Li County is located in the northwest of Sichuan Province and is an alpine mountainous area. It is the third-tier base of Chengdu's "autumn light" vegetables. It has no pollution in air, water and soil, and is an ideal place to produce pollution-free Chinese cabbage. There are currently 12,000 acres of pollution-free Chinese cabbage production base, and 5 local standards for Chinese cabbage in Li County have been formulated. Lixian Chinese cabbage has obtained pollution-free product certification from the Ministry of Agriculture. In 2005, the Lixian Chinese cabbage standardization demonstration project passed the inspection and acceptance of the provincial and national quality supervision bureaus, and the "Miyaluo" and "Taoping Qiangzhai" fresh agricultural product trademarks were registered. The geographical certification trademark of Lixian Dabaicai is being registered. More than 15,000 acres of Chinese cabbage are sown all year round (including multiple plantings), with a total output of more than 73,000 tons and an annual output value of more than 25 million yuan. Planting Chinese cabbage has helped many farmers in Li County get rid of poverty and become rich. The cultivation techniques are now summarized as follows:

1. Soil selection

Chinese cabbage avoids continuous cropping. Generally, the previous crop should be selected. It is a non-cruciferous crop with high and dry terrain, convenient drainage and irrigation, low groundwater level, deep, loose, fertile soil and is planted in plots far away from pollution.

2. Variety selection

Select varieties that are disease-resistant, high-quality, high-yield, strong in stress resistance, good in commercialization, and pure. High-quality varieties, and choose appropriate varieties according to the planting season. Spring sowing: Choose varieties with a growth period of 70 to 80 days, such as Jianchun and Liangqing from Japan, Gaolengdi, Qiangli, Chunqiu 54, Kaixin No. 1 from Korea, etc.; Summer and autumn sowing: Mainly choose Korean varieties with a growth period of about 55 days. A series of varieties, such as Four Seasons King, Spring and Summer King, Dingshang, Chun Dawang, Chun Daqiang, Wangchun, Yingchun, Chunfugui, etc.

3. Land Preparation

1. After land preparation and harvesting of the previous crop, time should be taken to plow the soil deeply to the depth of the plow layer. It is 15~20cm. Li County adopts a combination of deep plowing and shallow plowing. Deep plowing uses the winter leisure time to deeply plow the frozen soil to improve soil permeability and moisture retention capacity, eliminate sources of diseases and insect pests, restore soil fertility, and promote the development of Chinese cabbage root systems into deep layers. Absorb more nutrients and water. Shallow plowing is carried out 7 to 8 days before sowing. To prevent underground pests, 2.5% trichlorfon powder or 5% carbaryl powder can be sprayed 2 to 2.5 kg per acre before shallow plowing; or 5% phoxim 1 to Mix 1.5 kg with base fertilizer and spread it.

2. Fertilizing Chinese cabbage has a high yield and requires a large amount of fertilizer. Chinese cabbage with a yield of 5,000kg per mu needs to absorb 13.5kg of nitrogen, 7.5kg of phosphorus and 10kg of potassium. Half or more of the total fertilizer amount should be used as base fertilizer. . Most soils in Li County are deficient in nitrogen and potassium and should be supplemented. It is recommended that the base fertilizer be mainly organic fertilizer or bio-organic fertilizer. It is prohibited to use industrial waste, urban garbage and sludge. It is not allowed to use organic fertilizers such as human and animal excrement that have not been fermented and decomposed, have not reached the harmlessness index, and have excessive heavy metals. Combined with land preparation, apply more than 3,500kg of fully decomposed organic fertilizer, 40-60kg of superphosphate and 12-16kg of urea per mu.

3. After plowing the border land, it should be strictly leveled to meet the standards of soil as broken as a surface, ground as flat as a mirror, and ridges as straight as a line, so as to create basic conditions for achieving complete seedlings. Make the border 2 to 3 days before sowing, and make the border surface into a turtle-back shape. Chinese cabbage in Li County is mostly cultivated in deep ditches and high borders to facilitate drainage and irrigation and reduce diseases. The box width (covering the ditch) is 80-87cm, planted in 2 rows, and the ditch depth is more than 10cm.

