1 Nutrient solution tank. The nutrient solution tank is a device for storing nutrient solution, which is generally made of bricks and cement and placed underground. Due to the large capacity of this nutrient solution tank, the temperature of the nutrient solution does not change much in both winter and summer. However, the use of nutrient solution tanks must be powered by the pump, so it must be used in a place where there is a power supply. The volume of the nutrient solution tank, generally 667m2 hydroponic area, requires a standard design of 5-7t water, and the specific width can be flexibly designed according to the greenhouse topography. The construction of the nutrient solution tank is a highly technical work. It is generally made of bricks and cement, but it can also be built with reinforced cement. In order to make the liquid tank not leak, seepage and water return, it is necessary to add impermeable materials during construction, and coat the inner wall of the liquid tank with water removal materials. In addition, in order to facilitate the cleaning of the liquid tank and maintain a certain amount of water for the water pump, a small water tank of 20cm square should be made at the corner of the liquid tank in the design and construction, so as to facilitate the cleaning of the nutrient solution tank.
2 cultivation beds. The cultivation bed is the site where crops grow and is the main part of the hydroponic facility. The roots of the crop are fixed and supported in the bed, and water, nutrients and oxygen are obtained from the cultivation bed. The cultivation bed is composed of two parts: the bed and the planting board (also known as the cultivation board).
l) Bed The bed is a device used to hold nutrient solution and grow crops. The cultivation bed body is made of polystyrene material. There are two types of bed sizes, one is 75cm long, 96cm wide and 17cm high. The other is 100cm long, 66cm wide, and 17cm high. Both sizes are used in combination according to the span of the greenhouse. The bed of this polystyrene material has the characteristics of light weight, easy assembly, etc., and has a service life of more than 10 years. In order to prevent the nutrient solution from leaking and protect the bed, a black film with a thickness of 0 15 mm and a width of 1 45 m is laid inside.
2) Cultivation plate The cultivation plate is used to fix the roots, prevent dust from entering, block the entry of light, prevent algae production and maintain the stability of the temperature of the nutrient solution in the bed. The cultivation board is also made of polystyrene board, 89 cm long, 59 cm wide, and 3 cm thick, with planting holes with a diameter of 3 cm arranged on top, and the distance between the holes is 8 cm 12 cm. The row spacing can be adjusted according to the needs of different crops. The service life of the cultivation board is also more than 10 years.
3. Feeding and discharging device and nutrient solution circulation. In hydroponic facilities, the nutrient solution is usually pumped into the cultivation bed by a water pump. The water level in the bed is maintained at a depth of 5-8cm, and the facilities for adding liquid to the cultivation bed are composed of an iron or plastic dosing main pipe and a plastic dosing branch, and the plastic branch pipe has a small hole with a diameter of 3mm every 1 5m. The nutrient solution flows into the cultivation bed from the small pores. The nutrient solution circulation path is that the nutrient solution is pumped out of the nutrient solution tank by the water pump, enters the cultivation bed through the liquid addition main pipe and the liquid addition branch, and is sucked by the crop roots. The nutrient solution that is higher than the discharge port flows back to the nutrient solution tank through the drainage ditch along the discharge port to complete a cycle.
There are many varieties of leafy vegetables suitable for hydroponics, and the leafy vegetable varieties suitable for hydroponics have been successfully tested by Beijing Vegetable Research Center after experiments include lettuce, chicory, kale, cabbage, cabbage, mustard greens, kale, purple-backed geranium, watercress, cress, celery, trifolium, amaranth, chives, potatoes, etc.