植物生态学报 ›› 2020, Vol. 44 ›› Issue (1): 70-79.DOI: 10.17521/cjpe.2019.0270

• 研究论文 • 上一篇    下一篇

北方农牧交错带温性盐碱化草地土壤呼吸对不同形态氮添加和刈割的响应

胡姝娅1,2,刁华杰1,3,王惠玲3,薄元超3,申颜1,孙伟4,董宽虎3,黄建辉1,2,王常慧1,*()   

  1. 1中国科学院植物研究所植被与环境变化国家重点实验室, 北京 100093
    2中国科学院大学, 北京 100049
    3山西农业大学动物科技学院, 山西晋中 030801
    4东北师范大学植被生态学教育部重点实验室, 长春 130024
  • 收稿日期:2019-10-15 修回日期:2020-01-05 出版日期:2020-01-20 发布日期:2020-03-26
  • 通讯作者: 王常慧
  • 基金资助:
    国家自然科学基金项目(31770526);国家自然科学基金项目(31872406);国家重点研发计划(2017YFA0604802);国家重点研发计划(2016YFC0500703)

Response of soil respiration to addition of different forms of nitrogen and mowing in a saline-alkali grassland in the northern agro-pastoral ecotone

HU Shu-Ya1,2,DIAO Hua-Jie1,3,WANG Hui-Ling3,BO Yuan-Chao3,SHEN Yan1,SUN Wei4,DONG Kuan-Hu3,HUANG Jian-Hui1,2,WANG Chang-Hui1,*()   

  1. 1State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
    2University of Chinese Academy of Sciences, Beijing 100049, China
    3College of Animal Science and Veterinary Medicine, Shanxi Agricultural University, Jinzhong, Shanxi 030801, China
    4Key Laboratory of Vegetation Ecology, Ministry of Education, Northeast Normal University, Changchun 130024, China
  • Received:2019-10-15 Revised:2020-01-05 Online:2020-01-20 Published:2020-03-26
  • Contact: WANG Chang-Hui
  • Supported by:
    National Natural Science Foundation of China(31770526);National Natural Science Foundation of China(31872406);National Key R&D Program of China(2017YFA0604802);National Key R&D Program of China(2016YFC0500703)

摘要:

农牧交错带草地生态系统兼受农业和牧业的影响, 属于脆弱生态系统, 尤其是养分贫瘠的盐碱化草地, 其生态系统结构和功能对外界干扰的响应更加强烈。位于晋西北地区的农牧交错带盐碱化草地, 地理位置独特, 区别于天然牧区草地生态系统。由于毗邻农田, 农业氮肥的过量使用促进了活性氮气体排放, 同时使得农牧交错带草地土壤碳氮循环发生改变。刈割是北方农牧交错草地生态系统的主要管理方式, 为了深入探究氮添加和刈割管理方式对农牧交错带草地碳循环的影响, 进一步厘清该区域草地生态系统的碳动态问题, 该研究设置了一个不同形态氮添加和刈割的裂区实验, 测定土壤呼吸对不同形态氮肥添加和刈割的响应, 为进一步科学管理该区域草地提供可靠的依据。实验样地位于山西省右玉县境内的“山西农业大学农牧交错带草地生态系统野外观测研究站”, 于2017年设置不同形态氮添加和刈割处理, 实验处理包括对照(不刈割和刈割)、尿素添加、缓释尿素添加、刈割+尿素添加、刈割+缓释尿素添加, 每种处理6个重复, 共36个小区。在不同处理条件下测定土壤呼吸速率、土壤温度、土壤水分、土壤微生物生物量、土壤无机氮含量、植物地上和地下生物量, 并计算土壤累积碳排放量及CO2通量。研究结果表明: (1)短期(2017-2018年)尿素和缓释尿素的添加显著提高了该地区土壤呼吸速率和土壤累积碳排放量。与添加缓释尿素相比, 添加尿素处理下的土壤呼吸速率和累积碳排放量更高; (2)刈割显著降低土壤呼吸速率和累积碳排放量; (3)短期氮添加和刈割的交互作用对土壤呼吸速率没有显著影响。因此, 短期氮添加促进了北方农牧交错带盐碱化草地土壤碳释放, 刈割抑制土壤呼吸, 降低了累积碳排放量, 这可能是由于刈割移除地上植物, 减少了凋落物的输入, 底物减少导致土壤微生物活性降低。但是随着处理时间的延长, 氮添加和刈割对该农牧交错带盐碱化草地土壤碳动态的影响还有待进一步探究和发现。

关键词: 刈割, 氮形态, 土壤呼吸, 农牧交错带, 盐碱化草地

Abstract:

Aims The agro-pastoral ecotone is considered as fragile ecosystems which are strongly affected by agriculture and animal husbandry. The saline-alkali grassland is a unique grassland type in the agro-pastoral ecotone. A large amount of fertilizers are used to increase productivity in this area, which also promotes the emission of reactive nitrogen (N) gases and leads to the changes in soil carbon and N cycles. Mowing is a primary management practice in the agro-pastoral grassland in northern China. In order to explore the impact of N addition and mowing on carbon dynamic in this saline-alkali grassland located in the agro-pastoral ecotone, we determined the response of soil respiration to N addition and mowing.
Methods This study area is located in Youyu County, an agro-pastoral grassland ecosystem in northern China. The field experiment was set up in May, 2017. The treatments included: control (without mowing and mowing), addition of urea, addition of slow release urea, addition of urea + mowing, addition of slow release urea + mowing. Each treatment included 6 replicates. Therefore, there were totally 36 plots in this experiment. Soil respiration rate, soil temperature, soil moisture content, microbial biomass, inorganic N content, above-ground and below-ground biomass were measured under different treatments, and the cumulative carbon emissions and CO2 fluxes were calculated.
Important findings Our results showed that: (1) Short-term (2017-2018) N addition significantly increased soil respiration rates and soil cumulative carbon emissions. Meanwhile, soil respiration rates and cumulative carbon emissions were significantly higher under urea treatment than those under slow release urea addition. (2) Mowing significantly reduced soil respiration rates and cumulative carbon emissions. (3) The interaction of short-term N addition and mowing had no significant effect on soil respiration rate. Therefore, short-term N addition can promote soil carbon release from the saline-alkali grassland in the agro-pastoral ecotone of northern China. Mowing can reduce soil respiration and decrease cumulative of carbon emissions. This may be because that mowing reduced the input of litter and further reduced soil substrate for microbes, which led to a decrease in soil microbial activity. However, long-term effect of N addition and mowing on soil carbon dynamics in saline-alkaline grasslands in the agro-pastoral ecotone still needs to be further explored.

Key words: mowing, nitrogen forms, soil respiration, agro-pastoral ecotone, saline-alkali grassland