Application of hydroponic nutrient solution in cultivation of Chinese chives

Abstract

The invention relates to preparation and application of a hydroponic nutrient solution, in particular to application of the hydroponic nutrient solution in cultivation of Chinese chives. In combination with different requirements of leek on nutrients in different growth stages such as a germination accelerating and sowing stage, a seedling stage, a field planting stage and a harvesting stage, nutrients are supplied to leek in a targeted manner, and the problem that an existing hydroponic nutrient solution does not configure and supply nutrient elements according to different nutrient requirements of crops in different growth stages is effectively solved. While the yield of the hydroponic Chinese chives is increased, the content of nitrate in the Chinese chives can be effectively reduced, the content of Vc, soluble sugar and soluble solids is increased, and no Chinese chive maggots occur after multiple crops of continuous planting.

Description

Technical Field

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

[0002] As an important part of modern agriculture, facility agriculture is developing rapidly with its incomparable advantages over traditional agriculture, and has become an effective means for farmers in many regions to get rich and increase their income. However, in the production process, the planting structure is relatively simple, the simple pursuit of output and the excessive use of quick-acting fertilizers, this high-consumption and low-efficiency production method, has led to serious problems in facility agriculture. The problems caused by continuous cropping such as secondary salinization of facility soil and soil-borne diseases are becoming more and more serious, which not only reduces the yield and quality of vegetables, but also pollutes the production environment, restricting the sustainable development of facility agriculture. Soilless cultivation is one of the measures to fundamentally solve the obstacles to continuous cropping of soil.

[0003] Inorganic substrate cultivation is one of the forms of soilless cultivation, which refers to the use of vermiculite, sand, perlite, etc. as fixed support materials for crop growth, and the nutrient solution provides the crops with water, fertilizer, oxygen and environment required for growth. As an important soilless cultivation substrate, perlite has been widely used due to its stable physical and chemical properties, good water retention and air permeability. It is an inert, sterile substrate with good stability. The mineral components it contains will not interfere with the nutrient solution, nor can it provide nutrients that can be absorbed and utilized by plants. Therefore, perlite is increasingly used in soilless cultivation, especially in fruit and vegetable production. Nutrient solution preparation is the core technology for the normal growth of vegetables in substrate cultivation. It is also the basis and key to soilless cultivation. The success of inorganic substrate cultivation depends largely on whether the nutrient solution formula, concentration, ratio of various nutrient elements, pH, liquid temperature are appropriate, and whether the nutrient solution management during plant growth can meet the requirements of different growth stages. Only by using the correct nutrient solution formula, preparing and managing the nutrient solution in an appropriate way, and keeping the plants in the most suitable nutrient solution environment at any stage of growth and development, can we obtain rapid, high-yield, and high-quality cultivation results. The composition and concentration of the nutrient solution vary depending on the type of crop, different growth period, different environmental conditions, and cultivation purposes. Different crops have different requirements for nutrient solution concentration, which is related to the fertilizer tolerance of the crop.

[0004] Cucumber is second only to tomato in terms of the area of ​​facility cultivation in my country. It belongs to the genus Cucurbitaceae. Cucumber is rich in nutrients and is a world-wide and popular vegetable. With the improvement of people's living standards, changes in eating habits and the continuous strengthening of awareness of cucumber health, the demand for cucumbers is increasing, and higher requirements are also placed on the quality of cucumbers. Soilless cultivation of cucumbers not only solves the quality problems of cucumbers caused by serious soil-borne diseases, but also increases cucumber yields, reduces environmental pollution, saves resources, and improves water and fertilizer utilization. The concentration (EC value) of cucumber nutrient solution has different requirements at different growth stages. The configuration of scientific and reasonable nutrient solution can not only promote balanced growth of plants, but also improve the utilization efficiency of fertilizers. Most of the nutrient solutions currently used are Japanese garden test and Yamazaki nutrient solution formulas, which are difficult to adapt to the diverse needs of different production areas, different cucumber varieties and cultivation seasons. Whether the formula of soilless cultivation nutrient solution is reasonable affects the solubility of nutrients and the absorption of plants, thereby affecting crop growth. Reasonable nutrient solution concentration (EC) and pH (pH) are conducive to plant absorption and transportation, improve water and fertilizer utilization, and reduce environmental pollution. Therefore, it is very important to develop a nutrient solution formula suitable for soilless cultivation.

[0005] The patent documents retrieved by the applicant include:

[0006] Patent document with publication number CN108191536A discloses a nutrient solution for soilless cultivation of cucumbers and a preparation method thereof, wherein the nutrient solution is composed of the following components in weight percentage: 1-3 parts of cardamom, 4-9 parts of kelp powder, 5-10 parts of wood vinegar, 0.5-3.5 parts of boric acid, 10-20 parts of peel, 2-6 parts of chitosan, 30-40 parts of sucrose, and 600-800 parts of water. The nutrient solution is rich in nitrogen, phosphorus, potassium and other trace elements required for the growth of cucumbers, which can promote the balanced and comprehensive absorption of trace elements by cucumbers, promote their growth and root development, and prevent the occurrence of physiological diseases. Its nutrition far exceeds the nutrients that the soil can supply, and is more conducive to the growth of cucumbers.

