Effects of Combined Application of Different Organic Fertilizer and Tobacco-special Chemical Fertilizer on Soil Microbial Biomass,and Growth,Yield,Quality and Black Shank of Flue-cured Tobacco

The field location experiments were carried out to compare and study the effects of the combined application of different organic fertilizer and tobacco-special chemical fertilizer on soil microbial biomass,and the growth,yield,quality and black shank of flue-cured tobacco. The results showed that: in comparison with the local conventional fertilization( CK),the combined application of 3750 kg / hm2multiple-effect biological organic fertilizer and 70% tobacco-special chemical fertilizer( treatment T1)or the combined application of 7500 kg / hm2 farmyard manure and 70% tobacco-special chemical fertilizer( treatment T2) could promote the growth and development of tobacco plants,siginificantly increase the microbial biomass in soil,significantly improve the yield and quality of flue-cured tobacco,and reduce the occurrence of black shank. As compared with CK,the treatment T1 increased the yield,production value and middle-high-class tobacco leaf proportion of flue-cured tobacco by 13.5%,41.9% and 13.6% respectively,enhanced the microbial biomass carbon and microbial biomass nitrogen in soil by 87% ~ 96% and 8% ~ 28%respectively,and reduced black shank disease index by 51.1%; the treatment T2 increased the yield,production value and middlehigh-class tobacco leaf proportion of flue-cured tobacco by 11.1%,24.7% and 5.9% respectively,enhanced the microbial biomass carbon and microbial biomass nitrogen in soil by 67% ~ 81% and 1.5% ~ 10.2% respectively,and reduced black shank disease index by 28.9%.