IF 5.4 1区农林科学 Q1 GEOSCIENCES, MULTIDISCIPLINARY

Catena

Pub Date : 2024-10-11 DOI: 10.1016/j.catena.2024.108460

This study aims to assess the co-evolution of soil development and soil organic carbon (SOC) accumulation along a postglacial soil chronosequence in southeast Alaska. We hypothesize that in the early stages of soil development, larger SOC stocks are primarily found in surficial soil horizons and gradually become more abundant in subsurface horizons over time. Seven moraines were dated using dendrochronology, yielding ages of 73, 82, 89, 128, 155, 207, and 247 years. SOC and pedogenic Fe oxyhydroxide values from mature Spodosols, sampled outside the chronosequence, were used as a reference for the steady state of Spodosols in the region. From 73 to 128 years, soils were classified as Typic Cryorthents; by 155 years, as Spodic Dystrocryepts; and as Typic Haplocryods in the older moraines. A shift in SOC accumulation rates and depth distribution occurred once spodic properties developed. During the Entisol phase, most SOC stocks were concentrated in surficial horizons. After meeting spodic criteria, there was a shift toward subsurface mineral horizons, hosting over 50 % of SOC stocks. This shift in SOC depth distribution was supported by a significant positive relationship between subsurface SOC stocks and age, but not with surficial SOC stocks. Similarly, surficial SOC accumulation rates were elevated during early pedogenesis (e.g., 0.26 Mg C ha^-1 yr⁻¹), while subsurface SOC accumulation was lower (0.04 Mg C ha^-1 yr⁻¹), increasing to 0.19 Mg C ha^-1 yr⁻¹ once spodic properties were met. A significant positive correlation between pedogenic Fe and age highlights the role of SOC in enhancing the weathering of Fe-bearing minerals. Our findings support the hypothesis that subsurface SOC stocks rapidly become dominant over time with Spodosol development. This study underscores the consequences of glacier retreat on a portion of the terrestrial ecosystem, with direct impacts on carbon cycling.

本研究旨在评估阿拉斯加东南部冰川期后土壤年序中土壤发育与土壤有机碳（SOC）积累的共同演化过程。我们假设，在土壤发育的早期阶段，较大的 SOC 储量主要存在于表层土壤层中，随着时间的推移，其在地下土壤层中的含量会逐渐增加。我们使用树龄测定法对七条冰碛进行了年代测定，得出的年龄分别为 73、82、89、128、155、207 和 247 年。在年代序列之外取样的成熟 Spodosols 中的 SOC 和生成的氢氧化铁值被用作该地区 Spodosols 稳定状态的参考。从 73 年到 128 年，土壤被归类为典型冰冻土壤；到 155 年，土壤被归类为典型冰冻土壤；在较早的冰碛中，土壤被归类为典型冰冻土壤。一旦形成旋生特性，SOC 的积累率和深度分布就会发生变化。在 Entisol 阶段，大部分 SOC 储量集中在表层地层。在达到陆相标准后，SOC 储量向地下矿层转移，占 50% 以上。地表下 SOC 储量与年龄之间存在显著的正相关关系，而与地表 SOC 储量之间则不存在显著的正相关关系。同样，表层 SOC 的积累率在早期成土过程中较高（如 0.26 兆克碳当量/公顷-年-1），而次表层 SOC 的积累率较低（0.04 兆克碳当量/公顷-年-1），一旦满足地形特征，则增加到 0.19 兆克碳当量/公顷-年-1。成土铁元素与年龄之间存在明显的正相关，这突出表明了 SOC 在促进含铁矿物风化方面的作用。我们的研究结果支持这样一种假设，即随着时间的推移，地表下的 SOC 储量会随着 Spodosol 的发展而迅速占据主导地位。这项研究强调了冰川退缩对部分陆地生态系统造成的后果，以及对碳循环的直接影响。

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引用次数: 0

Large variability in permafrost degradation over the Northern Hemisphere 北半球永冻土退化的巨大差异

