It's worth planting asparagus for 15 years at a time
Asparagus, also known as asparagus, is a perennial herb of asparagus. The young seedlings can be used for vegetable food. Asparagus is very popular with people. It is rich in nutrition and is one of the top ten famous dishes in the world and is known as the "king of vegetables". Asparagus is known as the king of vegetables because of its medicinal effect. Herbs are usually perennial through asparagus seeds plant Asparagus can be harvested continuously for more than 15 years from the second year except that it can not be harvested in the first year. Why don't we plant asparagus so well? It's worth planting asparagus for 15 years at a time!
The reason why asparagus is known as the king of vegetables is closely related to its medicinal and food functions. Asparagus not only contains a variety of proteins, vitamins, minerals and other elements necessary for human body, but also contains an element called "selenium". This element can prevent cancer cells from dividing and growing, inhibit the activity of carcinogens and accelerate detoxification, even reverse cancer cells, stimulate the immune function of the body, and promote the formation of antibodies. At present, asparagus is a variety of anti-cancer drugs and protection Raw materials of health products.
Herbs are usually perennial through asparagus seeds plant Asparagus can be harvested continuously for more than 15 years from the first year, and can be harvested except dormancy in winter, especially in spring and autumn, which can be harvested every day with sufficient water and fertilizer.
Asparagus has a strong adaptability. It is resistant to high temperature and cold. It can survive the winter safely in the severe cold of - 30 degrees in the north, so it can be used in both the north and the south plant 。 Asparagus is the best nursery plant from April to August, and from March to September in southern China.
Asparagus is planted in the first year for the development of its root system, which is similar to bamboo shoots. Asparagus root system is very developed, its root system can reach more than 2 meters. Asparagus Planting In the spring of the second year, a small amount of fruit can be picked, and the harvest period can be as long as 15 years from the third year. If the family grows more than ten asparagus trees, they really don't have to buy asparagus at a high price.
Asparagus is so good, my dear friends, come and have a try.
Asparagus has strong adaptability to temperature. It is cold resistant and heat-resistant. It can be cultivated from sub cold zone to subtropical zone. But it is most suitable for temperate cultivation with four distinct seasons and pleasant climate. In the alpine zone, when the temperature is - 33 ℃ and the thickness of permafrost reaches 1 m, it can still survive the winter safely. The initial germination temperature of asparagus seeds was 5 ℃, and the optimum temperature was 25-30 ℃. When the temperature was higher than 30 ℃, the germination rate and germination potential decreased significantly. It can grow continuously for more than 10 years by seed propagation. In winter, the root is not withered.
It is extremely resistant to low temperature during dormancy. When the ground temperature rises to above 5 ℃ in spring, the buds begin to sprout; the tender stems begin to elongate above 10 ℃; the most suitable temperature for bud formation is 15-17 ℃; the tender buds are thin and weak above 25 ℃, the scales are scattered and the tissues are aging; the buds at 30 ℃ extend fastest; the plant growth is inhibited at 35-37 ℃, even withers and enters into the summer sleep. The optimum temperature for asparagus photosynthesis is 15 ~ 20 ℃. When the temperature is too high, the photosynthetic intensity is greatly weakened, the respiration is strengthened and the photosynthetic production rate is reduced.
Asparagus sprouts new stems 2-3 times a year or more. Generally, the young stems sprouted in spring are used for food, and their growth depends on the nutrient supply stored in the roots in the previous year. The growth and yield formation of young stems were positively correlated with the number of completed stems and the degree of branches and leaves in the previous year. With the growth of plant age, the number of tender stems and yield increased year by year. With the continuous development of rhizome, the development of plant cluster tends to decline, the aboveground stem is becoming smaller and smaller, and the yield and quality of tender stem also gradually decline. Generally, 4-10 years after planting is the peak production period.
Asparagus is suitable for sandy loam soil rich in organic matter, and grows well on the fertile soil with loose soil, deep soil layer, fertilizer and water conservation and good air permeability. Asparagus can tolerate mild saline alkali, but when the soil salt content is more than 0.2%, the plant development is obviously affected, the absorption roots shrink, the stems and leaves are thin and weak, and gradually wither. Asparagus has a strong adaptability to soil pH, which can be cultivated in the soil with pH between 5.5 and 7.8, and pH 6-6.7 is the most suitable.
Asparagus has low transpiration, developed root system and drought tolerance. However, if the shoots are too dry, the tender stems will be thin and weak, the growth buds will shrink back and the yield will be seriously reduced. Asparagus is extremely resistant to waterlogging, and waterlogging can lead to root rot and death. Therefore, the planting area should be high and dry, pay attention to drainage in rainy season. 
