Effect of integration of water and fertilizer on soil water–nitrogen transport characteristics in Bubbled-root Irrigation

Improving water and fertilizer use efficiency in arid and semi-arid regions can not only promote the sustainable development of regional crop production, but also effectively meet the challenges of future global water shortage and food security. Bubbled-root irrigation is a new water-saving irrigation technology developed for arid and semi-arid areas. It not only has the characteristics of precision irrigation (improving water and fertilizer utilization and irrigation efficiency), but also has the advantage of not being easily blocked. In this study, the infiltration capacity, wetting front transport characteristics, water and nitrogen transport, and transformation characteristics of Bubbled-root Irrigation under water and fertilizer coupling conditions were investigated in the arid region of Northwest China. The results showed that under the same infiltration time, the higher the fertilizer concentration, the greater the cumulative infiltration and wetting front (horizontal, vertical upward, and vertical downward wetting front) transport distance. Based on the results, a mathematical model with cumulative infiltration or wetting front as the dependent variable, fertilizer concentration and infiltration time as independent variables was constructed. The model has high reliability (The relative deviation between the fitted value and the measured value is within ± 10