Xing Liheng, Li Yu, Zeng Jia, Fang Jingbo, Niu Yanfeng, Guo Yang, Yuan Linshan, Ren Chengjie, Yang Gaihe, Han Xinhui
College of Agronomy, Northwest Agriculture & Forestry University, Yangling, 712100, Shaanxi, PR China; Shaanxi Engineering Research Center of Circular Agriculture, Yangling, 712100, Shaanxi, PR China.
College of Agronomy, Northwest Agriculture & Forestry University, Yangling, 712100, Shaanxi, PR China; Shaanxi Engineering Research Center of Circular Agriculture, Yangling, 712100, Shaanxi, PR China.
J Environ Manage. 2025 Sep;392:126754. doi: 10.1016/j.jenvman.2025.126754. Epub 2025 Jul 30.
Grassland ecosystems, as one of the most significant ecological units on Earth, play a crucial role in the global carbon cycle and biodiversity conservation due to their extensive coverage and huge soil carbon storage. Litter, as an important component of soil ecosystems, plays a crucial role in soil nutrient cycling, organic matter dynamics, and the structure and function of grassland ecosystems. However, the mechanisms by which different quality litter and their decomposition differences affect the soil multifunctionality (SMF) and quality index (SQI) of grassland remain unclear. Through a 450-day in situ decomposition experiment in the field, we explored the mechanisms by which high-quality (low C:N ratio; Lespedeza dahurica (leaf: LL, root: LR)) and low-quality (high C:N ratio; Artemisia sacrorum (leaf: AL, root: AR)) litter decomposition affect the SMF and SQI of grassland. The results showed that the litter decomposition rate (K) was higher for high-quality litter than for low-quality litter (LL > AL, LR > AR). Moreover, K was significantly correlated with litter N, P, C:N ratio, and C:P ratio, Enzymatic stoichiometry revealed a transition from N to P limitation around 180 days, with P limitation intensifying progressively during decomposition. Despite variations in litter quality, all treatments similarly enhanced SMF and SQI, with no significant intergroup differences detected. Specifically, after 450 days of decomposition, the 0-5 cm soil layer LL, LR, AL, and AR increased SMF by 151.45 %, 128.33 %, 149.81 %, and 134.19 %, respectively; the 5-10 cm soil layer increased SMF by 163.90 %, 157.52 %, 175.94 %, and 155.32 %, respectively. Random forest and segmented regression analysis indicated that litter nutrient release rate and P limitation in the two soil layers (0-5 cm, 5-10 cm) were the key factors driving SMF and SQI, and were significantly positively correlated with SMF and SQI. Our research shows a similar capacity of contrasting-quality litters to improve SMF and SQI, revising the traditional quality-benefit paradigm. This functional equivalence challenges the traditional 'quality-benefit' paradigm, suggesting that low-quality litters could be equally effective in grassland restoration, particularly under resource-limited conditions.
草原生态系统作为地球上最重要的生态单元之一，因其广泛的覆盖面积和巨大的土壤碳储量，在全球碳循环和生物多样性保护中发挥着关键作用。凋落物作为土壤生态系统的重要组成部分，在土壤养分循环、有机质动态以及草原生态系统的结构和功能中起着至关重要的作用。然而，不同质量的凋落物及其分解差异影响草原土壤多功能性（SMF）和质量指数（SQI）的机制仍不清楚。通过为期450天的田间原位分解实验，我们探究了高质量（低C:N比；达乌里胡枝子（叶：LL，根：LR））和低质量（高C:N比；铁杆蒿（叶：AL，根：AR））凋落物分解影响草原SMF和SQI的机制。结果表明，高质量凋落物的分解速率（K）高于低质量凋落物（LL > AL，LR > AR）。此外，K与凋落物的N、P、C:N比和C:P比显著相关，酶化学计量学表明在180天左右从N限制向P限制转变，且在分解过程中P限制逐渐加剧。尽管凋落物质量存在差异，但所有处理均同样增强了SMF和SQI，未检测到显著的组间差异。具体而言，分解450天后，0 - 5厘米土层的LL、LR、AL和AR分别使SMF提高了151.45%、128.33%、149.81%和134.19%；5 - 10厘米土层分别使SMF提高了163.90%、157.52%、175.94%和155.32%。随机森林和分段回归分析表明，两个土层（0 - 5厘米，5 - 10厘米）的凋落物养分释放速率和P限制是驱动SMF和SQI的关键因素，且与SMF和SQI显著正相关。我们的研究表明，不同质量的凋落物在改善SMF和SQI方面具有相似的能力，修正了传统的质量 - 效益范式。这种功能等效性挑战了传统的“质量 - 效益”范式，表明低质量凋落物在草原恢复中可能同样有效，特别是在资源有限的条件下。