There are two propagation methods of asparagus: ramet propagation and seed propagation.
It is through the excellent and high-yield seed plant, dig out the root, after dividing the underground stem, planted in the field. The advantages of this method are that the characters of plants are consistent and neat, but they are laborious, time-consuming, inconvenient to transport, weak growth after planting, low yield and short life span. Generally, it is only used for breeding and cultivation of improved varieties.
It is easy to transport, with large propagation coefficient, strong growth, high yield and long life. This method of reproduction is often used. Seed propagation can be divided into direct seeding and seedling raising.
Direct seeding cultivation
It has the advantages of early plant height, early growth and strong yield. However, it has some disadvantages, such as low emergence rate, large amount of seeds, difficult management at seedling stage, easy breeding of weeds, uneconomical land use, high cost, shallow distribution of roots and plants, easy lodging of plants and short economic life. Therefore, asparagus is not widely used in areas with large land, warm climate and long growth period. However, since the 1970s, due to the popularization of plastic film mulching technology and herbicides, the problems of low seedling emergence rate and weed breeding have been solved, and the application has gradually increased. 
It is the most commonly used method in production. It is convenient for careful management at seedling stage, with high seedling emergence rate and less seed consumption. It can shorten the cultivation period of roots and plants in the field and improve the land use efficiency.
(1) Seedling raising
Asparagus can be divided into small seedling and large seedling according to its seedling age. According to the place and method of seedling raising, it can be divided into open field direct seeding, protected field sowing and seedling raising, etc.
The seedling age is 60-80 days, the seedling height is 30-40 cm, and the number of stems is 3-5. Generally, it is sown in the protected field in cold season and planted in the field after the final frost, so as to prolong the growth season in the year. This kind of seedling is easy to plant, time-saving, labor-saving, and will not damage the root, not easy to infect soil diseases. The growth and development of the plant after planting is rapid, which can greatly shorten the formation period of plant cluster. Generally, it is sown from February to march in the Yangtze River Basin and North China, planted in May, and harvested in the following year. However, in the early years of planting, the coverage of branches and leaves in the field is low, and it is easy to be damaged by grass, and the plants are easy to fall down due to shallow planting. Therefore, we should pay attention to weed control and soil cultivation for many times.
Big seedlings are also called annual seedlings. Generally, the seedling age is as long as 5 months, and the frost free period is short in high and cold regions, and it takes one year. It has the advantages of convenient seedling management and rotation arrangement, can be deeply planted, and later grow out of the ground stem is thick, and the number of stems is less, it is not easy to fall down, the coverage of branches and leaves in the early planting year is large, and the weeds are less. However, seedling and planting are laborious and laborious, with heavy root injury and susceptibility to soil diseases; the growth and development of root plants are slow, and the early yield and total yield are low. However, in the cold area with short annual growth period, the cultivation period of field plant cluster can be shortened, and the survival rate of planting in arid area is high. Therefore, this method is still used in cold areas and areas with less annual precipitation. In the range of 20-2500cm, the effective root weight is 30-100cm.
(1) Selection of open field nursery site open field nursery is often used to cultivate large seedlings, and large seedlings have a long period, seedling height, and many and long roots. Therefore, it is necessary to have a good seedling field in order to cultivate strong seedlings.
The following points should be considered in the selection of nursery land:
Firstly, the seedling ground should be suitable for the development of asparagus root system, which is conducive to the growth of seedlings, and at the same time, it is easy to start seedlings and separate seedlings. Generally, the soil with loose soil, rich organic matter, low groundwater level, good drainage, strong water holding capacity, slightly acidic, pH 5.8-6.7 is suitable. Do not choose sticky soil to grow seedlings, otherwise the fleshy roots between plants will adhere to each other, which will cost labor to start and separate seedlings, and will cause serious root damage.
Secondly, soil without Rhizoctonia solani and purple feather disease should be selected. In order to avoid the spread of these two diseases in seedling stage. Therefore, any land with these two diseases, such as orchard, mulberry garden, carrot, cotton, ramie and so on, should not be used as nursery ground, and even less suitable for continuous cultivation with asparagus.
Third, asparagus seedling growth is very slow, and the row spacing is large, easy to breed weeds. Therefore, we should choose the land with few weeds, especially perennial weeds.
(2) Soil preparation
In order to make the seedlings grow vigorously and the root system develop well, 30000 kg of rotten manure was applied per hectare and ploughed into the soil. In places with high soil acidity, 1130 kg of hydrated lime should be spread to correct soil acidity. Shallow ploughing is required in order to avoid the root system entering into the soil too deep, which is not conducive to seedling. In order to prevent the damage of underground pests, 15kg of phoxim per hectare was mixed in the soil during soil preparation, and then a 1.5m wide high border should be built, and drainage ditches should be dug to facilitate drainage and irrigation. Generally, the ratio of seedling nursery to field is 1:10.
