不同调理剂对农田镉污染稳定效果及水稻吸收的影响

Effects of Different Passivators on Immobilizing Cadmium in Soil and Reducing Cadmium Uptake by Rice(Oryza sativa L.)in Contaminated Paddy Soil

采集浙江杭州郊区富春江沿岸镉(Cd)污染水稻土,选择前期试验筛选的对土壤Cd钝化效果良好、可显著降低稻米Cd的4种调理剂,开展室内培养试验和温室盆栽试验,探讨不同调理剂种类(袁梦YM、祝天峰ZTF、天象一号TX1、永清YQ)、用量(推荐用量、3倍推荐用量)和调理剂与生石灰配施对污染水稻土Cd的稳定效果及对水稻生长和糙米Cd含量的影响。室内培养试验结果发现,添加调理剂能使土壤pH显著升高,落干条件下土壤pH增幅较淹水条件下更为明显;施用推荐用量调理剂,土壤硝酸铵提取态Cd显著下降,调理剂推荐用量+生石灰处理较调理剂推荐用量处理下降更为显著;总体上,同一调理剂3倍推荐用量处理下硝酸铵提取态Cd降幅更大,表明硝酸铵提取态Cd受土壤pH影响显著,且YM、TX1调理剂对硝酸铵提取态Cd的降低效果较好。盆栽试验结果显示,施用石灰和商品调理剂均可实现水稻稳产或增产,并显著降低水稻糙米Cd含量,与调理剂施用后土壤Cd有效性降低相一致。含钙、能调节土壤pH并辅以有机质和养分的复合调理剂因兼具养分作用,对水稻稳产增产、糙米Cd含量降低更为有效。

A lab incubation experiment and a pot experiment were conducted to investigate the effects of four recommended passivators(Yuanmeng(YM),Zhutianfeng(ZTF),Tianxiang 1(TX1),Yongqing(YQ)),application dosage(recommended dosage,triple-recommended dosage),and the combination of the four passivators with lime(CaO)on immobilizing cadmium(Cd)in soil and Cd uptake by rice(Oryza sativa L.).The soil used for the experiments was Cd contaminated and collected from the suburb of Hangzhou,near Fuchun River.The four recommended passivators were selected from a previous experiment and have significant effects on immobilizing Cd and reducing Cd uptake by rice.The results show that soil pH increases significantly after the application of different passivators,and a greater increase is found under aerobic condition compared with flooded condition.Soil NH_(4)NO_(3) extractable Cd decreases obviously after the application of the recommended dosages of passivators.Generally,the treatment of triple-recommended dosage shows a greater decrease for soil Cd extractability than the treatment of recommended dosage+CaO,followed by the treatment of recommended dosage.It indicates that soil NH_(4)NO_(3)-Cd is greatly affected by soil pH.The passivators of YM and TX1 show better Cd immobilization efficiency in general.Moreover,it is found that the application of lime and commercial passivators significantly reduces Cd concentration in brown rice along with an obvious decrease for soil Cd availability but without reduction and even a promotion for rice yield.The combination of the four passivators with lime shows a greater efficiency in reducing Cd concentration in brown rice and yield guarantees by increasing soil pH as well as providing some soil nutrients,especially calcium,organic matter and macronutrients.