土壤-小麦体系的镉积累特征及影响因素

Accumulation of Cadmium and Major Controlling Factors in Soil-wheat System

选取我国主要农作区的33个典型土壤,开展了两个常规小麦品种(蓉麦4号(RM4)和山农22号(SN22))的盆栽试验,研究了土壤–小麦体系内Cd的积累特征,并探究了相关土壤主控因子。结果表明:RM4和SN22两个品种小麦籽粒Cd含量分别为0.21(0.040~0.99)mg/kg和0.18(0.037~0.70)mg/kg,据GB 2762—2017,Cd超标率分别为75.6%和69.7%;小麦籽粒Cd的生物富集系数(BCF)分别为0.92(0.24~2.55)和0.81(0.16~1.67),均表现出较强的Cd富集能力。多元逐步回归和广义Boosted模型分析发现,土壤全Cd和pH是影响小麦籽粒Cd吸收的主控因子,分别解释33个土壤中变量的81.3%和80.5%。

Two main wheat cultivars(RM4 and SN22)were planted in thirty-three typical soils collected in the main rice-wheat rotation regions in China to investigate the characteristics of cadmium(Cd)translocation in soil-wheat systems and the major controlling factors.The results show that Cd concentration in wheat grains is 0.21(0.040–0.99)mg/kg for RM4 and 0.18(0.037–0.70)mg/kg for SN22,and the percentage of exceeding Cd limit(GB 2762—2017)is 75.6%for RM4 and 69.7%for SN22.The bio-concentration factor(BCF)of Cd in wheat grains is 0.92(0.24–2.55)for RM4 and 0.81(0.16–1.67)for SN22,respectively,both showing strong ability of accumulating Cd.Multiple stepwise regression analysis and Generalized Boosted Models(GBM)indicate that soil Cd concentration and pH are the two most important variables which influencing Cd accumulation in wheat grains,which explain 81.3%and 80.5%among five soil variables of the thirty-three soils.