Content area
Full Text
Abstract The simulated nitrogen deposition [control check (CK), 0 kg.hm2/a; low nitrogen (LN), 25 kg.hm2/a; medium nitrogen (MN), 50 kg.hm2/a; high nitrogen (HN), 150 kg.hm2/a] was performed from July 2014 to August 2015 in the forest-grassland boundary in Zhuqudeng Village, Bujiu Township, Linzhi City, Tibet Autonomous Region to analyze the activity of enzymes (mvertase, catalase, urease, amylase, cellulase, polyphenol oxidase, and β-glucosidase) in soil layers of 0-20 em and 20-40 em and explore the effect of different levels of nitrogen deposition on enzyme activity different layers of soil The results showed that CD different levels of simulated nitrogen deposition had remarkable effects on sucrase, amylase, cellulase, polyphenol oxidase and β-glucosidase in the soil layer of 0-20 em (p < 0.05) and unremarkable effects on catalase and urease (p > 0.05); in the soil layer of 20-40 em, the response made by sucrase, catalase, urease, amylase, cellulase, polyphenol oxidase and β-glucosidase to nitrogen deposition reached a significant level (p < 0.05). ® In the soil layer of 0-20 em, the activity of urease and polyphenol oxidase reduced under LN treatment and enhanced under HN treatment, and the activity of invertase, catalase, amylase, cellulose, and β-glucosidase was inhibited by nitrogen deposition. ® In the soil layer of 20-40 em, the activity of polyphenol oxidase and β-glucosidase reduced under under LN treatment and enhanced under HN treatment, and the activity of invertase, catalase, urease, amylase, and cellulase was inhibited by nitrogen deposition. @ With the deepening of the boundary soil layer (from 0-20 em to 20-40 em), urease and β-glucosidase made different responses to the different levels of nitrogen deposition, while invertase, catalase, amylase, cellulose, and polyphenol oxidase showed the same response to nitrogen deposition.
Keywords Nitrogen deposition, Linzhi, Boundary soil, Soil enzyme activity, Forest-grassland
DOl 10.16785/jjssn 1943-989x.2018.4.021
Nitrogen deposition has attracted much attention in recent decades. Since the mid-201h century, influenced by human activities such as the burning of fossil fuels, the production and use of chemical nitrogen fertilizers, and the booming of animal husbandry, active nitrogen compounds released into the atmosphere sharply increased, and atmospheric nitrogen deposition also shot up['l, leading to the accumulation of nitrides in the atmosphere and settlement in terrestrial and aquatic ecosystems[ZJ. The subtropical region in central and southern China has...