Aerated irrigation offsets the negative effects of nitrogen reduction on crop growth and water-nitrogen utilization

High nitrogen (N) fertilizer application in croplands causes environmental problems, including soil quality deterioration and water contamination, which threaten the sustainable development of agricultural systems. Aerated irrigation (AI) is an effective irrigation technique put forward to mitigate root zone oxygen deficiency, improve the root growth environment, and promote crop production and water-fertilizer use efficiency. We conducted this study, therefore, to explore this new and promising strategy in order to balance the negative impacts of N reduction on crop productivity and water-nitrogen utilization. Greenhouse experiments on muskmelon, cucumber, and tomato were carried out for 2 years in Yangling, China. Reducing N application rates inhibited photosynthesis and decreased aboveground dry matter and N absorption compared to conventional N application (i.e., 225, 360, and 250 kg ha−1 for muskmelon, cucumber, and tomato, respectively). AI combined with 150 kg ha−1 (for muskmelon and tomato) or 240 kg ha−1 (for cucumber) of N, however, improved photosynthesis, aboveground dry matter, and N accumulation, thereby resulting in better yield, fruit quality, water-nitrogen utilization, and economic benefits. These findings imply that AI has great potential for balancing the negative effects of N reduction on crop productivity and water-fertilizer utilization in facility agricultural production. We propose that the adoption of an appropriately reduced N application combined with AI can be an effective means to achieve high crop yield, efficient resource utilization, and sustainable agricultural development. More experiments with multiple N application reduction levels should be carried out to determine the optimal N application amount to be used alongside AI.