4. Mulch mulching

Mulch mulching cultivation is an important technology for achieving stable, high yield and high quality Chinese cabbage. Herbicides should be sprayed before mulching to prevent weeds from overgrowing. When covering the film, it must be tightened and flat so that the film and the ridge surface are tightly covered. The surrounding areas of the film must be tightly pressed with soil to prevent the film from being easily blown by the wind.

Covering with mulch can be done after Chinese cabbage is sown or before sowing. Generally, when sowing Chinese cabbage in spring, it is covered with plastic film after sowing, which is helpful to increase the ground temperature and speed up the emergence of seedlings. However, after emergence, the seedlings should be released in a timely manner so that the seedlings are exposed outside the film to prevent the seedlings from being injured due to excessive local temperature under the mulch film at noon. After planting the seedlings, pay attention to sealing the openings in time to ensure the insulation effect of the mulch film. Chinese cabbage sown in summer, autumn and some spring sowing are mostly covered with film before sowing, that is, after covering with film, holes are drilled according to the plant spacing requirements, and the film holes are sealed with wet soil in time.

When the plastic film is damaged, it should be pressed with soil and covered tightly in time.

5. Precision sowing

1. The sowing period should be reasonably arranged according to the production season, market, and varieties. Chinese cabbage in Li County is generally divided into three modes: spring sowing, late spring and summer sowing, and late summer and autumn sowing. It is mainly from July to October when the autumn season is light. Spring sowing type: the production areas are Putou Village, Zhuangfang Village, Xindianzi Village, Ganbao Township, and Ganbao Village in Putou Township. Sowing is usually done in early March and harvested in early June; late spring and summer sowing type: the production area is Miyaluo Town, Jiabi Township, Zagunao Town, Shangmeng Township, Xiameng Township, generally sow from the end of April to early May and harvest in early July; late summer and autumn sowing type: the production area is the towns above Zagunao Town (including Shangmeng Township) , Xiameng), usually sown from mid-June to the end of July and harvested from August to October.

2. Seed treatment: Dry the seeds for 1 day before sowing. When sowing, the seeds can be dressed with Zinc powder. The dosage is 4g per kilogram of seeds.

3. Sowing method: Chinese cabbage in Li County mostly adopts hole sowing, that is, holes are made according to the predetermined plant row spacing, and 4 to 5 seeds are sown in each hole. After sowing, cover it lightly with fine soil, and the seed amount is 50 to 80g. /mu. On sunny days and when the soil is dry, water the hole first, wait until the water seeps into the soil, then sow seeds with a shallow cover, and then press lightly to make the seeds and soil closely connected.

4. Planting density Density is one of the key factors affecting the yield of Chinese cabbage. Within a certain range, appropriately increasing density is an important technical measure to obtain high yields of Chinese cabbage. The planting density of Chinese cabbage in Li County is: the spring sowing density is about 4,500 plants, the late spring and summer sowing density is 3,800 to 4,000 plants, and the late summer and autumn sowing density is about 3,500 plants.

6. Field management

After sowing, keep the field surface moist and do not let the topsoil turn white or dry. In order to avoid missing seedlings and cutting off the ridges or newly emerged seedlings from being burned.

