曲靖中海拔红壤烟区烤烟镁含量分布及影响因素

为研究云南曲靖中海拔红壤烟区烤烟镁含量状况及影响因素,连续两年采用田间实地调查及室内化验分析的方法,明确了区域内不同县(市)烟区和主栽品种烤烟镁含量状况及土壤p H值、有机质含量、速效钾含量、交换性镁含量等对烤烟镁含量的影响趋势,结果表明:曲靖中海拔红壤烟区烟叶镁含量范围为0.07~1.15%,平均含量0.42%±0.18,变异系数42.86%。烤烟镁含量处于我国适宜镁含量范围的样品占46.78%。除师宗县外,其他各县(市)烟区有一半以上烤烟样品镁含量缺乏;主栽的9个品种中,中烟100、K326、云烟85和云烟97镁含量分别为0.70%、0.53%、0.43%和0.41%,处于适宜水平,适合在该区域大面积推广。根据土壤肥力标准分组后,烤烟镁含量随有机质和有效镁含量的增加而增加,烤烟镁含量与土壤p H值和速效钾含量呈抛物线关系,总体表现为随土壤p H值和速效钾含量的增加呈现先增加后降低的趋势。

Magnesium Contents in Flue-cured Tobacco and its Influential Factors in Red Soil with Middle Altitude in Qujing

Field investigation and laboratory analysis were conducted to study the status and influential factors of magnesium (Mg) content in flue cured tobacco in red soil with the middle altitude in Qujing.Typical samples of flue-cured tobacco leaves and plough-layer soils were collected.Mg contents in tobacco leaves,soil pH,and contents of soil organic matter,available potassium,available Mg were measured.The results showed that:Mg content in leaves ranged from 0.07％ to 1.15％,with a mean of 0.42％ and a coefficient of variation 42.86％.About 46.78 ％ of leaf samples were in the suitable grade of Mg content.Except for Shizong County,more than half of leaf samples in other regions were insufficient in Mg.Mg contents of leaves were 0.70％,0.53％,0.43％ and 0.41％,respectively,in the variety of Zhongyan 100,K326,Yunyan 85 and Yunyan 97 (0.41％),generally in the suitable grade.After grouping according to related soil fertility standard,Mg content in leaves increased with the increases of soil organic matter and available Mg,but showed the parabolic relationship with soil available potassium and pH.It increased first and then decreased with the increase in soil available potassium and soil pH.