Asparagus, also known as asparagus, asparagus and glutinous rice, is a perennial plant in Liliaceae. Young stems of asparagus are green when exposed to light, which is mainly used for fresh food, but white when softened by soil, which is mostly used as raw materials for canned food. Asparagus contains protein, fat, calcium, iron and various vitamins. It is a valuable vegetable with delicious taste. At the same time, asparagus can be harvested continuously for 1 ~ 15 years once planted, growing all year round in the south and dormant in the north in winter. In the next year, asparagus will continue to grow. Asparagus has strong adaptability, easy cultivation, and lax requirements on temperature. The underground part can withstand the low temperature of -2℃ in the soil in winter and the high temperature of 35 ~ 37℃ in the growing period. It also has the advantages of less labor, convenient management and high yield in cultivation. Take a farmer's planting in Lao Zhang, Xinyuan Town as an example. In the first year, the total cost of planting was about 667 square meters of 8 yuan (including seedlings, fertilizer, labor and other expenses), and in the second year, the input cost was reduced to about 667 square meters of 3 yuan (mainly fertilizer, labor and so on). In the second year after planting, 25 kilograms of asparagus was harvested every 667 square meters, earning 2 yuan. Harvest 1 kilograms of asparagus every 667 square meters in the third year < P > I. Seed treatment < P > Soak in warm water at 25℃ ~ 3℃ for 3 ~ 5 days before sowing, change the water for 1 ~ 2 times a day, fish out the seeds after they have absorbed enough water, mix with fine sand or vermiculite, put them in a container, cover them with wet towels, and put them at 25 ~ 3℃ for germination, turning them twice a day.
second, raising seedlings
friends who are potted at home and planted in a small garden can raise seedlings by using peat soil or seedling soil with a seedling tray and seedling blocks with a seedling box, and the covering thickness is about 2-3 cm. It is best to raise seedlings at 25-3 degrees.
In agricultural production, use the following methods
1. Prepare the seedbed. The seedbed should be fertile and loose sandy loam, with 25-3 kg of decomposed farmyard manure, 2 kg of diammonium phosphate and 15 kg of potassium fertilizer applied to each mu of seedbed, which should be ploughed into the soil for fine soil preparation and made into the border with a width of 1.3-1.5 meters.
2. Raise seedlings in greenhouse. ① Preparation of nutrient soil: 3% of decomposed farm manure, 3% of peat, 2% of aged furnace ash and 2% of farmland soil (no pesticide residue) with 5g of diammonium phosphate per kilogram of nutrient soil; ② Seeding in nutrient pots (8× 12cm), sowing a seed in each pot, covering the soil with 2cm, and watering; ③ Temperature and humidity management, asparagus germination is suitable. It is advisable to keep the soil moist. After seedling emergence, the roots of seedlings are weak, water them in time during drought and weed them in time. 7 ~ 1 days before planting, the seedlings are tempered with large ventilation to adapt to the external natural environment and reach the standard of healthy seedlings. There are more than 3 aboveground stems and 5 ~ 7 underground storage roots.
3. Planting
1. Selecting land. Choose sandy loam with loose soil, good air permeability, high terrain, smooth drainage, deep soil layer and rich organic matter, with a suitable PH value of 5.8 ~ 6.7, and it is not suitable to grow carrots and beets in the previous crop.
2. Soil preparation and fertilization. Ridge with a depth of 2 ~ 25 cm, apply 3 kg of decomposed farmyard manure per mu and 25 kg of ternary compound fertilizer as base fertilizer. Ridge width is 1.2 ~. Plant spacing is 3 ~ 4 cm, dig a planting ditch with a spade, with a depth of 3 cm and a width of 3 ~ 4 cm. Apply 25 kg of ternary compound fertilizer and 15 kg of organic fertilizer per mu in the ditch, apply them into the ditch and mix them evenly, and then sprinkle the topsoil with a thickness of 1 cm. The center of the ditch is slightly high. Put the graded bamboo shoots into the ditch, one for each hole of big and strong seedlings and two for each hole of weak seedlings. Extend the root system around. It is convenient for management of soil cultivation and harvesting. Hold the seedling body with one hand, first cover a small amount of soil and compact it, then cover it with fine soil of 4-5cm, pour it with water, and cover it with soil of 1-2cm after the water seeps, so as to prevent hardening and water evaporation. Check the seedlings and replant them in time 3-4 days after transplanting to prevent the lack of seedlings.
