【摘要】：蒸散是水量平衡和能量平衡的重要組成部分,也是農(nóng)田生態(tài)系統(tǒng)水分消耗的主要途徑。為探究黃土塬區(qū)農(nóng)田蒸散的日動態(tài)變化規(guī)律,運用渦度相關(guān)法、土壤水分及常規(guī)微氣象觀測系統(tǒng)等,于2013年作物生長季(4—10月)對試驗區(qū)農(nóng)田作物(冬小麥、春玉米)蒸散特征及影響因素進行分析。結(jié)果表明,降水對蒸散的影響較為顯著,降水過后的日蒸散量較降水前會有所增加;農(nóng)田0~100 cm土壤含水量變異系數(shù)較大,土壤水分變化劇烈,作物根系的集中分布范圍在0~80 cm之間,因此0~100 cm土壤水分主要參與蒸散過程;晴天蒸散的累積量大于陰天,晴天和陰天的日均蒸散量分別為4.5、3.8 mm d-1,相差0.7 mm d-1。陰天蒸散開始的時間較晴天晚,陰天條件下的蒸散更易受到氣象因子的擾動;不同天氣條件下凈輻射均為蒸散的主要影響因子,蒸散速率與凈輻射變化趨勢一致,但在時間上滯后于凈輻射;在不同的土壤水分環(huán)境條件下,蒸散的過程和強度差異較大,水分脅迫條件下,全天蒸散量水平較低,"蒸散高地"的持續(xù)時間較長;而水分相對充足時,全天蒸散水平較高,"蒸散高地"持續(xù)時間較短,維持較高的蒸散速率的時間較長。
[Abstract]:Evaporation is an important part of water balance and energy balance, and it is also the main way of water consumption in farmland ecosystem. In order to explore the diurnal dynamic variation of farmland evaporation in Loess Plateau, the characteristics and influencing factors of farmland crop (winter wheat, spring corn) evaporation in the experimental area were analyzed in 2013 crop growth season (April to October) by using vorticity correlation method, soil moisture and conventional micrometeorological observation system. The results showed that the effect of precipitation on evaporation was significant, and the daily evaporation after precipitation was higher than that before precipitation, the coefficient of variation of soil water content in farmland was large, the soil water content changed violently, and the concentrated distribution range of crop root system was between 0 鈮，

本文編號：2517398