关键词: 生态水文学法;水文变异点;最小生态流量;适宜生态流量;改进Tennant法;漾弓江;

Abstract: In order to explore the relationship between groundwater depth and precipitation with soil moisture content during summer maize growth period in Huaibei Plain, the atmospheric precipitation, soil water and groundwater in Huaibei Plain were analyzed by using 26 years’ series data of the Wudaogou experimental station and hydrogen and oxygen stable isotope tracing method. The results showed that with the increase of soil depth, the average soil moisture content decreased first, then increased, and finally decreased. The average soil moisture content in 0~0.2m soil layer was the lowest, and that in 0.3~0.5m soil layer was the highest. The average values of δ18O and δD in soil water decreased with the increase of soil depth, indicating that soil water evaporation led to the enrichment of soil heavy isotopes, and the enrichment degree decreased from the surface to deep layer. The seasonal variation of stable isotopes of hydrogen and oxygen in soil water decreased with the increase of soil depth. The most obvious variation of soil water was at the depth of 30 cm and 50 cm, because in this layer the soil was easily recharged by precipitation, and the soil evaporation was relatively strong.

Key words: atmospheric precipitation; soil moisture; groundwater; water movement; hydrogen and oxygen stable isotope; Huaibei plain