Timely cultivation of licorice

I. seed germination habits

(1) the water absorption of licorice seeds and the emergence rate of germinated licorice seeds are low, generally about 10%, so they should be treated before sowing. The untreated seeds absorb water very slowly and most of the seeds do not absorb water; the seeds treated with concentrated sulfuric acid absorb water very quickly, reaching more than 100% in 4 hours. Generally speaking, when the water absorption is more than 100%, it has a very neat germination ability. If the water absorption is different, the germination rate is different. when the water is absorbed for more than 1.5 hours at 2O ℃, the germination rate is more than 80%, and the water content is about 95%. After 4 hours, the germination rate can reach about 90%, and the water content is more than 150%.

(2) the effect of temperature on germination the germination rate of untreated seeds is very low under various temperature conditions, while the germination rate of seeds treated with concentrated sulfuric acid is greatly increased under different temperature conditions. For example, the germination rate can also reach 63.3% under the condition of 10 ℃, but the germination rate is fast and neat under the condition of 25 ℃; if the condition is less than 10 ℃, the germination rate decreases to 59%. It can be seen from above that imbibition at low temperature has a harmful effect on seed germination. Licorice, like the seeds of many legumes, is sensitive to low temperature and prone to chilling injury. Therefore, it is better to sow seeds at 15 ℃ in production. If the temperature is lower than this, it is easy to cause chilling injury and affect the production.

Second, growth and development and its requirements for environmental conditions Glycyrrhiza uralensis belongs to xerophytic plants, and Glycyrrhiza uralensis has the strongest drought tolerance. The annual precipitation in its growing area is mostly within 1OOmm, and even only 15mm. Even if the groundwater level is 1-8m deep, it can grow and develop, and some can form communities. The aboveground part of Glycyrrhiza uralensis dies every year at the end of autumn, overwintering with roots and rhizomes in the soil, and new buds grow from the rhizomes in the early spring of the following year. Its buds grow rapidly upward, with long branches and leaves, luxuriant branches and leaves from May to June, blossom and bear fruit from June to July, and pods mature and fall to the ground in September. In the wild, because the soil drought is not conducive to seed germination, it is rare to see the seedlings of seed propagation. The rhizome of Glycyrrhiza uralensis has a strong germinating power and extends horizontally around the old plant dozens of meters below the surface. Dozens of new plants can be produced from a licorice plant in several years, and new plants can grow at a distance of 3-4 m away from the mother plant 3 years after planting. Its vertical rhizome and horizontal rhizome can grow roots, and the depth of the root system varies according to the soil quality and the depth of the groundwater table, generally in the range of 1-2m, and some are as deep as lOm. The deep root system absorbs groundwater to adapt to the arid environment. Licorice is distributed in continental climate zone, which is mainly characterized by drought, large temperature difference, severe cold in winter, temperature of-40 ℃-(- 30 ℃), permafrost depth of more than 1 m, and extremely hot summer, strong light, less rain and air relative humidity of 30% and 40% in open desert and semi-desert areas. Because licorice has the characteristics of cold resistance, drought resistance, like light and heat resistance, it grows well under the above ecological conditions. It is not only an indicator plant of calcareous soil, but also a plant with strong salt resistance, and the soil salt content should not exceed 0.2%.

III. Methods of reproduction

(1) this method is often used in new producing areas.

1. Seed collection and seed treatment direct seeding licorice blossomed and fruited in the 4th year, and rhizome and ramet propagation could blossom and bear fruit ahead of time. After the seeds matured in August and September, the seeds were cut and dried, and the seeds were obtained by rolling and stored in a ventilated and dry place. There are wild distribution places can be collected in the field, because licorice seeds contain sweeteners, the rate of insect borer is high, should be soaked, Amoy to float above the moth-eaten seeds. In addition, licorice seed coat is hard, impervious to water and air, hard seed rate is high, not easy to germinate, need to be treated before sowing.

The germination rate of untreated seeds is only 30%, 40%, and the germination rate should be increased by breaking the skin. The specific methods are:

The main results are as follows: (1) crushing method: type 20 vertical centrifugal rice mill is used to collide seeds, in the process of seed collision. The central grinding wheel of the rice grinder can break the seed coat in the rapid rotation, so that the seed is easy to absorb water and germinate, and the place where the rice grinder can not be found temporarily can be replaced by milling. This method is fast and simple, the treatment capacity is large, the seed decay rate after treatment is low, and the germination rate can reach more than 90%. It is a method commonly used in domestic producing areas at present.

(2) friction method: mix and rub the coarse river sand or glass slag with the same amount of seeds for 1 hour, then soak in water for 12 hours, and then continue to rub hard and repeatedly for 2 times and 3 times. This method can make the germination rate reach more than 80%. But the treatment capacity is small, the efficiency is low, and the seed decay rate is high, so it is suitable for a small amount of planting.

(3) sulfuric acid method: add 2OmL 80% concentrated sulfuric acid per kilogram of seeds, mix them evenly with wooden sticks, make all seeds stick with sulfuric acid, soak seeds in 20 ℃ environment for 3 hours, rinse off concentrated sulfuric acid repeatedly after the seed coat is burnt, and the germination rate can be increased to more than 85%. The advantage of this method is that the first treatment capacity is large, but the disadvantage is the change of ambient temperature, the treatment time is not easy to grasp, too long, it is easy to make the seed burn lose its germination power, and it is too short to break hard. And concentrated sulfuric acid is easy to injure people and animals carelessly, and it is not often used in home planting areas.

two。 Sowing is divided into direct seeding and seedling transplanting.