IF 5.4 1区农林科学 Q1 GEOSCIENCES, MULTIDISCIPLINARY

Catena

Pub Date : 2024-10-10 DOI: 10.1016/j.catena.2024.108440

Permafrost in the Northern Hemisphere has been degrading under climate change, affecting climatic, hydrological, and ecological systems. To reveal the temporal and spatial characteristics of permafrost degradation under climate change, we quantified permafrost thermal states and active layer thicknesses using observational data covering various periods and different areas of the Northern Hemisphere. The soil temperatures at 20 cm depth in the circumpolar Arctic permafrost regions were much lower than in the Qinghai-Tibet Plateau. The thaw period is 114 days in the circumpolar permafrost regions compared to 167 days in the Qinghai-Tibet Plateau. The active layer thickness (ALT) was largest in transitional permafrost regions and sporadic permafrost regions, and lowest in the high latitude permafrost regions and continuous permafrost regions, and the ALT generally exhibited an increasing trend. The average ALT was 1.7 m, and increased by 3.6 cm per year in the Northern Hemisphere. The mean annual ground temperature (MAGT) was largest in the high-altitude permafrost regions and isolated permafrost regions, and lowest in the high latitude permafrost regions and continuous permafrost regions. The warming rate of the MAGT was largest in the high latitude regions and lowest in the high altitude regions, and gradually increased from isolated permafrost regions to continuous permafrost regions, with an average warming rate of 0.3 °C per decade for the whole Northern Hemisphere. These findings provide important information for understanding the variability in permafrost degradation processes across different regions under climate change.

北半球的永久冻土在气候变化下不断退化，影响着气候、水文和生态系统。为了揭示气候变化下永久冻土退化的时空特征，我们利用北半球不同时期和不同地区的观测数据，对永久冻土的热状态和活动层厚度进行了量化。环北极永久冻土区 20 厘米深处的土壤温度远低于青藏高原。环北极永久冻土区的解冻期为 114 天，而青藏高原为 167 天。过渡冻土区和零星冻土区的活动层厚度（ALT）最大，高纬度冻土区和连续冻土区的活动层厚度（ALT）最小，且活动层厚度（ALT）总体呈上升趋势。平均 ALT 为 1.7 米，北半球每年增加 3.6 厘米。年平均地温（MAGT）在高纬度永久冻土区和孤立永久冻土区最高，在高纬度永久冻土区和连续永久冻土区最低。MAGT的升温速率在高纬度地区最大，在高海拔地区最低，并且从孤立冻土区到连续冻土区逐渐升高，整个北半球的平均升温速率为每10年0.3°C。这些发现为了解气候变化下不同地区冻土退化过程的变异性提供了重要信息。

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引用次数: 0

Beyond monocultures: Optimizing soil carbon sequestration with diverse planting strategies on the Loess Plateau 超越单一种植：在黄土高原采用多样化种植策略优化土壤固碳

IF 5.4 1区农林科学 Q1 GEOSCIENCES, MULTIDISCIPLINARY

Catena

Pub Date : 2024-10-10 DOI: 10.1016/j.catena.2024.108447

Monoculture plantations, often characterized by low species diversity and simple structure, are significant contributors to limited carbon stocks, forced ecosystem degradation, and reduced long-term resilience. To tackle these issues, mixed-species plantations have gained popularity as a promising strategy. However, current knowledge about the effects and mechanisms of increasing planting diversity on soil carbon storage (SCS) remains limited. Furthermore, there is a lack of scientific guidance on selecting the most appropriate mixed afforestation strategy. In this study, pure Robinia pseudoacacia (RP) plantations and RP plantations mixed with tree species Pinus tabuliformis (RP-PT), shrub species Forsythia suspense (RP-FS) and Caragana korshinskii (RP-CK) were selected to assess differences of vegetation diversity, litter characteristics, soil properties, and SCS across the soil profile (0–60 cm) on the Loess Plateau, China. We used random forest analysis and variance decomposition to examine the relative effects of various environmental factors on SCS. Structural equation models (SEM) were employed to determine how these variables directly or indirectly affect SCS in mixed plantations. Our findings demonstrated that species mixtures notably enhanced SCS in RP-PT by 23.2 % and RP-CK by 27.7 % comparing with RP plantations. Soil properties, particularly soil water content and nitrogen content, emerged as the most influential factors on SCS. Litter characteristics were more impactful on SCS in the upper soil layers (0–30 cm), while vegetation diversity had a greater effect on deeper soils (30–60 cm). SEM analysis showed that the predictor variables collectively explained 67 % to 87 % of the variation in SCS, with soil properties directly influence SCS, while litter biomass, litter carbon, litter nitrogen, and the Shannon-Wiener diversity index (H) primarily indirectly affect SCS by influencing soil factors. H can also have a direct positive impact on deeper SCS. These results suggest that, given the region’s water and nutrient limitations, the optimal afforestation strategy should focus on improving water-use efficiency and nutrient availability. Incorporating a mix of coniferous and broadleaved species, as well as nitrogen-fixing species, could be an effective approach to enhancing ecological health and carbon sequestration on the Loess Plateau.

