摘要
为阐明土壤盐碱化程度对氮素气态损失的影响,本研究通过随机采集30个不同盐碱化程度的稻田土壤(0~20 cm)样品,根据盐碱化程度将其划分为轻度(含盐量0.1%~0.3%,碱化度5%~15%)、中度(含盐量0.3%~0.5%,碱化度15%~30%)和重度(含盐量0.5%~0.7%,碱化度30%~45%)盐碱土3类,每个类别中依据最小归类样品数选取盐碱化程度接近的3个土样作为3次重复,进行实验室模拟培养分析,探究不同盐碱化土壤氮素反硝化和氨挥发动态变化特征及其主要影响因素。结果表明,随着土壤盐碱化程度的增加,氮素的反硝化作用显著降低,氨挥发作用显著增加,硝酸还原酶、亚硝酸还原酶和脲酶活性显著降低(P<0.05)。与轻度盐碱土相比,中度和重度盐碱土相同培养时间的氮素反硝化速率分别降低了18.9%和37.8%,累积反硝化氮量分别降低了13.7%和29.4%,氨挥发速率分别增加了30.8%和64.8%,累积氨挥发量分别增加了36.6%和59.4%。逐步回归分析表明,EC、ESP(碱化度)、CO_(3)^(2-)和TN是影响苏打盐碱地稻田土壤累积反硝化氮量的主要因素,EC、CO_(3)^(2-)和SOM(土壤有机质)是影响累积氨挥发量的主要因素。土壤盐碱化虽然抑制了氮素的反硝化作用,但是显著增强了氨挥发作用。
Nitrogen loss caused by fertilization in farmland is an important source of environmental pollution.In order to clarify the effect of different degrees of soil salinization on nitrogen gas loss,30 paddy soil samples with different degrees of salinization were randomly taken at 0-20 cm depth.According to the degree of salinization,the samples were divided into light(0.1%-0.3% salt content,5%-15% exchangeable sodium percentage),moderate(0.3%-0.5% salt content,15%-30% exchangeable sodium percentage),and severe(0.5%-0.7% salt content,30%-45% exchangeable sodium percentage)saline-sodic soils.In each category,three soil samples with a similar degree of salinization were selected,according to the minimum number of classified samples(three replicates)for laboratory simulation culture analysis,in order to explore the dynamic characteristics of nitrogen denitrification and ammonia volatilization as well as their main influencing factors in soils with different degrees of salinization.The results showed that nitrogen denitrification decreased significantly,ammonia volatilization increased significantly,and the activities of nitrate reductase,nitrite reductase,and urease decreased significantly with increasing soil salinization(P<0.05).The maximum denitrification rate and cumulative nitrogen denitrification in moderate and severe saline-sodic soil were 18.9%and 37.8%,13.7%and 29.4% lower than those of light saline-sodic soil,respectively.The maximum ammonia volatilization rate and cumulative ammonia volatilization in moderate and severe saline-sodic soil were 30.8% and 64.8%,36.6% and 59.4% higher than those of light saline-sodic soil,respectively.Stepwise regression analysis showed that EC,ESP(exchangeable sodium saturation percentage),CO_(3)^(2-),and TN were the main factors affecting cumulative nitrogen denitrification,while EC,CO_(3)^(2-),and SOM(soil organic matter)were the main factors affecting cumulative ammonia volatilization.Furthermore,higher Na^(+)and CO_(3)^(2-)content were the fundamental reasons for increased gaseous nitrogen loss in saline-sodic paddy fields.Although soil salinization inhibited nitrogen denitrification,it significantly enhanced ammonia volatilization,resulting in increased overall gaseous nitrogen loss and loss rate.
作者
黄立华
杨易
刘伯顺
杨靖民
王平
黄广志
蒋小曈
HUANG Lihua;YANG Yi;LIU Baishun;YANG Jingmin;WANG Ping;HUANG Guangzhi;JIANG Xiaotong(Northeast Institute of Geography and Agroecology,Chinese Academy of Sciences,Changchun 130102,China;Jilin Da’an Farmland Ecosystem National Observation and Research Station,Da’an 131317,China;College of Resources and Environmental,Jilin Agricultural University,Changchun 130118,China;Management Center of Jalaid National Modern Agricultural Industrial Park in Inner Mongolia Autonomous Region,Jalaid 137600,China)
出处
《农业环境科学学报》
CAS
CSCD
北大核心
2023年第8期1748-1757,共10页
Journal of Agro-Environment Science
基金
国家自然科学基金面上项目(41977148)
吉林省科技发展创新人才项目(20220508110RC)
中国科学院黑土地保护与利用科技创新工程专项(XDA28110103)。
关键词
苏打盐碱土
氮素
反硝化
氨挥发
影响因素
saline-sodic soil
nitrogen
denitrification
ammonia volatilization
influencing factor
