减施化肥对水稻土壤nirK型反硝化菌丰度的影响

Effect of Reduced Chemical Fertilizer on the Abundance of NirK-type Denitrifiers in the Paddy Soil

设置不施肥(CK)、单施化肥(NPK),紫云英配施80%化肥(MF80)、紫云英配施60%化肥(MF60)和紫云英配施40%化肥(MF40)5个施肥处理,采用荧光定量PCR技术,研究了紫云英配施减量化肥对水稻土壤nirK型反硝化菌丰度的影响。结果表明,MF60处理是一种既节能又高效的施肥制度;种植绿肥的,土壤有机质含量明显增加,在化肥减施的情况下,土壤全氮和有效氮的含量并不降低;与单施化肥相比,绿肥配施减量化肥降低了土壤反硝化潜势;种植绿肥的土壤nirK基因丰度显著低于单施化肥处理;土壤nirK基因丰度与土壤反硝化潜势呈极显著正相关。

The objective of this study was to explore the effect of long-term application of green manure and reduced chemical fertilizer on the abundance of nirK-type denitrifiers in a paddy soil. This study includes 5 treatments(i.e.no fertilizer treatment,CK;chemical fertilizer alone(NPK);green manure plus 80% of the chemical fertilizer(MF80);green manure plus 60% of the chemical fertilizer(MF60);green manure plus 40% of the chemical fertilizer(MF40)). Results showed that MF60 treatment is the most appropriate fertilization regime. Application of green manure significantly increased the soil organic matter contents,and reduced chemical fertilizer did not decrease the contents of total nitrogen and available nitrogen. Green manure combined with reduced chemical fertilizer decreased the denitrification potential relative to that of the NPK treatment. NirK gene abundance in the green manure treatments was significantly lower than that of the NPK treatment. The abundance of nirK gene was positively correlated with the denitrification potential.