The above are all reasons that restrict the profitability of soilless cultivation. In fact, from the perspective of the development of soilless cultivation in various countries in the world, they all start with the recycling of gravel cultivation, and the cost is relatively high. The NFT system appeared in the mid-1970s. Various natural and artificial substrates developed at the same time. Europe found rock wool and considered it the best substrate, while Canada used sawdust as the substrate because of the advanced timber industry. The vast majority of substrate cultivation is that the nutrient solution is not recycled, and the cost is low. It has become the main method of soilless cultivation in various countries.

In developed countries such as the Netherlands, Japan, the United States, Denmark, the United Kingdom, France, Germany, and Israel, the production of soilless culture has achieved a high degree of mechanization, automation, electronics, and specialization. The environmental conditions (temperature, humidity, CO2 concentration, ventilation, light) and nutrient solution preparation of the greenhouse are completely controlled by the computer. The production process, including sowing, thinning, transplanting, pest control, harvesting, and grading packaging, is fully automated. , Realizing one-stop factory production, reaching the annual supply of products, high output value, and significant economic benefits; although the initial investment is relatively high, with the gradual maturity of technology and equipment, and the reduction of labor and energy consumption in the later period, the level of income has been Continued growth.

Another trend is mainly in developing countries, mainly based on their national conditions and economic and technical conditions, using simple equipment to obtain materials on site and manual operations. The purpose of developing soilless culture in these countries is to transform the environment, save water and soil resources, and solve the basic needs of people's lives. For China, the main goal of soilless cultivation technology is to study popular soilless cultivation facilities suitable for my country's national conditions in order to reduce investment and production costs. And high-tech applications such as microelectronics, computers, and the Internet of Things are applied to soilless cultivation facilities to realize real-time monitoring of the nutrient solution storage, liquid temperature, pH value, conductivity and supply time. In addition, high-end soilless cultivation can also be carried out for greenhouse parks with conditions. For example, China’s climate and environmental characteristics are more suitable for tomato production. At present, several large modern tomato production greenhouses that are launched use soilless cultivation. Good income has been achieved.

Soilless cultivation refers to a cultivation technique that uses substrates, water, and nutrient solutions containing essential elements for plant growth and development to provide nutrients without using natural soil, so that plants can complete the entire life cycle normally. At present, the United States has listed soilless culture as one of the top ten high-tech developments in the country. In Japan, soilless culture technology has also been used by many scientists as a powerful means to study "cosmic farms".

Undoubtedly, soilless cultivation technology has a wide range of advantages, which can not only effectively prevent soil continuous cropping obstacles and soil-borne diseases; improve crop yield and quality; save water, fertilizer, and labor, but also greatly expand agricultural production space and make crops Can not rely on soil for production. However, in the promotion process, the separation from the soil also brings corresponding problems, restricting the industrial development of soilless culture technology. Many people have some doubts about whether the soilless culture model is profitable, and adopt the wait-and-see mode! Let’s analyze, can the soilless cultivation model be profitable?

Reasons that restrict the profitability of soilless cultivation

1. Lack of buffer, once the victim is injured, the loss will be serious
That is, it can automatically adjust its acidity, alkalinity, trace element and various nutrient concentrations, microbial community distribution and other necessary elements for cultivated plants according to the external situation. And the cultivation base of soilless culture is completely artificially adjusted, and a single defect will immediately impact the normal growth of the plant, causing plant disease or death.

2. The initial investment is too large 

Soilless cultivation needs to be implemented in a smart greenhouse. All facilities such as the pre-construction greenhouse, soilless cultivation facilities, water and fertilizer integration system must be pre-purchased and constructed. All heating, cooling, ventilation, aeration, oxygenation, and destruction Insects, sterilization and other equipment must be operating normally and fully controlled. These are very expensive and consume a lot of energy to run. 

3. High nutrient solution requirements

For soilless culture technology, nutrient solution is the only way for plants to obtain nutrients. Different plants have different requirements for the environment in different seasons and different growth stages, and their nutritional requirements will be very different. This needs to be very clear in advance about the growth law of the plant, and every link must not be deviated. Once it makes a mistake, it will be wiped out. Especially the reproduction of microorganisms. Once a microorganism is suitable for growth in the nutrient solution, it will multiply in an explosive manner until the original ecological balance is completely destroyed, causing all-out plant disease and death.

4. Management is complicated and cumbersome

General field management advocates fine management, and soilless cultivation is "super fine management". There is no big or small matter, and every link must be scientific and accurate. This is too demanding for ordinary agricultural practitioners.