iv. management after planting
15 days after planting, carry out intertillage weeding, loosen soil, ventilate and conserve moisture, keep soil moisture at 6% ~ 7%, water moderately in case of drought, and dig drainage ditches in rainy season to prevent water from rotting roots.
fifth, the year of picking bamboo shoots in the second year of planting and beyond
1. In order to go on the market early, the shed can be buckled according to the ridge, with the arch height of 3cm and the width of 4cm-5cm, and covered with plastic film. After the bamboo shoots are taken out, it is appropriate to have a temperature of 25℃, and if it exceeds 3℃, it should be ventilated and cooled in time. When the outside temperature reaches 2℃, the plastic film can be removed, and the height of bamboo shoots is generally 2℃. The following years will be the same. The green asparagus should be dark green in color, fresh and neat, the scales at the tip of the bamboo shoots should be tightly clasped and not lost, the bamboo shoots should be straight and not bent, deformed or corroded by insects, and the harvesting time should be 9-11 am.
3. The harvesting method is to cut off the tender stems neatly with a special stainless steel knife, and the stems should not be stubbled, and put them in a basket, covered with a wet towel and placed in the shade. Leave 1-2 robust stems per plant for photosynthesis. When the height reaches 7 cm, pick the core in time to control the plant height.
4 Apply fertilizer, accelerate germination and combine ploughing in spring. Ditching can be done at a distance of 3-5 cm from the plant, and 2 kg of ternary compound fertilizer can be applied per mu. Topdressing can be done once a month during the long bamboo shoot period, and 5-1 kg of ternary compound fertilizer or urea should be applied per mu, and watering should be done after topdressing.
VI. Prevention and control of pests and diseases
1. Diseases: The main diseases are stem blight and brown spot, and the prevention and control methods are mainly agricultural control, so as to thoroughly clean the fields in winter and spring, apply more organic fertilizers and potassium fertilizers, promote the plants to be strong, enhance the disease resistance, remove the accumulated water in the fields in time, reduce the humidity of underground water and fields, and control the disease conditions. The chemicals prevent and control 75% chlorothalonil 6 times and 7% thiophanate methyl 8 times. Prevention and control measures: Clean up the garden field and uproot weeds. It is forbidden to use unpolished farmyard manure. If pests are found, 5 grams of 9% trichlorfon crystals can be dissolved, 5 kilograms of fried corn flour can be added and mixed evenly to make poison bait, which can be spread in the pest area, with about 25 grams per small pile, or 1 times of 4% phoxim emulsifiable concentrate can be used to irrigate the roots.
Asparagus has strong adaptability to temperature, which is both cold-resistant and heat-resistant, and can be cultivated from sub-cold zone to subtropical zone. But it is most suitable for temperate cultivation with distinct seasons and pleasant climate. In the frigid zone, when the temperature is -33℃ and the thickness of frozen soil reaches 1 meter, it can still survive the winter safely. Although the yield is low, the quality is good. The initial germination temperature of asparagus seeds is 5℃, and the optimum temperature is 25 ~ 3℃. When it is higher than 3℃, the germination rate and germination potential decrease obviously. Breeding with seeds can continue to grow for more than 1 years. In winter, the aboveground parts wither in cold areas, and rhizomes and fleshy roots enter dormancy to overwinter; In warm areas in winter, the dormancy period is not obvious. The dormancy period is extremely resistant to low temperature. When the ground temperature rises above 5℃ in spring, the scale buds begin to sprout; The tender stems begin to elongate above 1℃; 15 ~ 17℃ is most suitable for bud formation; Above 25℃, the buds are thin, the scales are scattered and the tissues are aging; At 3℃, the bud elongation is the fastest; At 35 ~ 37℃, the growth of plants was inhibited, and even withered into summer sleep. The suitable temperature for photosynthesis of asparagus is 15 ~ 2℃. When the temperature is too high, the photosynthetic intensity is greatly weakened, the respiration is enhanced, and the photosynthetic productivity is reduced.
