The dynamics for abundance of nitrite reductase genes nirK and nirS in abandoned land

Determination of nitrite reductase gene (nirK and nirS) specific fragment by real-time quantitative PCR method, we studied the dynamics of denitrification microbial abundance in abandoned land soil with different abandoned years. The results showed that the nirK genotype denitrifier abundance were significantly higher than nirS genotype denitrifier abundance in 3 kinds of abandoned land for 1, 5, and 25 years and light grazing grassland. Both of genotypes denitrifier abundance were significant difference between the light grazing grassland and the three abandoned land soils (P<0.05), but there was no significant change among the 3 kinds of abandoned land soil. Moreover, there were extremely significantly negative linear relationship between the two genes abundance in the investigation soils (P<0.001), indicating that the nirK and nirS show different response to the environmental factors on their growth.