Scientific cultivation and management techniques of carrots

Carrot (Daucus carrot), also known as Xunxun, is a carrot of Umbelliferae, which belongs to biennial herbs. Eat with fleshy roots as vegetables. Originated in southwest Asia, Afghanistan is the earliest evolution center, with a cultivation history of more than 2000 years.

Morphological characteristics of carrots

Straight root system, the main root system is distributed in the soil layer of 20-90 cm, with a depth of 180-250 cm. The upper part of the taproot includes a small part of Hypocotyl hypertrophy, forming fleshy roots, deep below the soil surface, on which four rows of slender lateral roots are planted. Fleshy roots are round, flat, conical, cylindrical and so on. The root colors are purple, orange, pink, yellow, white and turquoise. It is mainly composed of secondary phloem, fine xylem and core column. The outer part of taproot is smooth.

The foliage grows on the short stem and is tripinnately compound. The petiole is slender, the leaf color is dark green, the leaf area is small, the leaf surface is densely fluffy, the fleshy root bolts and blossoms after overwintering, the main bolting occurs first, and the lateral branches are regenerated, and each flower branch is composed of many small umbels to form a large compound umbel. A plant often has more than a thousand florets, flowering for about a month, complete flowers, white or yellowish, insect-pollinated flowers. Double hanging fruit, divided into 2 when mature, generally mistakenly called seed, oval, leathery, densely spiny on longitudinal ribs. The seed embryo is very small, often stunted or non-embryonic, the soil yield is poor, and the germination rate is as low as 70%.

Herbs biennial, 15-120 cm tall. Stem solitary, all with white hirsute. Basal leaves thin membranous, oblong, 2-to 3-pinnatisect, ultimate segments linear or lanceolate, generally 5-15 mm long and 0.5-4 mm wide, tip acute, apically pointed, smooth or hispid; petiole 3-12 cm long; cauline leaves subsessile, sheathed, ultimate segments small or slender.

Inflorescences compound, peduncle 10-55 cm long, hispid; involucre with numerous bracts, leaflike, pinnatifid, rarely indehiscent, lobes linear, 3-30 mm long; rays numerous, 2-7.5 cm long, outer margin rays curved inward as a result; involucral bracts 5-7, linear, undivided or 2-3-lobed, margin membranous, ciliate; flowers usually white, sometimes reddish. Flower stalk unequal, 3-10 mm long. Fruit ovoid, 3-4 mm long and 2 mm wide, with white bristles on ribs. Flowering from early May to mid-July.

Scientific cultivation and management techniques of carrots

Seed and plant selection

Seed collection of carrots is like collecting seeds from adult plants. When selecting field plants before and after "the Beginning of Winter" harvest, we should select some excellent individual plants with few leaves, positive leaf color, erect leaf clusters, small fleshy root head, neat shape, fine root tail, dark color, bright skin color, smooth epidermis, no division, no bifurcation, no disease and insect infection, and leave the petiole with long 1cm to cut off the leaf cluster as the seed plant.

Seed and plant storage

The seeds are generally stored in trenches and cellars, which can dig ditches with 1 m wide, 80cm depth and unlimited length, and sprinkle a thin layer of wet soil with carrots in the ditches. When the carrot layer is as deep as 40--50cm, it is covered with wet soil with 10cm thickness. In the future, the soil can be covered layer by layer with the cold weather, and the thickness of the cover should be that the seed and plant should not be frozen.

Planting time and method

After planting, the root growth of carrot is weak, and most of the roots are fibrous roots, and the drought resistance and absorption are poor, so the seed production field should apply fertilizer reasonably and prepare the soil in advance, which is the basis to improve the yield of seed production.

Inter-species isolation

In addition to the interval of 2000m between different varieties, it is also necessary to remove the wild carrots around the field to ensure the purity of the seeds.

Planting time

The soil thawed in the next spring, and when the soil temperature was stable at 8 Mel 10 ℃ (Shandong Province was usually in the middle or late March), the seeds were taken out of the cellar and planted. The practice shows that if the seed plant is placed outside the cellar for a long time, the fleshy root shrinks, the growth is not prosperous after planting, and the yield decreases obviously, so it is best to take the seed plant from the cellar and plant it with colonization, and the seed plant that is not planted temporarily after coming out of the cellar can be covered with wet soil to prevent the fleshy root from shrinking.

