Modelling and Mapping of Soil Salinity Related to Soil Characteristics and Irrigation in a Semi-Arid Context

Abstract

Soil salinity is a key challenge to maintaining agricultural operations in regions primarily defined by a semi-arid environment. Irrigation techniques are used to mitigate the impact of insufficient precipitation. However, excessive use of irrigation water creates significant problems of soil salinity. Utilising advanced methodologies, this investigation is dedicated to making models and maps of soil salinity. The approach involves the computation of the Normalised Differential Salinity Index (NDSI) while systematically examining potential correlations among the various physicochemical parameters under scrutiny: Soil Organic Matter (SOM), Electrical Conductivity (EC), pH, Texture, total limestone (CaCO3) and Evapotranspiration (ET0), in order to determine the parameters controlling salinity. The results showed a predominance of the sand fraction (57.5%), EC varied from 0.90 to 1.32 dS.m-1, and exhibited varying salinity levels. Additionally, within the climate conditions of the region, climate analysis unveiled a noteworthy evapotranspiration rate (ET0) ranging between 4 and 9 mm.day-1. The model developed showed an adequate result in estimating soil salinity with an R2=0.90. Moreover, the map generated using NDSI showed that 36% of the total area displayed no evidence of salinity impact, 23% showed mild salinity, 24% indicated moderate soil salinity, and 17% showcased extreme levels of soil salinity. The proactive cartography of soil salinity in dry and semi-dry areas, coupled with an advanced modelling technique employing remote sensing data, stands as an integral methodology for informed decision-making processes.