If the seedlings are raised in nutrient bowl, it is better to prepare nutrient soil. Nutrient soil should be fertile and loose, keep water and air permeability, increase soil temperature easily, and be free of pathogens, pests and weeds seeds. Generally, 5 parts of clean garden soil, 2-3 parts of rotten compost, 1 part of river mud, 1 part of plant ash, and 2% - 3% of superphosphate are used. They are fully mixed, sprayed with 100 times solution of 40% formaldehyde, and then piled up into piles, sealed with plastic film, so as to fully fumigate, decompose and ferment, and kill the seeds of pests and weeds. If the soil acidity is large, lime should be added for correction. The composting should be carried out in summer. Before sowing the next year, the soil should be placed in a nutrient bowl with a diameter of 6-8 cm.
① The results showed that the seedling growth of asparagus should be based on the temperature requirements of seed germination
It depends on the development law, ecological conditions and cultivation methods.
First of all, according to the requirements of seed germination temperature. Open field sowing should start at the ground temperature above 10 ℃. When the ground temperature is above 30 ℃, it will hinder seed germination and young stem growth, so it is not suitable for sowing. In addition to spring sowing, it is also feasible to plant in spring.
Secondly, the sowing date is determined according to the accumulated temperature standard required for seedling growth. In general, the accumulated temperature of standard seedlings is 2500-3000 ℃. In this way, in the cold zone, due to the short growth period, we should strive for early sowing in spring, otherwise the growth period is insufficient, because the seedlings are small and the sugar content of roots is low, it is easy to suffer from freezing injury in the overwintering period. Sowing should be delayed in areas with long growing season to avoid excessive seedling size.
Thirdly, seedlings should be sown 60-80 days before planting. On the premise of no frost damage, the earlier the seedlings are planted, the longer the growth period is, the more robust the root plant development is, the more storage nutrients are accumulated, and the higher the yield of the next spring harvest is, which will continuously affect the yield of the following years. Therefore, the ideal sowing and seedling raising period of seedlings should be 60-80 days before the final frost or the safe planting period. If it is necessary to postpone sowing and seedling raising due to crop rotation, it is also necessary to arrange early sowing and early planting in the previous stubble. Otherwise, the superiority of seedling planting can not be brought into full play, and the survival rate of seedling planting will be reduced due to late planting, warm and rainy weather, and more plants missing due to warm and rainy weather.
② Sowing rate
The sowing rate should be conducive to stem and leaf extension and root development, ventilation and light transmission, and reduce disease occurrence. In addition, it should be determined according to the seed germination rate.
Generally, the row spacing of big seedlings is 40-45 cm, and the hole spacing is 10 cm. Two seeds are sown in each hole, and the seed spacing is 3 cm. The sowing rate per hectare nursery is about 3750g, which can be transplanted to 7-10 ha. When sowing, dig a 3 cm deep sowing ditch according to the row spacing, and then plant the seeds according to the plant spacing, cover with soil 1-3 cm, and slightly suppress.
When transplanting seedlings, the sowing rate per square meter is 30-40 grams, and there are more than 1500 seeds. Before sowing, sufficient bottom water should be poured and 1-2 cm thick soil should be covered after sowing. When the first stem is 10-15 cm high after emergence and the second stem is not sprouted, the seedlings should be transplanted separately. The row spacing was the same as that of direct seeding.
Large seedling planting, generally suitable in cold bed or warm bed, row nutrition bowl seedling. The diameter of the nutrition bowl is 6cm. Two seeds are sown in each bowl, the grain spacing is 3cm, and the covering soil is 1-2cm thick. After emergence, only seedlings were kept in each pot. If it is directly sown on the bed soil, the row spacing should be expanded to facilitate seedling emergence and reduce root damage. Generally, the row spacing is 20 cm and the grain spacing is 5 cm. It is better to use the prepared culture soil for the development of root and seedling.
③ Methods of promoting seed germination and emergence
As asparagus seed is leathery, poor water permeability, slow water absorption, different dormancy depth, slow germination at low temperature and long emergence period, the following methods can be adopted to accelerate the germination and emergence of asparagus seeds:
Seed soaking: before sowing, the seeds were soaked in water temperature of 20-25 ℃ for 2 days (new seeds were soaked in water temperature of 35 ℃ for 2 days). Change the water every morning and evening.
Low temperature treatment: the new seeds were soaked and treated at 0-5 ℃ for 60 days, or the seeds and wet yellow sand were accumulated in the open field for winter, so as to complete the dormancy period.
