设施黄瓜土壤重金属与养分的分异特征及其相关性研究

Differential characteristics and correlation forecasting model of heavy metals and nutrients in greenhouse cucumber

采用野外调查和室内分析相结合的方法,以河北省永清县蔬菜主产区黄瓜温室土壤为研究对象,调查研究不同质地土壤重金属与养分的分异特征,分析黄瓜温室土壤重金属与土壤养分的相关性,构建两者之间的关系预测模型,并结合温室蔬菜土壤重金属的限值标准,提出温室黄瓜管理模式下导致重金属超标的土壤养分环境安全阈值。结果表明:设施黄瓜中壤质土壤表层Cd的变异系数达53.1%,具有空间分异型分布特征,Hg的变异系数达42.5%,属于弱分异型分布,其余重金属均表现为均匀分布特征。中壤土养分元素N、P、K和有机质在土壤中的变异系数均大于25%,表现出了分异或弱分异的特征,分异特征明显;设施黄瓜重壤土与中壤土表现基本一致。该研究对具有分异特征的重金属元素Cd、Hg与养分元素构建了相关预测模型,包括线性方程、对数方程、二次方程、幂方程、指数方程5种类型,Cd均达到了显著或极显著相关水平,而Hg均未达显著水平。利用Cd和养分之间呈显著相关的预测模型确定了中壤土速效氮、磷、钾养分的环境安全阈值分别为66.67,244.59,685.70mg/kg,有机质为13.38g/kg。设施黄瓜重壤土速效氮、磷、钾养分的环境安全阈值分别为125.38,401.34,751.17mg/kg,有机质为20.00g/kg。

A field survey and laboratory analysis were combined to study the differential char-acteristics and correlation forecasting model of heavy metals and nutrients in different types of soil texture in Yongqing county,Hebei province.And the environmental safety thresholds of nutrients which led to heavy metals overproof upon the cucumber greenhouse management pattern combining the limiting value standard of soil heavy metals in vegetable greenhouses were raised in order to provide theoretical basis for safety and scientific fertilization in vegetable greenhouses.The results showed that coefficient of variation of Cd and Hg in the medium loam of cucumber greenhouse were 53.13%and 42.49%,which belonged to spatial differential features and inferior differential features respectively,and the rest of heavy metals（Cr,Pb,As）showed uniform distribution characteristics.Coefficient of variation of N,P,K and organic matters in medium loam were over 25%,showing marked differential or inferior differential features which were the same as that in heavy loam.Correlation analysis between the heavy metals of Cd,Hg and nutrients were studied,which set up five forecasting models for Cd,Hg and nutrients for different types of soil texture.The forecasting models included linear,logarithmic,quadric,power 2and index equations,and there were significantly positively correlations between the levels of Cd and soil nutrients,while Hg did not reach the significant level.Moreover,environmental safety thresholds of available nitrogen,phosphorus,potassium and organic matters were 66.67,244.59,685.70 mg/kg and 13.38g/kg,respectively,calculated by prediction model of Cd and nutrient in medium loam cucumber greenhouses,while for that in heavy loam were 125.38,401.34,751.17mg/kg and 20.0g/kg,respectively.