楚雄植烟土壤交换性镁含量及空间分布研究

Study on Content and Spatial Distribution Exchangeable Magnesium of Tobacco-growing Soil in Chuxiong

为了解云南楚雄植烟土壤交换性镁含量分布情况,测试楚雄州10县市400个土壤样本的交换性镁含量,分析楚雄州植烟土壤交换性镁含量适宜样本分布,县域差异,土壤类型差异、海拔差异及空间分布,并探讨了不同前作、不同pH环境和不同有机质含量情况下交换性镁含量的分布特征。结果表明：（1）楚雄烟区植烟土壤交换性镁含量平均值为2.186cmol·kg^-1,主要为适中到丰,不同市县之间的交换性镁含量差异达到极显著水平;楚雄州植烟土壤交换性镁含量分布规律不明显,总体上呈现斑块状分布。以1.179-2.540cmol·kg^-1为主要分布面积。在大姚、楚雄和姚安出现斑块状高值区域;（2）7个pH组和8个有机质组的植烟土壤交换性镁含量随着pH升高而升高,不同组别之间差异极显著,pH与交换性镁含量存在强相关关系,有机质与交换性镁含量之间存在弱相关关系,不同组别之间变异系数均较大,离散程度较高;（3）4种土壤中交换性镁含量差异达到显著水平,紫色土交换性镁含量显著低于黄壤和红壤;不同前作田土壤交换性镁含量不存在显著差异,前作为小麦、大麦和油菜的植烟土壤交换性镁表现较好;（4）4种海拔高度植烟土壤交换性镁含量没有显著差异。海拔在1 700m以下的植烟土壤交换性镁含量较为适宜;（5）楚雄烟区植烟土壤有12%的样品钙镁比大于10,在生产中应注意通过改变施肥种类和施肥方式来改善钙镁比。

In order to understand the distribution of exchangeable magnesium content in the tobacco growing soil in Chuxiong,the distribution frequencies of exchangeable magnesium contents,differences in different counties,differences in different soil types,differences in different altitudes and the spatial distribution of exchangeable magnesium contents were analyzed based on 400 soil samples from 10 counties.And the distribution of exchangeable magnesium content in different preceding cropsfileds,different phfields,different organic matter content fields were discussed.The results were as follows：（1）The exchangeable magnesium contents in the tobacco soil were generally suitable or more for tobacco cultivation with a mean of 2.186cmol·kg^-1.There existed extremely significant differences among different counties in the contents of exchangeable magnesium.The spatial distribution of exchangeable magnesium was of irregular patchy distribution with 1.179-2.540cmol·kg^-1.The patchy area of high value exchangeable magnesium was in Dayao,Chuxiong,Yaoan county.（2）The content of exchangeable calcium among 7groups of pH and 8groups of organic matter soil raised with the increase of pH,existed extremely significant differences.pH have a strong relation with the content of exchangeable magnesium.Organic matter have a weak relation with the content of exchangeable magnesium.Variation coefficient was great and discrete degree was high among different groups.（3）There existed extremely significant differences among 4soil types in the contents of exchangeable magnesium.The content of exchangeable magnesium in purple soil was significantly lower than that in yellow soil and red soil.There didn＇t exist extremely significant differences among different crops fields soil in the contents of exchangeable magnesium.The content of exchangeable magnesium in previous wheat,barley,rape fields soil were suitable.（4）There didn＇t exist extremely significant differences among 4different altitudes tobacco planting fields soil in the content of exchangeable magnesium.The content of exchangeable magnesium in the soil below 1 700 m were suitable.（5）Calcium magnesium ratio was larger than ten in 12% of the samples from tobacco planting soil in Chuxiong,which should be improved through paying attention to change fertilizer types and fertilization methods in tobacco leaf production.