单一物种种植园通常以物种多样性低和结构简单为特点，是造成碳储量有限、生态系统被迫退化和长期恢复能力下降的重要因素。为了解决这些问题，混合物种种植园作为一种有前途的战略受到欢迎。然而，目前有关增加种植多样性对土壤碳储存（SCS）的影响和机制的知识仍然有限。此外，在选择最合适的混合造林策略方面也缺乏科学指导。本研究选择了中国黄土高原的纯刺槐（RP）人工林和刺槐与乔木树种赤松（RP-PT）、灌木树种连翘（RP-FS）和卡拉干达（RP-CK）混交的人工林，以评估整个土壤剖面（0-60 厘米）上植被多样性、枯落物特征、土壤特性和 SCS 的差异。我们采用随机森林分析和方差分解来研究各种环境因子对 SCS 的相对影响。我们采用结构方程模型（SEM）来确定这些变量如何直接或间接地影响混交种植园中的SCS。研究结果表明，与 RP 种植园相比，物种混交显著提高了 SCS，RP-PT 提高了 23.2%，RP-CK 提高了 27.7%。土壤特性，尤其是土壤含水量和含氮量，是对 SCS 影响最大的因素。垃圾特性对上层土壤（0-30 厘米）的 SCS 影响更大，而植被多样性对深层土壤（30-60 厘米）的影响更大。SEM 分析表明，预测变量共同解释了 SCS 变异的 67% 至 87%，其中土壤特性直接影响 SCS，而枯落物生物量、枯落物碳、枯落物氮和香农-维纳多样性指数（H）主要通过影响土壤因子间接影响 SCS。H 也会对深层 SCS 产生直接的积极影响。这些结果表明，鉴于该地区的水和养分限制，最佳造林策略应侧重于提高水利用效率和养分供应。将针叶树和阔叶树以及固氮树种混合种植，可能是提高黄土高原生态健康和固碳能力的有效方法。

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引用次数: 0

Residual benefits of alum, gypsum, and magnesium sulfate amendments in reducing phosphorus losses to snowmelt runoff 明矾、石膏和硫酸镁添加剂在减少融雪径流磷损失方面的剩余效益

IF 5.4 1区农林科学 Q1 GEOSCIENCES, MULTIDISCIPLINARY

Catena

Pub Date : 2024-10-10 DOI: 10.1016/j.catena.2024.108450

Phosphorus (P) in snowmelt runoff from agricultural fields across the Canadian prairies is a major source of pollution to freshwater bodies. Soil amendments have previously been shown to reduce P loss from soils in laboratory-simulated and field snowmelt studies; however, their residual benefits beyond one snowmelt event are unknown. This study examined the effectiveness of alum (Al₂(SO₄)₃·18H₂O), gypsum (CaSO₄·2H₂O), and magnesium sulfate (MgSO₄·7H₂O) in reducing P losses to snowmelt 18 months after amendment application. The study was conducted on a silty clay loam soil in Manitoba. Amendments were applied in the fall of 2020 at a rate of 2.5 Mg/ha. The amended treatments, including an unamended control with four replicates, were arranged in a randomized complete block design. Daily snowmelt was collected from each field plot in the spring of 2022, volume recorded, and analyzed for dissolved reactive P (DRP), pH, and cation concentrations. Snowmelt DRP concentrations increased over the sampling period regardless of treatment, with higher concentrations after the soils had thawed. In the latter days of sampling, the field plots that received amendments had snowmelt DRP concentrations 9 – 31 % lower than the control treatment, but the differences were not statistically significant. Snowmelt DRP loads showed a significant positive relationship with snowmelt volume but not with DRP concentration, suggesting that DRP load is largely controlled by the snowmelt volume rather than the snowmelt DRP concentration. Our results suggest that the amendments applied at this rate were ineffective in reducing DRP loads 18 months after application.

