One-time fertilization in flue-cured tobacco: nutrient dynamics, chemical composition and economic performance across different soil textures.

Introduction: One-time fertilization is a promising strategy to reduce labor costs and improve efficiency in agriculture. While its benefits are documented in staple crops (e.g., wheat, rice, maize), the efficacy of this approach in high-value crops like flue-cured tobacco and its interaction with soil texture remain poorly understood. Therefore, this study aimed to 1) evaluate the feasibility of one-time basal application of a specialized fertilizer in flue-cured tobacco, and 2) determine how soil texture (loamy vs. sandy) mediates its agronomic and economic efficacy. Methods: Four treatments were compared: a no-fertilizer control (CK), conventional split fertilization (CF), one-time application of specialized fertilizer (T1), and specialized fertilizer plus a seedling-raising fertilizer (T2). Results: Results showed that in loamy soil, T1 and T2 significantly enhanced late-stage nitrogen (N) and potassium (K) accumulation, increasing N use efficiency by 54.5~56.7% compared to CF. The economic gains were highly soil-specific. Although both T1 and T2 reduced labor costs, T2 in sandy soil generated the highest net income. It significantly increased production value by 14.8% and the proportion of high-grade tobacco by 16.7%, respectively (p<0.05), compared to CF. This gain was driven by improved leaf quality rather than increased biomass yield. Discussion: Loamy soil excelled in nutrient retention and utilization efficiency. This study demonstrates that soil texture mediates the success of one-time fertilization. The T2 strategy offers a profitable, labor-saving alternative, especially in sandy soils, providing a scientific basis for soil-specific fertilization policies to optimize productivity and economic sustainability.