Indoor Vegetable soilless cultivation technology has been introduced into the agricultural demonstration park of Huzhu County in Qinghai Province, China since 2010. It has been tested, demonstrated and promoted in the past two years. The technology of soilless cultivation has a wider range of applications. The nutrient regulation technology and management of cultivation are more demanding than soil cultivation, and the regulation of the facility environment is more strict. Mastering the nutrient regulation technology of soilless culture is the basic condition and inevitable factor for the development of modern agriculture.

Hydroponic vegetable refers to the vegetable that is cultivated under the traditional soil cultivation form, in which most of the roots are grown in the layer of nutrient solution and liquid, which only provides water, nutrients, and oxygen through the nutrient solution. Hydroponic vegetables have a short growth cycle and are rich in vitamins and minerals essential to the body. The hydroponic plants cultivated by soilless culture vegetables using this soilless cultivation technique are favored by domestic and foreign flower consumers for their cleanliness, elegant style, strong ornamental, environmental protection and pollution-free.

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1 Production and use of organic nutrient sources

Firstly, Organic nutrient sources and their use livestock manure, cake fertilizer, biogas fertilizer, bio-organic fertilizer (mainly from plants and/or animals) (bio-organic residues or active microbial fertilizer) as a nutrient source for soilless cultivated crops. Hydroponic vegetable refers to the vegetable that is cultivated under the traditional soil cultivation form, in which most of the roots are grown in the layer of nutrient solution and liquid, which only provides water, nutrients, and oxygen through the nutrient solution.

The advantage of Hydroponic vegetables is that have a short growth cycle and are rich in vitamins and minerals essential to the body. The use of organic fertilizer in substrate cultivation must first be carried out by high-temperature fermentation to avoid bringing pathogenic microorganisms, eggs and grass seeds into the cultivation system.

Secondly, it must be dried and pulverized to a particle size of less than 3 mm. When used as base fertilizer, it can be directly mixed with the matrix. The amount of the active ingredient of the fertilizer source is determined according to the amount of the active ingredient. Generally, 10 to 15 kg of pure chicken manure can be mixed into the matrix per cubic meter. , or cake fertilizer 15 ~ 20kg, or other types of organic fertilizer 20 ~ 50kg.

There are two ways to do topdressing:

One is to apply the method of surface application, and the water is drip directly after application. The disadvantage of this method is that it must be applied artificially, and it can only be applied on the surface, and the surface concentration of the substrate is easy to occur. The low concentration of the lower part is not conducive to the balanced absorption of nutrients by the root system.

The fertilizer solution is diluted with water to a conductivity concentration of 1.8 to 2.5 ms/cm, and the pH value is adjusted to between 5.5 and 6.5. The effect of the supply method is relatively stable and uniform, and there is no rooting phenomenon. When using organic fertilizer alone, it is necessary to determine the type and amount of inorganic fertilizer added according to the main element content of different organic fertilizers to ensure a comprehensive and balanced absorption of various nutrients.

For example, chicken manure contains more calcium, phosphorus and contains nitrogen, which contains the least amount of potassium. Therefore, when using chicken manure for long-term use, it must be combined with potassium fertilizer and nitrogen fertilizer. It can be mixed with 1.5-2.0kg of potassium sulfate in 10kg chicken manure or Potassium nitrate is applied.

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2 Inorganic nutrient sources

The use of inorganic nutrition is currently the most common nutrient source for soilless culture applications.

Generally, a large number of elements are selected from industrial grade or chemically pure compound raw materials, and trace elements are selected from chemically pure or analytically pure raw materials. The source of the purchased raw materials should be authentic, the color should be pure, the solubility should be good, and there is no impurity, that is, the formulated nutrient solution is clear and not turbid. If the raw materials can be qualitatively and quantitatively analyzed, it is more accurate for the preparation of the nutrient solution. And convenient.

2.1 Principles of preparation of inorganic nutrient solution

Firstly, the basic formula of nutrient solution is determined, and the nutrient ratio of each growth stage is adjusted according to different growth stages.