asparagus shoots new stems 2-3 times or more every year. Generally, the tender stems sprouted in spring are used for food, and their growth depends on the nutrient supply stored in the roots the year before. The growth of tender stems and the formation of yield are positively related to the number of mature stems and the lush 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 branching of rhizomes, the development of plant clusters tends to decline, the aboveground stems become smaller and smaller, and the yield and quality of tender stems gradually decline. Generally, 4 ~ 1 years after colonization is the productive period.
Asparagus is suitable for sandy loam rich in organic matter, and grows well in fertile soil with loose soil, deep soil layer, good fertilizer and water retention and good air permeability. Asparagus can tolerate mild saline-alkali, but when the soil salt content exceeds .2%, the plant development is obviously affected, the absorption roots shrink, the stems and leaves are thin and weak, and gradually die. Asparagus has strong adaptability to soil pH, and can be cultivated in any soil with pH between 5.5 and 7.8. And pH 6 ~ 6.7 is the most suitable. Asparagus has small transpiration and developed root system, and is relatively drought-tolerant. However, it is too dry in the bamboo shoot picking period, which will inevitably lead to tender stems, shrinking growth buds and serious yield reduction. Asparagus is extremely hard-working, and stagnant water will lead to root rot and death.
Asparagus can be divided into three types: early, middle and late. Early-maturing type stems are many and thin, while late-maturing type stems are few and thick. Asparagus is usually harvested from April to May in spring.
When picking bamboo shoots, be sure not to damage underground stems and scale buds. In the peak period of bamboo shoot production, it is harvested once a day in the morning and once a day in the evening. Green asparagus harvesters cut off the green asparagus when the tender stems are 23 ~ 26 cm high. Every harvest, whether good or bad, should be cut completely, otherwise the remaining tender stems will consume nutrients and affect the yield.
cultivated in southern China, there is no frost in winter, and asparagus can grow all year round without dormancy. In these areas, such as annual harvest, it is bound to affect the yield because there are too few nutrients accumulated in the underground. In order to make plants shoot more tender stems, a certain number of stems and leaves should be cultivated during harvesting to carry out photosynthesis and increase the nutrients needed for shooting tender stems.
selection, retention and renewal of mother stems. Before a large number of tender stems are produced every spring, all the mother stems are cut off. After cleaning the garden, fertilizing and ridging the soil, the plants will be encouraged to sprout strong new tender stems. Except for a few stout tender stems selected from the middle, which can be used as mother stems, the remaining tender stems are harvested in batches. When the tender stems become thinner, apply the second fertilizer. After fertilization, the tender stems become thicker, from which strong tender stems are selected one after another to cultivate new mother stems, and the aging mother stems are cut off in batches. In autumn, the climate is mild and the plants are suitable for growth. Let all the young stems grow into branches and leaves, and stop harvesting, so as to accumulate more nutrients underground and prepare sufficient nutritional conditions for the next year's bamboo shoots. The mother stems with diseases, disabilities and pests should be removed at any time. Where the mother stem is left, there should be 1 ~ 2 young stems in each place, so that each growing point of underground stem has more nutrient supply and can develop normally.
apply decomposed organic fertilizer once before selecting the mother stem. When the mother stem grows to 5 cm high, remove the top tip to inhibit it from stretching high and prevent lodging. Remove female flowers and young fruits to avoid consuming nutrients. Cutting off the mother stem should be carried out in sunny days to avoid cutting off the wound and infecting the disease in rainy days. Young stems are mainly harvested in spring and autumn. In summer, if the plants grow poorly in high temperature, the harvesting should be stopped for 4 ~ 5 days. Autumn harvest should stop at the end of October, not too long; Otherwise, the plant will accumulate too little nutrients, which will affect the yield in the next year. .