加拿大大草原农田融雪径流中的磷（P）是淡水水体的主要污染源。在实验室模拟和实地融雪研究中，土壤改良剂曾被证明可以减少土壤中磷的流失；但是，它们在一次融雪事件之后的剩余效益尚不清楚。本研究考察了明矾（Al2(SO4)3-18H2O）、石膏（CaSO4-2H2O）和硫酸镁（MgSO4-7H2O）在施用土壤改良剂 18 个月后减少融雪中 P 损失的效果。这项研究是在马尼托巴省的淤泥质粘壤土上进行的。添加剂于 2020 年秋季施用，添加量为 2.5 兆克/公顷。施用过改良剂的处理（包括未施用改良剂的对照组，共四个重复）采用随机完全区组设计。2022 年春季，从每个田块收集每日融雪，记录融雪量，并分析溶解性活性磷（DRP）、pH 值和阳离子浓度。在采样期间，无论采用哪种处理方法，融雪水中的 DRP 浓度都在增加，土壤解冻后浓度更高。在取样的后几天，接受了改良剂的田块的融雪 DRP 浓度比对照处理低 9 - 31%，但差异在统计学上并不显著。融雪 DRP 负荷与融雪量呈显著正相关，但与 DRP 浓度无关，这表明 DRP 负荷主要受融雪量而非融雪 DRP 浓度控制。我们的研究结果表明，在施用添加剂 18 个月后，以这种比例施用的添加剂无法有效降低 DRP 负荷。

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引用次数: 0

Rock fragment content mediates the plant effect on soil water content in the arid valley of southwest China 岩石碎屑含量对中国西南干旱河谷土壤含水量的植物效应具有中介作用

IF 5.4 1区农林科学 Q1 GEOSCIENCES, MULTIDISCIPLINARY

Catena

Pub Date : 2024-10-10 DOI: 10.1016/j.catena.2024.108414

As a crucial aspect of terrestrial ecosystems, water plays a key role in soil hydrological cycling and ecological management. However, limited knowledge exists on how soil water varies along rock fragment content (RFC) beneath plants. In this study, we investigated soil water content (SWC) and relative soil water deficit (DSWC) with four RFC levels ranging from 0 to 75 % (V/V) under four native species, including A. vestita, B. brachycarpa, C. szechuanensis, and S. davidii, and their relationships with soil physical properties and plant functional traits. Results showed that an increase in RFC significantly decreased SWC (except A. vestita) at soil depth of 10–50 cm and altered its vertical trend from unimodal to increasing under each plant. Notable differences in SWC between the wet and dry seasons in 75 % RFC disappeared under A. vestita and B. brachycarpa, suggesting that the RFC changed the spatiotemporal patterns of the SWC. DSWC generally decreased as soil depths deepened under A. vestita with shallow roots, in contrast to increasing under other deep-rooted species (B. brachycarpa, C. szechuanensis, and S. davidii). The seasonal variance of DSWC basically decreased with soil depth. This indicated that the plants generally deceased SWC, particularly in the wet season, and the effect depended on interspecific traits. SWC and DSWC had closely relationships with soil physical properties and plant performing. We suggest that varying RFC indirectly impacted soil water not only via altering soil structure and temperature, but also by shaping plant characteristics (especially root distribution and architecture), mediating plant effect on the spatiotemporal dynamics of SWC.

作为陆地生态系统的一个重要方面，水在土壤水文循环和生态管理中发挥着关键作用。然而，人们对植物下的土壤水分如何随岩石碎屑含量（RFC）变化的了解十分有限。在本研究中，我们研究了四种本地物种（包括 A. vestita、B. brachycarpa、C. szechuanensis 和 S. davidii）在四种 RFC 水平（从 0% 到 75% (V/V)）下的土壤含水量（SWC）和相对土壤缺水量（DSWC），以及它们与土壤物理特性和植物功能性状的关系。结果表明，在土壤深度为 10-50 厘米的土壤中，RFC 的增加会显著降低 SWC（马缨丹除外），并改变其垂直趋势，使其在每种植物下从单模式变为递增模式。在 A. vestita 和 B. brachycarpa 下，雨季和旱季中 75% RFC 的 SWC 显著差异消失，这表明 RFC 改变了 SWC 的时空模式。在浅根系的 A. vestita 下，随着土壤深度的加深，DSWC 通常会减少，而在其他深根物种（B. brachycarpa、C. szechuanensis 和 S. davidii）下，DSWC 则会增加。DSWC 的季节差异基本上随土壤深度的增加而减小。这表明，植物一般都会减弱 SWC，尤其是在雨季，而这种影响取决于种间性状。SWC和DSWC与土壤物理性状和植物表现密切相关。我们认为，RFC的变化不仅通过改变土壤结构和温度间接影响土壤水分，还通过塑造植物特征（尤其是根系分布和结构）间接影响土壤水分，从而介导植物对SWC时空动态的影响。