[0007] The patent document with the publication number of CN106116913A discloses a cucumber soilless culture nutrient solution, which includes the following components by weight: 5-10ppm of iron sulfate, 1-5ppm of zinc sulfate, 1-5ppm of ammonium molybdate, 3-12ppm of boric acid, 10-20ppm of manganese sulfate, 5-10ppm of copper sulfate, 120-150ppm of magnesium sulfate, 150-200ppm of potassium chloride, 300-500ppm of potassium dihydrogen phosphate, 0.5-1% of urea, 0.1-0.5% of EDTA, 0.1-0.5% of wormwood extract, and 0.1-0.5% of houttuynia cordata extract. Compared with the prior art, the soilless culture nutrient solution has sufficient nutrients, antibacterial and anthelmintic effects, promotes the healthy growth of cucumbers, increases yield, and improves quality.

[0008] The patent document with the publication number CN107721564A discloses a soilless culture nutrient solution for increasing the yield of cucumber and its preparation method. The soilless culture nutrient solution includes 0.5-1.5 parts of macroelements, 0.002-0.01 parts of trace elements, 0.05-0.5 parts of active substances, and 500-2000 parts of deionized water by weight. The preparation method is to prepare mother solution A, mother solution B, and mixture C with macroelements, trace elements, and active substances respectively, mix mother solution A and mother solution B according to the weight of macroelements and trace elements, and then add mixture C according to the weight ratio of active substances, and stir evenly to obtain nutrient solution. The nutrient solution can meet the needs of various elements in the growth process of cucumbers. The obtained cucumbers have thick stems, short internodes, enlarged leaves, and developed root systems; it can give full play to the production potential of crops, promote the differentiation of new roots and vascular systems, and consume less water. Compared with soil cultivation, the yield is increased by 30%, which promotes the development of agricultural modernization.

[0009] The above patent documents on cucumber nutrient solution all have a single formula throughout the entire growth period, do not provide the optimal EC value of the nutrient solution at different growth stages, and do not mention the liquid supply plan and whether the nutrient solution can improve the quality of cucumbers on the basis of high yield. Summary of the invention

[0010] The purpose of the present invention is to disclose the application of hydroponic nutrient solution in the cultivation of leeks, and to form a soilless leek intelligent light simplified nutrient solution efficient circulation cultivation management technology system for leeks in view of the quality and safety problems caused by the annual planting mode of leeks. While increasing the yield of hydroponic leeks, the nitrate content in leeks is effectively reduced, the soluble sugar, Vc and soluble solid content are increased, and the occurrence of pests and diseases and the generation of agricultural residues are avoided. The leeks produced meet the quality requirements of "safety + flavor + freshness", ensure the quality and safety of leek products, and increase benefits.

[0011] The overall technical concept of the present invention is:

[0012] The application of hydroponic nutrient solution in cultivating leek is characterized by comprising the following process steps:

[0013] A. Germination and sowing period: Wrap the sun-dried and sterilized seeds with gauze and soak them in the second nutrient solution for 8 to 10 hours, wash with clean water, dry and then germinate; when sowing, fill the plug tray with substrate and sow, the germination temperature is 18℃ to 20℃, and the substrate humidity is 80% to 90%;

[0014] B. Seedling stage: Cultivate on a tidal nursery bed, adjust the pH of the first nutrient solution to 5.5-6.5, and the EC to 1.3-1.5 ds / m. The EC value gradually increases with crop growth; the frequency of liquid supply is once a day, and the application amount is applied to a depth of 2 cm on the nursery bed and maintained for 3-5 minutes. After 50-60 days of cultivation, 4-5 leaf seedlings are grown, which is the right age for planting;

[0015] C. Planting period: Select leek seedlings with healthy growth, no pests and diseases, 4 to 5 leaves and 1 heart, compact root, and 12 cm to 15 cm plant height for transplanting and planting in the cultivation trough of the inorganic matrix vermiculite; adjust the pH of the first nutrient solution to 6.5-6.8, EC to 1.5-1.8ds / m, and the EC value gradually increases with the growth of the crop; the liquid supply frequency is 1 time / day in winter, 2 times / day in spring and autumn, and 3 times / day in summer, and the liquid supply volume is 0.6 liters / time / hole; apply the second nutrient solution 5 days after planting, apply 2-3 times every 7 days, and the liquid supply volume is 0.3 liters / time / hole, and replace the nutrient solution with clean water 3 days before harvesting for nitrogen weaning treatment;

[0016] D. Harvest period: Harvest when the leek grows to a plant height of 30cm-35cm and / or 6 leaves and 1 heart to 7 leaves and 1 heart, harvest at 2-3cm above the bulblet, harvest once every 20-25 days after the first harvest, once every 35-45 days in winter, 5-6 crops per year, rooting in July-August;

[0017] The first nutrient solution in steps B and C is supplied by drip irrigation, and the pH of the first nutrient solution is 5.5-6.8; EC is 1.3-1.8 ds / m; the first nutrient solution is prepared by diluting the following raw materials with water and adjusting the EC value and pH value to meet the use requirements:

