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喷水法在预报有霜冻出现时,于凌晨2~3时在作物或塑料薄膜上喷水2~3次,隔1小时喷1次。由于喷水使田间空气和植株间的湿度增大、水分增多,当水汽凝结成露滴时会放出凝结潜热,同时水温比气温高(初霜时期气温0℃时水温约15℃),水在作物上遇冷凝结会释放热量,故采用喷水法防御一般不会有霜冻形成。灌水法可在预计有霜冻出现的前1天傍晚灌水。因为水的热容量大,导热性好。灌水不仅可以增加土壤水分,还可增大近地面层的空气湿度,它可减缓夜晚地面长波辐射的散热程度,因而起到保护地面热量的作用,可提高地温2℃左右。
Water spray method in the forecast of the emergence of frost, at 2 to 3 am in the crop or plastic film on the water 2 to 3 times, spray 1 every 1 hour. As the water spray increases the humidity between the air in the field and the plants, the water content increases. When the water condenses into a dew drop, the latent heat of condensation will be released and the water temperature will be higher than the air temperature (the water temperature is about 15 ° C at 0 ° C in the initial frost period) Condensation of crops on the meeting will release heat, so the use of water-based defense is generally not a frost formation. The irrigation method can be used to irrigate the evening before the expected frost occurs. Because of the heat capacity of water, thermal conductivity is good. Irrigation can not only increase soil moisture, but also increase the air humidity near the ground surface, which can slow the night-long surface wave radiation degree of heat dissipation, and thus play a role in protecting the ground heat can increase the ground temperature about 2 ℃.