Contribution Of Snow Melt Water To Soil Water And Its Dynamic Change In Spring

In the context of global warming,the significant warming in the Northeast has led to early and accelerated snow melting,and the premature evaporation of snowmelt water has increased the spring drought.The Northeastern area is an important grain production base in the country.The occurrence of the spring drought has affected it.Spring plowing affected by the spring drought further reduces grain quality and yield.The application of stable isotope techniques to quantitatively explore the contribution of spring snowmelt to soil water can provide a deeper understanding of the significance of spring snowmelt water and its mechanism of action.It is also expected that this result can help prevent spring droughts and provide scientific guidance and suggestions.This paper is based on outdoor control experiments.From March to early June 2019,the method of artificial snow piling was adopted at Wuying Meteorological Station in Yichun,with three snow depths and a bare land control set to collect soil samples before and after snowmelt in different places.Precipitation samples and groundwater samples have also been selected.Based on isotope-related theoretical knowledge,we analyze the changes in the distribution of isotope in soil water,the contribution of snowmelt water to soil water and its dynamic changes.The results show:(1)There was significant difference in 0.05 probability between 20-30cm layer and the other two layers at the same snow depth,and there was no significant difference in soil water isotope values at 0-10cm and 10-20cm soil depths;For different snow depths and the same soil depth,there is a significant difference in soil water isotope values between the 50cm snow depth plot and the corresponding soil depths of other snow depths at the probability level of 0.05,and there is no significant difference among the other three plots.(2)The LMWL of Wuying in spring is:?D=7.70?¹⁸O+5.59,and its intercept and slope are less than the global and National MWL.(3)Soil Water Line:bare land 0-10cm soil depth:?D=6.83?¹⁸O-20.19(R²=0.96),10-20cm soil depth:?D=6.83?¹⁸O-12.50(R²=0.92),20-30cm soil dept:?D=3.72?¹⁸O-39.71(R²=0.46);10cm snow depth 0-10cm soil depth:?D=7.22?¹⁸O-11.97(R²=0.97),10-20cm soil depth:?D=6.33?¹⁸O-16.11(R²=0.91),20-30cm soil depth:?D=7.66?¹⁸O-0.54(R²=0.84);30cm snow depth 0-10cm soil depth:?D=7.07?¹⁸O-11.08(R²=0.97),10-20cm soil depth:?D=7.73?¹⁸O-0.40(R²=0.97),20-30cm soil depth:?D=6.38?¹⁸O-13.05(R²=0.88);50cm snow depth 0-10cm soil depth:?D=7.36?¹⁸O-8.13(R²=0.98),10-20cmsoildepth(R²=0.93):?D=6.71?¹⁸O-11.74(R²=0.93),20-30cm soil depth:?D=6.87?¹⁸O-8.38(R²=0.92).The shallower the soil layer is,the closer it is to the atmospheric drawdown line,and the more strongly affected by precipitation.(4)Under the same snow depth,with the increase of soil depth,the contribution of snow melt water lasts longer and the reduction rate decreases gradually;At the same soil depth,with the increase of snow depth,the contribution of snow melt water increases to a certain extent,and the contribution to soil water lasts longer.