中文摘要：

通过田间实地调查与取样分析,运用简单相关、回归方程拟合和主成分分析等方法,研究了关中设施蔬菜种植区土壤中镉（Cd）的生物有效性及其与土壤速效磷含量（AP）、有机质含量（OM）和pH值等土壤基本理化性质的相关性,并研究了各基本理化因子对其的调控作用。结果表明：（1）研究区内设施菜地土壤中镉的有效态含量（DTPA浸提,CdA）与设施菜地土壤中速效磷含量、有机质含量和pH值均存在显著相关关系（P〈0.05）,与土壤阳离子交换量、电导率不相关。（2）通过对土壤有效镉含量和与其呈显著相关关系的土壤基本理化性质指标分别进行回归方程拟合得出：y1[CdA]=0.501 5x1[AP]＋0.010 6（R^2=0.345 2,P〈0.01）、y2[CdA]=0.370 7x2[OM]＋0.028 6（R^2=0.139 0,P〈0.01）、y3[CdA]=-0.055 2x3[pH]＋0.564 1（R^2=0.050 9,P〈0.05）,土壤中有效镉含量主要受以上三个因子的影响;通过多元回归方程拟合,土壤有效态镉含量的表达式为y4[CdA]=0.174 8＋0.435 2x1[AP]＋0.049 0lgx2[OM]-0.013 2x3[pH]（R^2=0.368 6,P〈0.01）;主成分分析发现,土壤速效磷含量是设施菜地土壤中镉的生物有效性的关键调控因子。（3）研究区蔬菜果实中镉含量与土壤镉有效态含量的相关系数为0.464,高于其与土壤镉全量（CdT）的相关系数（0.387）,从食品安全和健康风险控制的角度考虑,在设施菜地土壤污染风险评价中,认为以土壤镉有效态含量替代土壤镉全量可以更准确地表征土壤镉的安全风险。因此,设施蔬菜生产过程中,应严格控制土壤速效磷含量,以降低土壤有效镉含量,从而保证设施蔬菜产品的食品安全。

英文摘要：

A large number of soil samples from greenhouse facilities was obtained to study the phytoavailability of cadmium（Cd）and its influencing factors using correlation, regression and principal component analysis. The content of available Cd（CdA）in the soils was correlated significantly with soil available phosphorus（AP）, organic matter（OM）and pH value（P〈0.05）, but not with soil cationic exchange capacity and electric conductivity, implying that AP, OM and pH were the main influencing factors of CdA. Single regression equations of CdAAP, CdA-OM, and CdA-pH were y1[CdA]=0.501 5x1[AP]＋0.010 6（R^2=0.345 2, P〈0.01）, y2[CdA]= 0.370 7x2[OM]＋0.028 6（R^2=0.139 0, P〈0.01）and y3 [CdA]=-0.055 2x3 [pH]＋0.564 1（R^2=0.050 9, P〈0.05）, respectively, while multiple regression equation y4 [CdA]=0.174 8 ＋ 0.435 2x1 [AP]＋ 0.049 0lgx2[OM]-0.013 2 x3[pH]（R^2=0.368 6,P〈0.01）. Principal component analysis showed that AP was the key regulator of CdAin the greenhouse soils. Correlation coefficient（R=0.464）between Cd contents in vegetable fruits（CdP）and soil CdAwas higher than that（R=0.387）between CdPand total cadmium（CdT）, suggesting that CdAwould be better to assess Cd contamination in vegetable fruits and to predict the safety risk for vegetable production than soil CdT. Therefore, it is necessary to regulate soil available phosphorus to reduce Cd phytoavailability so as to guarantee the food safety of greenhouse vegetables.