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草业学报 ›› 2025, Vol. 34 ›› Issue (2): 221-232.DOI: 10.11686/cyxb2024146

• 研究简报 • 上一篇    

氮添加对黄土丘陵区草地土壤微生物养分限制特征的影响

贾蕴欢1(), 胡雯颖1, 邓健1,2(), 赵雪3, 陈子玥1, 王亚楠1, 李江文1,2, 张晓曦1,2   

  1. 1.延安大学生命科学学院,陕西省红枣重点实验室,陕西 延安 716100
    2.黄土高原应用生态陕西省高等学校重点实验室,延安大学,陕西 延安 716000
    3.西北大学城市与环境学院,陕西 西安 710127
  • 收稿日期:2024-04-29 修回日期:2024-07-01 出版日期:2025-02-20 发布日期:2024-11-27
  • 通讯作者: 邓健
  • 作者简介:E-mail: deng050702@126.com
    贾蕴欢(2000-),女,宁夏吴忠人,在读硕士。E-mail: jyh3983@163.com
  • 基金资助:
    陕西省自然科学基础研究计划项目(2024JC-YBMS-224);延安市科技计划项目(2023-CYL-120);榆林市科技计划项目(2023-CXY-212);国家级大学生创新创业训练计划项目(202310719001)

Effects of nitrogen addition on soil microbial nutrient limitation characteristics in grassland in the Loess Hilly Region

Yun-huan JIA1(), Wen-ying HU1, Jian DENG1,2(), Xue ZHAO3, Zi-yue CHEN1, Ya-nan WANG1, Jiang-wen LI1,2, Xiao-xi ZHANG1,2   

  1. 1.College of Life Sciences,Shaanxi Key Laboratory of Chinese Jujube,Yan’an University,Yan’an 716100,China
    2.Key Laboratory for Applied Ecology of Loess Plateau,Shaanxi Province,Yan’an University,Yan’an 716000,China
    3.College of Urban and Environment Science,Northwest University,Xi’an 710127,China
  • Received:2024-04-29 Revised:2024-07-01 Online:2025-02-20 Published:2024-11-27
  • Contact: Jian DENG

摘要:

不断加剧的大气氮沉降会改变土壤养分平衡,进而引起土壤微生物养分限制,但目前关于氮沉降对黄土丘陵区草地土壤微生物养分限制特征的影响还不清楚。研究基于野外模拟氮沉降控制试验,通过测定土壤微生物生物量和养分转化酶活性,结合土壤理化性质分析,揭示了不同氮添加水平下草地土壤微生物养分限制特征及其影响因素。结果表明:氮添加导致土壤pH下降,并引起土壤养分平衡特征变化,具体表现为土壤有机碳、全氮含量的增加,而全磷无显著变化;氮添加导致了土壤速效养分含量增加,且速效磷含量增加速率大于可溶性碳和矿质氮,引起速效养分碳氮的相对不足。草地土壤微生物生物量和胞外酶活性在低浓度氮添加下降低,在高浓度氮添加下升高。随着氮添加浓度的增加,草地土壤微生物氮限制加剧而碳限制缓解;微生物碳限制同时还影响着微生物碳利用效率特征;氮添加引起的土壤全量和速效养分不平衡变化通过调控微生物生物量和酶活性共同决定着土壤微生物的养分限制特征。研究为理解氮沉降背景下草地土壤养分循环特征提供了进一步的认识。

关键词: 氮沉降, 草地, 养分限制, 胞外酶活性, 养分利用效率

Abstract:

Increasing atmospheric nitrogen deposition is affecting the soil nutrient balance. This may result in decreased nutrient availability to soil microbes. However, the effect of nitrogen deposition on the characteristics of nutrient limitation for soil microbes in grassland in the Loess Hilly Region is still unclear. The objective of this study was to investigate the effects of nitrogen deposition on soil microbial nutrient limitation in this region. A field-based controlled experiment simulating nitrogen deposition was conducted, and the soil microbial biomass, nutrient-transforming enzyme activities, and soil physicochemical properties were determined. This allowed us to elucidate the characteristics of nutrient limitation for grassland soil microorganisms, and its influencing factors, under different nitrogen addition levels. The results showed that nitrogen addition led to a decrease in soil pH, and altered the soil nutrient balance. More specifically, nitrogen addition increased the soil organic carbon and total nitrogen contents, but did not significantly affect the total phosphorus content. In addition, nitrogen addition enhanced the contents of soil available nutrients, with a greater increase in the available phosphorus content than in the soluble carbon and mineral nitrogen contents. This resulted in a relative shortage of carbon and nitrogen as available nutrients. Notably, the soil microbial biomass and extracellular enzyme activities decreased under low nitrogen addition but increased under high nitrogen addition. Further analyses using an enzyme stoichiometric model indicated that with increasing amounts of nitrogen addition, nitrogen limitation for soil microorganisms was intensified, while carbon limitation was alleviated. Microbial carbon limitation also affected the microbial carbon utilization efficiency. The imbalance of soil total and available nutrients caused by nitrogen addition jointly affected the characteristics of nutrient limitation for soil microorganisms by regulating microbial biomass and enzyme activity. In conclusion, these findings provide new information about the characteristics of soil nutrient cycling in grassland as affected by increasing nitrogen deposition.

Key words: nitrogen deposition, grassland, nutrient limitation, extracellular enzyme activity, nutrient use efficiency