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引用次数: 0

Soil organic carbon and total nitrogen stocks related to land use and basic environmental properties − assessment of soil carbon sequestration potential in different ecosystems 与土地利用和基本环境属性相关的土壤有机碳和全氮储量 - 不同生态系统的土壤固碳潜力评估

IF 5.4 1区农林科学 Q1 GEOSCIENCES, MULTIDISCIPLINARY

Catena

Pub Date : 2024-10-10 DOI: 10.1016/j.catena.2024.108435

Soil organic carbon (SOC) and total nitrogen (TN) stocks are crucial for the development of wild plants and crops. This paper examines the current SOC and TN stocks and their variability within land uses under different environments, assessing the relationships between SOC and TN stocks with basic environmental properties and quantifying the magnitude of SOC sequestration potential for a better land use management. We studied 991 soil profiles, from steppe to wet mountain-soils. The land use was essential in influencing soil organic C and total N stocking, with the forestland showing the significantly highest SOC stocks specifically in mountain soils, followed by grassland and cropland. Altitude, clay content, pH and plant available phosphorous and potassium were other influencers of SOC and TN stocks. The best predictive multiple linear regression model explained 68 % of the 0.5 m depth SOC stock variability for forest, 61 % for grassland and 37 % for cropland, while Random Forest model explained 70 %, 65 %, and 28 % for the same land uses. The obtained models rank factors contribution and may be useful in management. Lands having the highest C sequestration potential occurred within fine-textured soils, mainly in croplands. The most favorable soil depth for further C sequestration is below C-saturated topsoil and this could be achieved by deep-rooting crops and conservative technologies. Additionally, changing some low-fertile soils of cropland into forestland or grassland would improve SOC sequestration. These measures might contribute to sequester additional C amounts in soils, in order to bolster initiatives for climate-change mitigation and adaptation.

土壤有机碳（SOC）和总氮（TN）储量对野生植物和农作物的生长至关重要。本文研究了当前土壤有机碳（SOC）和全氮（TN）的储量及其在不同环境下土地利用中的变化，评估了土壤有机碳（SOC）和全氮（TN）储量与基本环境属性之间的关系，并量化了土壤有机碳（SOC）固存潜力的大小，以便更好地进行土地利用管理。我们研究了从草原到潮湿山地土壤的 991 个土壤剖面。土地利用对土壤有机碳和全氮储量的影响至关重要，特别是在山区土壤中，林地的有机碳储量明显最高，其次是草地和耕地。海拔、粘土含量、pH 值以及植物可利用的磷和钾是影响 SOC 和 TN 储量的其他因素。最佳预测多元线性回归模型对森林、草地和耕地 0.5 米深度 SOC 储量变化的解释率分别为 68%、61% 和 37%，而随机森林模型对相同土地用途的解释率分别为 70%、65% 和 28%。所获得的模型对各因素的贡献进行了排序，可能有助于管理。固碳潜力最大的土地是细粒土壤，主要是耕地。最有利于进一步固碳的土壤深度低于碳饱和表土，这可以通过深根作物和保守技术来实现。此外，将一些耕地中的低肥力土壤改为林地或草地也会提高 SOC 固存。这些措施可能有助于在土壤中螯合更多的碳，以支持减缓和适应气候变化的举措。

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引用次数: 0

Early-mid Holocene vegetation and diversity evolution on the Ningshao Plain, eastern China 中国东部宁绍平原全新世早中期植被与多样性演变

