Three‐dimensional simulation on spatiotemporal variation of salinity in reclaimed saline soil and yield reduction risk assessment

Abstract Amelioration of saline soil to grow crops could increase food production and improve food security. However, the long‐term effects of different methods for ameliorating saline soil still need to be evaluated. In this study (2014–2021), the salinity variations of saline soils under different amelioration methods (T1: salt isolation by a stone layer + cropping; T2: subsurface drainage + cropping; T3: 5‐year cropping; T4: 3‐year cropping; CK: bare land) were monitored using electromagnetic induction. Besides, the long‐term effects of different amelioration methods and yield reduction risk were assessed using the three‐dimensional sequential Gaussian simulation (3D‐SGS). The 3D‐SGS results showed that soil salinity increased during abandonment (2014–2015) and then decreased during reclamation (2016–2021). Salt accumulated in the 0–40 cm soil layer in T3, T4, and CK treatments, while it accumulated in the 40–80 cm soil layer in T1 and T2 treatments. The proportion of high‐risk areas in T1, T2, T3, and T4 treatments reduced after reclamation, but soil salinity only slightly reduced in T3 and T4 treatments, showing a high risk of yield reduction. Besides, the time‐specific regression model had the highest prediction accuracy for soil salinity. Therefore, probabilistic evaluation based on 3D‐SGS is an effective method to evaluate the effectiveness of saline soil amelioration methods, and could help decision‐makers formulate scientific saline soil amelioration plans.