1. Thinning, patching and setting seedlings are the basis for the yield of Chinese cabbage. The main goal of management is to ensure that the seedlings are intact, complete and strong. It is necessary to check the seedlings and replenish them in time. If the seedlings are missing from the nest, they should be replanted with adjacent strong seedlings in time. The seedlings should be brought up with soil when they are raised. Timely uniform seedlings and firming of seedlings. Live-seeding Chinese cabbage requires three times of thinning. The principle is "early thinning, late seedling thinning, and divided seedlings." The first time was during the "pull cross" stage, that is, when the two leaves are in one center, seedlings with late emergence, deformed cotyledons, weak growth, crowded together, and seedlings with obviously uneven sizes of the first pair of true leaves were pulled out; At the four-leaf and one-heart stage, select seedlings that are strong and have normal leaf growth and keep them; for the third time, at the five-leaf and one-heart stage, hybrid seedlings with dark leaves, hairless leaves, and slender petioles without leaf wings are eliminated. When the Chinese cabbage has 7 to 8 true leaves, the seedlings are fixed and one plant is left in each nest.

2. After cultivating, weeding and thinning, the soil must be cultivated in time. Chinese cabbage needs to be cultivated twice during the growth period. The first time is after the seedlings are established, the depth of cultivating is 5 to 6cm to promote the root system to develop deeper; the second time is after the seedlings are established. In the middle stage of the rosette, before the plants are sealed, the depth of cultivation is 2 to 3 cm, and care should be taken not to damage the roots.

3. The quantity and quality of top dressing and watering and fertilization have a great impact on the yield and quality of Chinese cabbage. Reasonable watering and fertilization are one of the key measures for high yield. Watering should be based on the characteristics of Chinese cabbage's water requirements in different growth stages, and combined with the local climate, soil and rainfall to determine the frequency and amount of watering. Water management should follow the principle of keeping the soil moist during the seedling and rosette stages, and keeping the soil moist during the balling stage. That is, water frequently during the seedling and rosette stages; in the early and middle stages of balling, watering is usually once every 5 to 7 days; in the later stage of balling, reduce the amount and frequency of watering; and stop watering 5 to 7 days before harvest. .

In addition to applying sufficient base fertilizer, the period and amount of top dressing should also be determined based on the appearance of Chinese cabbage in different growth stages. It is necessary to adhere to the principle of "promoting first and promoting to the end", and advocate the use of soil testing and formula fertilization. Chinese cabbage production in Li County is divided into four top-dressing fertilizers, namely: seedling-raising fertilizer, tree-growing fertilizer, ball-forming fertilizer and filling fertilizer.

Provide fertilizer for seedlings - during the seedling stage, after thinning or cultivating, topdress 2,000kg of decomposed human excrement per acre, add water 10 times and pour it near the roots of the seedlings.

Fertilizer - Topdressing during the rosette stage, which is the beginning of vigorous growth of Chinese cabbage. Strengthening fertilizer and water management is the key to creating a high yield of Chinese cabbage.

Generally, after the seedlings are established, ditches or small ditches are dug between rows or plants for top dressing, and about 2,000~2,500kg of fully decomposed farmyard manure is applied per acre, and 40% of nitrogen, phosphorus, and potassium compound fertilizers are mixed. ~50kg or 12~15kg of urea and 5~6kg of potassium fertilizer, and then pour shallow water once.

Balling fertilizer and filling fertilizer - carried out during the initial and middle stages of balling, which is the period when Chinese cabbage products are formed. During this period, the root system develops to the maximum extent and the growth of leaves increases sharply. If At this time, nutrients cannot keep up, and the balls are often not tight, affecting yield and quality. It is best to use quick-acting fertilizers in both cases and apply them in advance. Generally, top dressing is applied immediately when the core wrapping begins, with 1,500 to 2,000kg of fully decomposed human and animal manure per mu, about 10 to 20kg of urea, about 5 to 8kg of potassium fertilizer, or the recommended available nitrogen, phosphorus, and potassium fertilizers. After pumping out the cylinder, apply quick-acting fertilizer again. This time, human and animal excrement is generally prohibited, and 10-15kg of urea can be applied per acre. Each application of fertilizer can be combined with moisture and irrigation. It is best to use slow water irrigation, and the best irrigation time is before 10 am and after 4 pm.

