Leeks are common vegetables and are mostly grown by ordinary farmers. The nutritional value of leeks is very high, and in Chinese medicine, some people also call leeks "intestinal washing grass", and many people in the folk say that leeks are "rising grass".
Leeks are rich in fiber, and the main nutrients include vitamin C, vitamin B1, vitamin B2, niacin, carotene, carbohydrates and minerals. Therefore, eating leeks in moderation is very good for the human body.
When it comes to leeks, there is always a saying in the folk that "spring food is fragrant, summer food is smelly". Zhou Yong, a writer of the Southern Song dynasty and Qi dynasty whose ancestral home was an anjoining runan, Henan, once left a famous sentence saying, "Early leeks in early spring, late autumn and late chimes." What he means is that the quality of leeks in early spring is the best, the leeks in late autumn are worse than those in spring, and the quality of leeks in summer is the least flattering.
The poor growth of leeks in summer is inseparable from the high temperature and strong light and hot rain in summer. The leeks grown by ordinary farmers are more likely to be infected and harmed by the climatic environment and pathogens and pests and pests every summer under the pure natural environment and relatively extensive management, and thus turn yellow and hairy, making the leeks become the "stinky leeks" in the eyes of rural people.
Many farmers plant leeks in the vegetable field, in the summer because of improper management of yellow hair firewood, serious often lose their edible value, can only be cut down and thrown away.
In fact, the adaptability of leeks is still quite strong, it is hardy and heat-resistant. In the case of soil pH 5.5-6.5, medium intensity, ambient temperature 15 °C - 25 °C, and relative humidity of air 60%-70%, leeks will grow very well.
The reason why the leeks grown in the homes of farmers in the summer will mostly grow into yellow and turn wood is due to management failures, which have caused the destruction of leeks such as high temperature glare, epidemic disease, thrips and late-eyed mushroom mosquitoes.
It is not impossible to make the leeks in the field grow fresher in the summer. Farmers who are ready to try to manage their leeks to get rid of the situation of turning yellow in the summer can actually try the following three measures that are not too troublesome and not too laborious.
First, tie a fence or set up a shade net to shade the leeks in the house.
Leeks like cold and cold. Summer light is too strong, the temperature is too high, easy to become more fiber, poor quality.
In summer, leeks are shaded, and ordinary farmers can follow the example of planting a fence on the north side of the east-west settled leek furrow in order to promote the early onset of leeks in winter and spring. The stalks of tall crops are used to set up a fence for leeks to shade the south side of the east and west long furrows, so that the leeks can enjoy some shade in the hot and hot afternoons of summer.
If you don't want to tie a fence or have a large area, or if the north-south colonization of the fence plays a small role, you can try to pull up a shade net for the leeks. Using a shade net to shade leeks and resist the strong light and high temperature in summer is not only effortless, but also the cost is not high.
Second, control the dryness and wetness in the leek field, and don't forget to help the leeks raise roots.
Any crop needs to absorb nutrients with the help of a well-developed and strong root system to be able to grow robustly, and leeks are certainly no exception.
Leeks are root vegetables that grow every spring by sprouting from dormant roots in winter. When a spring grows, leeks must be cut at least 2-3 stubble before entering the summer, which requires a lot of nutrients.
The harsh environmental factors in summer will cause certain problems in the root system of leeks for one reason or another. In the process of subsequent growth, it is necessary to help the leeks raise their roots by strengthening management, rather than choosing extensive management once and for all.
Leek rooting should control the dry and wet in the field, can not be too dry and can not often let the humidity of the leek field maintain or even more than 80% - 90%, the humidity is too large leeks are easy to root.
After the rain, it is necessary to pay attention to draining the leek field and dispersing the wet in the middle cultivation. In order to help the growth of weak leeks to recover, organic fertilizers and phosphorus and potassium fertilizers should be reasonably applied to leeks after autumn every year.
Third, prevent and control pests and diseases, and avoid leeks being worse caused by injuries.
After spring, leeks are susceptible to thrips and late-eyed mushrooms and summer leek blight.
The main hazard periods of thrips are April-June and October-November, and the main hazards of Leek Late-Eye Mushroom Mosquitoes are March-June and September-November. However, both pests can form a continuous hazard after the sting and before the start of wintering, but the summer is relatively light due to rainy and wet reasons.
Leeks that have been harmed by thrips and late-eyed mushrooms are highly susceptible to leek blight. Leek blight is between 25 °C and 32 °C, the relative humidity of the air is more than 95%, and it is easy to occur when there are water droplets and mist dew on the surface of the leek. After heavy summer rains, it suddenly turns sunny, and leek blight will occur frequently and develop quite rapidly. The roots, stems, leaves and flowers of leeks can be harmed by diseases, in the early stage or when the damage is mild, there will be water-stained spots on the leaves and bulbs and the root plate, and after severe disease, the diseased parts shrink and turn yellow or brown and rot, the leaf sheath is easy to fall off, the root hairs are reduced, and the plant stops growing or dying.
For Late-eyed mushroom mosquitoes, armyworm plates can be set to trap adult insects. At the peak of feathering, adult mushrooms can spray 40% octyl thion emulsion or 80% dichlorvos emulsion 1000 times liquid. In the early spring and late autumn of the late-eye mushroom larvae, it can be sprayed with 1.8% avermectin emulsion 2000 times liquid, or 25% urea suspension 1000 times liquid and other agents, and the underground leek maggots can be sprinkled with 5% octyl thion granules, and can also be poured with 1.1% matrine powder with water.
For adult thrips, it is also necessary to set up a sticky worm plate to trap. Both adult thrips and larvae can be controlled with sprays such as 1.8% avermectin emulsion 2000 times liquid, or 10% imidacloprid wettable powder 2000-3000 times liquid, or 2.5% polycycidecin suspension 3000 times liquid.
For the epidemic diseases caused by tobacco Phytophthora in summer, 72% frost urea and manganese zinc wettable powder can be sprayed 500-600 times liquid, or 76% hexen urea cyanide wettable powder 400-500 times liquid, or 60% zole ether and daisen water dispersible granules 1500 times liquid, or 25% pyrazole ether ester emulsion 1000 times liquid, etc., which need to be continuously controlled 2-3 times.
In short, it is precisely because leeks are easily affected by the environment and pests in the unfavorable growth environment in summer, and grow into the appearance of yellow hair and firewood, which affects consumption. Therefore, in order to cultivate and eat relatively tender leeks, it is more necessary to take measures to strengthen management. As long as you pay, there will be a return.