Why is melting snow colder than snow?

Snow melting is colder than snow melting because it is an endothermic process. Low altitude is controlled by cold air pressure, and the temperature begins to drop. When it snows, cold air carries moisture, and when water vapor turns into snowflakes, it also releases some heat. In winter, when the cold wave in the north comes into contact with the warm and humid air in the south, because the cold air is heavy, the warm air is thrown into the sky, and the water vapor in the warm and humid air condenses into ice crystals, releasing heat, which makes the weather not very cold before and during the snow.

Snow is a natural phenomenon that water or ice condenses in the air and falls, or refers to falling snowflakes. Snow is the solid form of water. Snow will only appear under the influence of temperatures below zero degrees Celsius and extratropical cyclones, so the probability of snow in subtropical and tropical areas is relatively small.

Effects of Snow on Crops

1, soil protection

The snow covering the soil surface is soft, just like a quilt, which has the function of keeping warm, and can lock the heat in the soil inside to avoid freezing crops. Moreover, the snow in winter is not easy to melt, and the warmth retention effect is better.

Step 2 supplement nutrition

Snow will absorb carbon dioxide, sulfur dioxide, hydrogen sulfide and other gases in the air. After the temperature rises, the snow will melt and transport the mineral elements contained in it to the soil, thus synthesizing salts with the acidic substances in the soil to provide nutrition for crops.

Step 3 eliminate pests

Snow is a low-temperature substance, and its own temperature is low, while pests in farmland have poor cold tolerance. In snowy weather, pests will be covered with snow and die of frostbite. When the snow melts in the next spring, the number of pests will be greatly reduced, so that crops can grow better.

Production management after snow

1. When it snows during the day, try to uncover the plastic film, which will not only help to keep the indoor temperature and photosynthesis by using scattered light, but also help to clear the snow on the shed in time. When it snows at night, it is best to cover the mulch with a plastic film, which is not only convenient for snow removal, but also can avoid soaking quilts, mulch and other mulch films.

2. After the heavy snow, the weather suddenly becomes sunny, so we should pay attention to ventilation in time, but don't open the vent too wide to prevent the sudden change of temperature from affecting plants. And gradually extend the time and quantity of uncovering until the plants no longer wither, and then turn to normal uncovering management.

3. After uncovering the plastic film, if the vegetables are wilted, they should be covered immediately, and then uncovered after the leaves are restored, and repeated several times until they are no longer wilted. Vegetable farmers who don't use blinds can alternately uncover the grass film to prevent the temperature from rising too high, and at the same time heat the ground in turn to promote the temperature rise. When it is found that the seedlings are wilting, clear water or 1% glucose water can be sprayed on the wilted seedlings to restore the plant growth as soon as possible.