Management Rules for Autumn Onion

After entering the beginning of autumn festival, the air temperature and air humidity decrease obviously, and the suitable temperature and humidity make green onions enter a period of rapid growth. During this period, it is necessary to strengthen field management, focus on promoting roots, strong trees and soil softening, and scientifically apply fertilizer and water to create a suitable growth environment for the formation of green onions, so as to improve the yield and quality of green onions. In production, it is necessary to grasp the following four points: 1. After topdressing and watering the Beginning of Autumn, the air temperature gradually decreased, the root absorption function turned to the peak period, entered the peak period of leaf development, and the need for water and fertilizer increased. During the period from the Beginning of Autumn to White Dew, the principle of watering is "light watering, morning and evening watering", combined with watering and topdressing "leaf attacking fertilizer". 1500 kg of rotten farm manure, 20 kg of superphosphate and 10 kg of potassium sulfate are applied per mu. To promote the rapid development of leaves. After White Dew, the weather was cool, the temperature difference between day and night increased, and green onions entered a period of green onion formation, which was also a critical period of fertilizer and water management. from White Dew to the Autumn Equinox, quick-acting nitrogen fertilizer was the main topdressing, urea was better, and about 20 kg per mu was suitable. 15 kg potassium sulfate was applied. The principle of watering is "frequent watering, re-watering", often keep the soil moist, in order to meet the green onion growth needs. After Frosts Descent, the weather became cooler and cooler, the growth of leaves became slower and slower, and the transpiration of foliar water decreased, so watering should be reduced gradually, and watering should be stopped 7-8 days before harvest to improve the storability of green onions. 2. Cultivate the soil to soften the agricultural proverb: "if you want green onions to get up, the soil must grow to the heart of green onions." The production practice shows that the deeper the soil of green onions is, the longer the white onions are. Soil cultivation is an important measure to soften leaf sheath, prevent lodging and improve the yield and quality of onion. From the Beginning of Autumn to 4 times before harvest (the Beginning of Autumn, the End of Heat, White Dew and the Autumn Equinox), the thickness of soil should be cultivated to the outlet of the uppermost leaf, and the heart leaf should not be buried so as not to affect the growth of green onion. 3. To control diseases and insect pests and control the damage of leaf miners in time, 1.8% avermectin EC 1500 times, or 75% miramine wettable powder 3500 times, or 72% Klu wettable powder 600 times 800 times; during the peak spawning period to the early stage of larval hatching, spray 20% fenvalerate EC 2000 times 3000 times, or 2.5% deltamethrin EC 2000 times, spray once every 7 days for 3 times. When black spot or purple spot occurs in the leaves of scallions, 500 times of 50% carbendazim wettable powder or 600 times of 70% mancozeb wettable powder can be sprayed every 7 to 10 days for 2 times in a row. Drugs should be used in rotation to prevent drug resistance. 4. Harvest the farmer's proverb at the right time: "if Cold Dew does not harvest onions, the longer he is, the more empty he will be." Green onions should be harvested at the right time, early harvest, onion white is not fully expanded, resulting in reduced production, late harvest, water loss at the upper end of the pseudostem becomes soft, affecting the commercial value of green onions. The central and southern parts of our province are generally harvested before the Beginning of Winter.