So what are the important factors that affect the service life of greenhouses? For details, follow the domestic professional construction company- Xiamen Wellgain Greenhouse Engineering Co., Ltd. take you to learn more about it!

1. The light transmission effect is better
The greenhouse is a lighting building, so it must have good light transmission conditions when constructing the greenhouse. The light transmittance is the basic indicator of the intention to evaluate the light transmission performance of the greenhouse. The light transmittance refers to the amount of light that penetrates into the greenhouse and the amount of outdoor light. The light transmittance of the greenhouse is affected by the light transmittance of the light-transmitting cover material of the greenhouse and the shadow rate of the greenhouse stock price. Later, with the different solar radiation angles in different seasons, the light transmittance of the greenhouse also changes at any time, so the light transmittance The high or low rate becomes the direct influence factor of crop growth and selection of plant species.

Second, the thermal insulation performance of the greenhouse
Greenhouses should also pay attention to thermal insulation performance. Improving the thermal insulation performance of the greenhouse and reducing energy consumption are direct means to increase the efficiency of greenhouse production. The thermal insulation ratio of the greenhouse is an important indicator of the intention to measure the thermal insulation performance of the greenhouse. The thermal insulation ratio of the greenhouse refers to the thermal resistance ratio. The ratio of the coverage area of the small greenhouse light-transmitting material to the coverage area of the greenhouse maintenance structure with greater thermal resistance. The larger the heat preservation ratio, the better the heat preservation performance of the greenhouse.

Three, the greenhouse must be durable
The construction of greenhouses needs to consider its durability. The durability of greenhouses is affected by the aging resistance of greenhouse materials. Influenced by factors such as the carrying capacity of the main structure of the greenhouse, the durability of the light-transmitting material is not only its own strength, but also shows the constant attenuation of the light transmittance of the material over time, and the degree of attenuation of the light transmittance affects the light-transmitting material The determinant of the service life, because the greenhouse runs for a long time in a high temperature and high humidity environment, the anti-corrosion of the surface of the components is also one of the important factors affecting the service life of the greenhouse.

The large-scale construction of greenhouses is a large project. Not only the area occupied by the greenhouses, but also the area of open land needs to be considered. In addition to natural conditions, a reasonable plan should be made for the disposable land, and the overall scale of the greenhouse should be properly arranged.

1. Introduction

Hydroponic vegetable refers to the vegetable that most of the root system grows in the nutrient solution layer and only provides water, nutrient and oxygen through the nutrient solution, which is different from the vegetables cultivated under the traditional soil cultivation method. Hydroponic vegetables have a short growth cycle and are rich in vitamins and minerals necessary for the human body.

The most common hydroponic vegetables are leafy vegetables, which are easy to manage. In addition to some leafy vegetables, there are also some fruit and vegetable vegetables that can also be hydroponics, such as cucumbers, melons, tomatoes and so on.

2. Hydroponics

Hydroponics is a kind of soilless culture, classified into non-substrate cultivation. Substrate-free cultivation type refers to the environment where the plant roots grow without substrate to fix the root system. The root system grows in nutrient solution or humid air containing nutrient solution, but when raising seedlings Some matrices may be used. Hydroponics refers to the soilless culture (Water Culture, Solution Culture) in which most of the roots of plants grow directly in the nutrient solution layer. Mainly include: Nutrient Film Technique (NET, Nutrient Film Technique), where plants are planted on a 1-2cm thick shallow nutrient solution layer that continuously circulates; Deep Flow Technique (DFT, Deep Flow Technique), nutrition The depth of the liquid layer is at least 4-5cm, the deepest is 8-10cm, and sometimes even deeper. The nutrient solution circulates at a set frequency; FCH (Floating Capillary Hydroponics), in the deeper (5-6cm) nutrient solution A piece of foam covered with a non-woven fabric is placed in the liquid layer, and the root system grows on the wet non-woven fabric.

Characteristics of hydroponic vegetables

1. The root system is mainly milky white capillary root to absorb water and nutrition;

2. The root system adapts to the aquatic environment, and there are some aerial roots around it to absorb oxygen;

3. Short growth cycle and early listing.

As the growing area of greenhouses is larger and larger, it means that the number of greenhouses should increase. If the service life of the greenhouse is long enough, the quality of the main steel pipe must be better. Today, I will introduce to you what kinds of greenhouse steel pipes there are.

1. Welded pipe: It is made of steel plate or strip steel as raw materials, first rolled and formed, and then welded. Its main advantages are:

The production process is relatively simple, the production efficiency is high, and the varieties and specifications are diverse. However, its service life is not as good as galvanized pipe.

