What are the growth and development characteristics of feed carrots?

Feed carrots need two years from sowing to seed maturity. The first year is the vegetative growth period, when it grows into fleshy tuberous roots, it overwinters in the open field in the south and in the kiln in the north. Sowing in the spring of the next year, then bolting, flowering and fruiting to complete the reproductive growth stage. After sowing in the first year, the lowest temperature of seed germination is 6 ~ 8℃, and it takes 15 ~ 20 days to germinate. The optimum germination temperature is 18 ~ 25℃, and the seedlings can germinate in 8 ~ 10 days. It takes about 25 days from true leaves to 4 ~ 5 leaves, which is the seedling stage. The cotyledons of the seedlings are linear, and the first leaves are deeply split and flaky, with smooth surface or a small amount of short hair, green leaves and no waxy layer. During this period, the ability of photosynthesis and root absorption is weak and the growth is slow. It takes 3 ~ 5 days to grow a new leaf, which has poor weed resistance and is sensitive to growth conditions. It grows faster at 23 ~ 25℃ and slower at low temperature.

After 4 ~ 5 leaves, it enters the leaf growth period, also known as rosette period, which is a period when the leaf area expands and the straight root begins to grow slowly, also known as the prophase of fleshy root growth, which takes about 30 days. Pay attention to the balanced growth of the above-ground and underground parts. At this time, the assimilation products are still mainly aboveground parts, so the principle of "promoting but not flourishing" should be mastered in the supply of water and fertilizer.

Then enter the fleshy root growth period for a long time, accounting for about half of the whole vegetative growth period. The new leaves continue to grow, and the old leaves at the bottom keep dying, so the leaves can keep a certain number and area. During this period, the largest leaf area should be maintained, fertilization and irrigation should be appropriate, and photosynthesis should be strengthened, so that a large number of nutrients formed can be transported and stored to fleshy roots. The roots and assimilating organs of forage carrots are formed in the first half of growth, so attention should be paid to the supply of nutrients. However, in the period of forming fleshy roots, a lot of nutrients will be absorbed, and it is more important to supply enough nutrients at this time. Feeding carrots can effectively utilize the late autumn growth period and accelerate the formation of root sugar at lower temperature. Harvesting spring-sown carrots 90 ~ 100 d after sowing; Harvest autumn carrots in cold areas in the middle and late June of 65438+ 10. In areas where freezing is late, they will be harvested after winter begins. Harvest should not be too late to avoid freezing and storage of fleshy roots.