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为了合理开发利用水资源,提高半干旱地区水资源利用率,为现代农业发展提供更精细化的气象服务,通过研究阜新地区土壤水分与降水量关系及特征,找出了阜新地区土壤水分变化规律,并在此基础上,建立了阜新地区农田抗旱需水量评估方法。结果表明:(1)较大降水后,浅层土壤增墒迅速,几小时内土壤重量含水率可达到最大值,并在20 cm左右土壤中形成1个高含水层;深层增墒相对缓慢,需要十几到二十几小时达到最大值;(2)较大降水发生1天后,10~50 cm层土壤重量含水率达到最大值,然后在无降水的情况下土壤重量含水率缓慢下降,基本呈直线型,直到下一次较强降水的到来,重量含水率再次上升;(3)降水增墒速度大于墒情递减速度;(4)受多种因素影响,降水后10~50 cm层各月土壤增墒率和晴好天气下各月逐日土壤墒情递减率有各自的变化规律。其中,4月、7月降水增墒率相对较小,9月最大,8月次之;4月、5月逐日土壤墒情递减率最小,6—9月相对较大,其中,7月最大。土壤墒情递减率对抗旱需水量中流失的水分计算起到重要作用;(5)实际抗旱需水量大于设定重量含水率所需的含水量,因为要考虑土壤蒸发、作物吸收、深层渗透、降水径流等流失的水分;(6)抗旱需水量评估方法对抗旱方面的政府决策气象服务起着重要作用。可用于自然降水对旱情缓解的分析、节水灌溉工程的精细化气象服务等。
In order to rationally develop and utilize water resources, improve the utilization rate of water resources in semi-arid areas and provide more refined weather services for the development of modern agriculture, the relationship between soil moisture and precipitation and the characteristics of Fuxin area was studied to find out the variation law of soil moisture in Fuxin area On this basis, a method to evaluate drought-resistant water requirement of farmland in Fuxin area was established. The results showed as follows: (1) After heavy rainfall, soil moisture increased rapidly in shallow soil, the soil moisture content reached the maximum within a few hours and a high aquifer was formed in about 20 cm of soil; It takes 10 to 20 hours to reach the maximum value; (2) One day after the occurrence of larger precipitation, the soil moisture content of 10-50 cm layer reaches the maximum value, then the soil moisture content decreases slowly without precipitation, (3) the rate of precipitation and soil moisture increase is greater than the rate of soil moisture decline; (4) Affected by many factors, soil layers of 10-50 cm layer after precipitation Moisture increase and sunny weather each month the soil moisture decline rate has its own variation. Among them, the precipitation in April and July was relatively small, which was the largest in September and followed by August; the soil moisture in April and May was the lowest, and it was relatively large in June-September, of which the maximum was in July. (5) The actual water requirement for drought resistance is greater than the water content required to set the moisture content of the water, because soil evaporation, crop absorption, deep penetration and precipitation should be taken into account Runoff and other loss of moisture; (6) Drought water demand assessment methods for the government decision-making weather services drought plays an important role. It can be used for the analysis of drought relief by natural precipitation and meticulous weather service of water-saving irrigation project.