IF 5.4 1区农林科学 Q1 GEOSCIENCES, MULTIDISCIPLINARY

Catena

Pub Date : 2024-10-09 DOI: 10.1016/j.catena.2024.108446

The study of Holocene vegetation diversity changes and mechanisms in the Ningshao Plain is of great significance for understanding their responses to the coupled relationship between climate, sea level, and human activities. In this study, we analyzed pollen and charcoal from the Tianluoshan and Jingtoushan sites (TLS1402 and JTS1501) to represent the regional vegetation history, particularly changes in vegetation diversity during the early to mid-Holocene. The findings show that after 7.5 cal kyr BP, arboreal pollen (AP) declined significantly and that subtropical evergreen deciduous broad-leaved mixed forest replaced deciduous broad-leaved forest as the predominant vegetation type. The increase in Poaceae (>38 μm) and charcoal corresponds well with the decrease of AP (mainly manifested as deciduous species), suggesting that vegetation change may be related to human activities and that coniferous taxa (mainly Pinus) are more sensitive to fire response. Vegetation diversity based on the Hill numbers (N0, N1, N2 and Evenness) is shown to decline three times, viz. at 8.5, 8.2, and 7.5 cal kyr BP, among which the decrease around 8.5 and 7.5 cal kyr BP corresponds to two regional sea level rise events. The decrease in Jingtoushan diversity at 8.2 cal kyr BP may have superimposed signals of human interference beyond the influence of climate. The development of the Jingtoushan Culture commenced after the first sea level rise events (around 8.3–7.8 cal kyr BP), but was then interrupted by the second sea level transgression. Thereafter, the sea level became relatively stable, and the emergence of fire-assisted agriculture marked a new stage in the relationship between humans and the environment. Changes in vegetation diversity are closely related to regional fires and human activities. In addition, during the Jingtoushan and Hemudu cultures, the impact of human activities on AP diversity was significantly greater than that on non-arboreal pollen (NAP) taxa.

研究宁绍平原全新世植被多样性变化及其机制，对于理解其对气候、海平面和人类活动耦合关系的响应具有重要意义。本研究分析了天露山和井头山遗址（TLS1402和JTS1501）的花粉和木炭，以反映区域植被历史，尤其是全新世早中期植被多样性的变化。研究结果表明，7.5 cal kyr BP之后，乔木花粉（AP）明显减少，亚热带常绿落叶阔叶混交林取代落叶阔叶林成为主要植被类型。草本植物（38 μm）和木炭的增加与树木花粉（主要表现为落叶物种）的减少非常吻合，这表明植被变化可能与人类活动有关，针叶类群（主要是松树）对火灾反应更为敏感。基于希尔数（N0、N1、N2 和均匀度）的植被多样性显示出三次下降，即 8.5、8.2 和 7.5 千年前，其中 8.5 和 7.5 千年前的下降与两次区域海平面上升事件相对应。8.2 cal kyr BP 时井头山多样性的减少可能叠加了气候影响之外的人为干扰信号。井头山文化的发展始于第一次海平面上升事件之后（约 8.3-7.8 cal kyr BP），但随后被第二次海平面跃变所打断。此后，海平面变得相对稳定，火耕农业的出现标志着人类与环境的关系进入了一个新阶段。植被多样性的变化与区域火灾和人类活动密切相关。此外，在井头山文化和河姆渡文化时期，人类活动对旱生花粉多样性的影响明显大于对非旱生花粉类群的影响。

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引用次数: 0

Exploring the RUSLE-based structural sediment connectivity approach for agricultural erosion management 探索基于 RUSLE 的结构沉积物连通性方法来治理农业侵蚀

IF 5.4 1区农林科学 Q1 GEOSCIENCES, MULTIDISCIPLINARY

Catena

Pub Date : 2024-10-09 DOI: 10.1016/j.catena.2024.108420

Models play a crucial role in guiding agricultural erosion management, though their incorporation of sediment connectivity and management strategies varies. This study evaluated the RUSLE/IC/SDR model’s potential for simulating agricultural erosion management at both the field scale and across two catchments. We tested the model’s ability to simulate erosion management measures at a high spatial resolution (2 m × 2 m) across diverse topographies, assessed whether incorporating sediment connectivity improves RUSLE-based erosion management planning within catchments, and explored its capacity to tailor measures based on local connectivity characteristics. Our findings showed significant variability in sediment sources and connectivity. The simulation of no-till and buffer strip measures effectively demonstrated their varying effectiveness across fields and catchments. At the catchment scale, erosion management planning that incorporates sediment connectivity through the RUSLE/IC/SDR approach did not contribute to significant additional sediment delivery reduction compared to using RUSLE alone. However, at the field scale, RUSLE/IC/SDR offered improved opportunities for tailoring erosion management measures to local sediment connectivity characteristics. These simulations highlight both the potential and limitations of RUSLE/IC/SDR, advancing our understanding of its application for erosion management. In conclusion, while RUSLE/IC/SDR represents a valuable extension of RUSLE, further research is needed to fully realize its practical applications. Nonetheless, it shows promise for high-resolution simulation of sediment connectivity and erosion management at the field scale, across large catchments and regions.

