不同施肥方式下半夏重金属污染评价

Pollution Evaluation on Heavy Metals in Pinellia ternata under Diverse Fertilizing Methods

对施专用肥、习惯种植(草木灰+普钙)、不施肥3种处理的半夏(Pinellia ternata)块茎烘干后,按照直径d>1.5 cm、1.0 cm≤d≤1.5 cm、d<1.0 cm进行分级,测定半夏中铅(Pb)、镉(Cd)、砷(As)、铜(Cu)的含量,并采用单项与综合污染指数法对半夏中重金属污染进行评价。结果表明,施专用肥与习惯种植两种处理对半夏中重金属含量的影响相当,不施肥处理的影响较小。半夏中重金属的平均污染指数从大到小为Cd、Cu、Pb、As,综合污染指数未达污染级别。3种处理得到的半夏,中等大小(1.0 cm≤d≤1.5 cm)的块茎各重金属含量、平均污染指数、综合污染指数均达到安全标准,属于安全级别。施专用肥的半夏块茎4种重金属平均含量较低,是3种处理中最优的施肥方式。Cd为影响半夏清洁度的主要因子,在专用肥料的推广中,应注重对土壤中Cd的控制。

Test includes three processing： applying fertilizer, planting habits （ash ＋ SSP）, not fertilization. According to the testing requirements the researcher need to drying each processing of pinellia ternate. In accordance with the grading stan- dards P. ternata is divided into large （d〉l.5 cm）, medium （1.0 em≤d≤l.5 cm） and small （d〈l.0cm）. Next it is necessary to determine the content of Pb,Cd,As,Cu that exists in different P. ternata tuber size. In the evaluation process researcher takes advantage of individual pollution index method and composite contamination index method. The results show that, specif- ic fertilizer effect on heavy metal content in P. ternata with habits planting methods in the same. Average pollution index of heavy metal in P. ternata：Cd〉Cu〉Pb〉As. From the point of comprehensive pollution index, P. ternata is not polluted. Medium size of P. ternata belongs to the cleaning level,and its average pollution index and synthetic pollution index don＇t exceed the limit. The average concentrations of heavy metals of P. ternata that use special fertilizers in the lowest and the yield in the highest,it was agreed that fertilizer is optimal fertilizer application in three ways. Cd is the main factor affecting the cleanliness of P. ternata. In the procedures of fertilizer marketing, research and development, should focus on the control of Cd in soil.