[0018] Ca(N03)2·4H2O: 236mg / L; KNO3: 303mg / L; KH2PO4: 408.3mg / L; NH4NO3: 320mg / L; MgSO4·7H2O: 492mg / L; (NH4)2SO4: 132mg / L; NaCl: 292.2mg / L; Fe-EDTA: 20mg / L; MnSO4·4H2O: 2.13mg / L; H3BO3: 2.86mg / L; ZnSO4·7H2O: 0.22mg / L; CuSO4·5H2O: 0.08mg / L; (NH4)2MoO4·4H2O: 0.02mg / L; the balance is water;

[0019] The second nutrient solution is prepared by the following method:

[0020] The raw materials are prepared in a mass ratio of decomposed cow dung: microbial agent: brown sugar: water = 100-200: 5: 100: 1000, and then naturally fermented at room temperature for not less than 30 days, and the extract is filtered and extracted to obtain the second nutrient solution.

[0021] The nutritional requirements, growth characteristics and application requirements of the first nutrient solution at each growth stage of leek hydroponics in the present invention are:

[0022] For the concentration management of the nutrient solution of the same crop, the requirements are changed according to the different growth stages and climatic conditions. The concentration can be lower in the seedling stage and early growth stage, and higher in the peak growth stage. Since most of the crop roots grow in the nutrient solution and absorb water, nutrients and oxygen, the concentration, composition, pH and dissolved oxygen in the nutrient solution are constantly changing; the absorption of the crop roots changes the number and proportion of various compounds and ions in the nutrient solution, so the concentration, pH and dissolved oxygen content of the nutrient solution also change accordingly; at the same time, some organic matter is secreted during the metabolism of the root system, and the shedding, death and even aging and death of some root epidermal cells remain in the nutrient solution, causing microorganisms to reproduce in the nutrient solution, thereby more or less changing the properties of the nutrient solution. Changes in the environment and climate will also affect the changes in the temperature of the nutrient solution. On the other hand, plants have different requirements for the concentration of the nutrient solution at different growth stages. Therefore, in order to meet the requirements for the optimal growth of crops, the concentration and pH of the nutrient solution should be reasonably adjusted and managed. More importantly, the EC value and pH of the nutrient solution will change with the change of temperature, which is something that technical personnel in this field should know and understand, and the above changes do not affect the use of the nutrient solution and the growth of the plants.

[0023] The process conditions of each process step are as follows:

[0024] The matrix in the present invention is preferably an inorganic matrix. A more preferred technical implementation method is that the matrix in the hole tray in step A is the matrix disclosed in application number 201610645253.3.

[0025] In order to meet the needs of leek seed germination and seedling growth and facilitate transplanting, the preferred technical implementation means is to sow 8 to 10 seeds in each hole in the hole tray in step A.

[0026] To meet the needs of leek growth and harvesting, the preferred technical implementation means is that the conditions after transplanting in step C are: 8 to 10 plants / hole, the hole distance is about 15 cm, and the tillering nodes are not buried.

[0027] The second nutrient solution in the present invention is an organic liquid fertilizer, which contains rich nutrients and active substances such as amino acids and auxins, can be quickly absorbed by vegetables, can promote vegetable growth and development, and improve vegetable quality. Biogas slurry has a significant inhibitory effect on vegetable diseases and insect pests, and can effectively prevent and control the occurrence of leek maggots. Its preparation can adopt a variety of technical implementation means. In order to improve the fermentation effect, the preferred technical implementation means is that the microbial agent is produced by Hubei Zhongxiang Bioengineering Co., Ltd., the trade name is Jun Xiaobai, and the effective viable count is ≥2 billion / gram.

[0028] In order to improve the application effect of the nutrient solution, the preferred technical implementation means is that the supply time of the first nutrient solution in steps B and C is 8:00-18:00.

[0029] Since the pH of the first nutrient solution will change after preparation, in order to meet the needs of crop growth, the preferred technical implementation means is to use H3BO3 to adjust the pH in steps B and C.

[0030] In order to facilitate the preparation of the hydroponic nutrient solution, the preferred technical solution is that the first nutrient solution is prepared by the following method:

[0031] a. Place Ca(N03)2·4H2O, KNO3 and NH4NO3 in a liquid storage tank, mix and dissolve, add water to the volume according to the concentration multiple of the raw material content and stir evenly to prepare the first mother liquor;

[0032] b. Place KH2PO4, MgSO4·7H2O, (NH4)2SO4, NaCl, Fe-EDTA, MnSO4·4H2O, H3BO3, ZnSO4·7H2O, CuSO4·5H2O, and (NH4)2MoO4·4H2O in a liquid storage tank, mix and dissolve, add water to the volume according to the concentration multiple of the raw material content, and stir evenly to prepare a second mother solution;

[0033] 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.

[0034] The main functions of the components in the hydroponic nutrient solution of the present invention are as follows:

[0035] The leek nutrient solution contains the macro-elements and trace elements required for plant growth, among which the macro-elements are N, P, K, Ca, Mg, etc.; the trace elements are Fe, B, Mn, Zn, Mo, Cu, Na, etc.