(1) Direct broadcast: the seeds can be sown from April to July every year. In areas without irrigation, it is best to sow seeds in the rainy season. Sow seeds with a seeder or rice on the ground where the base fertilizer is fully applied. Line spacing 50cm, deep 3cm. The sowing rate per mu of irrigated land is 1.5kg, and the sowing rate of dry land or land with poor soil moisture can be increased appropriately. After sowing, the grass can be covered and moisturized, and the seedlings will emerge in about 1-2 weeks.

(2) Seedling transplanting, that is, first raising seedlings in the nursery for one year, and then transplanting the seedlings into the field the following year. Sowing method is the same as live broadcast, line spacing 3Ocm. Transplanting is generally carried out in late autumn and early spring, and the one-year-old seedlings are planted according to the row spacing of 5Ocm × 30cm on the ground with sufficient basal fertilizer. 6000-7000 plants can be planted per mu. After planting, the first and second watering must be thoroughly watered, and the field management work should be done well in the future.

(2) this method is mostly used in the old producing areas. The expansion of Glycyrrhiza uralensis population is mainly through the horizontal underground rhizome germination of new plants, one plant can produce dozens of new plants. Rhizome propagation is to dig out the rhizome in the spring and autumn, cut into 7-8cm segments, each section has 1-2 buds, according to soil moisture, buried in the ground about 13-16cm, can germinate new plants. The distance between rows and plants is the same as raising seedlings and transplanting. Ramet propagation is to dig out the new plant next to the old plant in the spring and autumn, plant it separately, and plant the seedlings at the same time.

IV. Field management

(1) the seedling height 6cm of direct seeding in the current year should be 10-15cm in the planting year, and the plant spacing should be 3Ocm in the second year.

(2) drainage and irrigation water, no matter direct seeding or rhizome propagation of licorice, keep the soil moist before emergence. Licorice has strong drought resistance, and its growth needs can be met by natural precipitation after emergence. However, it should be watered during a long drought, and the watering times should not be too frequent, but it should be watered thoroughly each time, which is beneficial to the downward growth of the root system. Pay attention to drainage in the rainy season.

(3) weeding licorice in the first year of ploughing should remove weeds frequently, loosen the soil timely, and loosen the soil from shallow to deep. After the plant grows up, the weeds become less, pay attention to pull out the big grass, should not hoe, so as not to damage the new plants germinating from the rhizome.

(4) topdressing the ground part of licorice at the end of autumn after withering, 2000kg mature farm manure per mu can cover the border to increase soil temperature and soil fertility. Phosphate fertilizer can be applied every year in early spring. Because licorice root has nodules and has the effect of nitrogen fixation, it is generally not necessary to apply nitrogen fertilizer, and there is no shortage of nitrogen fertilizer.

Diseases and insect pests and their control

(1) there are yellow-brown scar spots on the back of the leaves infected by rust, and brown powder is scattered after the epidermis is ruptured, which is the summer spore pile of the pathogen, which forms a black-brown winter spore pile from August to September, which leads to the withering and yellowing of the leaves and even falling off. Prevention and treatment methods: remove the diseased and residual plants and burn them centrally; at the initial stage of the disease, the disease was sprayed with 1000-fold solution of 15% powder or 97% diazepam sodium.

(2) Brown spot harms the leaves, and the damaged leaves produce round or irregular disease spots. The edge of the spot is brown, the middle is grayish brown, and there are grayish black mildew on both sides of the spot. Prevention and treatment methods: clear the garden in winter, deal with the diseased remains, spray 200x solution of non-toxic high ester film, spray with 65% mancozeb or 50% mancozeb at the initial stage of the disease, and spray with 1500 times of methyl topiramate wettable powder.

(3) powdery mildew harms the front and back of the leaves and produces powdery mildew, which can be prevented by spraying with 15% powder rather than 800Mel 1000 times.

(4) the leafhopper is mainly damaged by elm leafhopper and small green leafhopper, which occurs in the whole growing period of licorice, and the damage is the most from late June to mid-August. nymphs and adults feed on licorice leaves, buds and young branches. first showed silver spots, then the leaves lost green and yellowish, and finally fell off.

Control methods: remove elm trees and other leafhopper overwintering hosts around licorice fields; spray 2.5% deltamethrin 1000Mel 1500 times solution at the peak of damage; and biological control with natural enemies such as grass ridges and ladybugs.

(5) whether the licorice production of underground pests can develop rapidly and obtain good economic benefits at the present stage lies in the control of underground pests. In addition to Ningxia Carmine scale, the emergence stage is mainly mole cricket, he's oriental crab beetle, and the adult stage is mainly black wrinkle Gill beetle, yellow brown heteropodium beetle, golden needle beetle, pseudo-step beetle and so on. Control methods: select habitats and areas where underground pests are light and not conducive to occurrence before sowing; fine soil preparation, deep ploughing and heavy rake, destroy their habitats and kill insects; apply rotten stable manure to prevent pests from being brought into licorice field; pay attention to seed germination treatment before sowing, you can mix seeds with 40% methyl isomaliphate 0.2% (seed weight) 50% 1605 EC 0.2% phoxim 25% EC 0.1%, etc. Under the condition that the population of underground pests is large, the soil can also be treated with methamphetamine powder and 1605 powder before sowing, and 3-5-year-old licorice can be picked in time.