腐植酸钝化剂对土壤重金属形态和玉米生长的影响

Effects of Humic Acid Passivator on Heavy Metal Forms of Soil and Corn Growth

为明确腐植酸型土壤重金属钝化剂(HSF)对土壤重金属的形态及其对作物生长和其在籽粒中积累的影响,揭示HSF对农田土壤重金属钝化效应机理和适宜用量,通过在沈阳污灌农田设置田间试验,研究了HSF对休耕土壤及玉米地土壤的重金属形态和玉米籽粒重金属累积及产量的影响。试验结果表明:随着HSF施用量的增加,休耕土壤酸可提取态、还原态和氧化态重金属向着残渣态方向转化,其中施HSF 750 kg/667 m^2的处理残渣态镉(Cd)较对照提高181.64%,残渣态铅(Pb)较对照提高217.30%。与对照比,玉米地土壤施HSF的处理还原态Cd减少17.53%,残渣态Cd提高34.7%;Cd在玉米各器官含量大小为根>茎>籽粒,钝化处理后玉米籽粒中Cd含量下降62.20%,玉米产量提高60.72%。因此,HSF有效降低了重金属的生物有效性,可改变土壤重金属形态分布;HSF的适宜用量为500 kg/667 m^2。

The effects of humic acid type soil heavy metal passivator(HSF)on heavy metal forms in soil,crop growth and accumulation in grains were examined to know the mechanism and appropriate dosage of HSF in farmland soil.The field trials were carried out in sewage irrigation area of Shenyang and were set to explore the effects of HSF on heavy metal forms in fallow soil and corn-growing soil,heavy metal accumulation in com grain and com yield were studied.The results showed that the acid soluble state,reduction state and oxidation state of heavy metal shifted to residual with the increasing of HSF in fallow soil.Among of them,the treatment of applying HSF of 750 kg/667 m^2,the residual Cd and Pb contents increased by 181.64%and 217.30%compared with the control.The Cd content has significant difference between before and after applying HSF in corn-growing soil:the content of reduced Cd decreased by 17.53%,while residual Cd increased 34.7%,respectively.The content of Cd in com was root>stem>grain.After passivation treatment,the com yield increased by 60.72%,while Cd content in com grain decreased by 62.2%.Therefore,HSF can effectively reduce the bioavailability of heavy metals and change the distribution of heavy metals in soil;the appropriate dosage of HSF was 500 kg/667 m^2.