Lotus root is one of the aquatic vegetables people like to eat. Most of them are cultivated in open field and harvested in late July. In recent years, I have been exploring the use of greenhouses for winter and spring cultivation, so that the harvest time of lotus roots advance to early June. On the one hand, it can be combined with open cultivation to achieve the annual supply of fresh pods to meet the market supply of off-season vegetables, and on the other hand, it can increase the economic benefits of lotus root production. Now we introduce the technology as follows: 1. Build a greenhouse and choose sheltered from the sun, irrigation and drainage Convenient, sizeable paddy fields or rice fields to build sheds. Greenhouses are generally 10 meters wide, 50 meters long and east-west. In the north, a 1.8-2.5 m high earth wall is built, and on the east and west sides, a sloped earth wall with a slope of 20-30 degrees is built. In the shed, a wooden or cement column and a bamboo stand are used, and a shed film is put on top to cover the grass according to climate conditions.苫 Or indoor fire heat. Second, soil preparation, seed selection and planting, basal fertilization before the construction of the shed, a good place. Choose early-maturing varieties with high yield, strong cold resistance and vigorous growth. The selected pod species need to be hypertrophied, with thick axillary buds, complete apical buds, lateral buds, and leaf buds. The hoe, lotus root, and back stem should be complete in order to ensure that the new plant grows vigorously. The digging species must be digged, transported, and planted. The planting time is from December to February of the following year. The planting density was 1 meter spacing and the row spacing was 1.5-2.0 meters. At the time of planting, the top buds of the seed pods are slightly deeper into the mud, generally about 15 cm, so as to prevent over-emergence of shallow floating dead-end buds and timely irrigation after planting. Third, to maintain water temperature control? If you choose good water retention along the lake rice soil, do not need underground film preservation. After planting, the water layer is 3 to 5 centimeters during the day and 5 to 10 centimeters in water at night or in cloudy weather. If the weather is mutated cold, add water to prevent freezing and heat. When a floating leaf appears, keep the water depth 5-10 cm. After 2 or 3 true leaves appear, keep the water depth 10-20 centimeters. In mid-March, after the lotus leaf covers the roof, the outdoor temperature gradually increases and the water depth is maintained at 5 to 7 cm. At noon when the outside temperature reaches around 20°C, the temperature inside the shed may be as high as 30°C or more, and it must be shaded or ventilated in time. When the average temperature rises to about 20°C on that day, grasshoppers and shed films can be removed and the water level is maintained at about 10 cm. Fourth, fertilization and weeding lotus root lotus needs large amounts of fertilizer, and the need for nitrogen, phosphorus, potassium with a suitable proportion, should be reused base fertilizer, generally accounted for 70% of the total fertility required for fertility, top dressing accounted for 30%. Base fertilizer can be applied at the site preparation. Generally, 5000 kg of quality circle fertilizer per mu, or 2000-2500 kg of human excrement, or 1000-1500 kg of large manure, and 100-200 kg of plant ash, 50 kg of diammonium phosphate and 20-30 kg of urea. Fertilizer should be in the 2 to 3 true leaves appear and in late April to early May after the film was lifted, the topdressing 1 times, each time per mu recovery of human waste 1000 kg or urea 10 to 15 kg. In late April, for the pre-scarring period, 10 kg of potassium sulfate can be topdressed, but the amount of nitrogen fertilizer applied should not be too large to prevent the upper stem and the lotus leaf from becoming mad and greedy, delaying the period of scarring. Protected cultivation of lotus root, due to the low temperature, slow growth, before the lotus leaf seal line, prone to weeds, to be repeated weeding. Especially in the newly opened fields along the lake, weeding is the key to success or failure of greenhouses. Before the topdressing, we must first pull the net weed or weeding while wetting the top. After fertilizers are applied, they must maintain about 10 cm of water, and prevent fertilizer and water loss. Fifth, the prevention of pests and diseases? Lotus root disease is mainly corruption, the early stages of disease should be timely removal of diseased plants, with 200 times 50% carbendazim 200 times acupuncture or spray. Insect pests include aphids and leaf-living chironomid, which can be treated with 10% imidacloprid 1500 times or 25% enemy-killed 2000 times spray, and can be used as a chimpanzee for lotus leaf latent leaf, using 35% oviparous net emulsion 1.500 times or 25% quetiapine Phosphorus 1500 times spray control. Sixth, harvest? Into the month of June, lotus root is full of fat, you can harvest Nenbu listed. When digging, dry the water first, then remove the upper layer of soil and carefully pry the rake out. ?