Seed selection: 1 year old seeds should be selected for sowing, but should be kept in a dry and airtight place.
Watering: pay attention to water supply from sowing to emergence to prevent drought. When sowing in dry season, the bottom water should be poured thoroughly, and sowing should be done when the soil moisture content is suitable. After sowing, plastic film should be covered to prevent water evaporation, increase soil temperature and promote seed germination.
Temperature: the area with long frost free period should be planted late and sowed when the temperature is higher. Where the frost free period is short and must be sown early, as well as in the case of seedling colonization, the seedlings can be raised in the protected field or sowed in the protected field, and then transplanted to the open field nursery after emergence and leaf expansion. The bed temperature should be maintained between 20 ℃ and 25 ℃ during seedling emergence.
(4) Seedling management
① When there are two seedlings in each hole, one should be removed. In case of lack of plants, replanting should be done with the seedlings pulled out from between or with the seedlings prepared in advance.
② In general, the seeds should be kept warm and moist after sowing, and the temperature should be kept above 20 ℃. After germination and emergence, ventilation should be paid attention to. The temperature should not exceed 30 ℃ during the day, and water should be often used to avoid soil drying. In order to promote the growth and survival of the transplanted seedlings, water should be controlled and the temperature should be lowered to refine the seedlings. Generally, the temperature is about 15 ℃ during the day and 10 ℃ at night. The transplanting of seedlings should be carried out under the condition of suitable humidity in the field, and the seedlings should be watered immediately. Before the transplantation, when it is in strong sunlight, reed curtain or black shading net should be used for shading for about 1 week.
③ The growth of asparagus seedlings is slow, and the row spacing is large, which is easy to breed weeds. Therefore, it is necessary to often cultivate weeds or spray herbicides to control them. Generally, 1500 g of herbicide liguron was used per hectare, and 1500 kg of water was added. The border and furrow were sprayed 3-5 days after sowing, but manual weeding was still needed after 2 months.
④ In the management of fertilizer and water, after thinning or transplanting, the thin liquid fertilizer of human manure and urine was poured once, 10500-15000 kg / ha. About 20 days later, trace the thin human feces and urine once more. Then, from July to August, the fertilizer was applied in autumn, about 300 kg per hectare. If the seedlings grow vigorously at this time, less or no application can be applied. In order to avoid excessive fertilizer, excessive growth of stems and leaves, lodging, and poor ventilation and light transmission, easy to induce stem blight and brown spot disease.
In addition to sufficient water supply after seed sowing and slow seedling stage of seedling transplanting, water should be regularly watered in case of dry weather during the growth period, so as to avoid drought damage and promote seedling growth. Generally, water is applied every 5-7 days to keep the soil dry and wet. However, water should be controlled one month before frost to inhibit the growth of aboveground parts and transfer nutrients to underground rhizomes for storage. In rainy season, we should pay attention to open ditches and drainage, do not make the field ponding, otherwise it is not conducive to the development of root system, but also easy to induce disease.
(5) Management of nursery in protected area
The management of temperature and water should be taken as the center in the management of seedling stage under plastic shed and other facilities. From sowing to emergence stage, in addition to providing sufficient water and covering the surface of bed soil or nutrient bowl with plastic film for moisture preservation, the surrounding of plastic film should be sealed and kept warm, and the greenhouse temperature should be kept as high as possible to accelerate the emergence of seedlings. After emergence, the plastic film should be removed and ventilation should be carried out to reduce the bed temperature, so as to prevent the young stem from growing too long and lodging. As the outside temperature rises, the ventilation rate should be increased. At night, we should cover with plastic film and straw to avoid frost damage and frost damage. Generally, the bed temperature is maintained at about 25 ℃ during the day, the maximum temperature shall not exceed 30 ℃, the minimum temperature at night is 12-13 ℃, and the daily average temperature is about 20 ℃. Because of frequent ventilation, the bed soil is very easy to dry, and the nutrition bowl seedling is easy to lose water, so it should be watered frequently. Generally, water is given every 3-5 days. The first application of urea was 105-150 kg per hectare after the first young stem was spread out, and then applied again about 20 days later.
Thinning was carried out when the second young stem was about to take place, and each pot (hole) was selected to stay. Thinning seedlings should be prized loose the culture soil and removed with roots, otherwise the remaining roots will still sprout stems and leaves.
When the height of the seedling is more than 25 cm and the number of stems is 3-5 branches, it is necessary to remove the plastic film before planting in the field to make the seedlings in the open bottom condition, and control the water supply, so as to enrich the roots, adapt to the field environment, shorten the slow seedling period, and develop new roots early.