Zhang Changhua

烟梗(末)有机肥对烟田土壤养分、病害发生及烟叶产质量的影响

为资源化利用废弃烟梗（末），通过连续3 年的田间试验，研究了复烤厂废弃烟梗（末）有机肥对烟田土壤养分、病害发生和烟叶产质量的影响。结果表明，在烟梗（末）有机肥与化肥配施的土壤中，有机质含量增加，土壤pH 无显著变化，烤烟生长后期土壤碱解氮含量与单施化肥处理相近，但土壤有效磷和速效钾含量显著高于单施化肥处理。烟梗（末）有机肥与商品有机肥均可显著降低烟草花叶病、青枯病、黑胫病及赤星病的发病率及病情指数，且烟梗（末）有机肥与化肥配施的防治效果优于单施烟梗（末）有机肥。烟梗（末）有机肥与化肥配施处理的烟叶产量、产值、均价和上中等烟比例分别比单施化肥处理增加4.82%、3.91%、7.69%和2.42%，且与商品有机肥配施化肥的效果相当。烟梗（末）有机肥与化肥配施的烟叶钾和总糖含量分别比单施化肥处理提高22.51%和12.43%，烟碱含量有所降低。因此，烟梗（末）有机肥具有商品有机肥的肥力效应。

Occurrence and Development of Leaf Spot Caused by Corynespora cassiicola in Guizhou Flue-cured Tobacco

The occurrence,development,latent period,pathogens life cycle of leaf spot caused by Corynespora cassiicola in Guizhou fluecured tobacco were studied in the field.The results showed that: 1) the disease developed very slowly by the late June(5 to 6 weeks after transplanting);from the end of June to mid July,in persistent rainy days,the disease developed rapidly while source of infection was rich,it developed gradually if the source of infection was not enough;2) the disease index obviously decreased with the increase of distance from disease focus;3) from the end of May to mid July,the latent period of leaf spot was 16 to 33 hours when the tobacco plant was kept moisture for 38 hours after inoculating;4) when the bigger spots on the leaves inoculated in the ends of May and June and the early August were sampled,kept moisture for 2 days and then examined under microscopy;it was found that on the samples with a few spots,spores appeared in 11,8 and 7 days after inoculating,respectively.