Summer sowing techniques, common problems and solutions of broccoli

Preparation in advance

(1) varieties. The first generation hybrid varieties with early maturity, strong stress resistance and the highest yield were selected. The main varieties are jade crown, super jade crown, ten thousand green and so on.

(2) parcels. Sandy loam or clayey loam which requires rich organic matter and good drainage, moderate water retention capacity, moderate acidity and alkalinity, and has not planted cruciferous crops in the previous crop.

(3) soil preparation and fertilization. Early release of previous crops to remove weeds, ploughing and soil preparation to make the soil loose, and the field is flat and fertile. Apply 6000-8000 kg of high-quality farm manure and 35 kg of compound fertilizer per mu, with ridges 80 cm wide.

Sowing and raising seedlings

(1) Seedling bed. Select the fields with higher topography, good water source conditions and high organic matter content, and apply 300-400 kg of high-quality farm manure after repeated ploughing before sowing.

(2) sowing seeds. Summer sowing can be carried out in June, the seedbed will be fully watered before sowing, and after drying, sprinkle a thin layer of sifted fine soil and then sow seeds, the dosage is 3-5 grams per square meter, and then cover with culture soil.

(3) Seedling raising mode and seedbed management. There should be shading facilities such as shading net, which should be covered at 9 am in sunny day, uncovered at 5 pm and not covered in cloudy day. after emergence, the bed soil should be watered with a watering kettle, covered with 0.5 cm culture soil to protect buds, and the seedlings should be watered once with 500 times potassium dihydrogen phosphate after growing out of true leaves.

Planting and field management

(1) colonization. When the summer sowing seedlings are 30-35 days old and 5-6 leaves are transplanted with soil, the row spacing is 50 cm × 60 cm, and the planting water is poured after planting to slow down the seedlings.

(2) topdressing.

① was mainly available fertilizer before budding. 7-10 days after planting, seedlings were raised with 200x compound fertilizer or 10 times of mature human feces and urine, and 2kg urea per mu at the same time, and 15kg urea per mu after 14 days.

② first appeared buds, urea 10-15kg per mu was applied around the plant, and sprayed alternately with 200x urea solution and 1000-fold solution for pest control every 14 days.

After the main buds of ③ were harvested, 10 kg of urea and 3 kg of potash fertilizer were applied per mu, combined with irrigation to promote the development of lateral buds.

(3) ploughing and irrigation. High temperature and drought should be irrigated in time to maintain soil moisture, irrigation combined with fertilization. Drainage should be carried out in time when it is cloudy and rainy, so as not to make the plant get soaked. Mid-tillage is generally carried out after rain or irrigation combined with weeding, fertilization and soil cultivation. The first time to chase the middle ploughing and weeding once, and carry on the soil cultivation, and stop the middle ploughing in the later growth stage.

(4) Disease and pest control. Box mildew mainly occurs in the seedling stage and can be sprayed with 70% mancozeb 600 times or 75% chlorothalonil 600 times. Aphids use 25% water dispersible granules to avoid aphids, and spray 20 grams or 32% Shongjing emulsion 2000 times per mu. Pieris rapae and Plutella xylostella were killed with 2.5% enemy or 2.5% Kung Fu 2000 times solution.

Harvest

The harvest time of summer sowing is from late August to early September. The buds are fully grown and the buds have not yet been loosened. It will be on the market in time after harvest in the early morning on a sunny day.

Common problems and preventive measures

1) bolting

Early bolting occurs when the plant does not grow big enough, which is characterized by small florets accompanied by thick flower grains, mainly due to low temperature injury at the seedling stage, and bolting is more likely to occur if accompanied by stress factors such as weak root system and lack of fertilizer at the seedling stage.

Solution:

① chooses suitable sowing time, ② chooses seedlings with good root system, ③ covers plastic film to maintain soil temperature, and ④ manages water and fertilizer well.

2) Ball formation

After the beginning of heading, the temperature is too high or changes violently, there will be some abnormal bouquets, which will show different characteristics according to different growth stages and temperature conditions. Too much fertilizer or too much humidity during the heading period can also have these symptoms.

3) Cat's eyes

The flower grain size of the flower ball is uneven, and it is easy to occur when the temperature changes sharply during the day and night.

Solution:

Each variety of ① should choose a suitable sowing date; ② should avoid applying too much fertilizer from budding to the bulb expansion stage; ③ should maintain good soil moisture conditions throughout the growing season, and it is easy to cause flower head damage under the conditions of drought and drastic water changes.

4) the flower is purple.

Rosette purplish mainly occurs in low temperature environment, others such as lack of fertilizer, drought and too humid may also occur.

Solution:

① avoids sowing in late summer, ② should not apply appropriate amount of fertilizer in the late growth stage, and ③ keeps the root system healthy.

5) Brown and yellow flower grains

The plant does not have enough energy to keep all the flower grains green, causing the flower grains at the top of the bulb to die and turn yellow. High temperature, root damage and lack of fertilizer can cause the flower grains to turn brown.

Solution:

① avoids high temperature, ② keeps roots healthy, ③ maintains proper fertilizer supply, and ④ is harvested in cool conditions.

6) the influence of waterlogging

Solution:

① crushed the hard lumps in the soil to make the soil more loose; ② applied organic fertilizer to improve soil conditions; ③ dug deep drainage ditches for good drainage; ④ high ridge cultivation.

7) Boron deficiency

The symptoms are as follows: the flower stem is damaged and scabs are formed.

Causes and solutions:

① soil boron deficiency: soil boron fertilizer application; ② nitrogen fertilizer excess: improve fertilizer application rate and proportion; ③ root damage caused by drought, too much water, and low temperature: keep the root system healthy

8) Hollow

Boron deficiency causes the pores in the stem to grow rapidly and finally turn brown.

Cause of formation:

Low density planting of ①, high temperature and high soil moisture of ②, excessive nitrogen fertilizer application of ③, boron deficiency of ④.

9) magnesium deficiency

Cause of formation:

① magnesium deficiency; ② soil PH value is too high; ③ too much phosphate or manganese, copper, salt accumulation; ④ drought.

10) White flower stem

Since this is caused by whitefly, it can happen a lot in warm conditions.

11) Root swelling disease

Fungi are soil-borne diseases that infect the root hairs of cruciferous plants. High temperature, high soil moisture and acidic soil contribute to the occurrence and increase of the disease.

Solution:

① quarantines plots where root swelling occurs; ② uses fungicides; ③ crop rotation or disease-resistant varieties; ④ regulates PH; ⑤ improves drainage; ⑥ increases beneficial microorganisms.

12) the bouquet is rotten.

Symptoms: ring spots on the leaves and black spots on the surface of the bouquet.

Solution:

So far, there is no more effective fungicide, which can be solved by the following methods.

① has good drainage and good ventilation to control disease; ② keeps healthy plants (not too large) ③ to avoid applying too much nitrogen fertilizer and supplement trace elements.

13) rotting at the top of the bouquet

Symptoms: the head turns yellow and decays.

Solution:

So far, there is no more effective fungicide, and the same solution can be used as the rotten spot of the flower ball.

14) Black rot

Symptoms: the "V" spot occurs at the edge of the leaf and turns yellow or black around the spot.

15) Black heart disease

Symptoms: the stem blackens, and people taste bitter when they eat these parts. This disease is often seen during winter harvest, and it prefers humid and cool environments.

Solution:

① is suitable for spraying fungicides; ② improves air circulation and drainage; ③ reduces the use of nitrogen fertilizer and increases the use of trace elements.