[0036] Ca(N03)2·4H2O mainly provides calcium and nitrogen elements required for plant growth. It provides calcium ions required for plant growth, improves the selective absorption capacity of root cell membranes, enhances the resistance to environmental stress, and promotes the normal growth of plants. At the same time, it provides nitrogen elements required for plant growth, meets the demand for nitrogen elements for plant growth, and promotes the development of plant leaves.

[0037] KH2PO4 mainly provides phosphorus and potassium elements required for plant growth.

[0038] KNO3 mainly provides potassium and nitrogen elements required for plant growth. The roots absorb potassium ions, which change the root system's absorption of water and oxygen in the external environment, effectively regulating the root system's absorption rate of oxygen in the external environment, and preventing the root system from rotting due to lack of oxygen during the growth process of the plant. It can promote fruit development.

[0039] NH4NO3 is a commonly used nitrogen fertilizer, which is effective in promoting the lush growth of plant stems and leaves, making the leaves dark green, and increasing the protein content of plants.

[0040] (NH4)2SO4 mainly provides the nitrogen element required for plant growth and the components of amino acids and proteins in plants. It is also a component of chlorophyll, which plays a decisive role in plant photosynthesis.

[0041] NaCl mainly provides the sodium element required for plant growth.

[0042] MgSO4·7H2O mainly provides magnesium elements required for plant growth. By directly providing magnesium ions to the solution, the plant's demand for magnesium ions is met, promoting plant photosynthesis and protein synthesis.

[0043] MnSO4·4H2O mainly provides the manganese element required for plant growth.

[0044] Fe-EDTA mainly provides the iron element required for plant growth. At the same time, sodium iron acts as a plant growth regulator, further regulating the absorption rate of external nutritional factors during plant growth.

[0045] H3BO3 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 and accelerate the growth of plants.

[0046] (NH4)2MoO4·4H2O mainly provides the molybdenum element required for plant growth.

[0047] ZnSO4·7H2O mainly provides the zinc element required for plant growth, promoting the hydrolysis of substances in plants and the progress of photosynthesis.

[0048] CuSO4·5H2O 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.

[0049] The CuSO4·5H2O, MnSO4·4H2O, Ca(N03)2·4H2O, MgSO4·7H2O and ZnSO4·7H2O in the above-mentioned components may also be made of corresponding anhydrous compounds and converted according to the dosage; the nitrogen, phosphorus and potassium nutrient elements may also be made of other forms of soluble salts and the dosage may be verified through experiments. The above-mentioned changes do not deviate from the essence of the present invention.

[0050] The substantial features and significant technical advances achieved by the present invention are:

[0051] 1. The raw materials of the soilless culture nutrient solution involved in the present invention are easy to obtain and the preparation process is simple.

[0052] 2. After leek was cultivated using the soilless culture nutrient solution of the present invention, various biological indicators were significantly better than those of the control, and no leek maggots occurred in continuous planting of multiple crops under this cultivation method.

[0053] 3. According to the existing national standard for determining nitrate in vegetables, the applicant determined the nitrate content in the leeks cultured in the leek soilless culture nutrient solution provided by the present invention, and the nitrate content met the national standard (≤3000 mg / kg).

[0054] 4. The applicant tested the soilless culture nutrient solution of the present invention on leeks and found that the yield of leeks was significantly improved after applying the hydroponic nutrient solution of the present invention. The yield of Pingfeng No. 7 leek hydroponic cultured with nutrient solution and inorganic matrix was 1871.98 kg / mu / crop, with a relative yield increase of 145.06% over the control.

[0055] 5. This formula can effectively reduce the nitrate content of leek on the basis of increasing production, increase the content of Vc, soluble total sugar and soluble solids, and effectively improve the quality of leek. The nitrate content of Pingfeng No. 7 leek hydroponic in nutrient solution with inorganic matrix is ​​2845.81 mg / kg, which is 20.63% lower than that of the control. The total soluble sugar content of Pingfeng No. 7 leek hydroponic in nutrient solution with inorganic matrix is ​​10.59 mg / kg, which is 80.72% higher than that of the control. The Vc content of Pingfeng No. 7 leek hydroponic in nutrient solution with inorganic matrix is ​​13.73 mg / 100g, which is 5.69% higher than that of the control. The soluble solids content of Pingfeng No. 7 leek hydroponic in nutrient solution with inorganic matrix is ​​5.40%, which is 5.26% higher than that of the control. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] Figure 1 This is a schematic diagram comparing the field growth of leeks grown with different nutrient solutions.

[0057] Figure 1 The four treatments were arranged in random blocks with three replicates, planted in cultivation troughs, and placed in the same growth period and environmental conditions with the same field management measures.

[0058] Figure 2 It is a schematic diagram of the growth of different replicates of leeks randomly selected from each treatment at harvest time.

[0059] Figure 2 The growth potential includes plant height, stem thickness, leaf length, leaf width, tiller number and other indicators. Figure 2 It can be seen that treatment three has the strongest growth potential. DETAILED DESCRIPTION

[0060] The present invention is further described below in conjunction with embodiments, but it should not be construed as limiting the present invention. The protection scope of the present invention shall be based on the contents recorded in the claims, and any replacement of equivalent technical means made according to the description shall not depart from the protection scope of the present invention.

