【摘要】：華北平原的水資源問題日益嚴(yán)峻,尤其以石家莊市區(qū)為代表的城市,人口多、經(jīng)濟較發(fā)達(dá),降水量減少,水資源緊缺,生態(tài)系統(tǒng)變脆弱。由于地下水位逐年下降,土壤水在水資源合理利用和生態(tài)系統(tǒng)水循環(huán)中的作用更為重要。根據(jù)2013年4月到2014年5月測得的石家莊市區(qū)降水和2013年石家莊市雨季土壤水、灌溉水的穩(wěn)定氫氧同位素,通過穩(wěn)定同位素示蹤的方法,結(jié)合對土壤機械組成的測定分析,從時間和空間的角度分析了不同土壤層水穩(wěn)定同位素的變化規(guī)律,進而推斷土壤水分遷移過程。研究結(jié)果表明:石家莊2013年全年的降水量為596.55mm,樣地降水的大氣降水線為y=6.547x-1.667(R2=0.941,p0.001),過量氘均值為6.1885‰,反映了石家莊2013—2014年降水主要來自季風(fēng)帶來的海洋水汽,同時有一定的局地蒸發(fā)。石家莊土壤水的來源主要是降水,灌溉水則主要在雨季前期有緩解干旱的輔助作用,且雨季的降水量足以對土壤進行適當(dāng)補給。石家莊市土壤機械組成的測定結(jié)果表明,石家莊市0—100cm土壤質(zhì)地都屬于壤土層,0—70cm為較粗的沙粉壤土,80—100cm為較細(xì)的粉土壤土。70—80cm是比較明顯的土層交接層,容易出現(xiàn)土壤水積聚。從不同的時間尺度上對土壤進行取樣,分析土壤水分運移過程,研究結(jié)果表明:(1)4月份的一次較大降水之后,降水在土壤中的入滲速度并不均勻,40-70cm處為100mm/d,70-80cm入滲速度為33mm/d。由于土壤質(zhì)地和降水時間、降水量的影響,土壤水的垂直入滲呈由快到慢的過程,70cm常為阻隔層。(2)從5月開始對土壤水每半個月一次的觀測得知,10cm到100cm土壤水的δ18O值隨深度增大而減小;雨季最大蒸發(fā)深度在40cm左右,5月和9月由于降水量較少,土壤水的蒸發(fā)作用最為明顯,都達(dá)到了40cm的蒸發(fā)深度;5月到9月取樣期間基本上形成了一個土壤水δ18O峰值沿剖面徘徊中不斷向下推進的情況,0—70cm受土壤水入滲的影響較80—100cm明顯,此過程反映了降水的入滲和新舊水混合的相互作用。
[Abstract]:The problem of water resources in North China Plain is becoming more and more serious, especially in Shijiazhuang city, where the population is large, the economy is more developed, the precipitation is reduced, the water resources are in short supply, and the ecosystem is fragile. Soil water plays a more important role in the rational utilization of water resources and ecosystem water cycle due to the decrease of groundwater level year by year. According to the precipitation in Shijiazhuang city from April 2013 to May 2014 and the stable hydrogen and oxygen isotopes of soil water and irrigation water in the rainy season of Shijiazhuang city in 2013, the stable hydrogen and oxygen isotopes of irrigation water were analyzed by using the method of stable isotope tracer and the determination and analysis of soil mechanical composition. From the point of view of time and space, the variation law of water stable isotopes in different soil layers was analyzed, and the process of soil water migration was inferred. The results show that the precipitation of Shijiazhuang in 2013 is 596.55mm, the precipitation line of sample land is y=6.547x-1.667 (R2C0.941kp0.001), the average deuterium excess is 6.1885 鈥，

本文編號：2155008