Despite dramatic advancements which have been made in the production of flue-cured tobacco leaves in China, there are still a number of unsolved quality problems limiting their universal use in the manufacturing of high standard cigarettes. The limitations of the use of flue-cured tobacco leaves produced in China are seen in the generally low potassium contents and widespread imbalances in the sugar : nicotine ratios. In a number of field trials in one of China's most famous tobacco growing regions in the Yunnan Province, a systematic approach has been undertaken to improve agronomic measures leading to an enhanced K uptake and accumulation in the leaves. The impact on other quality forming parameters, e.g. nicotine : sugar ratios and leaf grading should also be considered. For this purpose, field experiments have been set up in 1996 comprising tests on different rates and sources of potassium including a combination of a variety of nitrogen forms. In more recent experiments, the employment of plastic mulch, the placement and timing of potassium application were studied. Preliminary results indicate that K2SO4 in combination with ammonium nitrate as nitrogen source produced good quality leaves. K contents could be greatly increased by the use of plastic mulch which may be explained by better juvenile growth in the rather cool springs in the study area and the improved root growth enhancing the K acquisition by the tobacco plants. In the highly weathered soils with low K status of Yunnan Province, the placement and timing of potassium application also improved access to K and hence potassium uptake and quality of flue-cured tobacco.