Cultivation techniques of interplanting licorice in returning farmland to forest land

Interplanting licorice on the land of returning farmland to forest can not only conserve soil and water, but also increase economic income, so as to achieve the goal of "win-win" of economy and ecology. Since 2002, the 137 regiment has carried out the cultivation experiment of interplanting licorice in the returned farmland, and a breakthrough has been made after several years of attempt and exploration.

1. Land selection

The land with low saline-alkali content, few weeds in the field and good drainage was selected to interplant licorice in the land of returning farmland to forest. The main tree species in the sowing area are Lycium barbarum seedlings, the planting mode is furrow planting, the distance between the center of the ditch is 6 meters, the width of the mouth of the ditch is 1.8 meters, the width of the back of the ditch is 4.2 meters, and the effective sowing area of licorice is 3.8 meters. 40 cm deep in autumn for winter irrigation or early spring irrigation, rake the ground to preserve soil moisture before sowing.

two。 Seed treatment

Licorice seed coat is hard, impervious, airtight and not easy to germinate; its natural germination rate is only about 20%, which needs special treatment to improve seed germination rate.

In the sulfuric acid treatment method, 20 ml of industrial sulfuric acid with a concentration of 80% was added to each kilogram of seeds, stirred evenly with wooden sticks, so that all seeds were glued with sulfuric acid, then soaked in 20 ℃ for hours to 3 hours, and washed repeatedly after the seed coat was burnt, until the sulfuric acid was washed, so that the germination rate of seeds could be increased to more than 85%. The advantage of this method is that the capacity of one-time treatment is large, but the disadvantage is that due to the change of ambient temperature, the treatment time is not easy to grasp, too long is easy to burn the seeds and lose the power of germination, too short injury less skin, the effect is not good.

The rice milling machine collision treatment method makes use of the high-speed rolling of the rice milling machine to make the seeds rub against each other at high speed so as to achieve the purpose of crushing the seed coat. The effect of using this method to deal with a large number of seeds is the best, generally grinding one or two times, the seed coat can be slightly broken, and the germination rate can reach about 95%.

3. Sowing seeds

The day before sowing, 100 kg of licorice seeds were mixed with 0.25 kg phoxim emulsion to prevent underground pests from eating seeds and buds. After mixing, the seeds were covered and sealed with plastic sheeting to be sown.

Sowing rate direct seeding underground seed quantity is 30 kg to 40 kg per square kilometer, seed quality standard: germination rate is about 85%, purity is about 97%.

The sowing time from April 20 to May 20 is the suitable sowing time for licorice, when the ground temperature is more than 12 ℃ and the air temperature is between 20 ℃ and 25 ℃, which is the most suitable for licorice seed germination.

The sowing method uses a small four-wheel hanging seeder to sow on the film. The width of the film is 1.2 meters, the width of the film is 4 lines, the distance between the nests is 8 cm, and the depth of the hole is 3 cm to 4 cm. About 6 days after sowing, licorice seedlings were unearthed one after another, and almost all the seedlings could be released in 12 days. At this stage, attention should be paid to liberating the seedlings in time.

4. Field management

The main results are as follows: (1) Glycyrrhiza uralensis seedlings unfold two cotyledons from 3 to 4 days after they are unearthed. If there is a phenomenon of broken ridges at this time, artificial replanting should be organized in time to ensure the emergence of whole seedlings in the field.

(2) when licorice seedlings grow 3 true leaves, the larger weeds between the rows of licorice should be removed and attention should be paid to the protection of licorice seedlings.

(3) when licorice grows from 6 to 10 true leaves, the temperature increases and the weeds in the field begin to grow. At this time, ploughing 1 to 2 times, topdressing 75 kg to 150 kg urea per square kilometer, so that licorice seedlings grow rapidly and close ridges as soon as possible.