In addition to soil top dressing, foliar top dressing can also be carried out. 0.5% urea plus 0.3% potassium dihydrogen phosphate is commonly used during the rosette stage and the early and middle stages of balling. For varieties that are sensitive to calcium deficiency and prone to "heartburn", you can spray 0.5% calcium chloride aqueous solution on the heart leaves every 7 to 10 days starting from the rosette stage. When applying, pay attention to spraying on the heart leaves 2 to 3 times in a row. . Foliar top dressing should be carried out in the evening or early morning, and avoid spraying under the hot sun. Within 15 days before harvesting Chinese cabbage, no available nitrogen fertilizer and human and animal excrement should be used.

7. Prevention and Control of Diseases and Pests

To produce safe, high-quality and pollution-free Chinese cabbage, the prevention and control of diseases and pests should implement the principle of "prevention first, The plant protection policy of "comprehensive prevention and control" gives priority to agricultural, physical and biological control, and cooperates with the scientific and rational use of chemical pesticide control. Throughout the growth period of Chinese cabbage in Li County, the main diseases include black rot, soft rot, viral diseases, downy mildew and anthracnose; the main pests include aphids, cabbage caterpillars, diamondback moths, cutworms and grubs.

1. Agricultural prevention and control should use disease-free seeds and disease-resistant varieties; rational layout and implementation of crop rotation; strengthen cultivating and weeding, clean fields, scientific fertilizer and water management, and reduce the number of sources of diseases and insect pests.

2. Biological control protects natural enemies and creates environmental conditions conducive to the survival of natural enemies. Choose biopesticides or biochemical preparations that are harmless or extremely toxic to humans, animals, and natural enemies. For example: use BT preparations and granular virus agents to control cabbage caterpillars, diamondback moths, etc.; use agricultural antibiotics B0-10 to control anthracnose; use agricultural streptomycin and neophytomycin to control bacterial diseases; use 1.5% Tetrabutyl 1 000 Doubling liquid to control cabbage caterpillar and beet armyworm.

3. Physical control utilizes the phototaxis of insects. Black light lamps can be used to kill mole crickets, small cutworms, etc.; yellow boards can be used to trap and kill aphids; frequency vibration insecticidal lamps can be used to kill cutworms, scarabs, mole crickets, and armyworms. Branch and other pests.

4. Strictly implement the local standards of Sichuan Province (DB51/337 Pesticide Use Standard for Pollution-free Agricultural Products) for pesticide prevention and control, and rationally mix, rotate, and alternate pesticides to prevent and delay the occurrence and development of resistance to pests and diseases.

(1) Soft rot is a disease caused by bacteria. The outer leaves wilt, the bulbs are exposed, white bacterial pus overflows, the tissue becomes sticky and rotten, and there is a foul smell. In severe cases, the stems are completely rotten. , the whole plant died. High temperature and high humidity are more severe. Control method: Spray the plants with 72% agricultural streptomycin 400 times or neophytomycin 4,000-5,000 times. Once every 5 to 7 days, spray 2 to 3 times in a row.

(2) In the early stage of the onset of downy mildew, small yellow spots appear, which later expand into polygonal light brown lesions restricted by leaf veins. When wet, there is a white mold layer on the back of the lesions. If it rains and the humidity is high, the disease will become more serious. Prevention and control methods: You can spray 25% metalaxyl wettable powder 750 times liquid or 40% triethylphosphorus aluminum wettable powder 300-500 times liquid or 50% Anke wettable powder 2 500 times liquid or 69% Anke Manganese Spray zinc wettable powder 1 000 to 2 000 times, and use it alternately and in rotation. Spray once every 7 to 10 days, 2 to 3 times in a row.

(3) Virus diseases include wrinkled leaf type and mosaic type. The damage is severe, the plants shrink, become short, and cannot form balls. The disease will be more serious when aphids occur due to high temperature and drought.

