华北山前平原灌溉农田深层土壤水分动态特征及渗漏量估算

以中国科学院栾城农业生态系统试验站的大埋深土壤水分剖面观测设施为依托,利用中子水分仪对15.4m深度的土壤水分进行连续1年的定位观测,同时通过定期采集深层土壤和水分样品,对该区土壤水分变动特征和深层入渗量进行了定量研究。结果表明:土壤水分在垂直剖面上的分布受土壤质地组成控制,同时在年内受降水事件和灌溉的影响而波动,随着土壤深度的增加,土壤水分的变异性呈减弱趋势;根区土壤水分受降水(灌溉)和作物耗水的共同影响而变化剧烈,根区以下土壤水分对降水的响应有一定延迟;在观测期间,整个15.5m深度的土壤剖面上有水分的盈余,土壤水贮量增加了216mm,但在小麦生育期土壤水分表现出耗损过程(土壤水贮量减少了208mm)。最后利用氯质量平衡法估算560cm深度处渗漏量约为65mm。

Dynamic Characteristics and Drainage Assessment of Deep Soil Profile in North China Plain Typical Irrigated Farmland

This experiment depended on the deep soil water profile observation system in Luanchen experimental station, using neutron moisture viewer to observe the soil water content on 15.4 meter soil profile in situ for one continuous year. Combine with the deep soil ahd water sample collection test at regular interval, analysised the dynamic changes of soil water and quantitated the drainage volume in deep soil layer. The follow results showed that the distribution charactoristics of soil moisture were controled by soil texture and it fluctuated with the influence of precipitation and irrigation event. The variability of soil moisture decreasing along with the increasing soil depth. With the influence of precipitation (irrigation) and evapotranspiration, dramatic variations of soil moisture occurred in the root zone. However, response to the precipitation for the soil moisture below the root zone was delayed. The soil water contents were surplus in the whole soil profile (15.4 meter) during the observation period and the gained soil water storage were 216 mm. Nevertheless, the soil water contents lost in the wheat seasons and the soil water storage depleted 208 mm. Based on the chloride mass balance method, the deep drainage were estimated. It was almost 65 mm soil water that percolated through the soil layer which beneath the 560 cm depth.