[0061] Example 1

[0062] The application of hydroponic nutrient solution in cultivating leek is characterized by comprising the following process steps:

[0063] A. Germination and sowing period: Wrap the seeds that have been dried and sterilized with gauze and soak them in the second nutrient solution for 8 to 10 hours, wash with clean water, dry and then germinate; when sowing, fill the plug tray with substrate and sow, sow 8 to 10 seeds per hole in the plug tray, the germination temperature is 18°C ​​to 20°C, the substrate humidity is 80% to 90%, and the substrate is the substrate disclosed in application number 201610645253.3;

[0064] B. Seedling stage: Cultivate on a tidal nursery bed, adjust the pH of the first nutrient solution to 5.5-6.5, and the EC to 1.3-1.5 ds / m. The EC value gradually increases with crop growth; the frequency of liquid supply is once a day, and the application amount is applied to a depth of 2 cm on the nursery bed and maintained for 3-5 minutes. After 50-60 days of cultivation, 4-5 leaf seedlings are grown, which is the right age for planting;

[0065] C. Planting period: Select leek seedlings with healthy growth, no pests and diseases, 4 leaves and 1 heart to 5 leaves and 1 heart at the seedling age, compact root, and 12cm to 15cm in height for transplanting and planting in the cultivation trough of the inorganic matrix vermiculite. The conditions after transplanting are: 8 to 10 plants / hole, the hole distance is about 15cm, and the tillering node is not buried; adjust the pH of the first nutrient solution to 6.5 to 6.8, EC to 1.5 to 1.8ds / m, and the EC value gradually increases with the growth of the crop; the liquid supply frequency is 1 time / day in winter, 2 times / day in spring and autumn, and 3 times / day in summer, and the liquid supply volume is 0.6 liters / time / hole; apply the second nutrient solution 5 days after planting, apply 2 to 3 times every 7 days, and the liquid supply volume is 0.3 liters / time / hole, and the nutrient solution is replaced by clean water for nitrogen-free treatment 3 days before harvesting;

[0066] D. Harvest period: Harvest when the leek grows to a plant height of 30cm-35cm and / or 6 leaves and 1 heart to 7 leaves and 1 heart, harvest at 2-3cm above the bulblet, harvest once every 20-25 days after the first harvest, once every 35-45 days in winter, 5-6 crops per year, rooting in July-August;

[0067] The first nutrient solution in steps B and C is supplied by drip irrigation, and the pH of the first nutrient solution is 5.5-6.8; EC is 1.3-1.8 ds / m; the first nutrient solution is prepared by diluting the following raw materials with water and adjusting the EC value and pH value to meet the use requirements:

[0068] Ca(N03)2·4H2O: 236mg / L; KNO3: 303mg / L; KH2PO4: 408.3mg / L; NH4NO3: 320mg / L; MgSO4·7H2O: 492mg / L; (NH4)2SO4: 132mg / L; NaCl: 292.2mg / L; Fe-EDTA: 20mg / L; MnSO4·4H2O: 2.13mg / L; H3BO3: 2.86mg / L; ZnSO4·7H2O: 0.22mg / L; CuSO4·5H2O: 0.08mg / L; (NH4)2MoO4·4H2O: 0.02mg / L; the balance is water;

[0069] The second nutrient solution is prepared by the following method:

[0070] The raw materials are prepared in a mass ratio of decomposed cow dung: microbial agent: brown sugar: water = 100-200: 5: 100: 1000, and then naturally fermented at room temperature for not less than 30 days, and the extract is filtered and extracted to obtain a second nutrient solution; the microbial agent is produced by Hubei Zhongxiang Bioengineering Co., Ltd., the trade name is Jun Xiaobai, and the number of effective live bacteria is ≥ 2 billion / gram.

[0071] The process conditions of each process step are as follows:

[0072] The supply time of the first nutrient solution in steps B and C is 8:00-18:00.

[0073] In steps B and C, pH is adjusted using H3BO3.

[0074] The first nutrient solution is prepared as follows:

[0075] a. Place Ca(N03)2·4H2O, KNO3 and NH4NO3 in a liquid storage tank, mix and dissolve, add water to the volume according to the concentration multiple of the raw material content and stir evenly to prepare the first mother liquor;

[0076] b. Place KH2PO4, MgSO4·7H2O, (NH4)2SO4, NaCl, Fe-EDTA, MnSO4·4H2O, H3BO3, ZnSO4·7H2O, CuSO4·5H2O, and (NH4)2MoO4·4H2O in a liquid storage tank, mix and dissolve, add water to the volume according to the concentration multiple of the raw material content, and stir evenly to prepare a second mother solution;

[0077] 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.

[0078] To verify the effect of the above embodiment, the applicant conducted the following experiments:

[0079] 1. Test materials and experimental design

[0080] 1. Experimental time and location: The experiment will be conducted in the multi-span intelligent greenhouse of Hebei Modern Agricultural Experimental Park from 2023 to 2024.

[0081] 2. Test materials: Chinese chives Pingfeng No. 7.

[0082] 3. Hydroponic technology: Adopt closed inorganic matrix cultivation technology. Vermiculite is used as soilless cultivation matrix, which is inert and sterile, stable, has good water retention and air permeability, and the mineral components it contains will not interfere with the nutrient solution and cannot be absorbed and utilized by the plants.

