Botanical and biological features
The carrot (Daucus carota L.) belongs to the Apiaceae family. It is a biennial plant; it forms a crown and a root during the first year and seeds – during the second year.
The carrot is a moderately cold resistant plant. Germination occurs at 3–6˚С. The seedlings can withstand spring frosts of 3–4˚С below zero. The optimum growth temperature is 15–25˚С.
The carrot has very high soil moisture requirements, especially during germination and early plant development.
The light requirements are also very high, particularly early in the growing season. Too heavy seeding and untimely weeding result in drawn plants and a drop in yield.
The carrot has very high soil requirements. The soil should be light, well structured and fertile enough. The carrot plants are very sensitive to saline and acid soils (optimum pH=6-7).
The best preceding crops are early potato, grain legumes, cucumber and early cabbage.
For early harvest, sowing is performed at the first opportunity to go out to the field in early spring. In growing carrots for storage, sowing is made in May – second half of June. The depth of seeding is 1–3 cm. The distance between rows is 25–30 cm. The seeding rate is 6–10 g per 10 m2 (1,5–3 kg/ha when using precision seed drills). At 2–3 true leaves, the plants are thinned out to a distance of 1,5–4 cm between plants. The plant density should be 50 to 200 pl/m2, depending on the variety, cultivation purpose (fresh market, processing, or other) and the desired root size.
Upon sowing, under no circumstances should the soil be allowed to crust, otherwise the seedlings might die. It is good practice to spread a thin layer of humus over the sown rows of carrots to prevent the soil crust from forming.
To obtain a yield of 6 kg/m2 (60 ton/ha), fertilizers should be applied at a rate of 600 g of nitroammophoska per 10 m2 (N 100, P2O5 100, K2O 100 kg of active substance per hectare). The fertilizer application rates are adjusted according to the soil nutrient status data. Two thirds of the fertilizer gift are best applied with autumn plowing, and the balance of the fertilizer applied – as supplementary fertilizing. The carrot responds very well to magnesium fertilizer which is applied at a rate of 500–600 g per 10 m2 (Mg2O 80–100 kg of active substance per hectare). The total fertilizer application rate is calculated based on the soil nutrient status. It is not advisable to apply fresh manure; otherwise the carrot roots become forked, malformed (misshapen) and show poor storage ability. Forked carrot roots will also occur where there is strong soil compaction. The following measures will help overcome this problem: deep soil cultivation and growing long-rooted (over 20 cm long) carrot varieties and hybrids on seedbeds or ridges, especially when heavy soils are used for carrot cultivation.
To avoid root cracking, irrigation should be systematic. During the growing season, the crop is given 5 to 7 irrigations, the water application rate being 300–350 l per 10 m2 (300–350 m3/ha) per irrigation. Combining drip irrigation with application of water-soluble fertilizers through the drip irrigation system (fertigation) is a highly efficient technique resulting in a more uniform moisture and fertilizer distribution in the root zone, more efficient water use, less soil compaction, and no soil crust formed. Readily soluble mineral fertilizers are given with each water application.
The major pest is the carrot fly. Control measures: strict adherence to the crop sequence, early sowing, sprays with insecticides such as Decis or Shtefesin at the time of flight of the carrot fly (when the soil temperature is 15–17˚С).
The most important diseases are black leg, Phoma brown rot, Alternaria blight and powdery mildew. Control measures: sseed treatment, sprays with fungicides such as Ridomil MC, Acrobat MC, Cuproxat and others.
In carrot production, an important cultural practice is hilling-up of plants, which eradicates weeds and prevents the occurrence of green shoulders. Carrots grown for storage should be harvested prior to the onset of frosts and without any mechanical injuries. This is a key to successful storage.