2, hot dip galvanized steel pipe: the hot dip galvanized steel pipe is carried out in the hot dip plating tank, and the formed coating is more uniform, but also strong adhesion, so it can be used for a long time. Moreover, its corrosion resistance is also very good.

3, galvanized steel pipe: it will be adjusted to get, its price is lower than that of hot-dip galvanized steel pipe, but its corrosion resistance is not as good.

The difference between hot-dip galvanized steel pipe and galvanized strip steel pipe is as follows:

Difference one: its color, service life, performance and price are completely different, can not be confused.

Difference two: there will be some defects on the surface of hot-dip galvanized steel pipe, such as snowflakes on the surface, zinc nodules on the port, and galvanized steel pipe without

NFT is the abbreviation of Nutrient Film Technique, which is one of the important hydroponic technologies capable of commercial production.
The principle behind the NFT hydroponic system is simple. It can maintain a thin water film in the NFT planting tank throughout the life cycle of the crop, and the plant roots absorb the nutrient solution flowing in the tank to obtain the required nutrients and water. In addition, since part of the root system of the plant is immersed in the nutrient solution and part of the root system is exposed to the air, the contradiction between water absorption and oxygen absorption by the root system is simply and effectively solved.

The advantages of NFT flat cultivation hydroponic system include:
1. Maintenance is more convenient because there are fewer components in the system.
2. Compared with the A-frame hydroponic system, the NFT flat cultivation system has a simpler structure and is easier to install.
3. Due to the lighter weight of the entire flat cultivation system, larger leaf vegetable crops can be planted.
4. Obtain more uniform and better lighting conditions for plant growth.

5. It is easy to realize the automatic management of the production process.

Disadvantages of NFT flat cultivation hydroponic system
1. The space utilization rate is low.
2. The unit density is slightly lower than that of the A-frame hydroponic system.
3. It is difficult to harvest, especially the crops in the middle trough.

Advantages of A-Frame Hydroponics System
1. The layout will be more compact and the space utilization rate will be higher, because the NFT planting slots can be stacked layer by layer.
2. The yield is higher, usually slightly higher than the NFT flat cultivation hydroponic system.
3. Beautiful appearance, especially suitable for leisure and sightseeing agriculture.

Disadvantages of A-Frame Hydroponic Systems
1. A higher power pump is required to ensure that the nutrient solution can reach the same level in each NFT tank.
2. It is difficult to set planting technical parameters.
3. Uneven lighting conditions, especially for the bottom plants, may require the use of LED fill lights.
4. The types of crops that can be planted are limited.

Generally speaking, the NFT flat cultivation hydroponic system is suitable for crops with large plant size or high plant height, such as lettuce, spinach and basil. The A-frame hydroponic system is suitable for plants with smaller space, faster yield, short root system and short plants, because they limit the maximum growth of plants, such as bitter chrysanthemum, lettuce, rape, lettuce etc.

The ebb and flow seedbed is composed of seedbed tray, rolling shaft, bracket, seedbed frame, hand wheel, horizontal support and inclined rod. The standard height of the seedbed is generally 0.7 or 0.75m, which can be fine-tuned up and down; the standard width is 1.7m, and the length can also be determined according to the width of the greenhouse. The length can be customized according to user requirements, generally 20-30m, but the length of the seedbed should not exceed 40m, so as not to affect the shaking effect. The size of the seedbed tray is generally 1.7*4.5 (4 or 5) meters, and other specifications can also be designed according to needs. The seedbed tray is made of ABS material, which has high anti-corrosion performance, good load-bearing capacity and long service life.

The advantages of Ebb and flow table irrigation are high irrigation uniformity, low labor intensity, large greenhouse space utilization, crop leaves are not easily damped, leaf diseases rarely occur, and irrigation water can be fully recycled to reduce water waste.

Ebb and flow irrigation seedbed: ebb and flow phenomenon is a natural phenomenon in coastal areas. It refers to the periodic movement of seawater under the action of tidal forces of celestial bodies (mainly the moon and the sun). It is customary to call the vertical fluctuation of the sea surface as tide.

the technology of growing seedling

Sowing was carried out in the greenhouse. Coconut bran matrix was placed in a 72-well hole dish, and then placed on a tidal Greenhouse seedbed. Nutrient solution (EC: 1.6 mS/cm, pH: 7.4) was poured to saturate the substrate with water absorption. The seeded hole plates are placed in a centralized manner according to the varieties, and the varieties and sowing date are marked. After that, spray water on the surface of the seeded hole plates with a watering can until the seed coating is soaked. Finally, cover the holes with non-woven cloth for moisture, and remove the holes after the seeds bud. Check the moisture condition of the substrate every day, and water in time to prevent drying of the substrate. The temperature of the seedling area is 22~24℃ during the day, and it is heated according to the outside weather at night, and the curtain insulation is started at the same time. The temperature at night is kept at 12~14℃, and the seedlings can germinate in 3 days.

