Journal of Integrative Agriculture ›› 2021, Vol. 20 ›› Issue (9): 2512-2525.DOI: 10.1016/S2095-3119(20)63482-7

所属专题: 农业生态环境-有机碳与农业废弃物还田合辑Agro-ecosystem & Environment—SOC

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  • 收稿日期:2020-04-02 出版日期:2021-09-01 发布日期:2021-07-20

Changes in soil organic carbon pools following long-term fertilization under a rain-fed cropping system in the Loess Plateau, China

WANG Ren-jie1, SONG Jia-shan1, FENG Yong-tao2, ZHOU Jiang-xiang1, XIE Jun-yu3, Asif KHAN1, CHE Zong-xian4, ZHANG Shu-lan1, YANG Xue-yun1 
  

  1. 1 Key Laboratory of Plant Nutrition and the Agri-environment in Northwest China, Ministry of Agriculture and Rural Affairs/College of Natural Resources and Environment, Northwest A&F University, Yangling 712100, P.R.China
    2 Baoji Extension and Service Centre of Agricultural Technology, Baoji 721001, P.R.China
    3 College of Natural Resources and Environment, Shanxi Agricultural University, Taigu 030801, P.R.China
    4 Institute of Soil, Fertilizer and Water-saving Agriculture, Gansu Academy of Agricultural Sciences, Lanzhou 730070, P.R.China
  • Received:2020-04-02 Online:2021-09-01 Published:2021-07-20
  • Contact: Correspondence ZHANG Shu-lan, E-mail: zhangshulan@nwsuaf.edu.cn; YANG Xue-yun, Tel: +86-29-87080050, E-mail: xueyunyang@hotmail.com
  • About author:WANG Ren-jie, E-mail: wrj6433681@163.com;
  • Supported by:
    This work was sponsored by the Ministry of Agriculture and Rural Affairs of China under  Special funds for the Operation and Maintenance of Scientific Research Facilities
    (G202010-2).

摘要:

本研究选取黄土高原旱地农田系统三个长期定位试验:杨凌(25年)、天水(35年)、平凉(37年),研究长期不同施肥对SOC及其组分,例如:矿质结合态有机碳(MOC)和颗粒有机碳(POC,包含轻组颗粒有机碳和重组颗粒有机碳)的影响。每个试验点包括三个处理:对照(不施任何肥料,CK),施化肥(CF)和化肥与有机肥配施(MCF)。结果表明:施肥显著增加了耕层(0-20 cm)土壤固碳速率,杨凌、天水和平凉三个点化肥处理较CK分别提高134、89和129 kg ha-1 yr-1,有机无机配施 分别提高418、153和384 kg ha-1 yr-1。杨凌、天水和平凉三个点MOC库分别占总SOC储量的72、67和64%;三个地点CF处理的固碳速率分别为76、57和83 kg ha-1 yr-1,MCF分别为238、118和156 kg ha-1 yr-1且呈现出MOC饱和的趋势。相应的POC库储量在三个试验点分别占总SOC储量的27、33和36%,其中Light-POC占SOC总量的11、17和22%,Heavy-POC占17、16和15%。三个点CF处理POC库固碳速率分别为58、32和46 kg ha-1 yr-1,MCF分别为181、90和228 kg ha-1 yr-1。其中,Light-POC在CF处理中的贡献占POC的59、81和72%,在MCF处理中的贡献占POC的60、40和69%,其余则为Heavy-POC的贡献。相比CK处理,单施化肥对MOC和POC占总SOC的比例没有影响,而MCF处理显著降低了MOC占SOC的比例,增加了POC所占比例,主要表现为Light-POC组分的增加。SOC在不同库中的分布与土壤团聚体的分布和稳定性密切相关。本研究表明,施用有机肥不仅能够提高土壤有机碳储量,还可以显著改变土壤有机碳的组成,从而提高土壤有机碳的质量,可能与土壤有机碳的饱和水平有关。


Abstract:

Understanding the mechanism of soil organic carbon (SOC) sequestration is of paramount importance in sustaining crop productivity and mitigating climate change.  Long-term trials were employed to investigate the responses of total SOC and its pools, i.e., mineral-associated OC (MOC), particulate OC (POC, containing Light-POC and Heavy-POC), to fertilization regimes at Yangling (25-year), Tianshui (35-year) and Pingliang (37-year) under a rain-fed cropping system in the Loess Plateau.  The fertilization regimes in each trial included three treatments, i.e., control (no nutrient input, CK), chemical fertilizers (CF), and organic manure plus chemical fertilizers (MCF).  Relative to the CK, long-term fertilization appreciably increased SOC storage by 134, 89 and 129 kg ha–1 yr–1 under CF, and 418, 153 and 384 kg ha–1 yr–1 under MCF in plough layer soils (0–20 cm), respectively, at the Yangling, Tianshui and Pingliang sites.  The MOC pools accounted for 72, 67 and 64% of the total SOC at the above three sites with sequestration rates of 76, 57 and 83 kg ha–1 yr–1 under CF and 238, 118 and 156 kg ha–1 yr–1 under MCF, respectively.  Moreover, the MOC pool displayed a saturation behavior under MCF conditions.  The POC accordingly constituted 27, 33 and 36% of SOC, of which Light-POC accounted for 11, 17 and 22% and Heavy-POC for 17, 16 and 15% of SOC, respectively.  The sequestration rates of POC were 58, 32 and 46 kg ha–1 yr–1 under CF, and 181, 90 and 228 kg ha–1 yr–1 under MCF at the three respective sites, in which Light-POC explained 59, 81 and 72% of POC under CF, and 60, 40 and 69% of POC under MCF, with Heavy-POC accounting for the balance.  Compared with CK, the application of CF alone did not affect the proportions of MOC or total POC to SOC, whereas MCF application markedly reduced the proportion of MOC and increased the POC ratio, mainly in the Light-POC pool.  The distribution of SOC among different pools was closely related to the distribution and stability of aggregates.  The present study confirmed that organic manure amendment not only sequestered more SOC but also significantly altered the composition of SOC, thus improving SOC quality, which is possibly related to the SOC saturation level.
 

Key words: chemical fertilizer ,  organic manure ,  mineral-associated OC ,  particulate OC ,  Light-POC ,  Heavy-POC