1 production environment The nursery site is far from the source of pollution and a buffer zone or physical barrier that isolates the conventional production area. 1.1 Air environment The air quality index of the nursery site reached the second standard level. 1.2 matrix soil environment The quality index of the substrate nursery soil reached the second standard level. 1.3 Water quality environment The indicators for nursery irrigation water use meet the three types of irrigation water quality standards. 2 preparation before seedling 2.1 Matrix selection You can choose to purchase the special substrate for floating seedlings, or you can prepare the seedling substrate by yourself. The raw materials are mainly peat, vermiculite and perlite. It is recommended to mix peat, coco, perlite and vermiculite in a volume ratio of 4:2:2:1. After that as a floating seedling substrate. 2.2 seedling tray selection A 200-hole floating tray with a size of 660 mm 340 mm and 50 mm was selected for seedling. The used seedling tray can be reused after being disinfected, sprayed or immersed in 0.1%~0.5% potassium permanganate solution and rinsed with water. 2.3 variety selection Select non-physical treated conventional seeds and reproductive materials, such as green and green amaranth, oil green and coarse amaranth and four or nine cabbages and other early-maturing varieties, as well as oil green 80 days, oil green 100 days and willow evening vegetables and other mid-late ripening Variety. 2.4 nutrient solution preparation Since the seedling substrate is basically free of or contains a variety of mineral elements required for growth and development of a small crop, it is necessary to select a non-chemical synthetic fertilizer that conforms to organic cultivation as a floating seedling nutrient solution. At present, the fertilizer sources applied to organic floating seedlings are mainly fermented biogas slurry and fish protein organic liquid fertilizer. In addition, during the nursery period, necessary nutrient solution management is required to maintain the float level at 10-15 cm, and the EC value of the organic nutrient solution is maintained at 1.0-1.5 mS/cm. If the plant grows with new yellow leaves and slow growth, it is necessary to promptly add or even replace the organic nutrient solution to the floating pool. 3 seeding process 3.1 sowing time Caixin can achieve annual production in Guangdong. Generally, early-maturing varieties can be sown from May to late September, and mid-maturing varieties are sown in mid-March to April and September to mid-October. Late-maturing varieties are suitable for mid-October. Sowing in March of the next year. 3.2 Seeding method The 200-well floating tray is filled with the seedling substrate, and the hole is punched with a hole plate and then artificially sown or mechanically sown. Seed 1~2 seeds per hole, and put them into the floating pool without covering the soil. After the cotyledons of the cabbage seedlings are unfolded, the seedlings can be started, and one strong seedling is selected for each hole. 4 pest control 4.1 rickets It often occurs in the seedling stage of plants. Control method: reduce the number of pathogens by disinfecting the seedling substrate and the reused seedling tray. In addition, it can be supplemented with 3109 CFU/g root type Trichoderma harzianum wettable powder 500g per 1 nursery substrate. If a diseased plant occurs during the nursery, the belt should be removed from the shed and the lime should be applied to the affected area for disinfection. 4.2 Yellow curved stripe Yellow-curved beetle, also known as dog mites, is the most difficult pest to control in cruciferous leafy vegetables. It is recommended to hang 4~6 yellow plates in each floating pool during the non-pest occurrence period to monitor the density of the yellow beetle. In the event of a yellow snapper, the number of yellow plates can be increased. 0.5 yellow plates are suspended per 1 m2 to trap the adult, or 7.5% rotenone EC 600 times + 1.5% pyrethrum is applied at the beginning of the yellow bark. The water emulsion is 400 times liquid control. 4.3 Lepidoptera larvae such as Plutella xylostella, Pieris rapae and Spodoptera litura Lepidoptera adults such as Plutella xylostella, Pieris rapae and Spodoptera litura are generally used as food sources for nectar and dew, and are less harmful to agricultural crops. However, its larvae are herbivorous and are important pest groups in agricultural production. Generally, a black light or a frequency-vibration insecticidal lamp can be set in the nursery shed to trap the adult to reduce the amount of eggs in the field. In addition, it is advisable to spray 32000 IU/mg of Bacillus thuringiensis wettable powder 800 times liquid + 0.6% matrine water agent 400 times before the 3rd instar larvae. Disclaimer: Some articles on this website are transferred from the Internet. 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