Journal of Integrative Agriculture ›› 2024, Vol. 23 ›› Issue (5): 1703-1717.DOI: 10.1016/j.jia.2023.10.001

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秸秆覆盖通过抑制土壤小团聚体破碎改变了农田土壤径流中可溶性有机质的组成与流失量

  

  • 收稿日期:2023-06-13 接受日期:2023-08-14 出版日期:2024-05-20 发布日期:2024-04-24

Straw mulching alters the composition and loss of dissolved organic matter in farmland surface runoff by inhibiting the fragmentation of soil small macroaggregates

Shanshan Cai1, Lei Sun2, Wei Wang2, Yan Li3, Jianli Ding3, Liang Jin3, Yumei Li 2, Jiuming Zhang2, Jingkuan Wang1#, Dan Wei3#   

  1. 1 College of Land and Environment, Shenyang Agricultural University, Shenyang 110866, China

    2 Heilongjiang Academy of Black Soil Conservation and Utilization, Harbin 150086, China

    3 Institute of Plant Nutrition, Resources and Environment, Beijing Academy of Agricultural and Forestry Sciences, Beijing 100097, China

  • Received:2023-06-13 Accepted:2023-08-14 Online:2024-05-20 Published:2024-04-24
  • About author:Shanshan Cai, E-mail: css_0309@163.com; #Correspondence Jingkuan Wang, E-mail: j-kwang@163.com; Dan Wei, E-mail: wd2087@163.com
  • Supported by:
    This work was supported by the National Key Research and Development Project of China (2022YFD1601102), the Key R&D Plan of Heilongjiang Province, China (JD22B002), the Program on Industrial Technology System of National Soybean, China (CARS-04-PS17), the UNDP Project, China (cpr/21/401) and the National Natural Science Foundation of China (41771284).

摘要:

秸秆覆盖是被广泛采用的减少侵蚀土壤碳流失的方法。然而,秸秆覆盖对黑土可溶性有机质(DOM)径流损失的影响尚未被深入研究。当前,秸秆覆盖通过改变土壤团聚体来影响径流DOM组成和损失的机制仍未明晰。本文对东北黑土区坡耕地秸秆覆盖处理和不覆盖处理(对照)进行了对比研究。我们将土壤分为大团聚体(>2 mm)、小团聚体(0.25–2 mm)和微团聚体(<0.25 mm)。在五次降雨发生后,分析了秸秆覆盖对径流土壤团聚体中的DOM浓度(以可溶性有机碳含量表征组成(以荧光光谱分析)的影响。结果表明,秸秆覆盖减少了54.7%的径流量。因此,秸秆覆盖虽然增加了径流平均可溶性有机碳(DOC浓度,但却减少了径流中48.3%DOC损失。径流DOM的组成与土壤相似,都包含类腐殖酸和类蛋白质物质组分。秸秆覆盖处理后,随着降雨事件的发生,小团聚体中的蛋白质成分积累,径流中的类蛋白质成分减少。荧光光谱技术可以通过捕捉径流和土壤DOM特征的动态变化来了解降雨事件下物质迁移的水文路径。方差分解分析VPA)表明,微团聚体解释了覆盖处理下68.2%地表径流DOM变化,而小团聚体解释了秸秆覆盖处理下55.1%的径流DOM变化结果表明,秸秆覆盖减少了土壤小团聚体的破碎和微团聚体的损失,从而影响了土壤中DOM的组成减少了径流中DOM的损失。研究结果为坡耕地碳流失的阻控提供了理论依据。

Abstract:

Straw mulching is a widespread practice for reducing the soil carbon loss caused by erosion.  However, the effects of straw mulching on dissolved organic matter (DOM) runoff loss from black soil are not well studied.  How straw mulching affects the composition and loss of runoff DOM by changing soil aggregates remains largely unclear.  Here, a straw mulching treatment was compared to a no mulching treatment (as a control) on sloping farmland with black soil erosion in Northeast China.  We divided the soil into large macroaggregates (>2 mm), small macroaggregates (0.25–2 mm), and microaggregates (<0.25 mm).  After five rain events, the effects of straw mulching on the concentration (characterized by dissolved organic carbon (DOC)) and composition (analyzed by fluorescence spectroscopy) of runoff and soil aggregate DOM were studied.  The results showed that straw mulching reduced the runoff amount by 54.7%.  Therefore, although straw mulching increased the average DOC concentration in runoff, it reduced the total runoff DOM loss by 48.3%.  The composition of runoff DOM is similar to that of soil, as both contain humic-like acid and protein-like components.  With straw mulching treatment, the protein-like components in small macroaggregates accumulated and the protein-like components in runoff declined with rain events.  Fluorescence spectroscopy technology may help in understanding the hydrological paths of rain events by capturing the dynamic changes of runoff and soil DOM characteristics.  A variation partitioning analysis (VPA) indicated that the DOM concentration and composition of microaggregates explained 68.2% of the change in runoff DOM from no mulching plots, while the change in runoff DOM from straw mulching plots was dominated by small macroaggregates at a rate of 55.1%.  Taken together, our results demonstrated that straw mulching reduces the fragmentation of small macroaggregates and the loss of microaggregates, thus effecting DOM compositions in soil and reducing the DOM loss in runoff.  These results provide a theoretical basis for reducing carbon loss in sloping farmland.

Key words: dissolved organic matter , black soil ,  surface runoff ,  aggregates ,  fluorescence spectrum