Integrated soil-cotton management system enhances nitrogen use efficiency under different soil fertility levels

An integrated soil-cotton management system integrated with optimal management practices is projected to replace the conventional management system for enhancing nitrogen use efficiency. Field experiment was conducted in the more and less fertile soil with two treatments. Results showed that compared with conventional management system, integrated soil-cotton management system increased 9.5-21.2% soil-available nitrogen during the middle and later growth stages, in addition, improved average and maximum accumulation rate of nitrogen by 30.4-36.2% and 39.9-45.1%, and postponed the start time of the fast nitrogen accumulation phase by 3-6d, resulting in 32.5-38.3% higher final nitrogen accumulation. Furthermore, the increased nitrogen accumulation improved leaf area index, leaf area duration and boll number, finally enhanced agronomic nitrogen use efficiency and recovery nitrogen use efficiency. We suggest the nitrogen-based fertilizer of integrated soil-cotton management system could be omitted completely in the more fertile soil to enhance physiological nitrogen use efficiency ultimately by optimizing leaf area index. In addition, the decrement of nitrogen use efficiency was diminished under integrated soil-cotton management system. These results demonstrate ISMS might be a more profitable pattern for nitrogen use efficiency of cotton, especially to meet the challenge of soil degradation in future.