Pre-spike emergence nitrogen fertilizer application as a strategy to improve floret fertility and production efficiency in wheat

Context or problem

Effective nutrient management is critical for crop growth and development. However, using nitrogen-based fertilizers in agriculture raises substantial concerns about environmental pollution. The optimal timing for applying nitrogen to maximize floret fertility and production efficiency in wheat remains undetermined.

Objective or research question

This study investigated the optimal timing for N fertilizer application to enhance floret fertility and production efficiency in eastern Afghanistan's commonly cultivated Chonte#1 wheat variety.

Methods

A total of four experimental sets were conducted at Nangarhar University Faculty of Agriculture and Bihsood district during the 2019–2022 growing seasons. The first-year experiment consisted of two treatments: (1) control (no fertilizer) and (2) fertilized. The second and third-year experiments comprised four treatments, including (1) control (no fertilizer added), (2) basal dressing at the tillering stage (BDTS), (3) BDTS+light top-dressing (LD), and (4) BDTS+heavy top-dressing (HD) applied two weeks before spike emergence.

Results

The results indicated that the application of N topdressing had a significant (P<0.05) effect on the SPAD value and floret fertility percentage. In contrast, SPAD values showed a positive relationship with floret fertility rate and yield components but negatively correlated with unfilled grain per spike. The use of BDTS+LD treatment significantly increased spike length, spike weight, number of spikelets per spike, and filled grain per spike compared to the control. The number of unfilled grains ranged from 6.4 % to 51.9 % between the control and N application. The 1000-grain weight, number of spikes per m^–2, and floret number per m^–2 were also significantly higher in the N top-dressed groups. In the first experiment, fertilized treatment showed a 28.3 % increase in yield per m^–2. Meanwhile, in the second experiment, the yield range varied among the treatment groups compared to the control group, ranging from 30.7 % to 66.8 %.

Conclusion

The application of N two weeks before spike emergence in wheat significantly improved floret fertility and production efficiency and led to the increment of final yield.

Implications

The findings suggest that prior spike emergence nitrogen fertilizer application is crucial for maximizing floret fertility and yield, offering a potential strategy for farmers to enhance production efficiency.