Objective This study examined the growth characteristics of green manure crops and their effects on soil physicochemical properties to identify optimal green manure species for tobacco-growing regions in Yuxi, Yunnan province, to establish modern green manure-tobacco cropping systems.

Method Field experiments were conducted from 2019 to 2021, in which seven green manure species: smooth vetch, hairy vetch, broad bean, common vetch, rape, radish and corn were rotated after flue-cured tobacco harvest, with winter fallow serving as the control. The study evaluated multiple parameters, including growth duration, field coverage, above-ground biomass, nutrient content, nutrient return potential, and subsequent effects on soil physicochemical properties following incorporation.

Result Results indicated that leguminous green manures (smooth vetch, hairy vetch and common vetch) demonstrated superior performance in cropping compatibility, ground coverage, nutrient accumulation, and nutrient return compared to broad bean, rape, radish and corn treatments. All green manure treatments significantly improved soil physicochemical properties over the two years. Specifically, soil organic matter content increased by 14.8% ~ 26.6%, while available nitrogen, available phosphorus and available potassium increased by 8.6% ~ 24.0%, 2.4% ~ 10.9%, and 2.3% ~ 16.1%, respectively. Additionally, soil bulk density decreased by an average of 0.06 g/cm³ over the two years. Among all treatments, smooth vetch exhibited the highest soil quality index, showing a 25.7% improvement compared to the winter fallow control.

Conclusion It is evident that smooth vetch has significant advantages in crop rotation compatibility, field coverage, organic capacity conversion, and soil fertility enhancement, making it a preferred green manure species for rotation in the Yuxi tobacco-growing regions of Yunnan.