(1) Harvest time
The leeks planted in that year are generally not harvested. After the second year, they should take root as much as possible and harvest normally. Leek grows vigorously in spring, with crisp leaves, less fiber, good quality, good flavor and high yield, while the price of vegetables in early spring is often higher, which is the best time to harvest leeks. We should pay close attention to harvesting more times. Generally, varieties with strong cold resistance, such as 79 1 and Jin Jiu No.8, germinate early and yield forms early, and can harvest 3 ~ 4 knives in spring; Varieties with weak cold resistance, such as Pingjiu No.2 and Jinyin 1, germinate late and can harvest 2 ~ 3 knives in spring. From June to August, the quality of leek is poor and it is not suitable for harvesting. Leek stalks and leek flowers can be harvested and sold on the market. In autumn, the quality of leek improved, and the price also rose, but considering the need to raise roots in autumn, it is necessary to control the harvesting times. Two knives can be collected in warm winter areas in the south of the Yangtze River, and one knife in September in Shandong and North China. Try not to harvest in other areas with cold winter and short frost-free period. For the eliminated and updated plots, it can be harvested continuously until winter. Yunnan and other areas with mild climate can be harvested all year round as long as fertilizer and water are properly managed.
(2) Interval days
When harvesting leek continuously in spring and autumn, it must be separated according to the plant growth potential, the climate situation at that time and the market situation. The first crop of turning green in spring is low temperature and slow growth, which takes 35 ~ 40 days to harvest and 30 ~ 35 days for varieties with strong cold resistance. The second knife usually takes 25 ~ 30 days, and the third knife only takes 20 ~ 25 days. The more vigorous the plant growth, the higher the outside temperature, the better the water and fertilizer conditions, and the shorter the interval between two harvests.
(3) recovery rate standard
For most parts of China, the general standard for leek harvesting is that the plant height reaches 35 cm, with an average of 5-6 leaves per plant and the growth period is more than 25 days. The first harvest in spring, in order to grab the market early, the plant height is 20 ~ 25 cm, and 4 ~ 6 leaves can be harvested. Premature harvesting will not only affect the yield of crops in this season, but also reduce the nutrient accumulation in plants because the leaves do not have enough photosynthetic time, which will lead to the yield reduction of leeks in the next season due to insufficient nutrients. If the harvest is too late, it will not only affect the harvest times, but also reduce the total output of the whole year. If the plant is too large, it will also cause the quality to decline and affect the price.
Japan attaches great importance to the harvesting standards of leeks, especially the uniformity of plants. Leek with a plant height of 35-43 cm is the highest grade, followed by 30-43 cm, followed by 28-45 cm, and the remaining 28-45 cm belong to low-grade products. Therefore, the growth time of Japanese leeks will not be too long, generally not more than 30 days.
(4) Harvest time
It is not suitable to harvest leeks before rainy days, but should be done on sunny days. The best time of the day is early morning. The temperature in the morning is low, and the harvested leeks will not wither and rot due to high temperature, and the plants absorb enough water through the morning night dew, and the products are crisp and tender.
(5) harvesting method
The sickle for harvesting leeks should be ground well in advance, otherwise it is easy to strain the leek roots. Harvest quickly, and the stubble should be flat and tidy, neither high nor low. The harvesting depth should be about 4 cm away from the rhizome, where the stubble is generally yellow. If the stubble is green, it means that the stubble is too high, which affects the current yield and quality of stubble. If you see that the stubble is white, it means that the knife is too deep, which will damage the bulb, weaken the growth potential of the next knife and affect the future yield. An agricultural proverb says, "Raising the knife by 1 inch (about 3 cm) is equivalent to adding another layer of dung". Immediately after harvesting, shake off the leeks, bundle them, harvest them uniformly, and package them for the market. At present, the leek bundle in many areas is rough, which seriously affects the quality of listing. After Japanese leeks are harvested, they are stripped of dirt, sundries and dried leaves, and then tied into small bundles of 65,438+000 g with bright ribbons. Each bundle of 65,438+00 is put into a plastic bag, and every four bags are put into a packaging carton. Different grades of leeks are packaged separately, temporarily stored at low temperature and ready to be sent to the market. These practices are worth learning from.
(6) Finishing after harvest
After harvesting, remove the residual leaves and sundries with a rake in time, and flatten the border. You can sprinkle some plant ash on the stubble, which can not only prevent root maggots, prevent flies from laying eggs, but also play the role of topdressing. After 3 ~ 5 days, water and fertilize. Fertilizer can be decomposed cake fertilizer, manure, compost or compound fertilizer, or some fertilizers can be used at intervals, but it is best not to use only chemical fertilizers for a long time, otherwise it will easily cause soil hardening. When the new leaves of Chinese chive grow to 2 cm, fungicides can be sprayed once according to the situation to prevent diseases.