Secondly, it is necessary to analyze and know the content of various mineral ions in the local water quality, and it cannot be used for water sources with heavy metal ions exceeding the standard.

According to the water content of various effective mineral ions, the amount of the compound in the formula is increased or decreased to ensure the balance between the anion and the cation of the nutrient solution and the optimization of the effective nutrient distribution ratio.

Then it is necessary to fine-tune the nutrient ratio according to the chemical nature of the culture substrate and the effective mineral ion content.

2.2 The operating procedure for the preparation of inorganic nutrient solution

Accurately weighs the amount of each element compound according to the formulation requirements, and is divided into three groups according to the nature of the compound, named

  • No. 1 (mainly nitrogen, phosphorus, potassium, magnesium, sulfur),
  • No. 2 ( Mainly nitrogen, potassium, calcium),
  • No. 3 fertilizer (for trace elements).

Before preparing the nutrient solution, dissolve the solid compound with water (warm) before injecting it into the nutrient solution pool (or tank). Before the injection of the dope (mother liquor), the amount of water and the pH of the water should be measured first, and the pH should be adjusted to between 6.0 and 7.0 with phosphoric acid or ammonia nitrogen.

Then add the mother liquors No. 3, No. 2 and No. 1 respectively, and determine the amount of mother liquor according to the concentration of the crop at that time. In the process of adding the mother liquor, the water pump should be stirred under stirring to avoid contact between the high concentration mother liquor. , a chemical reaction occurs and precipitation occurs.

Before the liquid supply, the concentration (EC value) and pH (pH) of the prepared nutrient solution should be checked, and the liquid can be supplied when the indicator of the crop needs is required.

2.3 Distribution and management of nutrient solution

2.3.1 Management of cultivation season and EC value

In the summer high-temperature drying season, the supply concentration (EC value) of fruit seedlings is generally between 1.4 and 1.6 ms/cm, and the liquid supply during the growing period. The EC value is between 1.6 and 1.8 ms/cm; the spring and autumn seasons can generally be between 2.0 and 2.2 ms/cm; in winter (low temperature, high humidity, low light), the liquid concentration should be increased, generally in the range of 2.2 to 2.5. Between ms/cm. Most crops can be controlled between 5.5 and 6.5.

2.3.2 Management of growth stage and EC value

The concentration of nutrient solution in the general seedling stage to the crop result should be appropriately low management, and the result should be appropriately increased. The concentration of leafy seedlings is low, and it starts to increase after planting. It should be reduced to better before harvesting. At the same time, the amount of nitrate nitrogen should be reduced to reduce the accumulation of nitrate in the product.

2.3.3 Management of rhizosphere EC value and pH

The substrate roots have a small range of activity, and the buffering capacity of the substrate is not as good as that of the soil. The EC value and pH value in the matrix around the rhizosphere are relatively large. Generally, the EC value in summer and autumn is easy to rise. High, the winter and spring seasons are easy to decline. The pH value is opposite to the change in EC value. When the EC value is high, the pH value will decrease, and when the EC value is low, the pH value will increase.

The larger the plant, the stronger the absorption, and the greater the concentration and pH change in the root matrix. Therefore, the supply EC value should be adjusted according to the EC value of the crop root matrix. According to the cultivation experience of the past two years: the root substrate EC value of tomato, eggplant, zucchini, watermelon, etc.

Summer and autumn, the control is 2.5~2.8ms/cm, the highest is not more than 3.0ms/cm, and the winter and spring are controlled at 3.0~3.2ms. /cm, the maximum does not exceed 3.6ms/cm; the EC value of the roots of cucumber and pepper: between 2.2 and 2.5ms/cm in summer and autumn, not more than 2.8ms/cm, and 2.5 to 2.8ms/cm in winter and spring, the maximum not to exceed 3.2ms/cm is the safe range.

Therefore, the EC value of the root matrix should be detected every day in summer, and it can be detected once every 3 to 5 days in winter and spring so that the EC value and pH value of the root can be grasped at any time, and timely control measures are taken. On-line detection and on-line regulation of nutrient solution preparation and EC value and pH in the matrix can be achieved when conditions permit.

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