Multi-split nitrogen application via drip irrigation improved dry matter accumulation, nitrogen uptake and...

Flue-cured tobacco (Nicotiana tabacum L.), a key economic crop in China, is highly dependent on nitrogen (N) management. This study evaluated the effects of multi-split N application via drip irrigation on tobacco growth, N accumulation, and nitrogen use efficiency (NUE).

A randomized experiment was conducted with 10 treatments (T0-T9) in K326 tobacco grown in nutrient-rich brown soil. The treatments differed in terms of N application timing and proportions.

T2 and T3, which applied N twice post-transplant, led to the highest dry weight accumulation in roots, stems, and leaves, with T3 resulting in a 65.8% increase in root dry weight over that of T6. N accumulation followed the order of leaves > stems > roots, with T1 resulting in the highest total N accumulation, a 1.77-fold significant increase compared with that in T0 (p < 0.05). The fertilizer nitrogen (FN) was highest at T1 and T2, reaching nearly 46%, whereas T9 presented the lowest FN, decreasing by 22% compared with that at T1. T1 also retained the most N in the soil, whereas T3 had the highest N residues after the first top dressing. Uneven N applications resulted in significantly lower biomass and NUE.

These results highlight the importance of balanced multi-split N applications (T2 and T3) in improving dry matter accumulation, NUE, and crop quality. Optimizing N application through drip irrigation offers a promising approach to improving both yield and N management efficiency in flue-cured tobacco cultivation.