Planting method

Before planting, 60 000 kg/ / ha of rotten circle fertilizer was used as base fertilizer, and after deep ploughing and raking, the bed was made. Planting according to row spacing 50cm, plant spacing 30cm trench or trench oblique planting. When planting, first seal half of the soil and then water, wait for the water to seep down and then seal the top, the top of the root can be flat with the border surface or slightly higher than 1cm, after planting, step on the soil in time to preserve soil moisture.

Field management

Intermediate ploughing and weeding: from planting to bolting, the external temperature is low and the plant grows slowly. The main work at this stage is to loosen the soil by ploughing in order to increase the soil temperature and keep the root system growing. When the temperature rises gradually and the inflorescence is extracted, the combination of ploughing and weeding is carried out to ensure that there are basically no weeds in the field before sealing ridges, so that the plants blossom and bear fruit in a good environment.

Fertilizer and water management: in each growth stage of the seed plant, timely watering and topdressing should be carried out according to the need. Generally, when the inflorescence is as high as 15--20cm, the nitrogen, phosphorus and potassium compound fertilizer 225--300kg/ hectare should be applied, and water should be watered, otherwise the seed yield should be seriously reduced, and it is appropriate to keep the border surface dry and wet. In the full flowering stage, the fertilizer can be applied once, and the ammonium sulfate is applied to 150--225kg/ ha, which can be applied with water.

Plant pruning and support

If the carrot plant is not pruned, the main branch and one, two, three, …... The flower umbrellas of all branches bloom in turn, and with the increase of the number of flower rings, the flower rings become smaller and the seeds mature slowly. In order to concentrate nutrients and make the seeds full and mature, the pruning technique must be used to adjust the plant type. The production practice has proved that it is the most suitable method to leave four strong side branches of main stem and 3muri, and remove all the other side branches. Pruning is generally carried out when the plant is as high as 40--50cm, when the external temperature rises gradually, and a large number of lateral branches are produced, so pruning should be carried out in time. After the seed plant blossoms, in order to prevent lodging, soil can be cultivated or bracket tied at the base of the plant. One method is to insert a stick or small bamboo pole next to each plant, and then use plastic rope to surround and fix the main and side branches of the whole plant on the stick or bamboo pole. Another method is to pull two strings or plastic ropes on both sides of each plant, and fasten the two ends and the middle with wooden stakes to support the outer branches of the plant and avoid branch swaying and lodging.

Pest control

The common diseases and insect pests of species and plants are soft rot, sclerotinia disease and aphids. The soft rot plants showed that the leaves first withered and yellowed, and then the fleshy roots softened and rotted, giving out a bad odor. The disease should be mainly prevented, soil preparation before winter, full sun exposure, elimination of bacteria, and no continuous cropping. In addition, it is also necessary to control underground pests in time to avoid carrot fleshy root injury and infection. After the seed strain was infected with Sclerotinia sclerotiorum, the root was rotten and softened, white hyphae appeared on the surface, and sclerotia was formed if it developed, the diseased plant could not draw out new buds, the lower leaves were yellowish and saggy, and the aboveground parts shrunk and withered. The available agents were 1500 times solution of 50% Sukeling wettable powder, 50 times solution of 50% tophan wettable powder, 500 times solution of 50% Sclerotinia net wettable powder, 500 million times liquid of sclerotia net wettable powder, 750--900kg/ / ha spray solution. Spray once every 7 Murray for 10 days. Aphids can choose 50% aphid spray wettable powder 1500 times, 10% imidacloprid 1000 Mel 1500 times, 40% chrysanthemum EC 2000 Mel 3000 times or 40% omethoate EC 1000 Mel 1500 times foliar spray.

Timely harvest

The seeds of carrots can not mature until about 30 days after flowering. When the inflorescence changes from green to yellow, the inflorescence can be harvested with a flower stalk, that is, the inflorescence can be cut in time with scissors at the lower end of the inflorescence 10cm. After that, 20 trees were bundled into a bundle every 10 mures, and then placed in a ventilated and dry place to dry. After ripening, the plants were threshed for 10 days. The stalks and impurities were removed by cleaning, and the seeds could be packed and stored when the water content of the seeds was reduced to less than 14% after drying for 3 days.