河西盐渍化草地土壤氮组分及氮转化相关酶活性对不同形态氮输入的响应  

Response of soil nitrogen fractions and nitrogen transformation related enzyme activities to different forms of nitrogen input in salinized grassland of Hexi

作　　者：王帅钧 吴江琪 徐国荣 王雨媛 李姣姣 关宇淇 闫丽娟 李广[1] WANG Shuaijun;WU Jiangqi;XU Guorong;WANG Yuyuan;LI Jiaojiao;GUAN Yuqi;YAN Lijuan;LI Guang(College of Forestry,Gansu Agricultural University,Lanzhou 730070,Gansu,China)

机构地区：[1]甘肃农业大学林学院,甘肃兰州730070

出　　处：《草业科学》2025年第3期617-627,共11页Pratacultural Science

基　　金：国家自然基金项目(32360438);甘肃省拔尖领军人才项目(GSBJLJ-2023-09);国家自然科学基金青年基金项目(42307348);甘肃省教育科技创新基金项目(2022A-052);甘肃省青年科技基金计划项目(22JR5RA877);甘肃省研究生“创新之星”项目(2023CXZX-642)。

摘　　要：全球气候变化大背景下,持续的大气氮沉降深刻地影响着生态系统土壤氮循环。为探究氮沉降背景下土壤氮素、氮转化酶活性变化特征及其影响因素,本研究基于野外氮输入试验,以河西盐渍化草地为对象,共设置有机氮(ON)、无机氮(IN)、混合氮(MN)3种不同形态的外源氮输入处理和不添加氮肥对照(CK),氮添加量均为15 kg·(hm^(2)·a)^(−1),以分析不同形态的氮输入对土壤氮素及氮转化相关酶活性的影响。结果表明:不同形态的氮输入降低了亚硝酸还原酶活性,而混合氮和无机氮输入分别显著提高了硝酸还原酶活性20.2%和8.1%,无机氮输入显著提高了脲酶活性(16.0%)(P<0.05)。不同形态的氮输入均改变了土壤无机氮含量,且对铵态氮(NH_(4)^(+)-N)的促进作用较硝态氮(NO_(3)^(-)-N)更加明显。MN处理显著提高了土壤全氮(TN)、NH_(4)^(+)-N和NO_(3)^(-)-N含量。综上,混合形态氮输入提高了盐渍化草地土壤氮含量和酶活性,但是随着时间的延长,氮沉降对盐渍化草地土壤氮动态的影响还有待进一步探究。本研究结果可为评估和预测全球气候变化背景下盐渍化草地生态系统土壤氮循环提供科学依据。The impact of the atmospheric nitrogen deposition on the cycling of soil nitrogen in ecosystems is growing amidst the backdrop of global climate change.The effect of nitrogen deposition on soil nitrogen is dependent on differences in soil nitrogen convertase activity.To investigate changes in the characteristics of soil nitrogen and the factors influencing the nitrogen invertase activity of nitrogen deposition,three different forms of exogenous nitrogen input treatments were established in salinized grassland based on a field experiment in the Hexi Corridor,China:organic nitrogen(ON),inorganic nitrogen(IN),and mixed nitrogen(MN),in addition to a control(CK).The input of pure nitrogen was 15 kg·(hm^(2)·a)^(−1).The effects of different nitrogen inputs on the enzymatic activity of soil nitrogen conversion were analyzed.The results showed that nitrogen input of different forms decreased nitrite reductase activity compared with CK,while the input of mixed nitrogen and inorganic nitrogen significantly increased the nitrate reductase activity by 20.2%and 8.1%,respectively.Furthemore,the input of inorganic nitrogen significantly increased the urease activity(16.0%).The addition of various forms of nitrogen resulted in alterations to the soil’s inorganic nitrogen content,with ammonium nitrogen(NH_(4)^(+)-N)exhibiting a more pronounced promotional effect compared to nitrate nitrogen(NO_(3)^(-)-N).MN treatment significantly increased the total nitrogen(TN),NH_(4)^(+)-N,and NO_(3)^(-)-N content in the soil.Taken together,the results suggest that mixed nitrogen input enhances the soil nitrogen content and enzyme activity in salinized grassland.Further studies will be needed to determine the influence of nitrogen deposition on soil nitrogen dynamics in salinized grassland over time.These findings offer a scientific foundation for evaluating and forecasting the soil nitrogen cycle in salinized grassland ecosystems in the modern-day context of global climate change.

关 键 词：氮输入 氮组分 酶活性 盐渍化草地 碱性土 

分 类 号：S15[农业科学—土壤学]