Carrot cultivation techniques

A pair of environmental conditions

1 temperature requirements: 4-6C seed germination, germination temperature is 20-25C. The growth period is suitable for warming to 18-23C during the day, and the nighttime is 13-18C and the ground temperature is 18C. The growth was stopped below 3C. The meat roots above 25C were short, light in color, and had a sharp tail, low yield, and poor quality. The formation of carotene was the most at 15-21C. Carrot leaves are more resistant to high temperatures. Carrots belong to the green plant-sensing plants. Plants that grow to a certain size can feel the influence of low temperature through the vernalization stage. The general easy to bolting variety can feel flower bud differentiation at the low temperature of 4-5 true leaves at the seedling stage, while the 10 true leaves of the late maturity variety will flower at the low temperature below 15C for 25 days and then under the high temperature and long sunshine. It can pass the vernalization stage in 15-20 days under 1-3C conditions.

2 requirements for light: carrot is a long-day plant, under long-day conditions can bolting and flowering. The vegetative growth requires moderate sunshine, sufficient sunlight, and good leaf growth; when the light is insufficient, the leaves are small and the petioles are slender.

3 carrots on the water requirements: carrot roots developed, small leaf area, and therefore more drought. When germination is required, the soil is moist, and the soil moisture in the seedlings and leaves during the growth period should not be too much, or the leafy growth will affect the root swelling. In the middle and late period, the root swelling period requires 60%-80% of the water capacity in the field. Such as long-term lack of soil moisture, fleshy root cork, root small, multi-lateral root. If the soil moisture is often too high, it is easy to rot. The water supply is uneven and the meat is cracked.

4 Requirements for soil and nutrition: Carrots like deep sandy loam soil, carrots require the most potassium, followed by nitrogen, less phosphorus. Excessive nitrogen fertilizer leaves are long, fleshy roots are small, yield is low. Adequate potassium fertilizer can promote the activity of root formation. Obvious increase in production, in the late growth period requires a large amount of fertilizer.

Two cultivation techniques

1 Base fertilizer for soil preparation: Carrots require more soil than radish. The whole fleshy roots of carrots are buried in the soil and the lateral roots are well developed. The fleshy roots like loose loam or sandy loam. If the soil is heavy, hard, and poorly ventilated, the lateral roots are prone to protrusion, and the skin is rough, easily cracked, and bifurcated. For each mu, composted manure 3000-5000 kg, ternary compound fertilizer 40-50 kg, spread the fertilizer to remove bricks, stones, tiles and residual plastic, deep plowing 25-30 cm after the leveling to do.

3 Field Management

(1) Seedlings: When the seedlings have 1-2 true leaves, the first time the seedlings are kept, keeping the seedlings at a distance of 3-4 cm. Seedlings 4-5 true leaves for the second time. When seedlings are sowed, such as seedlings, spacing is 20 cm, and the spacing of plants is 8-10 cm. If sowing seedlings are planted at 10-12 cm, about 30,000 plants per mu.

(2) cultivating soil: carrots are unearthed and weeds grow quickly. Herbicides can be used. Available before sowing with 33% pendimethalin EC 100-120 ml per acre or 50% acetochlor EC 100-150 ml or 72% Metolachlor EC 120-150 ml or 50% Praxacum WP 100 -120 grams of watered evenly sprayed 40 kg. The dose should not be too large. If the humidity is high in the field and the temperature is low during the sowing, low doses should be used. If the field purslane, iron leeks can be used 33% Pendimethalin EC 50-100 ml + 50% Praxecot WP 50-75 g or ethoxyflorin EC 10-15 ml Watered 40 kg evenly spray. Spraying is not required to spray or re-spray. It is best to use a fan nozzle. In combination with cultivating and weeding, we can cultivate soil to prevent fleshy roots from appearing green on the ground.

(3) Top-dressing watering: Top-dressing can be divided into two times. The first time after thinning, three-component compound fertilizer is applied to 3-5 kg ​​per mu. The second time, after catching the seedlings, 10-15 kg of high-potassium, low-nitrogen-phosphorus compound fertilizer was chased. During the root enlargement of the fleshy root, timely watering to maintain the soil water holding capacity of about 70%. Stop watering in the late growth period, otherwise it will crack.

