waste cottonseed hull) to V (vermiculite) ratio of 2:1. In early spring, after 55-60 days of seedling cultivation, uniformly growing seedlings were selected and planted in cultivation troughs. After planting, nutrient solution was supplied by a water pump. An automatic control system was used to set the supply schedule and quota for different growth stages. Drip irrigation was performed using four drip tapes installed in each cultivation trough. Four nutrient solution formulations, corresponding to Examples 1-4, were used, with a control (CK) consisting of a Japanese Yamazaki formulation. Three replicates were used for each treatment, with completely randomized arrangement. Fifteen plants were randomly selected from each treatment for biological and quality indicators.

[0107] 3. Measurement Items and Methods

[0108] Growth indicators were measured at different growth stages, including plant height, stem diameter, relative chlorophyll content, and photosynthetic characteristics. Yield statistics and quality indicators were measured during the peak fruiting period, including soluble sugar content using anthrone colorimetry, organic acid content using NaOH titration, vitamin C content using titration, and soluble solids using a handheld refractometer.

[0109] 4. Data Statistics and Analysis

[0110] The experimental data were analyzed for variance using DPS software with the Duncan's new multiple range method.

[0111] 5. Results Analysis

[0112] 1. Comparison of eggplant growth under different nutrient solution formulas

[0113] Table 1 Comparison of eggplant growth in different nutrient solution formulas

[0114]

[0115] As shown in Table 1, the long eggplant cultivation results show that Examples 1-4 all outperformed the control, with significant differences from the control. In particular, the long eggplant cultivated in Example 3 showed the best growth, with the highest plant height, and greater leaf length and width. The round eggplant cultivation results show that Examples 1-4 all outperformed the control, with significant differences from the control. In particular, the round eggplant cultivated in Example 3 had higher plant height and stem diameter than the other treatments, and had superior leaf length and width compared to Examples 3 and 4, with Example 3 showing the greatest leaf width.

[0116] 2. Comparison of photosynthetic characteristics and yield of eggplant treated with different nutrient solution formulas

[0117] Table 2 Comparison of photosynthetic characteristics and yield of eggplant cultivated with different nutrient solution formulas

[0118]

[0119] As shown in Table 2, the photosynthetic characteristics of eggplants grown in Examples 1 to 4 are all better than those of the control, and the differences are significant. In particular, the net photosynthetic rate of Example 3 is the highest, reaching 8.61 μmol / m 2 / s. The per-acre yield of eggplants cultivated in Examples 1 to 4 was greater than that of the control, reaching 5320kg / mu to 6452kg / mu, and the relative yield increase rate compared with the control was 16.67% to 41.49%. From the results of the comparison of the photosynthetic characteristics of round eggplants, the photosynthetic rates of the eggplants cultivated in Examples 1 to 4 were greater than those of the control, and the differences were significant. The net photosynthetic rate of Example 3 was also the largest, reaching 17.64μmol / m 2 / s, the highest per mu yield was 6744 kg, with a relative yield increase rate of 25.63%. The per mu yield of the round eggplants cultivated in Examples 1 to 4 reached 5982 kg / mu to 6744 kg / mu, with a relative yield increase rate of 11.44% to 25.63% compared with the control.

[0120] 3. Comparison of eggplant quality treated with different nutrient solution formulas

[0121] Table 3 Comparison of eggplant quality cultivated with different nutrient solution formulas

[0122]

[0123] As shown in Table 3, the quality results of the cultivated eggplants are as follows: the nitrate content of Examples 1 to 4 is significantly lower than that of the control, with a reduction rate of 13.02% to 18.89%; the soluble total sugar, vitamin C, and soluble solids contents are all higher than the control, at 35.55 mg / kg to 38.30 mg / kg, 1.86 mg / 100 g to 2.29 mg / 100 g, and 4.50% to 4.9%, respectively. The relative increase rates compared with the control are 3.67% to 11.69%, 20.78% to 48.70%, and 4.65% to 13.95%, respectively. From the quality results of the cultivated round eggplants, the nitrate content of Examples 1 to 4 was significantly lower than that of the control, with a reduction rate of 22.49% to 48.38%; the soluble total sugar, Vc, and soluble solids contents were all higher than those of the control, at 31.65 mg / kg to 36.28 mg / kg, 1.13 mg / 100 g to 1.34 mg / 100 g, and 3.9% to 4.0%, respectively. The relative increase rates compared with the control were 4.59% to 19.89%, 34.52% to 59.52%, and 2.63% to 5.26%, respectively.

[0124] VI. Conclusion

[0125] Comprehensive analysis of biological indicators (including plant height, stem diameter, chlorophyll content, yield, etc.) and quality indicators (including nitrate content, soluble solids content, vitamin C content, soluble sugar, etc.) revealed that:

[0126] (1) Based on a large number of experiments, a low-cost and simple preparation process eggplant hydroponic nutrient solution formula was screened. This invention proposes a nutrient solution formula suitable for eggplant growth and proposes a nutrient solution supply scheme suitable for its different growth stages, namely the seedling stage, the flowering and fruiting stage, and the fruiting stage. It can ensure the optimal nutritional needs of eggplant throughout the growth period, maximize the utilization of nutrients, avoid the addition of salt ions as much as possible, reduce the accumulation of unnecessary ions in the matrix, and facilitate the reuse of nutrient solution.

