氮钾营养与氮钾平衡对几种烤烟病害的影响

云南是中国的主要烤烟生产区，目前由于单一品种大面积种植及施肥不合理等原因，烤烟病害比较严重，制约着烤烟的品质和经济收入。通过对云南中部地区烤烟中部叶片旺长中期（移栽后60~65d）氮、钾营养及氮、钾平衡研究及田间烤烟病害调查。结果表明；（1）烟叶氮含量普遍较高，而钾素偏低，导致氮/钾比偏高；（2）氮含量高时（N%>4%），钾素过高（K%>4%）和过低（K%<2%）都增加了烤烟对炭疽病和赤星病的感染率；（3）在氮素含量正常，钾素含量也正常时，氮/钾比协调，抗病能力最强；（4）烤烟烟叶氮/钾>2%，烤烟对病害的抵抗能力下降，且随氮/钾比偏离最适水平，烤烟发病逐渐加重。

Effect of Nitrogen and Potassium Concentrations and Nitrogen and Potassium Balance on Several Tobacco Diseases

Yunnan is a major tobacco-producing area,because large-scale cultivation of a single species and unreasonable fertilizers application,result serious tobacco diseases,which restricts the quality and income of flue-cured tobacco.nitrogen,potassium concentrations and nitrogen and potassium balance in tobacco middle leaves and anthracnose,brown spot diseases were investigated in the center of Yunnan province at the vigorous growing stage.Results showed that:(1) Nitrogen concentrations of flue-cured tobacco were relatively high,and potassium concentrations were low ,resulting nitrogen /potassium ration more high.(2) when nitrogen concentrations>4%,too much or too little potassium concentrations,disease indexes were increased.(3) when nitrogen and potassium concentrations were in normal range,tobacco plant had the strongest resistance to diseases.(4) when nitrogen /potassium ration >2%,the resistant of tobacco to diseases were reduced ,with nitrogen /potassium ration deviation from the optimum level,disease indexes of tobacco anthracnose and brown spot were increased.