Cultivation management and advantages and disadvantages of deep flow technology

1. Selection of cultivated crops

In the initial hydroponic production, some crops that are more suitable for hydroponics should be selected for planting, such as tomato, lettuce, chrysanthemum, chrysanthemum, etc., in order to achieve the success of hydroponics. For planting in greenhouses without temperature control, use crops that are fully adapted to the current season for planting, and do not plant off-season crops regardless of conditions, and do not misunderstand that soilless cultivation technology has an off-season function.

2. Seedling preparation and planting

Seedling raising-the plug seedling method produces seedlings (the details of the plug seedling method will be described separately later)

Transfer seedlings into the planting cup-prepare small non-calcareous gravel for seedling stabilization. Put 1-2cm small gravel at the bottom of the planting cup to prevent the root neck of the seedling from pressing to the bottom of the cup, and then put it in the seedling tray Pull out the seedling with the substrate and move it into the planting cup, and then cover the seedling root mass with a layer of small gravel to stabilize the seedling. The material for stabilizing seedlings must be small stones, because there is no capillary function, which can prevent the nutrient solution from rising and forming salt and frost. Do not use materials with strong capillary action (very finely divided peat, plant residues, etc.) to stabilize the seedlings, because these materials tend to form salt and frost.

Concentrated fostering in the transition trough-after the seedlings are moved into the planting cup, they could be moved into the holes of the planting plate on the planting trough immediately to become the right planting, but the hole spacing of the planting plate is determined according to the space that the plant needs to occupy when it grows up. When the seedlings are too thin, it will take a long time to fill the space. In order to improve the utilization rate of the greenhouse and hydroponics facilities, the very small seedlings that have been moved into the planting cup are densely placed in a transition trough, and the planting plate is directly placed on the bottom of the trough for transitional fostering. Put the nutrient solution 1-2cm deep into the bottom of the trough so that it can soak the bottom of the cup so that the seedling can absorb water and nutrients, grow up quickly and some roots stick out of the cup, and when it grows to a large enough plant shape , It was formally transplanted to the planting plate of the planting trough. After being moved in, the space will grow to the point where it can be harvested, which greatly shortens the time occupied by the planting tank. This method of concentrating Jiyang is very useful for leafy vegetables with a short growth period, but not very useful for fruits and vegetables with a long growth period.

Requirements for the liquid level in the tank after formal planting-After the planting cup with seedlings is moved into the planting plate on the planting trough, it is formal planting. When the root system does not stick out of the cup or only a few sticks out in the initial stage of planting, the liquid surface is required to soak 1-2cm from the bottom of the cup so that each seedling has the same opportunity to absorb water and nutrients in time. This is a key measure to ensure that the plants grow evenly and there will be no large and small seedlings. However, the liquid level should not be adjusted too high so as to stick to the bottom of the planting plate, hinder the diffusion of oxygen into the nutrient solution, and also soak the root neck of the plant, causing it to suffocate and die. When the plant sends out a large number of roots and penetrates into the nutrient solution, the liquid level is lowered and the space is expanded, and the root segment exposed to the humid air is longer, which is very useful for solving the root system's respiratory aerobic demand. Due to hanging cultivation, most of the weight of the plant and root system is not pressed at the bottom of the planting trough, but many root systems float in the nutrient solution, which will not form a thick root pad to block the circulation of the nutrient solution at the bottom of the root system, and avoid the cause The formation of a thick root pad causes severe hypoxia and necrosis inside the root pad, which completely overcomes this outstanding shortcoming of the nutrient liquid membrane technology.

Configuration and management of nutrient solution-at the beginning of planting, the liquid level should be immersed in the planting cup by 1-2cm. When the root system penetrates into the nutrient solution a lot, the liquid level should be lowered accordingly so that more root segments are exposed to the air. Facilitate breathing and save the energy consumption of circulating itchy filling. In this case, the roots exposed to the moist air will regenerate and need root hairs. These roots with many root hairs cannot be soaked in nutrient solution for too long, otherwise they will be necrotic and damage the entire root system, so the page cannot be without Arbitrarily rise and fall regularly. In principle, after the liquid level is lowered, if the upper root segment has produced a large amount of root hairs, the liquid level will stabilize at this level. It should also be noted that the amount of liquid remaining at the bottom of the tank is sufficient for the plant to absorb water for 2-3 days, and it should not drop too shallow to maintain the plant's water absorption for one day. In production, attention should also be paid to the problem that the water pump cannot supply liquid except for failure or power interruption.

Establish a scientific and efficient management system-this is necessary for socialized mass production. Each technical department and each technical measure must have a dedicated person responsible, clarify job responsibilities, establish management files, list the items that need to be recorded, make tables and work diaries, and register them item by item. Only in this way can we make a scientific analysis of the problems in production, so that it can be effectively solved. A scientific management system is a necessary guarantee for the functioning of advanced science and technology. Without a scientific management system, it is difficult for advanced science and technology to play a role in increasing productivity.

Evaluation of DFT

advantage

1. Deep liquid layer. The root system stretches into the deeper liquid layer, and a single plant occupies a lot of liquid. Due to the large and deep liquid volume, the concentration of the nutrient solution, dissolved oxygen, pH, and temperature per pound of water are not prone to drastic changes, providing a stable growth environment for the root system.

2. Hanging cultivation

The plants are hung on the planting board, which has the nature of semi-hydroponic and semi-aerobic culture, which makes it easier to solve the water-gas contradiction in the root system.

3. Circulation of nutrient solution

Increase the dissolved oxygen in the nutrient solution; eliminate the local accumulation of harmful metabolites on the root surface; eliminate the nutrient concentration difference between the root surface and the extra-root nutrient solution, so that nutrients can be delivered to the root surface in time, and more fully meet the needs of plants; The precipitated and ineffective nutrients are re-dissolved to prevent the occurrence of nutrient deficiency. Therefore, even if it is cultivated marsh plants or plants that can form oxygen transport tissue, it is necessary to circulate the nutrient solution.

4. There are many types of crops suitable for cultivation. Except for root and tuber crops, almost all fruit vegetables and leafy vegetables can be cultivated.

5. High nutrient utilization. It can reach more than 90-95% and will not or rarely pollute the surrounding environment.

shortcoming

1. The investment is large and the cost is high, especially the permanent deep-flow hydroponics facility is higher than the assembled one.

2. Higher technical requirements. The technology of deep-flow hydroponics is higher than that of substrate cultivation, but it is lower than that of nutrient liquid membrane.

3. The disease is easy to spread. Since deep-flow hydroponics is carried out in a relatively closed environment, and the nutrient solution is recycled, once root diseases occur, it is easy to cause mutual infection and even cause cultivation failure.