Effects of different intercropping systems on soil properties and tobacco yield and quality

Intercropping is widely recognized as a sustainable practice for enhancing soil fertility and crop productivity. This study evaluated the effects of different intercropping systems on the physicochemical properties of tobacco-planting soil, nutrient uptake in tobacco plants, yield, and economic benefits to optimize tobacco cultivation. A two-year field experiment (2023-2024) was conducted in Midu and Weishan, Yunnan province, with five treatments: tobacco monoculture (TT), tobacco-buckwheat (TM), tobacco-soybean (TS), tobacco-peanut (TP), and tobacco-sweet potato (TH) intercropping. We measured soil nutrient levels and the nitrogen (N), phosphorus (P), and potassium (K) content in the roots, stems, and leaves of tobacco plants, and comprehensively evaluated leaf yield and sensory quality. The results indicated that the TS treatment significantly increased soil N and P availability and enhanced nitrogen accumulation in plants, elevating leaf N content by 71.43% compared to TT in 2024. The TM treatment improved potassium supply and increased P content in roots and K content in leaves. Economically, TS yielded the highest net return, which was 18.89% greater than TT, with benefit-cost ratios (BCR) of 1.75 (2023) and 1.78 (2024). Conversely, TH had the lowest BCR due to its higher production costs. Sensory evaluation revealed that TS produced tobacco with superior aroma quality and harmony, scoring closely to TT, while TM and TP resulted in a moderate aroma with slightly stronger irritation. In conclusion, the tobacco-soybean (TS) intercropping system demonstrated optimal performance in improving soil nutrient supply, promoting plant nutrient accumulation, and enhancing leaf quality and economic returns, showing high potential for widespread adoption.