[0083] 2. Experimental Design

[0084] After being soaked and germinated in the second nutrient solution, the seeds are sown in a 128-hole hole tray containing V (mushroom residue and waste material): V (vermiculite) = 2:1, 8 to 10 seeds are sown in each hole, the germination temperature is 18°C ​​to 20°C, and the substrate humidity is maintained at 80% to 90%. During the seedling stage, the seedlings are cultivated on a tidal nursery bed, and the pH of the first nutrient solution is adjusted to 5.5-6.5, and the EC is adjusted to 1.3-1.5ds / m, and the EC value gradually increases with the growth of the crop; the liquid supply frequency is once a day, and the application amount is applied to a depth of 2cm on the seedling bed and maintained for 3-5 minutes; after 50-60 days of cultivation, 4-5 leaf seedlings are grown, which is the suitable age for planting; after 50-60 days of seedling cultivation, the leek seedlings that are healthy, free of pests and diseases, with 4 to 5 leaves and 1 heart at the seedling age, firm roots, and 12-15cm in height are transplanted and planted in a cultivation trough with an inorganic matrix of vermiculite;. After planting, the nutrient solution is supplied by a water pump, and the supply time, quota, EC value and pH of the first nutrient solution at different growth stages are set by an automatic control device (Delixi Group Co., Ltd.), and the EC value gradually increases with the growth of the crop; four drip irrigation belts are laid in each cultivation trough for drip irrigation. The first nutrient solution of treatments 1 to 4 was set up, with three replicates per treatment, arranged completely randomly, and 15 holes were randomly selected from each treatment to measure biological indicators and quality indicators. The first nutrient solution of treatments 1 to 4 was prepared by diluting the following raw materials with water and adjusting to the EC value and pH value that meet the use requirements:

[0085] Treatment 1: Ca(NO3)2·4H2O: 236mg / L; KNO3: 404mg / L; NH4NO3: 160mg / L; KH2PO4: 272mg / L; (NH4)2SO4: 132mg / L; MgSO4·7H2O: 246mg / L;

[0086] Treatment 2: Ca(NO3)2·4H2O: 346mg / L; KNO3: 395mg / L; (NH4)2SO4: 264mg / L; KH2PO4: 272mg / L; MgSO4·7H2O: 320mg / L;

[0087] Treatment 3: Ca(N03)2·4H2O: 236mg / L; KNO3: 303mg / L; KH2PO4: 408.3mg / L; NH4NO3: 320mg / L; MgSO4·7H2O: 492mg / L; (NH4)2SO4: 132mg / L; NaCl: 292.2mg / L;

[0088] Treatment 4: Ca(N03)2·4H2O: 427mg / L; KNO3: 267mg / L; (NH4)2SO4: 53mg / L; K2SO4: 116mg / L; MgSO4·7H2O: 260mg / L.

[0089] The trace elements in treatments 1 to 4 are as follows:

[0090] Fe-EDTA: 20mg / L; MnSO4·4H2O: 2.13mg / L; H3BO3: 2.86mg / L; ZnSO4·7H2O: 0.22mg / L; CuSO4·5H2O: 0.08mg / L; (NH4)2MoO4·4H2O: 0.02mg / L.

[0091] During the experiment, except for the different ingredients of the first nutrient solution in treatments 1 to 4, the rest of the methods were the same as those described in Example 1, and the same field management measures were adopted in the same growth period and under the same environmental conditions. Treatment 1 was a general formula for the hydroponic nutrient solution for leeks, and was therefore used as a control.

[0092] 3. Measurement Items and Methods

[0093] Growth indexes were measured at different growth stages, including plant height, stem diameter, relative chlorophyll content, photosynthetic characteristics, etc. Yield statistics and quality indexes were measured at the harvest stage, including soluble sugar content measured by anthrone colorimetry, organic acid content measured by NaOH titration, Vc content measured by titration, and soluble solids measured by handheld refractometer.

[0094] 4. Data Statistics and Analysis

[0095] The experimental data were analyzed for variance using DPS software using the Duncan's new multiple range method.

[0096] V. Results Analysis

[0097] The growth and results of the leeks cultivated in treatments 1 to 4 are as follows: Figure 1 , 2 shown.

[0098] 1. Comparison of the growth of leeks cultivated with different nutrient solution formulas

[0099] Table 1 Determination of biological indexes of leek (first crop) in different nutrient solutions

[0100] deal with Process 1 (CK) Process 2 Process 3 Process 4 Plant height (cm) 39.60b 39.94b 47.31a 47.18a Stem diameter (mm) 3.48b 3.61b 4.19a 3.98a Leaf length(cm) 32.82b 32.72b 38.43a 38.33a Leaf width(cm) 5.55b 5.37b 6.50a 6.22a Number of tillers 9.22c 11.56b 15.33a 12.67b Number of blades 39.78c 48.56c 79.78a 62.56b Yield per mu / crop (kg) 377.78b 359.96b 1125.0a 876.38a Relative yield increase rate (%) - - 197.79 131.98

[0101] As shown in Table 1, the number of tillers and leaves of leek cultivated with nutrient solution in treatment 3 is significantly better than that of other treatments, and the difference is significant at the 5% level. The biological indicators such as plant height, stem thickness, leaf length, leaf width and yield measurement results also show that treatment 3 is the best, and is significantly better than treatment 1 and treatment 2 (significant difference at the 5% level). The relative yield increase rates of treatments 3 and 4 are 197.79% and 131.98% respectively. Treatment 3 has the highest yield per mu, reaching 1125.0kg per crop. Therefore, the nutrient solution formula of treatment 3 is most suitable for the growth of leek.

