兰州土壤-蔬菜系统铅污染特征及全钾速效钾与pH对其富集特性影响

通过野外调查取样与实验测定相结合的方法,对兰州市农业生态系统土壤-蔬菜体系49个样点进行研究,分析探讨了研究区蔬菜与土壤的铅污染水平以及蔬菜铅富集效应特性。结果表明：①蔬菜种植地土壤铅平均含量为26.30 mg.kg-1,合格率为93.62%,在不同县区存在显著差异,其大小顺序为红古区〉榆中县〉永登县;②蔬菜铅平均含量为0.59 mg.kg-1,合格率为60.78%,在不同县区存在显著差异,其大小顺序为永登县〉榆中县〉红古区;③蔬菜铅富集系数为（1.69±2.99）%,永登县蔬菜的铅富集能力显著高于榆中县和红古区,不同种类蔬菜铅富集能力在不同县区具有差异性;④土壤全钾除与白菜和甘蓝有正相关性以外,与其他蔬菜均为负相关性,其中与白菜、番茄、土豆显著相关,与胡萝卜为极显著相关;⑤土壤速效钾与各种蔬菜的铅富集能力均为正相关性,其中与胡萝卜、甜菜、甘蓝为显著正相关,与番茄、土豆、菜花为极显著正相关;⑥土壤pH值与胡萝卜、甜菜铅富集系数呈显著负相关,与菜花呈极显著负相关。研究表明,兰州市不同蔬菜产区的各类蔬菜对土壤铅的富集具有明显的差异性,同时不同形态的钾元素及土壤pH值对蔬菜铅富集能力具有显著的影响。

Pb Pollution in Soil-vegetable System Related to the Effect of Total Soil K,Available K and pH in Lanzhou,China

Analyzing the data of Pb contents of soil and vegetable,soil total K,available K and pH from 49 plots around Lanzhou showed：① The mean content of Pb in soils with vegetable cultivated was 26.30 mg.kg-1,the rate of qualification（RQ）was 93.62%.The order of soil Pb contents was：Honggu DistrictYuzhong CountyYongdeng County;②The mean content of Pb in vegetables was 0.59 mg.kg-1 and the RQ was 73.47%.The order was：Yongdeng County Yuzhong County Honggu District;③ The mean Pb enrichment index of vegetables was（1.69±2.99）%.The enrichment index in Yongdeng County was significantly higher than that in Yuzhong County and Honggu District.Gener-ally,the enrichment ability of different vegetables in different county or district had difference;④The correlation between Pb enrichment in-dex and total soil K was positive in Chinese cabbage and cabbage and negative in others.The significant level was 0.05 for Chinese cabbage,tomato and potato,while 0.01 for carrot;⑤The correlation between Pb enrichment index and soil available K was positive in all vegetables.The significant level was 0.05 for carrot,beet,cabbage,and 0.01 for tomato,potato and cauliflower;⑥The correlation significant level be-tween soil pH and Pb enrichment index was 0.05 for carrot and beet and 0.01 for cauliflower.This study indicated that,the enrichment ability of kinds of vegetables to soil had significant difference in different county or district of Lanzhou,meanwhile,different types of potassium and the pH value significantly effected the enrichment ability of vegetables.