双氰胺在四川3种主要土壤上的硝化抑制作用

采用室内培养试验方法,在不同浓度双氰胺(DCD)处理条件下,对四川3种主要土壤(紫色土、黄壤、灰潮土)的N2O释放量,NH4+-N及NO3--N含量动态变化进行了研究.结果表明,DCD对3种土壤N2O释放及土壤NO3--N含量有明显抑制作用,随DCD浓度增加,其抑制效果越显著.DCD同时能推迟NO3--N含量达到高峰,使土壤NH4+-N含量在较长时间保持相对较高水平,提高氮肥利用率,减少氮素流失.DCD在3种土壤上硝化抑制效果存在差异,表现为紫色土＞灰潮土＞黄壤.同时提出DCD在3种土壤上的适宜添加量,紫色土上为普通碳铵施入量的0.5%,黄壤和灰潮土上为0.3%.

Effect of dicyandiamide on nitrogen transformation of ammonium bicarbonate in Sichuan soils

Incubation studies on the effect of dicyandiamide (DCD) on N2O emission and NH4 -N and NO3--N dynamics of ammonium bicarbonate (AB) in three soils. The results showed that DCD could inhibit N2O emission from the soil, and the inhibiting effects increase with concentration. DCD also could postpone the acme of NO3--N dynamics, which made soil preserve more NH4 -N in a longer period. Adding DCD could increase the utility efficiency of AB, and decrease its nitrogen losses. The nitrification of three soils was in the order: Purple soil>Grey alluvial>Yellow soil. So the DCD was applied at various concentrations in different soils. The concentration of DCD mixed with AB was 0.5% in Purple soil, and it was 0.3% in Grey alluvial and Yellow soil.