[0102] Table 2 Determination of biological indexes of leek (second crop) in different nutrient solutions

[0103] deal with Process 1 (CK) Process 2 Process 3 Process 4 Plant height (cm) 49.17b 47.31b 53.81a 51.94a Stem diameter (mm) 4.61b 4.59b 5.14a 4.97ab Leaf length(cm) 37.71bc 35.46c 43.28a 39.10b Leaf width(cm) 5.53 5.81 6.35 6.22 Number of tillers 12.56bc 11.22c 18.33a 16.44ab Number of blades 66.78bc 59.00c 97.89a 83.44ab Yield per mu / crop (kg) 763.88c 763.66c 1871.98a 1424.08b Relative yield increase rate (%) - - 145.06 86.43

[0104] As shown in Table 2, the plant height, stem thickness, leaf length, leaf width, tiller number, leaf number and total yield of leeks treated with nutrient solution in treatment 3 at harvest were better than those of other treatments, and were significantly better than those of treatments 1 and 2 (significant difference at the 5% level). Comprehensively considering various biological indicators, leeks cultivated with nutrient solution formula in treatment 3 had the best growth potential, and the highest yield per mu per crop was 1871.98 kg, with a relative yield increase rate of 145.06% over the control. Therefore, nutrient solution formula in treatment 3 was the most suitable for leek growth. Treatment 4 was the second best, with a yield per mu per crop of 1424.08 kg, with a relative yield increase rate of 86.43% over the control.

[0105] Table 3 Determination of quality indexes of leek (second crop) in different nutrient solutions

[0106] deal with Process 1 (CK) Process 2 Process 3 Process 4 Nitrate (mg / kg) 3585.60 3400.71 2845.81 2580.02 Relative increase rate (%) - -5.16 -20.63 -28.04 Total soluble sugar (mg / g) 5.86 7.78 10.59 7.05 Relative increase rate (%) - 32.76 80.72 20.31 Soluble solids (%) 5.13 5.18 5.40 5.33 Relative increase rate (%) - 0.97 5.26 3.89 Vc(mg / 100g) 12.99 12.80 13.73 13.60 Relative increase rate (%) - - 5.69 4.69

[0107] As shown in Table 3, the soluble total sugar content, soluble solids and VC content of the leek treated with the nutrient solution in treatment 3 were the highest, which were 10.59 mg / g, 5.40% and 13.73 mg / 100 g, respectively, which were 80.72%, 5.26% and 5.69% higher than those in the control (CK), respectively. The nitrate content of the leek cultivated in treatments 3 and 4 was within the standard range of green vegetables (nitrate content of green pollution-free leafy vegetables <3000 mg / kg), which were 20.63% and 28.04% lower than those in the control, respectively.

[0108] Conclusion: Combined with the results of biological indicators, yield and quality measurement of the first and second crops of leeks, it was concluded that the nutrient solution formula of treatment 3 was the best nutrient solution formula for cultivating leeks. The optimal nutrient solution and supporting cultivation technology effectively improved the quality of leeks.

[0109] 2. Comprehensive biological indicators (including plant height, stem diameter, chlorophyll content, yield, etc.) and quality indicators (including nitrate content, soluble solid content, Vc content, soluble sugar, etc.) analysis revealed that:

[0110] (1) Based on a large number of experiments, a low-cost and simple preparation process for the hydroponic nutrient solution for leeks was screened out. A nutrient solution formula suitable for the growth of leeks was proposed, and a nutrient solution supply plan suitable for the growth stage of leeks was proposed, which can ensure the optimal nutritional needs of leeks throughout the growth period, maximize the use 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.

[0111] (2) The formula can effectively reduce the nitrate content of leek on the basis of increasing production, increase the content of Vc, soluble total sugar and soluble solids, and effectively improve the quality of leek. The yield of Pingfeng No. 7 leek hydroponic in nutrient solution with inorganic matrix is ​​1871.98kg / mu·crop, and the relative increase rate is 145.06% compared with the control. The nitrate content of Pingfeng No. 7 leek hydroponic in nutrient solution with inorganic matrix is ​​2845.81mg / kg, which is 20.63% lower than the control. The soluble total sugar content of Pingfeng No. 7 leek hydroponic in nutrient solution with inorganic matrix is ​​10.59mg / kg, which is 80.72% higher than the control. The Vc content of Pingfeng No. 7 leek hydroponic in nutrient solution with inorganic matrix is ​​13.73mg / 100g, which is 5.69% higher than the control. The soluble solid content of Pingfeng No. 7 leek hydroponic in nutrient solution with inorganic matrix is ​​5.40%, which is 5.26% higher than the control. Under this cultivation method, no leek maggots occurred during continuous planting of multiple crops.

