Key points of field management of carrots in autumn

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.

The morphological characteristics of carrots are straight roots, the main roots are distributed in the soil layer of 20 cm to 90 cm, and the depth is 180 cm to 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. Autumn is a critical period for the growth of carrots, and it is very important to strengthen field management.

1. Sowing: carrot is one of the main vegetables in autumn. The method of sowing is often used before and after the Beginning of Autumn. Generally, the seed consumption of light seed per mu is 1.5jin, and that of hairy seed per mu is 2 ─ 3jin. After sowing, rake the border surface and compact it with your feet.

2. Interseedling and weeding: 1 ─ 2 true leaves, the first seedling, the distance between plants is 3 cm. Then shallow hoe, weeding to preserve soil moisture, to promote the growth of seedlings. In the second time, the seedlings were fixed with 4 ─ 4 true leaves and 4 ─ 5 leaves. The plant spacing of small and medium-sized varieties was 10 cm, and that of large varieties was 13 cm and 15 cm, respectively.

3. Irrigation and fertilization: before and after the seedling stage, after the "fixed pin stage", the head of the fleshy root is about the same as the finger, which is the fastest growing period of the fleshy root. It should be watered in time to keep the soil moist and stop water in the first half of the harvest. Carrots are generally topdressing twice, the first topdressing is carried out at 20 ─ 25 days after emergence, when there are 3 ─ 4 true leaves, about 15 jin of urea, 18 jin of calcium superphosphate and 5 jin of potassium chloride are applied per mu, and the second topdressing should be carried out at 40 ─ 50 days after emergence, generally 20-25 jin of urea, 8 jin of calcium superphosphate and 8 jin of potassium chloride per mu.

First, it is necessary to interplant seedlings in time, strengthen intermediate ploughing and weeding during the whole growth period, carrots need to be interspersed twice, the first time when the seedlings are in 1 to 2 true leaves, and then shallow hoe to weed and preserve soil moisture to promote the growth of seedlings. In the second time, when the seedlings had 3-4 true leaves, it was better to fix the seedlings. The plant spacing of small and medium-sized varieties was 10 cm, and that of large varieties was 13-15 cm. Reasonable close planting is one of the important measures for high yield of carrot. if the density is too high, it is easy to shade each other and weaken photosynthesis, especially the lower leaves are easy to die early, resulting in a reduction in yield.

Second, the scientific operation of fertilizer and water should not be short of water at the seedling stage, and the soil should be kept moist. Too dry and too wet are not conducive to seed germination and emergence. During the growth period, topdressing should be carried out for 2 to 3 times, and the first topdressing should be carried out during the soil breaking period of carrots, combined with watering, 1000 kg of feces and urine or 20 kg of urea per mu, and the second or third time after 20 days, with 15 kg of urea each time. And add a small amount of potash fertilizer appropriately. When entering the vigorous growth period of leaves, the water should be properly controlled to prevent overgrowth.

Third, it is necessary to harvest carrots in a timely manner, the growth period of carrots is generally 100,130 days, and it is appropriate to harvest carrots in central and southern Hebei from late October to early November.