Where did the carrots and cucumbers that China people first ate come from?

Carrots, native to western Asia, were introduced to China through Iran in the 12th century.

Cucumber, originally from ancient India, was introduced to China in the Western Han Dynasty after passing through Zhang Qian to the western regions.

Key points of carrot cultivation

1. Variety selection.

autumn cultivation generally chooses varieties with a growth period of 9 to 11 days, which requires strong adaptability, especially high and low temperature tolerance, strong disease resistance and high yield. Varieties suitable for northern cultivation include Xi 'an Carrot, Anyang Carrot, Beijing Whip Red, Touxin Red, Tongtou Red, Pheasant Red and so on.

2. Plot selection, soil preparation and fertilization.

In order to ensure the quality of carrots, it is suggested to choose loam or sandy loam with high terrain, good drainage, deep soil layer, loose texture and high organic matter content. For example, when planting in sticky soil, the amount of farmyard manure should be increased, or a certain amount of plant ash should be applied during ploughing.

dig the land deeply in time after harvesting, and the depth should be 25 to 3 cm. Combined with soil preparation, 3 to 5 kilograms of organic fertilizer, 3 kilograms of diammonium phosphate and 15 kilograms of potassium sulfate can be applied per mu. Remove sundries, rake the ground flat to make a border, usually made into a small high border, the border is 6 to 8 cm wide, 1 to 15 cm high, and the furrow is 2 cm wide. It is planted in a high border and deep ditch. For plots with poor drainage and heavy soil texture, high ridge cultivation can be implemented.

3, timely sowing.

carrots in summer and autumn in the north should be sown in the middle and late July, and should not exceed beginning of autumn at the latest. In autumn, dry seeds are generally used for direct seeding of carrots, but in order to improve the emergence rate, soaking seeds can also be used to accelerate germination.

The method is: soak the seeds in cold water for 3-4 hours, drain them, put them into cotton bags, keep moisture at 25 degrees to accelerate germination, and sow when 1%-2% of the seeds are white. Soak in cold water every 12 hours during germination to increase oxygen in the bag and prevent the formation of harmful substances such as organic acids and microorganisms. When sowing, ditch the top of the border with a row spacing of 15 cm, and the depth of the ditch is 1 to 2 cm. Water it first, then sow the seeds and cover the soil. And covered with wheat straw and hay.

Autumn-planted carrots are sown in the high temperature and dry season, and the temperature is not suitable for carrot seed germination and seedling growth, and the seedling rate is lower than that in spring. Therefore, the sowing amount should be appropriately increased, and the seed consumption per mu should be 1.2 to 1.5 kilograms. When the seeds are about to emerge, remove the covering, and then spray the surface of the border with a sprayer. Spray once a day for 3 to 4 days, which is beneficial to the emergence of carrot seeds. In areas with sufficient sunlight, the sunshade net can also be used for shading after sowing, and the sunshade net is required to be about 1 meter away from the ground.

in order to improve the emergence rate of carrots, it is best to arrange the sowing time after four o'clock every morning or afternoon. After sowing, sufficient water must be poured, and plots with poor soil moisture and convenient irrigation and drainage can be irrigated. In addition, the soil should be covered evenly after sowing, and no seeds can be exposed. Before emergence after sowing, in case of dry weather and poor soil moisture, water can be sprayed in the morning or in the evening, and the soil must be kept moist before emergence.

4. Field management

(1) Spacing and fixing seedlings.

when one or two seedlings have real leaves, carry out the first thinning to prevent the seedlings from crowding; 3 or 4 true leaves are used for the second thinning, mainly to retain the strength and remove the weakness, and the seedlings can be fixed. The spacing between seedlings and plants is about 15 cm, and 27, to 32, seedlings are left per mu. Every time the thinning is combined with intertillage weeding and loosening the soil. In order to make the epidermis of fleshy roots have the same color, there should be no "green head", and it is best to use the method of drilling to facilitate the soil cultivation during the swelling period of fleshy roots.

(2) reasonable watering.

furrow irrigation is adopted, and the appropriate watering amount is to wet the border surface. Ensure moisture during germination to facilitate emergence. Less water is needed in the seedling stage, so it is necessary to water less, so as to squat seedlings, inhibit the growth of shallow roots, and promote the deep roots into the soil layer. At the peak of leaf growth, the fleshy roots are gradually enlarged and need more water. At this time, attention should be paid to keeping the soil dry and wet, and the fleshy roots should be supplied with water evenly at the peak of leaf growth, so as to improve the quality and obtain high yield. Too much water should be avoided in the late growth stage of fleshy roots to avoid root cracking. In case of heavy rain in the southern region, it is necessary to ditch and drain in time to prevent water accumulation.

(3) topdressing.

topdressing for 2-3 times from seedling establishment to harvest * * *, and topdressing with 1-15 kg of urea can be applied each time with watering. In case of overgrowth of overground parts, paclobutrazol with a concentration of 1mg/L can be sprayed once or twice with an interval of about 1 days.

(4) prevention and control of pests and diseases.