[0127] (2) This formula can effectively reduce the nitrate content in eggplant on the basis of increasing yield, increase the content of Vc, soluble total sugar and soluble solids, and effectively improve the quality of eggplant fruit. Using the nutrient solution inorganic matrix hydroponic Knight (long eggplant) and Qieyou No. 1 (round eggplant) in the present invention, the per mu yield reached 5320kg / mu to 6452kg / mu and 5982kg / mu to 6744kg / mu, respectively, with relative yield increases of 16.67% to 41.49% and 11.44% to 25.63%, respectively. The nitrate content of Knight (long eggplant) and Qieyou No. 1 (round eggplant) hydroponic cultured with nutrient solution inorganic matrix was reduced compared with the control, by 13.02% to 18.89% and 22.49% to 48.38%, respectively. The total soluble sugar contents of Knight (long eggplant) and Qieyou No. 1 (round eggplant) hydroponically cultured in nutrient solution with an inorganic substrate were 35.55 mg / kg-38.30 mg / kg and 31.65 mg / kg-36.28 mg / kg, respectively, compared to the control, representing increases of 3.67%-11.69% and 4.59%-19.89%, respectively. The vitamin C contents of Knight (long eggplant) and Qieyou No. 1 (round eggplant) hydroponically cultured in nutrient solution with an inorganic substrate were 1.86-2.29 mg / 100g and 1.13 mg / 100g-1.34 mg / 100g, respectively, representing increases of 20.78%-48.70% and 34.52%-59.52%, respectively, compared to the control. The soluble solids contents of Knight (long eggplant) and Qieyou No. 1 (round eggplant) hydroponically cultured in nutrient solution with inorganic matrix were 4.50% to 4.9% and 3.9% to 4.0%, respectively, which increased by 2.63% to 5.26% compared with the control.

Claims

1. The application of soilless culture nutrient solution in cultivating eggplant is characterized by The process steps include: A. First stage: Adjust the pH of the first nutrient solution to 5.5-6.5, the EC of the first nutrient solution to 1.5-1.8 ds / m, and supply 1.0 L of solution per plant once a day. The first stage is from planting to the appearance of buds in the eggplants. B. Second stage: Adjust the pH of the first nutrient solution to 6.5-6.8, the EC of the first nutrient solution to 1.8-2.5 ds / m, and supply 1.0 L of solution per plant, twice a day. The second stage is the flowering and fruiting period, from flowering to the early stage of fruit expansion. C. The third stage: Adjust the pH of the second nutrient solution to 6.5-6.8, the EC of the second nutrient solution to 2.5-3.0 ds / m, and supply 1.5 L of solution per plant, twice a day. The third stage is the fruiting period, from the expansion of the eggplant fruit to the completion of the fruit harvest. The liquid supply time in steps A, B, and C is 8:00 to 18:00, drip irrigation is used for the liquid supply in steps A, B, and C, and vermiculite is selected as the soilless culture medium in steps A, B, and C; The first nutrient solution is composed of the following raw materials composition: Ca(N03)2·4H2O: 400mg / L~410mg / L; NH4H2PO4: 40mg / L~50mg / L; KNO3: 280mg / L~290mg / L; MgSO4·7H2O: 150mg / L~160mg / L; Fe-EDTA: 20mg / L~25mg / L; MnSO4·4H2O: 2.1mg / L~2.2mg / L; H3BO3: 2.80mg / L~2.90mg / L; ZnSO4·7H2O: 0.20mg / L~0.25mg / L; CuSO4·5H2O: 0.08mg / L~0.1mg / L; (NH4)2MoO4·4H2O: 0.02mg / L~0.03mg / L; the balance is water; pH = 5.5~6.8; EC = 1.5~2.5ds / m; The second nutrient solution is composed of the following raw materials: Ca(N03)2·4H2O: 400mg / L~410mg / L; NH4H2PO4: 40mg / L~50mg / L; KNO3: 400mg / L~410mg / L; MgSO4·7H2O: 150mg / L~160mg / L; Fe-EDTA: 20mg / L~25mg / L; MnSO4·4H2O: 2.1mg / L~2.2mg / L; H3BO3: 2.80mg / L~2.90mg / L; ZnSO4·7H2O: 0.20mg / L~0.25mg / L; CuSO4·5H2O: 0.08mg / L~0.1mg / L; (NH4)2MoO4·4H2O: 0.02mg / L~0.03mg / L; the balance is water; pH=6.5~6.8; EC=2.5~3.0ds / m.

2. The use of the soilless culture nutrient solution in cultivating eggplant according to claim 1, characterized in that In steps A, B and C, four drip irrigation belts are laid in each cultivation trough for drip irrigation.

3. The use of the soilless culture nutrient solution in cultivating eggplant according to claim 1, characterized in that The pH in steps A, B and C is adjusted using boric acid.

4. The use of the soilless culture nutrient solution in cultivating eggplant according to claim 1, characterized in that The first nutrient solution and the second nutrient solution are prepared according to the following steps: a. Calcium nitrate and potassium nitrate are placed in a liquid storage tank, mixed and dissolved, and water is added to the volume according to the concentration multiple of the raw material content and stirred to prepare a first mother liquor; b. Place ammonium dihydrogen phosphate, magnesium sulfate, chelated iron, manganese sulfate, boric acid, zinc sulfate, copper sulfate, and ammonium molybdate in a liquid storage tank, mix and dissolve them, add water to the volume according to the concentration multiple of the raw material content, and stir evenly to prepare a second mother liquor; c. When using, mix the first mother liquor and the second mother liquor in a volume ratio of 1:1, dilute with water, adjust the pH and EC value, and prepare the first nutrient solution or the second nutrient solution respectively.

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