Three pest control

(I) Physiological diseases

1 Carrot bifurcation: (1) poor seed quality, weak old seed, poor seed development. (2) Poor soil environment such as excessive soil viscosity, shallow soil layer, hard bottom layer, stones in soil, bricks, non-rotating firewood sticks, waste plastics chips hindering root growth (3) Organic fertilizer is not mature, Non-uniform rooting of the base fertilizer (4) The seedlings are not timely, the seedlings are too dense or the seedlings are too thin and nutrient surplus (5) The underground pests damage the main roots.

2 carrot roots: mainly uneven growth during the water supply

3 Malnutrious root coloration: Carrot coloring temperature is 16-21C. If the temperature is too high or too low, the coloring will be poor. The soil permeability is good and coloring is good. The supply of sufficient potassium and magnesium coloring is good and the quality is good.

(4) Thickness of the middle column of fleshy root: The excessive thickness of the middle column is related to the variety. Planting too thin to grow too large Wangzhong column is too large, too late harvest will make the column too large.

5 carrot bolting: variety characteristics easy to bolting, easy bolting varieties at the seedling stage to 4-5 leaf can feel the low temperature and flower bud differentiation, in the next long-day will be bolting. The early spring or early spring encountering cold temperatures in the spring cold may allow the seedlings to pass through the differentiation stage. In the long spring and summer sunshine bolting. Should choose difficult to bolting varieties. Nutrition can also affect bolting. Fertilization is less scientific organic fertilizer or fertilizer fertilizer, excessive nitrogen fertilizer, and loss of balance in growth. Spring cultivation easy bolting. Effects of growth regulators, auxin substances can promote bolting, such as 2.4-D class. Indole acetic acid. Naphthyl acetic acid and other antibiotics can inhibit the synthesis of auxin inhibiting the role of retarding bolting, gibberellic acid can promote long-day Plant bolting.

(b) Major Infectious Diseases of Carrots

1 black spot

(1) Symptoms: mainly damage the leaves. Tips and leaf margins are susceptible to disease. The initial brown spots have yellow halos and the dark brown spots are slightly brownish. In the later period, the leaf margins roll up and turn yellow from the lower leaves. Black mold on the spot when wet.

(2) Pathogens: It is caused by the fungus Alternaria anatipestifer, and the disease is heavy when the airflow is spreading and the temperature is high and the rain is heavy.

2 Black rot mainly damages fleshy roots, leaves, petioles

(1) Symptoms: Lesions are dark brown on the leaves, and the leaves die when they are severe. Petiole lesions are not obvious at the long edges. When the humidity is high, the surface of the black mold layer is dense. The fleshy root disease mostly forms irregular spots or dark spots with dark depressions at the head of the root; in severe cases, it expands to a depth of internal black rot.

(2) The pathogen is caused by the fungus Alternaria pyogenes. By airflow, high humidity is conducive to disease.

(3) Control methods: The following agents are available for black spot and black rot.

a 25% tebuconazole wettable powder 2000 times b 10% multi-streptomycin wettable powder 1000 times

c 5% iprodione wettable powder 1000 times d 10% difenoconazole water dispersible granules 1500 times

3 soft rot

(1) Symptoms: The main damage is fleshy roots, and the diseased roots are infected. In the beginning, it was wet and rot. Afterwards, the shape of the lesion was enlarged. The soft part of the fleshy root was brownish-brown, and the rotting sap had odor.

(2) Pathogens are caused by bacteria, spread by insects, rain, and water, and are invaded by wounds, and high humidity and high temperatures are prevalent.

(3) Control methods: a 72% agricultural streptomycin soluble powder 4000 times b 88% oxytetracycline soluble powder 1500 times c 70% sodium propionate soluble powder 600 times d 50% chlorobromoisocyanuric acid soluble powder 800-1000 Times e 3% Centrifugin Aqueous Solution 1000 times f 14% Complex Ammonia Bronze Aqueous Agent 300 times

The above agents can be used to spray at the beginning of onset and spray 2-3 times in 7-10 days. Since the soft rot pathogen is invaded from the wound, it is best mixed with the insecticide.