(4) aphids and green insects may occur when licorice grows 6 to 15 true leaves, which must be checked regularly every day, and should be sprayed immediately as soon as it occurs.

(5) during the period of 6 to 15 true leaves, licorice is about to close the ridge. Urea should be applied once more, with a dosage of 75 kg to 150 kg per square kilometer, and ploughed once in time to remove weeds in the field.

(6) when licorice grows 15 to 20 true leaves, the seedling is as high as 30 cm to 40 cm, and licorice is ridged. Field management work is basically over, send someone to take care of it, but also pay close attention to the growth of weeds, if there are too many weeds, they still need to be pulled out.

(7) during the withering period of stems and leaves, licorice was harvested when the stems and leaves were dry in autumn, which was used as feed for large livestock and irrigated once in winter before freezing.

5. Field management in the second year

After the beginning of spring, the direct seeding licorice began to turn green, watering once according to the soil moisture, when the licorice grew more than 10 centimeters high, the grass should be ploughed and weeded once or twice, and the big grass should be manually pulled out.

Licorice in the second year generally should not be watered during the growing period, but can be watered once or twice in very dry years.

6. Pest control

The main diseases of licorice are rust, brown spot and so on; there are many kinds of insect pests, such as leafhoppers, aphids, red spiders and so on.

Disease:

The leaves infected by rust produce yellow-brown scar spots, 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, resulting in withered and yellow leaves.

Methods of prevention and treatment: remove the diseased and residual plants and destroy them centrally. At the initial stage of the disease, 15% of the powder was sprayed with 1000 times of wet powder or 97% of diazepam sodium with 400 times of wet powder.

The spot on the leaf of brown spot is round or irregular, with a diameter of 1 mm to 2 mm, the center is dark brown, the edge is brown, and there are gray-black mildew on both sides, which is the fruiting body of the pathogen, which mostly occurs from July to August.

Control methods: during the disease period, 65% of the forest zinc wettable powder 100 times solution was sprayed once or twice, the garden was cleared in autumn, and the remains of the diseased plants were treated centrally.

Insect pests:

The nymphs and adults of the leafhopper feed on the leaves, buds and branches of licorice, first appear silver-white patches, then the leaves lose green and show light yellow, and finally fall off. The whole growth period can be harmful, and the damage is the most serious from June to August.

Control method: remove the elm and other leafhopper overwintering hosts around the licorice garden. Spray 2.5% deltamethrin EC from 1000 times to 1500 times during the peak period, preferably without broad-spectrum pesticides to protect natural enemies such as ladybugs.

Aphids, red spiders, leaf miners, etc., can be sprayed with 2000 to 3000 times of omethoate EC, once in 10 to 15 days, 2 to 3 times in a row.

7. Benefit analysis

It can be seen from the table that the growth of direct seeding licorice is relatively large in the second and third year, and the thickening and weight gain are very large, so licorice can be harvested after growing for 2 to 3 years. If the finished product is not produced due to land and field management reasons, the harvest can be extended by one year. The root depth of the direct seeding land is generally about 50 centimeters. The licorice special plough can be used to lift about 40 centimeters of products, and the hairy roots less than 40 centimeters can be abandoned. According to the actual calculation ratio, the loss rate is about 10 percent, and the damage degree is about 15 percent, which basically meets the agronomic requirements.

When returning farmland to forest land to plant licorice, the amount of fresh root grass of 2-3-year-old direct seeding licorice is about 15000 kg to 18850 kg per square kilometer, dry goods mixed licorice is 4500 kg per square kilometer, and Mao licorice is 4500 kg per square kilometer. at the current market price, licorice is 6 yuan per kilogram and Mao licorice is 2 yuan per kilogram, with a total output value of about 33000 yuan per square kilometer. The average total investment per hectare is between 13500 yuan and 16500 yuan, and the net income per hectare is about 16500 yuan to 19500 yuan, which is an effective way for contractors to return farmland to forests to get rich through hard work.