Evaluation of water deficits in deep soil of the loess region of southern Ningxia under various vegetation types
[Objective]The objective of this study was to quantitatively evaluate soil water deficits un-der different vegetation types in the loess region of southern Ningxia,with the aim of providing a theoretical basis for the scientific guidance of rational vegetation allocation and ecological restoration.[Method]The soil water relative deficit index(CSWDI)and desiccation index(SDI)were calculated for Prunus davidiana forest,Hippophae rhamnoides forest,Caragana korshinskii forest,alfalfa land,and farmland within soil pro-files of 0 to 100 cm depth.These calculations were used to quantify soil water deficits and their distribution under five distinct vegetation types in the Zhongzhuang small watershed of Pengyang,located within the loess area of southern Ningxia.[Result]The results showed that the characteristics of soil water variation in the deep layer under different vegetation types were significantly different.The average soil water con-tent within the 0 to 100 cm layer was as follows:farmland(16.29%)>Prunus davidiana forest(13.06%)>Hippophae rhamnoides forest(12.22%)>Caragana korshinskii forest(9.12%)>alfalfa land(8.08%).In the vertical profile,soil moisture initially decreased,then increased,and gradually stabi-lized with increasing soil depth.Within the 0 to100 cm layer,no water deficit or dry layer was observed in farmland,whereas other vegetation types exhibited varying degrees of soil water deficit.The average CSWDI values were 0,0.22,0.62,0.35,and 0.79,respectively,and the average SDI values were 185.5%,67.45%,51.55%,87.35%,and 36.10%,respectively.It was observed that the soil water deficit was most severe in alfalfa land,followed by Caragana korshinskii forest,Hippophae rhamnoides forest,Prunus da-vidiana forest,and farmland.The distribution of dry layers in Prunus davidiana forest,Caragana korshin-skii forest,and Hippophae rhamnoides forest ranged from moderate to severe,respectively.The depth of the dry soil layer(DSLT)was 890,860,800,and 920 cm,with corresponding soil water contents(DSL-SWC)of 12.42%,8.14%,11.56%,and 7.76%,respectively.[Conclusion]Different vegetation types signifi-cantly impact deep soil water deficits,leading to varying degrees of dry soil layer formation.Consequently,appropriate measures should be implemented to restore soil water,promote the sustainable use of regional water and soil resources,and support the healthy development of the local ecology.
vegetation typesoil waterwater deficitloess region of southern Ningxia
NETL
NSTL
万方数据
维普
