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- Title
氮沉降对喀斯特森林土壤氮循环及酶活性的影响.
- Authors
王 伟; 梁 燕; 罗绮婷; 吴芳兰; 蒙姿玉; 段 敏
- Abstract
A simulated nitrogen deposition experiment was conducted to examine the effects of nitrogen deposition on nitrogen cycling in karst forest soils. The experiment comprised five treatments in total: control (CK), oxidized nitrogen deposition with a low rate (Oxi-L, nitrogen addition rate of 40 mg·kg-1), reduced nitrogen deposition with a low rate (Red-L, 40 mg·kg-1), oxidized nitrogen deposition with a high rate (Oxi-H, 80 mg·kg-1), and reduced nitrogen deposition with a high rate (Red-H, 80 mg ·kg-1). Soil nitrogen indices were determined at 0 and 1, 3, 7, 14, 30, and 60 days after nitrogen addition, and the net transformation rates of soil nitrogen were calculated to determine the short-term effects of nitrogen deposition on soil nitrogen cycling in karst forests. The results showed that the application rates had no significant effect on the soil net nitrification rate. However, the effects of nitrogen deposition rates on soil net ammonification and nitrogen mineralization rates were related to the form of nitrogen deposition and incubation time. Oxidized nitrogen deposition had no significant effect on the soil net ammonification rate in the karst forest, but significantly reduced the soil net nitrification and nitrogen mineralization rates in the first 7 days of incubation (P<0.05). Reduced nitrogen deposition significantly reduced soil net ammonification and nitrogen mineralization rates (P<0.05), particularly in the first 7 days of incubation, and it significantly increased the soil net nitrification rate (P<0.05). Reduced nitrogen deposition significantly increased soil microbial biomass carbon content (P<0.05), whereas oxidized nitrogen deposition had no significant effect on it. High nitrogen deposition significantly reduced the soil MBN content (P<0.05), whereas high reduced nitrogen deposition significantly increased the soil MBN content (P<0.05). Nitrogen deposition had no significant effect on the soil urease activity. The effects of the form and rate of nitrogen deposition on soil nitrate reductase activity were regulated by deposition time. Nitrogen deposition form influenced soil nitrite reductase activity, but nitrogen deposition rate did not. The net nitrogen transformation rates of karst forest soil were mainly regulated by soil total nitrogen, dissolved organic carbon, dissolved organic nitrogen, microbial biomass carbon, ammonium nitrogen, and nitrate nitrogen and were not affected by soil urease, nitrate reductase, and nitrite reductase activities.
- Subjects
NITRITE reductase; NITROGEN in soils; FOREST soils; NITROGEN cycle; NITRATE reductase; UREASE; NITRIFICATION
- Publication
Journal of Forest & Environment, 2023, Vol 43, Issue 4, p346
- ISSN
2096-0018
- Publication type
Article
- DOI
10.13324/j.cnki.jfcf.2023.04.002