4 Sclerotinia

(1) Symptoms: only damage the fleshy roots, the onset of the growth period, causing softening of the underground fleshy roots, initial water-spotted lesions, and severe rot. On the surface of the diseased part, a white cotton-like material grows on the surface of the diseased part, and a rodent-like nucleus resembles a rodent. The sclerotia turned dark brown after it became white.

(2) The pathogen is caused by the fungus of semi-known Sclerotinia sclerotiorum, and it is prone to occur under the temperature and humidity conditions of 15-20C by wind and rain.

(3) Prevention and control methods: Apply rotation and reasonable fertilization to avoid excessive nitrogen fertilizer, properly close planting to keep the fields ventilated and transparent, scientific irrigation, and prevent excessive humidity. Chemical control can be started at the beginning of the disease by spraying 50% iprodione WP, 1000-1500 times, procymidone WP, 1000-1500 times, 5% ethylene nucleating agent, WP, 600 times, and 40% sclerotin. Wet powder 700-1000 times, spray once every 7 days, 3-4 times in a row.

5 knot nematode disease

(1) Symptoms: When the symptoms are mild, the symptoms are not obvious, and the serious diseased plants have poor growth. At noon, the leaves are wilting and then yellow, the diseased plants are short, and when severe, they die. Underground roots produce varying sizes of root knots with milky white nematodes.

(2) The pathogen is root-knot nematode

(3) Prevention: The rotation is implemented. Flooded at leisure. At the beginning of the disease, 500 grams of each strain was irrigated with 1.8% abamectin EC 1000 times, and once again after 10 days.

(c) Carrot pests

1蛴螬

(1) Harmfulness: Seeds that germinate and germinate, bite the seedling stem, and bite the main root to cause bifurcation. When the soil temperature reaches 5C or more, it rises to the depth of 13-18C in the shallow soil, and when the temperature reaches 23C or more, it subducts into the lower layer.

(2) Prevention: Do not apply non-perishable organic fertilizer. Do not put piles in the field for the seedlings that are grown underneath and the grass that is pulled out. Artificially digging insects and earthworms have a small range of activity in the soil. If they are found to be killed, they can be dug out in the vicinity. Chemical control can use 50% phoxim EC 800 times or 40% chlorpyrifos EC 800-1000 times. Irrigation, 4-5 kg ​​per square meter of liquid medicine.

2蝼蛄

(1) Harmfulness: Insects damage by larvae or adults. In addition to directly eating seeds, young shoots, and underground rhizomes, they cause seedlings to die. They also cause seedlings to lose water or death due Failure to die also affects normal growth.

(2) Control methods: apply organic fertilizer; spread the soil on the seeding ditch or ground. You can use 5% phoxim granules or 5% chlorpyrifos granules to mix in 20-30 kg of fine soil. Dispensing the scorpion, using a bean cake or wheat bran 5 kg saute to dilute 30 times the drug Stir evenly, place the scorpion into small piles or strips evenly placed in the field, the agent can use 50% phoxim EC or 90% crystal enemy Insects or 40% chlorpyrifos EC, put 2-2.5 kg bait per acre.

(3) Locust: It is possible to use 20% of 10% imidacloprid wettable powder or 25% of 3% acetamiprid EC. The above agents can be combined with pyrethroids to cure other pests.

2 sowing: Carrot seed peel thick, leathery, raw hair, containing volatile oil, water absorption difficulties, germination slow, irregular. Before the sowing, the bristles were removed and germination was carried out. The germination method is to soak the seeds in 45C water for 2 hours, remove and spread them, and moisten with a damp cloth under 20-25C conditions. Seeds can be sown when 70% of the seeds are white after 5-7 days. Sewage water before sowing, keep the soil moisture 65% -80%, kept moist during emergence.

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