减量钝化剂与常规肥料混施对镉钝化效果及土壤养分状况的影响

Effects of Reduced Passivation and Conventional Fertilizer on Cadmium Passivation and Soil Nutrient Condition

[目的]研制重金属钝化调理专用肥。[方法]以玉米秸秆为原料制作的生物炭和黏土矿物海泡石为对象,研究在连续2茬小白菜种植后的钝化效果及对肥料利用的影响。[结果]氮磷钾肥配施减量的生物炭和海泡石能提高土壤pH,各添加量显著高于对照(P<0.05)。土壤Cd的钝化效果以生物炭(B∶N=3∶1)及海泡石(S∶N=1∶1)处理最优,小白菜可食部分Cd含量最低。相比于对照,生物炭处理均能减少土壤中速效氮含量,而对有效磷和速效钾含量无显著影响,海泡石随着添加比例的增加,速效氮和速效钾含量逐渐增加。[结论]减量生物炭与氮磷钾肥料混施能有效降低污染土壤活性Cd含量,降低Cd的生物可利用性,还能对土壤中营养元素起到固持作用,提高肥料利用率。

[Objective]To develop heavy metal passivation repair fertilizer.[Method]Taking biochar made from corn straw and clay mineral sepiolite as the object,the passivation effect and the effect on fertilizer utilization of mixed application of nitrogen,phosphorus and potassium fertilizer in continuous two cropping conditions of Chinese cabbage were studied.[Result]Reduced biochar and sepiolite combined with N,P,K increased soil pH,and the added amount was significantly higher than that of control(P<0.05).The best treatments for the passivation effect of soil active Cd were biochar(B∶N=3∶1)and sepiolite(S∶N=1∶1),and the edible part of Chinese cabbage had the lowest Cd content.Compared with the control,biochar treatment reduced the content of available nitrogen,but had no significant effect on the content of available phosphorus and valid potassium.With the increase of the proportion of sepiolite,the content of available nitrogen and available potassium increased gradually.[Conclusion]Combined application of reduced amount of biochar and NPK fertilizer can effectively reduce the content of active Cd in contaminated soil and the bioavailability of Cd,which played a role in retaining nutrients in soil and improving the utilization rate of fertilizer.