云南曲靖植烟土壤交换性钙、镁与关联土壤属性的特征研究

利用GPS定位采集云南曲靖核心烟田耕层土壤样品651个,测定土样交换性钙、镁及pH、有机质、全氮、全磷、全钾含量,研究交换性钙、镁分布特征及其与土壤其他属性的关系。结果表明:①交换性钙、镁含量均值分别为3 054.3、258.12 mg/kg,变异幅度较大,且两者含量属适宜的占比较低,仅为6.3%和29.8%,总体含量丰富。不同烟区间交换性钙、镁含量差异较大;②交换性钙、镁含量与pH及有机质、全氮、全磷含量呈极显著正相关,交换性钙含量与全钾含量相关性不显著,交换性镁含量与全钾含量呈极显著正相关。采用曲线估计分析每两个属性之间的回归关系,共建立9个拟合曲线函数方程,决定系数为0.118～0.285,拟合误差均在3%以内,拟合优度较好,调节土壤pH、有机质、全氮、全磷和全钾含量对钙镁养分的平衡有重要影响。

Study on Characteristics between Exchangeable Calcium, Magnesium and Related Soil Properties of Tobacco-growing Soil in Qujing

651 soil samples were collected from typical tobacco-planting fields in Qujing, Yunnan Province, with sampling sites were located by GPS technology. The contents of exchangeable calcium (Ca), magnesium (Mg), pH, organic matter (OM), total nitrogen (TN), total phosphorus (TP) and total potassium (TK) were determined. The distribution characteristics of exchangeable Ca, Mg and their relationship with other soil properties were studied. The results showed that: 1) The average contents of exchangeable Ca, Mg in soil were 3 054.3 mg/kg and 258.12 mg/kg, respectively, both were in abundant levels with large variation, and the proportion below the appropriate levels were 6.3% and 29.8%. The contents of exchangeable Ca and Mg were differed from among 9 tobacco-growing areas. 2) There was significantly positively correlation between exchangeable Ca, Mg and pH, OM, TN and TP. Ca was not significantly correlated with TK, while Mg was significantly positively related to TK. The regression relationship between each two attributes was analyzed using curve estimation method, and a total of 9 curve fit function equations were established, with coefficient of determination varied from 0.118 to 0.285. The fit error was within 3%, which showed the goodness of fit was better. The adjustment of soil pH, OM, TN, TP and TK contents had important impact on the balance of Ca and Mg nutrients.