How to prevent "late spring cold" in fruit trees and wheat

In the face of the unpredictable "late spring cold" that harms some fruit trees and wheat every year, experts and scholars have different opinions recently and put forward the methods to prevent "late spring cold".

"Cold spring" happens almost every year.

Han, director of Shaanxi Yangling Meteorological Observatory, said that spring is the transitional season between winter and summer, with frequent cyclone activities and changeable weather. Sometimes at noon, the temperature drops below 10 degrees Celsius, and even there will be rain and snow, sometimes as long as 10 days and a half, which is what people call "cold in the spring". According to the analysis of Han Wei Province, there is a greater chance of "late spring cold" in warm winter. Last autumn and winter rainfall was basically the same as in previous years, and the temperature was normally low. He believes that it is unlikely that there will be a large-scale and long-term "cold spring". However, he also said that if there is a long-term rainfall process, the weather will suddenly clear up and the temperature will definitely drop sharply. Such a small-scale "cold spring" phenomenon occurs almost every year.

After decades of practical observation, Li Longshan, a professor at Northwest A&F University and an expert on fruit trees, came to the conclusion that "late spring cold" is harmful to all fruit trees, especially apricot, cherry, apple, pear, kiwifruit and other fruit trees that bloom early. The preventive measures he put forward are: winter irrigation and spring irrigation should be carried out when conditions permit, and winter irrigation can keep the ground temperature and avoid frostbite of fruit trees; Spring irrigation can reduce the ground temperature and delay the germination and flowering time. Secondly, coating the trunk with amino acids can increase the nutrition of the tree and enhance its cold resistance. Coupled with the pesticide Guinness diluted to 4000 times, it can kill the wintering pests lurking on the trunk. The trunk can also be coated with lime, sulfur mixture, salt and vegetable oil at a ratio of 5: 1:0.5:0.5. The purpose of adding salt and vegetable oil is to prevent cracks from falling off. Stone sulfur mixture can prevent frost and insects. In addition, Professor Li believes that the traditional fumigation and washing method is also very effective. The specific method is: when the temperature drops below zero, light firewood in the limelight of the orchard, and the firewood should not be too dry, otherwise there will be less smoke and the effect will not be satisfactory. Professor Li suggested that it is best for all orchards to act in unison, so that the effect will be the best.

Lei, a researcher at the Wheat Research Institute of Northwest A&F University, recently visited many places in Shaanxi. He saw that due to the late sowing date last year, the wheat population was generally less than in previous years. According to the analysis of seedling situation, it is unlikely that there will be "late spring cold" this year, but the possibility of "late spring cold" will not be ruled out for individual fields with early sowing and excessive seedling potential. Researcher Zhang said that wheat was attacked by "late spring cold", and the remedy was winter irrigation and water supplement; Topdressing in time, supplementing nutrients, improving intertillage, raising ground temperature and restoring its growth as soon as possible.