Soil denitrification rates in different type riparian zones in maoershan mountainous region of China

Soil samples were collected from forested,clear-cut,and grassy riparian zones under forest background and from forested and barren riparian zones under cropland background in the Maoershan mountainous region of China.The samples were incubated in laboratory,and their denitrification potentials were determined by nitrate-deduction method.The results showed that under cropland background,soil denitrification rate was the highest in forested riparian zone and the lowest in barren riparian zone,with the deduction rate of nitrate varied from 46.79%-91.13% and 15.64%-81.84%,respectively.Under forest background,soil denitrification rate decreased in the order of clearcut forested grassy riparian zone,with the deduction rate of nitrate being 42.06%-90.39%,28.24%-85.73% and 21.44%-83.11%,respectively.The denitrification rate was higher in subsurface layer than in deeper layer,and the denitrification potential was limited by the available carbon and nitrate,being the greatest in the forested riparian zone under cropland background.