Control methods: Clear weeds in the field, pull out diseased plants, and reduce the source of the disease. Combined with the prevention and control of aphids in the seedling stage, after planting, spray 20% virus A wettable powder 600 times + 10% imidacloprid 1,500 times or 1.5% Phytacloprid EC 1,000-1,500 times + 1,500 times once liquid spray. Spray once every 5 to 7 days, 2 to 3 times in a row.

(4) Black rot occurs in seedlings, the cotyledons appear water-soaked, and small black spots or thin black strips appear on the veins of the true leaves; the disease occurs in the adult plant stage, showing a fan-shaped or "V"-shaped yellowish brown color Plaques, leaf veins become necrotic and turn black, and in severe cases, the leaves die. Prevention and control methods: Find diseased plants, remove diseased leaves, and spray pesticides in time. You can use 72% agricultural streptomycin sulfate wettable powder 4,000 times liquid, or 77% killable wettable powder 500 times liquid spray. Spray once every 7 to 10 days and spray 2 to 3 times continuously.

(5) Anthracnose leaf lesions are small, round or nearly round, with a gray-white center and brown edges, translucent, and easy to perforate. The main vein lesions occur on the back of the leaf and are brown round spots or dark brown stripes and black spots. The petiole lesions are spindle-shaped or oblong, brown or dark brown, and sunken. When wet, the lesions have a pink sticky substance. Prevention and control methods: You can use 80% Dasheng wettable powder 500 to 600 times liquid spray, or 80% Anthrax Formica wettable powder 800 times liquid spray, or 50% Desenzine wettable powder 500 times liquid spray. Spray once every 7 to 10 days and spray 2 to 3 times continuously.

(6) Rapeseed caterpillar, the larvae of the cabbage butterfly, is green and feeds mainly on leaves. Prevention and control methods: You can use Wuda Oasis No. 1 wettable powder 1,000 times liquid, or 25% chloruride suspension 2,000-2,500 times liquid, or 5% Ruigent suspension 2,000-3,000 times liquid, or 1.5 % enemy-killing emulsifiable concentrate 1500 times of liquid spray to kill, use alternately and in rotation. Spray once every 7 to 10 days, 2 to 3 times in a row.

(7) The larvae of the cabbage borer spin silk and form webs in the heart of the cabbage, join the young leaves together, and eat the heart leaves, causing the damaged plants to stop growing. The older larvae are yellow-green with black heads. The control methods are the same as those for cabbage caterpillar.

(8) The first instar larvae of diamondback moth (Hypercarpus filariae) feed on the leaf mesophyses, leaving the epidermis behind. The 3rd to 4th instar larvae eat holes and notches in vegetable leaves. The control methods are the same as those for cabbage caterpillar.

(9) Aphids live in groups on the backs of leaves, sucking sap, causing leaf deformation, and are vectors of viruses. Prevention and control methods: 48% Lesbon 800 times liquid, or 50% pirimicarb wettable powder 2 000 to 3 000 times liquid, or 10% imidacloprid 1 500 times liquid spray can be used.

(10) The adults of yellow flea beetles eat leaves, and the larvae damage vegetable roots. The leaves are damaged, turn black and die, and spread soft rot. Prevention and control methods: Start spraying around the vegetable field and spray around. You can use 48% Lesbourne EC 800-1,000 times, or 58% Fengleiji EC 800-1,000 times, or 4.5% high-efficiency cypermethrin EC 1,500 times. Liquid spray or root irrigation.

8. Post-harvest treatment

When the leaf ball is fully grown, the top of the leaf ball will feel firm when pressed by hand. Pick sunny or cloudy days for timely harvesting to ensure high quality vegetable products. It is required that the tools used during the harvesting process must be clean, hygienic, and pollution-free. Commercial Chinese cabbage must be peeled off the outer leaves and yellow leaves, and the stem base must be flattened to remove diseases, insects, and damaged fruits to achieve sensory cleanliness.

(Contact number: Agricultural and Water Conservancy Bureau of Li County, Aba Prefecture, Sichuan Province 623100)