Agricultural Weather Stations: Empowering Freezing Damage Prevention in Crop Cultivation

Agricultural Weather Stations can real-time monitor meteorological parameters in fields, including temperature, humidity, light intensity, wind speed, wind direction, and rainfall. These data are crucial for understanding the impact of freezing damage on crops. Freezing damage, a type of agricultural meteorological disaster, refers to damage caused to crops when ice forms within them under low temperatures below 0°C.

Different crops exhibit distinct characteristics and negative impacts from freezing damage. Take winter wheat as an example: its freezing damage types mainly include winter severe cold type, sudden temperature drop at the beginning of winter type, and early spring freeze-thaw type. In the case of winter severe cold type freezing damage, winter wheat is prone to damage when there is no snow or unstable snow cover in winter. For the sudden temperature drop at the beginning of winter type, when the wheat seedlings stop growing or when the temperature drops sharply after sowing (especially if the early-stage temperature is high and the seedlings grow too vigorously before encountering cold air), the seedlings are highly susceptible to damage. Early spring freeze-thaw type freezing damage often occurs when the weather warms and thaws in early spring, and the seedlings start to germinate. If strong cold air strikes at this time, the wheat seedlings will be affected. When the freezing damage is mild, the young ears of the main stem and large tillers of the wheat plant are frozen, and although they can still head and set seeds normally, the number of grains per ear will significantly decrease. In severe cases, the young ears and heart leaves of the main stem and large tillers freeze to death, but the rest of the plant can still grow. When the freezing damage is extremely severe, the leaves and leaf tips of wheat become as hard and brittle as if scalded by water, then turn green and withered or appear blue-green, and the stems and young ears shrink and die.

For fruit trees like citrus, the critical temperature for severe freezing damage in adult fruit trees is -7 to -9°C. When the temperature drops to this range, citrus trees may suffer severe freezing damage. Freezing damage can freeze citrus flower buds, causing delayed flowering or deformed flower buds, which affects fruit yield and quality. The tender branches and leaves of fruit trees are also prone to freezing damage in low temperatures, leading to withered shoots and hindering normal growth. Moreover, during icy and low-temperature periods, the soil is prone to freezing, which affects the absorption function of fruit tree roots and hinders their growth.

In protected vegetable cultivation, freezing damage affects the temperature and light transmittance in greenhouses, slowing vegetable growth. Sustained low temperatures can cause freezing damage to greenhouse vegetables and open-field vegetables, and seedlings used for early spring cultivation may even freeze to death. Additionally, high humidity in greenhouses easily triggers diseases such as downy mildew and gray mold.

In terms of high-incidence areas, freezing damage occurs more frequently in mid-to-high latitudes. In China, the northern part of the winter wheat region is most affected by freezing damage, including the northern Xinjiang freezing damage area along the southern edge of the Junggar Basin, and the Loess Plateau freezing damage area in eastern Gansu, northern Shaanxi, and central Shanxi. Even in the Yangtze River Basin and southern China, where freezing damage occurs less frequently, hilly mountains block the southward-moving cold air, causing cold air to accumulate, leading to prolonged low temperatures accompanied by snow and freezing rain, which can severely damage crops like wheat, rapeseed, broad beans, peas, and citrus.

Data provided by Agricultural Weather Stations enable us to predict cooling weather. When the monitored temperature is about to drop to the critical freezing temperature of crops, farmers can promptly take measures such as covering crops with thermal insulation materials or watering to mitigate the impact of freezing damage and protect crop yield and quality as much as possible.