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

作　　者：郎漫[1] 聂浩 朱恺文 朱四喜 李平[1] LANG Man;NIE Hao;ZHU Kaiwen;ZHU Sixi;LI Ping(School of Ecology and Applied Meteorology,Nanjing University of Information Science&Technology,Nanjing 210044,China;School of Changwang,Nanjing University of Information Science&Technology,Nanjing 210044,China;School of Eco-Environmental Engineering,Guizhou Minzu University,Guiyang 550025,China)

机构地区：[1]南京信息工程大学生态与应用气象学院,南京210044 [2]南京信息工程大学长望学院,南京210044 [3]贵州民族大学生态环境工程学院,贵阳550025

出　　处：《农业环境科学学报》2025年第1期227-234,共8页Journal of Agro-Environment Science

基　　金：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)。

摘　　要：为探究草海自然保护区土壤氮素转化及氧化亚氮(N_(2)O)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N_(2)O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N_(2)O累积排放量为65.3μg·kg^(-1),于各处理中最高,其次为旱地土壤(29.3μg·kg^(-1))和菜地土壤(21.4μg·kg^(-1)),林地土壤的N_(2)O累积排放量(4.45μg·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N_(2)O排放量,却显著增强了氮素的矿化和硝化,可能会增加NO-3累积和向环境扩散的风险;林地转化为农业用地后N_(2)O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。This study aimed at exploring nitrogen transformations and nitrous oxide(N_(2)O)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 N_(2)O cumulative emission from marshland soil(65.3μg·kg^(-1))was the highest among the four land use types,followed by upland soil(29.3μg·kg^(-1))and vegetable soil(21.4μg·kg^(-1)),while the N_(2)O cumulative emission of forest soil(4.45μg·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.

关 键 词：草海 土地利用方式 矿化 硝化 N_(2)O 

分 类 号：S154.1[农业科学—土壤学]