草海自然保护区内不同利用方式土壤氮素转化和氧化亚氮排放特征

郎漫; 聂浩; 朱恺文; 朱四喜; 李平

文章摘要

郎漫,聂浩,朱恺文,朱四喜,李平.草海自然保护区内不同利用方式土壤氮素转化和氧化亚氮排放特征[J].农业环境科学学报,2025,44(1):227-234.

草海自然保护区内不同利用方式土壤氮素转化和氧化亚氮排放特征

Nitrogen transformation characteristics and nitrous oxide emissions from soils under different land use types in Caohai nature reserve

投稿时间：2024-01-09

DOI：10.11654/jaes.2024-0035

中文关键词: 草海土地利用方式矿化硝化 N₂O

英文关键词: Caohai land use type mineralization nitrification N₂O

基金项目:中央土壤污染防治资金项目（新集采单[2021]1468）；国家自然科学基金项目（41301345）

作者	单位	E-mail
郎漫	南京信息工程大学生态与应用气象学院, 南京 210044
聂浩	南京信息工程大学生态与应用气象学院, 南京 210044
朱恺文	南京信息工程大学长望学院, 南京 210044
朱四喜	贵州民族大学生态环境工程学院, 贵阳 550025
李平	南京信息工程大学生态与应用气象学院, 南京 210044	pli@nuist.edu.cn

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中文摘要:

为探究草海自然保护区土壤氮素转化及氧化亚氮（N₂O）排放规律，并为评估不同利用方式土壤的生态环境效应和土地合理规划布局提供科学依据，在25 ℃和60%田间最大持水量水分条件下进行15 d的室内培养试验，研究不同利用方式土壤的净氮转化速率和N₂O排放特征。结果表明：湿地土壤的净氮矿化速率为0.95 mg·kg^-1·d^-1，显著低于旱地土壤（1.61 mg·kg^-1·d^-1）和菜地土壤（1.29 mg·kg^-1·d^-1），显著高于林地土壤（0.24 mg·kg^-1·d^-1）。土地利用方式对净硝化速率的影响与净氮矿化速率基本一致，旱地土壤和菜地土壤的净硝化速率最高，分别为 3.71 mg·kg^-1·d^-1和 3.58 mg·kg^-1·d^-1，显著高于湿地土壤（1.64 mg·kg^-1·d^-1），林地土壤的净硝化速率（0.20 mg·kg^-1·d^-1）最低。湿地土壤的N₂O累积排放量为65.3 μg·kg^-1，于各处理中最高，其次为旱地土壤（29.3 μg·kg^-1）和菜地土壤（21.4 μg·kg^-1），林地土壤的 N₂O累积排放量（4.45 μg·kg^-1）最低。研究表明，湿地转化为旱地和菜地虽然能显著降低N₂O排放量，却显著增强了氮素的矿化和硝化，可能会增加NO₃^-累积和向环境扩散的风险；林地转化为农业用地后N₂O排放量、净氮矿化和净硝化速率都显著提高，对生态环境影响较大。

英文摘要:

This study aimed at exploring nitrogen transformations and nitrous oxide（N₂O）emissions from soils in the Caohai nature reserve as well as providing a scientific basis for ecological environmental effect evaluation of soils under different land uses along with the related rational land layout. We performed a 15-day laboratory incubation experiment at 25 ℃ and 60%WHC（water holding capacity）to study net N transformation rates and greenhouse gas emissions from soils under different land use types. Our results demonstrated a net N mineralization rate of marshland soil of 0.95 mg·kg^-1·d^-1, being significantly lower than that of upland and vegetable soils（1.61 mg·kg^-1· d-1 and 1.29 mg·kg^-1·d^-1, respectively）and significantly higher than that of forest soil（0.24 mg·kg^-1·d^-1）. The land use type effect on the net nitrification rate was in good agreement with net N mineralization rates, the latter being 3.71 mg·kg^-1·d^-1 and 3.58 mg·kg^-1·d^-1 for upland and vegetable soils, respectively, which was significantly higher than that of marshland soil（1.64 mg·kg^-1·d^-1）, while that of forest soil was the lowest（0.20 mg·kg^-1·d^-1）. The N₂O cumulative emission from marshland soil（65.3 μg·kg^-1）was the highest among the four land use types, followed by upland soil（29.3 μg·kg^-1）and vegetable soil（21.4 μg·kg^-1）, while the N₂O cumulative emission of forest soil （4.45 μg·kg^-1）was the lowest. Our results indicate that although marshland conversion into upland and vegetable fields might significantly reduce greenhouse gas emissions, the significantly stimulated N mineralization and nitrification could result in NO - 3 accumulation in the soil and increase the risk of N diffusion into the environment. Forest conversion into agricultural land significantly promotes greenhouse gas emissions and stimulates the net N mineralization and nitrification rates, leading to significantly negative effects on the ecological environment.

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