Halophyte-based saline irrigation: A remote sensing study of eco-hydrological impacts

Abstract

Saline irrigation with halophytes has emerged as a promising nature based solution for enhancing ecosystem functioning in arid saline environments; however, its long term Eco-hydrological effects remain poorly understood. This study examined long term Eco-hydrological impacts of a halophyte based saline irrigation system at the Karamay experimental site, Xinjiang, China, by using multi-source remote sensing data between 2015 and 2025. Indicators of seasonal growing period, such as normalized difference vegetation index (NDVI), soil salinity index (SI), evapotranspiration (ET), and land surface temperature (LST) were compared between a managed halophyte garden and an adjacent control area. Findings indicated that the halophyte garden always had higher NDVI, ET and lower SI, LST, compared to the control area, which meant better vegetation performance, less salinity stress, and thermal conditions. Mann Kendall and Sen's slope analyses revealed no significant year to year trends in NDVI, SI, ET, or LST in either area. Regression analysis indicated that SI and NDVI had a strong negative relationship. While there was a positive relationship between ET and NDVI. These findings affirm that salinity in soils was the primary constraint to vegetation growth, whereas water flux favored the growth of the plants. Multivariate regression and machine learning models (Random Forest and Extreme Gradient Boosting), further established SI to be the best predictor of NDVI, followed by land management and ET, but temperature and precipitation did not have significant effects. Importantly, halophyte systems do not eliminate salinity stress but mitigate its ecological impact, promoting vegetation tolerance. The findings underscore their possible potential as a nature based solution to sustainable land and water management in arid salty environments.