Introduction of soilless cultivation techniques for vegetables in the United States

related topicsThe United States was the first country to apply soilless cultivation to vegetable production. The main types of vegetables cultivated are tomatoes, cucumbers and lettuce. The yield of soilless cultivated vegetables in the United States is very high, the national average yield: tomatoes 135 to 150t/ha, cucumbers 135 to 225t/ha, dates 30 to 45t/ha. The high-yielding technical measures adopted by soilless cultivated vegetables in the United States are as: 1, the selection of good varieties
farmers attach great importance to the selection of good varieties suitable for soilless cultivation. The United States originally had a number of vegetable varieties suitable for greenhouse cultivation, but at present, soilless cultivation and production of vegetable seeds, many from the Netherlands to buy. Commonly used good varieties: tomatoes have Dombito, Rianto, Jumbo, cucumber have Daleva, Farbiola, etc. , ostinas, Salinas, Grand, Rapid and so on., choose the appropriate soilless cultivation system there are many soilless cultivation systems, according to different types of vegetables in the United States using appropriate soilless cultivation systems and related and facilities. Tomatoes, cucumbers mainly use substitly cultivated, its containers are mainly plastic bags, so also known as bagging, equipped with a set of drip irrigation facilities. The ferns are mainly cultivated using nutrient film, planted in white hard plastic pipes (about 8cm in diameter), equipped with a set of nutrient liquid circulation system, commonly used substations are: zircon, pearl rock, peat, rock wool, sand bark, wood chips, polypropylene foam and so on. Applications are often made with a mixture of substations, e.g. zircon (or pearl rock) 1 serving plus peat 1 serving, or mud 4 parts plus zircon and pearl rock 3 parts each. In recent years, rock cotton cultivation has developed rapidly, and most of the applied rock wool is Grodan rock cotton imported from Denmark. The substite and other substites can be applied continuously for two years, and the rock wool can only be applied for one year. The plastic bag developed by substring cultivation is often flat, white on the surface and black on the opposite side, and its size is generally 100cm×30cm × 8cm.third, the cultivation of short-age strong seedlings according to different soilless cultivation system, the use of the corresponding seedling methods, strictly control the environmental conditions of the seedling period, the cultivation of short-age strong seedlings. Rock cotton cultivation application rock cotton nursery, its size is generally 2 cubic meters, when planting will be seedling with seedlings into the rock cotton plate can be. For bag-peiling with other substrates such as zircon, seedlings are planted with plastic crucibles (with large bottom holes) and contained with substrates such as zircon and peat. Nutritional liquid film cultivation of the seedling with finger-shaped seedling small tube nursery, the tube put "fibre cotton" as the nursery substitut. With hand-held seeder in the finger-shaped nursery tube for fine seeding, seedling period strictly control the appropriate temperature and environmental conditions, generally: tomato 4 to 5 weeks, cucumber 3 to 4 weeks, 15 to 20d., good protection facilities the United States greenhouses or plastic sheds are relatively large, its single building span of more than 8m. The plastic shed is covered with polyethylene film and can be used continuously for 3 years. Often the application of double-layer film in the middle of the inflatable plastic shed, can increase insulation performance, energy saving 20% to 30%. Because the structure of greenhouses and plastic sheds is reasonable, the lighting conditions inside are good. In order to improve the indoor lighting conditions, soilless cultivation bed frame is mostly white, bag pei also uses surface white bag, to increase the reflection of indoor light. The temperature is raised indoors with hot air during the low temperature season. In summer, the "water curtain" method is widely used to cool down, which can be reduced by 5 degrees C compared to outdoors, but there are also spray methods to cool down, so as to regulate the indoor air temperature. Some greenhouses are also equipped with carbon dioxide generators, artificial lighting equipment, electric light sources using metal halide lamps or high-pressure sodium lamps, soilless cultivated vegetables are in strict environmental conditions in the protection facilities, these environmental conditions are using advanced automatic control equipment.