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草业学报 ›› 2026, Vol. 35 ›› Issue (7): 58-67.DOI: 10.11686/cyxb2025294

• 研究论文 • 上一篇    下一篇

黄土丘陵区撂荒草地新鲜和半分解层凋落物混合对彼此早期分解的影响

张晓曦1,2(), 梁倩怡1, 张泽强1, 罗媛媛1, 李利平1, 李若萱1, 刘鑫1, 胡博1   

  1. 1.延安大学生命科学学院,陕西 延安 716000
    2.黄土高原应用生态陕西省教育厅重点实验室,陕西 延安 716000
  • 收稿日期:2025-07-16 修回日期:2025-09-10 出版日期:2026-07-20 发布日期:2026-05-21
  • 通讯作者: 张晓曦
  • 作者简介:张晓曦(1990-),男,蒙古族,内蒙古锡林郭勒盟人,副教授,博士。E-mail: zhangxiaoxi712100@gmail.com
  • 基金资助:
    国家自然科学基金项目(31800370);国家自然科学基金项目(32360290);陕西省创新能力支撑计划项目(2024ZC-KJXX-006);研究生科研创新计划项目(YKY2025042);国家大学生创新创业训练计划项目(202410719016)

Mutual effects of fresh and semidecomposed litter from abandoned grasslands in the Loess Hilly Region during early mixed decomposition

Xiao-xi ZHANG1,2(), Qian-yi LIANG1, Ze-qiang ZHANG1, Yuan-yuan LUO1, Li-ping LI1, Ruo-xuan LI1, Xin LIU1, Bo HU1   

  1. 1.College of Life Sciences,Yan’an University,Yan’an 716000,China
    2.Key Laboratory for Applied Ecology of Loess Plateau,Shaanxi Province,Yan’an 716000,China
  • Received:2025-07-16 Revised:2025-09-10 Online:2026-07-20 Published:2026-05-21
  • Contact: Xiao-xi ZHANG

摘要:

草地生态系统中往往同时存在新鲜和半分解层凋落物,由于两者化学特性和定殖微生物的差异,其共同分解极有可能导致显著的混合分解效应,影响彼此和凋落物层整体的分解过程和系统内的物质循环。为验证上述现象是否存在、并分析其产生的潜在酶学机制,本研究以黄土丘陵区撂荒27 a左右草地内枯萎较早的硬质早熟禾和针茅的新鲜凋落物以及地表半分解层凋落物为对象,在20~25 ℃、恒湿条件下进行150 d的室内模拟混合分解试验。在分解过程中分离不同凋落物组分,测定各类型凋落物在参与混合分解时的分解速率、养分释放率和木质素酶活性,并将其与对应凋落物单独分解时的相应指标进行比较,据此分析两类凋落物混合分解时对彼此分解特征的影响及其机理。结果表明:1)总体而言,两类新鲜凋落物与半分解层凋落物混合时,均至少在试验后期显著促进彼此分解(P<0.05);2)分解150 d后,硬质早熟禾与半分解层凋落物显著促进彼此的碳释放,后者同时促进前者的氮和磷释放;针茅与半分解层凋落物显著促进彼此的碳和磷释放,前者同时显著促进后者的氮释放(P<0.05);3)总木质素酶活性与凋落物分解速率呈显著正相关(P<0.05),半分解层凋落物在分解30 d时显著提高硬质早熟禾凋落物的总木质素酶活性,但在150 d时产生抑制效应,其在上述分解时期均显著提高针茅凋落物的总木质素酶活性(P<0.05)。总体而言,新鲜和半分解层凋落物的混合有利于提高彼此的分解速率,在生态系统物质循环中可能发挥了积极作用。

关键词: 混合分解, 新鲜凋落物, 半分解层, 协同效应

Abstract:

Fresh and semidecomposed litter usually coexist in grassland ecosystems. Because of the differences in chemical traits and colonizing microorganisms, their mixing might lead to significant mixed decomposition effects and therefore the two mutually affect the decomposition of the other, and possibly also nutrient cycling in the entire ecosystem. To verify whether these mutual effects indeed exist and to clarify the underlying enzymatic mechanism of these effects, fresh litter from Poa sphondylodes and from Stipa grandis, which are early withering species, were collected from a 27-year-old abandoned grassland for this study. In addition, semidecomposed litter from the same grassland was also collected and used as the comparison. These two types of litter were mixed to conduct a 150-day indoor simulated decomposition experiment at 20-25 ℃. During each stage of decomposition, different types of litter were separated, the overall decomposition rates of the given litter in mixture were calculated, and the nutrient release rates and lignin-degrading enzyme activities were measured. These parameters were then compared with those observed when the corresponding litter decomposed individually. Via these methods, the possible mutual effects between fresh and semidecomposed litter during mixed decomposition were evaluated, and the underlying mechanism clarified. The results indicated: 1) In general, fresh and semidecomposed litter both significantly accelerated the decomposition of the other, and these effects occurred at least during the late stage of the decomposition experiment (P<0.05). 2) After 150 d of decomposition, P. sphondylodes litter and semidecomposed litter each significantly accelerated the C release of the other, while semidecomposed litter also significantly accelerated the N and P release of P. sphondylodes litter. S. grandis litter and semidecomposed litter significantly accelerated the C and P release of each other, whereas S. grandis litter also significantly accelerated the N release of semidecomposed litter (P<0.05). 3) The total lignin-degrading enzyme activity of the litter was significantly positively correlated with its decomposition rate (P<0.05). Semidecomposed litter significantly increased the total lignin-degrading enzyme activity of P. sphondylodes litter at the 30th day of decomposition, but had the opposite effect at the 150th day; However, it significantly increased the enzymatic activity of S. grandis litter at all mentioned stages (P<0.05). Generally, mixed decomposition is beneficial for the decomposition of both fresh and semidecomposed litter, which might play crucial positive roles in nutrient cycling in grassland ecosystems.

Key words: mixed decomposition, fresh litter, semidecomposed layer, synergistic effects