Effects of Slow-release Fertilizers and Nitrogen Reduction on Flue-cured Tobacco Quality and Nitrogen Utilization

In order to effectively reduce the potential non-point source pollution caused by large amount of available nitrogen fertilizer in the tobacco-planting area of Baoshan city of Yunnan province, the Jinzhengda slow-release fertilizerm(N):m(P₂O₅):m (K₂O)=10:10:25 was used in field experiment. The effects of different treatments on soil physicochemical properties, tobacco leaf quality and nitrogen balance utilization were studied. The results showed that:(1) Compared with no fertilizer (CK) and single application of chemical fertilizer (T1), slow release fertilizer (T2) and its nitrogen reduction treatment (T3) tended to concentrate the aggregate particle size and increase the available nutrients of the surface soil, including the contents of alkali hydrolyzed nitrogen, available phosphorus and available potassium; T3 compared with T2, only organic matter content was significantly reduced, and there was no significant difference in available nutrients; (2) Compared with CK, fertilization treatment increased the contents of total sugar, reducing sugar, total nitrogen, nicotine and potassium; Compared with T2, T3 reduced the contents of total sugar, reducing sugar, total nitrogen, potassium and nicotine, and increased the Potassium/chloride ratio and the sugar/base ratio; There was no significant difference in the quality of flue-cured tobacco among different fertilization treatments; (3) Compared with T1, T2 and T3 increased nitrogen fertilizer agronomic utilization rate (RE), agronomic efficiency (AE) and partial productivity (PFP), with T3 increased significantly (p<0.05); T3 significantly reduced nitrogen appearance leaching rate (LLR) compared to T1 and T2(p<0.05); Nitrogen was near balanced in T3, surplus in T2, and deficit in T1. In conclusion, slow release can maintain nitrogen balance utilization and flue-cured tobacco quality on the basis of nitrogen reduction. It can be considered in Baoshan tobacco-planting areas.