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中国沙漠 ›› 2026, Vol. 46 ›› Issue (1): 63-73.DOI: 10.7522/j.issn.1000-694X.2025.00337

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连续耕作对荒漠绿洲农田土壤无机氮含量和硝化过程的影响

王丽莎1(), 戴伊婷1, 王川1(), 陈龙飞2, 何志斌2()   

  1. 1.湖北文理学院 资源环境与旅游学院,湖北 襄阳 441053
    2.中国科学院西北生态环境资源研究院 中国生态系统研究网络临泽内陆河流域研究站/中国科学院内陆河流域生态水文重点实验室,甘肃 兰州 730000
  • 收稿日期:2025-11-23 修回日期:2025-12-23 出版日期:2026-01-20 发布日期:2026-03-09
  • 通讯作者: 王川,何志斌
  • 作者简介:王丽莎(1992—),女,河南永城人,博士,讲师,主要从事农田生态系统氮素循环。E-mail: 13639366653@163.com
  • 基金资助:
    国家自然科学基金项目(42507638);湖北省自然科学基金项目(2025AFB392)

Responses of soil inorganic nitrogen and nitrification to continuous cultivation in desert oasis farmlands in the Hexi Corridor

Lisha Wang1(), Yiting Dai1, Chuan Wang1(), Longfei Chen2, Zhibin He2()   

  1. 1.College of Resource Environment and Tourism,Hubei University of Arts and Science,Xiangyang 441053,Hubei,China
    2.Chinese Ecosystem Network Research Linze Inland River Basin Research Station / Key Laboratory of Ecohydrology of Inland River Basin,Northwest Institute of Eco-Environment and Resources,Chinese Academy of Sciences,Lanzhou 730000,China
  • Received:2025-11-23 Revised:2025-12-23 Online:2026-01-20 Published:2026-03-09
  • Contact: Chuan Wang, Zhibin He

摘要:

在干旱区荒漠绿洲生态系统中,连续耕作对土壤无机氮转化与硝化过程的长期影响及其微生物学基础尚不清楚,制约了对氮素管理与温室气体减排的科学认知。为揭示荒漠绿洲农田连续耕作对土壤硝化过程的影响,本研究以河西走廊典型绿洲区未开垦沙地(USL)、连续耕作24 a新农田(YOF)和连续耕作54 a老农田(OOF)为研究对象,系统分析土壤理化性质、无机氮动态、硝化潜势(PNR)、净硝化速率(NNR)、氨氧化潜势(PAO)、N2O排放速率及氨氧化细菌(AOB)和氨氧化古菌(AOA)的变化特征,并采用抑制剂法评估AOA和AOB对氨氧化潜势和N2O排放的相对贡献。结果表明:连续耕作降低BD和沙粒含量,质地由砂质向壤质转变,NH4+-N、NO3--N、TN、SOM和DOC等养分显著积累。连续耕作显著增强了土壤无机氮矿化和硝化强度,OOF处理的NH4+-N、NO3--N及其排放强度均最高(P<0.05)。PNR和NNR随耕作年限增加显著升高,OOF分别较USL提高约7.4倍和3.9倍。PAO亦随耕作年限增加而增强,且AOA驱动的PAO贡献更大。N2O排放在OOF处理中最高,且由AOB驱动的贡献占主导。qPCR结果表明,连续耕作显著提高AOA与AOB基因丰度(P=0.001),AOA拷贝数高出AOB 1~2个数量级。PLS-PM表明硝化功能基因丰度对PNR具有最强正向效应(0.575),PAO次之(0.274),而土壤物理性质表现为负效应(-0.516)。连续耕作通过改善土壤结构、促进氮素积累及氨氧化微生物活性显著增强了硝化潜势。

关键词: 绿洲农田, 氨氧化潜势, 潜在硝化速率, N2O排放, 无机氮

Abstract:

To investigate the effects of continuous cultivation on soil nitrification in desert oasis farmland, this study was conducted in typical oasis fields of the Hexi Corridor, including an uncultivated sandy land (USL), a young oasis field (YOF, 24 years) and a old oasis field (OOF, 54 years of cultivation). Soil physicochemical properties, inorganic nitrogen dynamics, potential nitrification rate (PNR), net nitrification rate (NNR), potential ammonia oxidation (PAO), N2O emission rates, and the abundance of ammonia-oxidizing bacteria (AOB) and archaea (AOA) were systematically analyzed. The relative contributions of AOA and AOB to PAO and N2O emissions were assessed using selective inhibitor assays. Results showed that continuous cultivation decreased bulk density and sand content, shifted soil texture from sandy to loamy, and significantly increased NH4+-N, NO3--N, total nitrogen, soil organic matter, and dissolved organic carbon. Prolonged cultivation enhanced inorganic nitrogen mineralization and nitrification, with OOF showing the highest NH4+-N and NO3--N concentrations and emission rates (P<0.05). Both PNR and NNR increased significantly with cultivation duration, with OOF being 7.4- and 3.9-fold higher than USL, respectively. PAO also increased with cultivation, with AOA-driven PAO contributing more than AOB. N2O emission rates were highest in OOF and dominated by AOB. qPCR analysis indicated that continuous cultivation significantly increased the abundance of both AOA and AOB (P=0.001), with AOA gene copy numbers being 1-2 orders of magnitude higher than AOB. Partial least squares path modeling (PLS-PM) revealed that the abundance of nitrification functional genes had the strongest positive effect on PNR (0.575), followed by PAO (0.274), while soil physical properties exerted a negative effect (-0.516). Overall, continuous cultivation significantly enhanced the soil nitrification potential by improving soil structure, increasing nitrogen accumulation, and stimulating ammonia-oxidizing microbial activity.

Key words: oasis farmland, potential ammonia oxidation, potential nitrification rate, N2O emissions, inorganic nitrogen

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