Lettuce transplanting

When the seedlings grow trifoliate, they will reach the colonization standard and can be transferred to the planting area in batches. Gently take out the vegetable seedlings in the substrate tray and place them upright in the cultivation holes. After each variety is transplanted, mark the variety name, sowing date and transplanting date. After the transplanting is completed, check again whether the cultivation tank is aligned with the water outlet.

Environment and water and fertilizer management after transplanting

After being transplanted to NFT Pipes Hydroponics , the temperature was controlled at 25℃ during the day and decreased to about 12℃ at night. After colonization, NFT system was used for irrigation of lettuce, which was set to irrigate once in 25~40 min and once in 3~5 min. Nutrient solution configuration is the core of NFT cultivation technology. Nutrient solution formulation and control directly affect crop growth, yield and quality. Can make lettuce professional formula, or general leaf vegetable special fertilizer, A fertilizer and B fertilizer separately configured, nutrient solution preparation water for clean and pollution-free RO pure water, configuration needs to adjust the EC at about 1.5 mS/m, pH at about 7.5.

recovery

In summer, the temperature is getting higher and higher, especially for saw tooth type greenhouse, so it is necessary to carry out effective air release to ensure the smooth "inhalation" of the greenhouse, and release the air layer by layer. When the greenhouse is closed for 1 hour or the temperature of the greenhouse reaches 20 degrees, a little breeze needs to be released, and the air outlet is as wide as 5cm to improve the photosynthesis of crops and discharge water or harmful substances from the body. When the temperature in the greenhouse rises to the high temperature required by the crops, the secondary air is released to slowly reduce the temperature to a range suitable for the growth and development of vegetables.

When there is no wind or a slight northeasterly wind (or southeasterly wind), the temperature at the western end of the greenhouse is generally 2-3 degrees higher than that in the eastern half, and when the wind is strong, the temperature at the eastern end is 2 degrees higher than that at the western end. When there is northwest or southwest wind, the temperature difference between the two sides of the item will be more than 3 degrees, and the greater the wind, the greater the temperature difference. Due to the different site conditions, the fresh air should be managed in sections.

The thermometer setting should be valid. The key to venting is according to the loading temperature in the thermometer. Whether its accuracy is directly related to whether the hydroponics vegetables are in a natural environment suitable for growth and development. Therefore, it is recommended to set three thermometers symmetrically on the east side of the arch shed, then take the average value to reduce the error, and place the vegetable sprout eye 10 cm above the thermometer. The humidity of the greenhouse environment increases strongly after watering and needs to be dehumidified immediately. Water at noon of the day, close the air outlet moderately, and open the air outlet in the morning to increase natural ventilation. Actual operation for 2-3 days can quickly reduce the environmental humidity of the greenhouse and reduce diseases.

Before seedling, put the seeds into warm water at about 50℃ to soak for a period of time. After the seeds are white, they can be evenly spread into the soil. After that, the seeds can be seeded into the soil dish one by one, and watered properly to protect moisture.

Seedling tray method of seedling raising

   The substrate should be prepared first when using the seedling tray. Plant ash, perlite and vermiculite can be mixed in a ratio of 2:1:1 to make cultivation substrate. Then the soil is mixed with insecticides and fungicides, mixed evenly with a layer of plastic film, and then placed in the sun for 3 to 6 hours.

   Then the seeds need to be accelerated germination treatment, the seeds need to be soaked in warm water about 50℃ for a period of time, when the water temperature drops to 30℃ and then soak for 12 hours, such as the seeds white and fully absorb water, and then the seeds can be spread to the soil equipped with cultivation matrix, so that the vegetable seeds can quickly emerge.

   After the seedling plate is cleaned, the prepared matrix can be loaded into the seedling plate, so that the height of the substrate and the height of the seedling plate is consistent, and finally the seed is placed into the plate according to the seeding method of a hole and a grain, and then the soil is covered with a layer of vermiculite.

  After sowing, place the tray into Hydroponic Rolling Bench  in the greenhouse. Water every other week to ensure that the soil is slightly moist. In addition, when watering the seeds, it is recommended to use nutrient-rich and pollution-free spring water or well water. Tap water can also be used after 1 to 2 days. And when the room temperature is higher than 30℃, it is necessary to spray water mist around the leaves regularly to cool down.