(1) Precision seeder system
According to the different working principles of seeder, precision seeder has two types: vacuum adsorption type and mechanical rotation type. Vacuum adsorption seeder has no strict requirements on the shape and particle size of seeds, and seeds can be sown without pelletizing before sowing; However, the mechanical rotary seeder has strict requirements on the size and shape of seeds. Except for some varieties of cruciferous vegetables, the seeds must be processed into nearly spherical shapes before sowing. Comparatively speaking, the efficiency of the former is far less than that of the latter. The mechanical rotary seeder produced by Venture Company in California, USA, is selected for the two nursery farms in Beijing Huaxiang and Shuangqing, including substrate pretreatment, substrate mixing, tray loading, hole pressing, precise seed sowing, covering and water spraying after sowing. The precision seeder is the core part of this production line, and can sow 5 ~ 8 discs per hour on average. The top speed can reach 15 discs per hour.
(2) Plug tray
Because of the different materials, plug trays can be roughly divided into two types: American tray and European tray. American tray is mostly made of plastic sheets, while European tray is made of foamed plastic by injection molding. Comparatively speaking, American plug is more suitable for China. At present, American plug is mainly used in domestic seedling farms.
at present, the plug made by Po1yform company in the United States and the plug made in Korea are selected in China. The length of the plug in the United States is 54.9 cm and the width is 27.8 cm, and the depth of the hole varies according to the size of the hole. According to the number of holes and the size of holes, the trays are divided into 5-hole trays, 72-hole trays, 128-hole trays, 2-hole trays, 288-hole trays, 392-hole trays and 512-hole trays. Most of the trays imported from China are 72-hole trays, 128-hole trays and 288-hole trays, each with a volume of 4,63ml, 3,645ml and 2,765ml respectively. There are three kinds of American blister trays: heavy tray, light tray and ordinary tray. The weight of light tray is about 13 grams, and the weight of heavy tray is more than 2 grams. Buying light tray with specific gravity can save 3% of expenses, but in terms of service life, heavy tray is used twice as often as light tray. If carefully used, each tray can be used continuously for 2 ~ 3 years. Compared with American plugs, Korean plugs have a smaller volume of 72 holes, only 3186 ml. The volumes of 128 holes and 288 holes are larger than those of American plugs, which are 4559 ml and 299 ml respectively. The self-weight of each tray is more than 18 grams. The price is cheaper than the American plate.
(3) Seedling substrate
The nutrient area of plug seedling is small, and the mass of substrate contained in each hole is very small. Therefore, in order to cultivate high-quality commercial seedlings, a seedling substrate with good physico-chemical properties must be selected. The so-called good physico-chemical properties refer to the comprehensive characteristics of air permeability, water retention capacity, ion substitution capacity, plant fixation, substrate specific gravity and pH, and so on. At present, it is unanimously recognized that peat soil and vermiculite are both at home and abroad.
Lentinus edodes or Pleurotus ostreatus with broad-leaved sawdust and peanut shells as the main materials can be added to the seedling substrate according to a certain proportion after being crushed and screened.
(4) Nursery greenhouse
Greenhouse is the main equipment of nursery center, and about 5% of the expenses for establishing a nursery center are the purchase of greenhouse and greenhouse facilities. Energy-saving solar greenhouse should be used for seedling cultivation in the area north of the Yellow River, and its span should be more than 8 meters, and 37,5 ~ 45, seedling trays can be placed in each hectare of greenhouse. In the design, the lowest indoor temperature should not be less than 12℃ in winter, and temporary heating measures should be taken in case of low temperature weather. Non-drip film must be used in seedling greenhouse to prevent water droplets from falling directly into seedling tray. Pay attention to rain-proof, ventilation and sun-shading equipment when raising seedlings in summer. The supporting facilities in the greenhouse should also have a seedbed with packed holes and a walking sprinkler system. In order to maintain a good bed temperature condition in winter and spring, the seedling tray should be stacked on the bedstead, not directly on the greenhouse floor, and the height of the bedstead should be between 2 and 7 cm. In order to facilitate the management of watering and other operations, channels should be reserved at certain intervals when the seedlings are stacked.
(5) Germination accelerating room
The traditional vegetable seedling raising method is to soak the seeds with slow germination to accelerate germination, and then sow them. In plug seedling, bare seeds or pelleted seeds are directly sown into plug trays by precision seeder. In winter and spring, in order to ensure that seeds can germinate quickly and orderly, plug trays watered in the sowing workshop are usually sent to the germination accelerating room, where the trays are staggered and stacked on the bedstead. The indoor temperature is controlled between 2 ~ 33℃ and the humidity is above 95%. A 6-m3 germination accelerating room can be packed into 3, at a time.