Prediction and Impact Analysis of Soil Nitrogen and Salinity Under Reclaimed Water Irrigation: A Case Study

• DOI: 10.3390/agronomy15020443
• Publication Date: 2025-02-11T16:54:06Z
• Authors: Zeyu Liu; Kai Fang; Xiaoqin Sun; Yandong Wang; Zhuo Tian; Jing Liu; Liying Bai; Qilin He
• Keywords: Reclaimed water

Reclaimed water irrigation is increasingly being applied to address global scarcity, yet its long-term effects on soil nitrogen cycling and salinity dynamics, particularly in agricultural agroforestry systems, remain complex insufficiently understood. Understanding these impacts crucial for developing sustainable practices that optimize resource use while ensuring the health viability of systems. This study employs genetic-algorithm-optimized random forest models (GA-RF1 GA-RF2) examine dynamics indicators (NO3−-N, NH4+-N, TN) (EC Cl−) under reclaimed irrigation. The achieved high predictive accuracy, with NSE values 0.918, 0.946, 0.936, 0.967, 0.887 NO3−-N, TN, EC, Cl−, respectively, demonstrating their robustness. Key drivers were identified as duration (years), fecal coliform levels, depth, primarily influenced by land type chemical composition water, including oxygen demand, total phosphorus, nitrogen. Spatial analysis revealed significant accumulation surface soils extended irrigation, farmland, where NO3−-N NH4+-N peaked at 25 mg/kg 15 mg/kg, respectively. EC exceeded 700 µS/cm during early stages but remained within crop tolerance levels. Conversely, grassland woodland exhibited minimal accumulation. These findings underscore need targeted management strategies mitigate buildup, ensure productivity