Enhancing the annual yield via nitrogen fertilizer application optimization in the direct seeding ratoon rice system

Area of Science:

• Agronomy
• Plant Science
• Soil Science

Background:

• The direct seeding ratoon rice (DSRR) system offers increased grain yield and efficiency but faces challenges with current nitrogen fertilizer management.
• Traditional nitrogen application methods, based on transplanted rice, are suboptimal for DSRR's specific growth characteristics, hindering population development and yield.
• Optimizing nitrogen fertilizer is crucial for maximizing the potential of the DSRR system.

Purpose of the Study:

• To determine the optimal nitrogen fertilizer application strategy for the direct seeding ratoon rice system.
• To evaluate the impact of different nitrogen application timings and amounts on DSRR growth, development, and yield.
• To identify a nitrogen management approach that enhances both main crop development and overall annual yield in DSRR.

Main Methods:

• Four nitrogen fertilizer treatments were applied to hybrid (Fengliangyouxiang1) and inbred (Huanghuazhan) rice under DSRR conditions.
• Treatments included no nitrogen (N0), traditional nitrogen (N1), 20% nitrogen transfer to tillering (N2), and reduced nitrogen from N2 (N3).
• Evaluated effects on dry matter accumulation, root activity, leaf area index, leaf senescence, and grain yield over two years.

Main Results:

• The N2 treatment, transferring 20% of nitrogen to the tillering stage, resulted in the highest main crop yield (6.6-63.3% increase over other treatments).
• Annual yield analysis showed N2 significantly outperformed N1 and N3 by 4.94% and 8.55%, respectively.
• N2 treatment enhanced aboveground dry matter accumulation, maintained higher root activity, and reduced leaf senescence compared to other treatments.

Conclusions:

• Transferring 20% of total nitrogen fertilizer from basal application to the tillering stage is an effective strategy for improving annual yield in the DSRR system.
• This optimized nitrogen management enhances main crop development, dry matter accumulation, root vigor, and delays leaf senescence.
• Further nitrogen reduction in this optimized strategy could significantly improve nitrogen use efficiency and profitability in DSRR cultivation.