Claims

1. The application of hydroponic nutrient solution in cultivating leek is characterized by The process steps include: A. Germination and sowing period: Wrap the sun-dried and sterilized seeds with gauze and soak them in the second nutrient solution for 8 to 10 hours, wash with clean water, dry and then germinate; when sowing, fill the plug tray with substrate and sow, the germination temperature is 18℃ to 20℃, and the substrate humidity is 80% to 90%; B. Seedling stage: Cultivate on a tidal nursery bed, adjust the pH of the first nutrient solution to 5.5-6.5, and the EC to 1.3-1.5 ds / m. The EC value gradually increases with crop growth; the frequency of liquid supply is once a day, and the application amount is applied to a depth of 2 cm on the nursery bed and maintained for 3-5 minutes. After 50-60 days of cultivation, 4-5 leaf seedlings are grown, which is the right age for planting; C. Planting period: Select leek seedlings with healthy growth, no pests and diseases, 4 to 5 leaves and 1 heart at the seedling age, compact root, and 12 cm to 15 cm in height for transplanting and planting in a cultivation trough of inorganic matrix vermiculite; adjust the pH of the first nutrient solution to 6.5 to 6.8, EC to 1.5 to 1.8 ds / m, and the EC value gradually increases with the growth of the crop; the liquid supply frequency is 1 time / day in winter, 2 times / day in spring and autumn, and 3 times / day in summer, and the liquid supply volume is 0.6 liters / time / hole; apply the second nutrient solution 5 days after planting, apply 2 to 3 times every 7 days, and the liquid supply volume is 0.3 liters / time / hole, and replace the nutrient solution with clean water 3 days before harvesting for nitrogen weaning treatment; D. Harvest period: Harvest when the leek grows to a plant height of 30cm-35cm and / or 6 leaves and 1 heart to 7 leaves and 1 heart, harvest at 2-3cm above the bulblet, harvest once every 20-25 days after the first harvest, once every 35-45 days in winter, 5-6 crops per year, rooting in July-August; The first nutrient solution in steps B and C is supplied by drip irrigation, and the pH of the first nutrient solution is 5.5-6.8; EC is 1.3-1.8 ds / m; the first nutrient solution is prepared by diluting the following raw materials with water and adjusting the EC value and pH value to meet the use requirements: Ca(N03)2·4H2O: 236mg / L; KNO3: 303mg / L; KH2PO4: 408.3mg / L; NH4NO3: 320mg / L; MgSO4·7H2O: 492mg / L; (NH4)2SO4: 132mg / L; NaCl: 292.2mg / L; Fe-EDTA: 20mg / L; MnSO4·4H2O: 2.13mg / L; H3BO3: 2.86mg / L; ZnSO4·7H2O: 0.22mg / L; CuSO4·5H2O: 0.08mg / L; (NH4)2MoO4·4H2O: 0.02mg / L; the balance is water; The second nutrient solution is prepared by the following method: The raw materials are prepared in a mass ratio of decomposed cow dung: microbial agent: brown sugar: water = 100-200: 5: 100: 1000, and then naturally fermented at room temperature for not less than 30 days, and the extract is filtered and extracted to obtain the second nutrient solution.

2. The use of the hydroponic nutrient solution according to claim 1 in cultivating leeks, characterized in that The matrix in the hole tray in step A adopts the matrix disclosed in application number 201610645253.

3.

3. The use of the hydroponic nutrient solution according to claim 1 or 2 in cultivating leek, characterized in that In step A, 8 to 10 seeds are sown in each hole of the hole tray.

4. The use of the hydroponic nutrient solution according to claim 1 in cultivating leeks, characterized in that The conditions after transplanting in step C are: 8 to 10 plants / hole, the hole distance is about 15 cm, and the tillering nodes are not buried.

5. The use of the hydroponic nutrient solution according to claim 1 in cultivating leeks, characterized in that The microbial agent is produced by Hubei Zhongxiang Bioengineering Co., Ltd., with the trade name of JIUXIAOBAI, and the effective live bacteria count is ≥ 2 billion / gram.

6. The use of the hydroponic nutrient solution according to claim 1 in cultivating leeks, characterized in that The supply time of the first nutrient solution in steps B and C is 8:00-18:

00.

7. The use of the hydroponic nutrient solution according to claim 1 in cultivating leeks, characterized in that In the steps B and C, the pH is adjusted using H3BO3.

8. The use of the hydroponic nutrient solution according to claim 1 or 6 in cultivating leek, characterized in that The first nutrient solution is prepared by the following method: a. Place Ca(N03)2·4H2O, KNO3 and NH4NO3 in a liquid storage tank, mix and dissolve, add water to the volume according to the concentration multiple of the raw material content and stir evenly to prepare the first mother liquor; b. Place KH2PO4, MgSO4·7H2O, (NH4)2SO4, NaCl, Fe-EDTA, MnSO4·4H2O, H3BO3, ZnSO4·7H2O, CuSO4·5H2O, and (NH4)2MoO4·4H2O in a liquid storage tank, mix and dissolve, add water to the volume according to the concentration multiple of the raw material content, and stir evenly to prepare a second mother solution; 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.

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