Evaluation of the perennial spatio-temporal changes in the groundwater level and mineralization, and soil salinity in irrigated lands of arid zone: as an example of Syrdarya Province, Uzbekistan

Abstract

Salt accumulation in irrigated lands is an intercontinental environmental issue that adversely influences the sustainable land use, agricultural land productivity and global food security. With the higher level of groundwater table (GWT) and its increased mineralization, global climate emergency in arid lands also obviously increase soil salinity (SS) in Uzbekistan. Analyses of perennial data on saline agricultural lands were performed by principally depending on conventional outdated methods. The integration of GIS approach to map the widespread of GWT, groundwater mineralization (GWM) and SS in irrigated lands of Syrdarya province in Uzbekistan were manipulated within the limited time period. Nevertheless, in particular irrigated areas where GWT is shallow and highly mineralized, insufficient scientific data and GWT maps created in accordance with GIS-based methods is identified, restricting a better establishment of tracing the SS of irrigated land over time as GWT and GWM rise. Thus, our study is to trace and delineate the dynamic and spatial changes in GWT, GWM and SS caused by climate factors over 2000–2019 by integrating traditional research methods and cross-validated GIS methods in the example of irrigated land of Syrdarya province in Uzbekistan. To reach this goal, a fieldwork was organized and relying on the in-situ data collected from around 3800 different points for soil sampling and 1500 observation wells for groundwater studies, GIS-based maps were created for four last experimental years 2016–2019 using the Inverse Distance Weighting (IDW) interpolation. By comparing the IDW maps with the in-situ data, an overall accuracy of maps per each variable was calculated and data from maps were quantified. A statistical approach was applied to examine the interrelationship between GWT, GWM, SS and climatic factors such as seasonal air temperature and seasonal precipitation. GWT and GWM are moderately correlated each other, but, these two variables are considered as the main drivers to the enlargement of saline irrigated areas in the province.