模型在指导农业侵蚀管理方面发挥着至关重要的作用，但模型对沉积物连通性和管理策略的考虑各不相同。本研究评估了 RUSLE/IC/SDR 模型在田间尺度和两个集水区模拟农业侵蚀管理的潜力。我们测试了该模型在不同地形的高空间分辨率（2 m × 2 m）下模拟侵蚀管理措施的能力，评估了沉积物连通性是否改善了集水区内基于 RUSLE 的侵蚀管理规划，并探索了该模型根据当地连通性特征定制措施的能力。我们的研究结果表明，沉积物来源和连通性存在很大差异。对免耕和缓冲带措施的模拟有效证明了它们在不同田块和集水区的不同效果。在集水区范围内，与单独使用 RUSLE 相比，通过 RUSLE/IC/SDR 方法将沉积物连通性纳入侵蚀管理规划无助于显著减少额外的沉积物输送量。但是，在实地尺度上，RUSLE/IC/SDR 为根据当地沉积物连通性特征定制侵蚀管理措施提供了更好的机会。这些模拟强调了 RUSLE/IC/SDR 的潜力和局限性，加深了我们对其在侵蚀管理中应用的理解。总之，尽管 RUSLE/IC/SDR 是 RUSLE 的重要扩展，但要充分实现其实际应用还需要进一步的研究。尽管如此，RUSLE/IC/SDR 仍显示了在大流域和大区域实地尺度上高分辨率模拟沉积物连通性和侵蚀管理的前景。

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引用次数: 0

Effect of calculation unit division in distributed hydrological models on the analysis of hydrological effects of land use change 分布式水文模型中计算单元划分对土地利用变化水文效应分析的影响

IF 5.4 1区农林科学 Q1 GEOSCIENCES, MULTIDISCIPLINARY

Catena

Pub Date : 2024-10-09 DOI: 10.1016/j.catena.2024.108445

Numerous papers have utilized distributed hydrological models to assess the hydrological effects of land use changes. However, can these models reflect actual land use changes? This study focuses on the effect of calculation unit division in distributed hydrological models on the analysis of hydrological effects of land use change. The Soil and Water Assessment Tool (SWAT) model is tested here, using the Dongjiang headwater region in southern China as the study area. Thirteen calculation unit division schemes are developed to analyze the effects of land use generalization caused by calculation unit division on runoff and sediment load simulations by SWAT. Two indices, including Land Use Identification Accuracy (LUIA) and Land Use Change Identification Accuracy (LUCIA) are employed to quantify the model’s precision in describing land use and changes under various scenarios. In addition, this study examines how differences in land use descriptions, resulting from calculation unit division, influence the hydrological effect of land use changes in the SWAT model. The findings indicate that: (1) Calculation unit division leads to the generalization of land uses identified by the SWAT model. As the sub-watershed Drainage Area Threshold (DAT) increases, the small land use types tend to aggregate into the larger land use types. (2) Land use generalization, resulting from calculation unit division, significantly affects runoff and sediment load simulations. An increase in DAT induces a significant rise in simulated runoff and sediment load (P<0.001). (3) Calculation unit division substantially impacts the model’s description of land use. LUIA and LUCIA show a significant downward trend as DAT increases. (4) Calculation unit division significantly alters the analysis results of hydrological effects of land use changes. Different calculation unit division schemes yield different analysis results of hydrological effects of land use changes. These results demonstrate that the division of calculation units in the SWAT model leads to land use generalization, which impacts the model’s description of land use changes and subsequently affects the assessment of the hydrological effects of land use changes. The research results imply that when analyzing the hydrological effects of land use change, a more refined calculation unit division scheme should be adopted as far as possible to improve the accuracy of model’s description of land use change and reduce the uncertainty of model simulation results.

许多论文利用分布式水文模型来评估土地利用变化的水文影响。然而，这些模型能否反映实际的土地利用变化？本研究的重点是分布式水文模型中计算单元划分对土地利用变化水文效应分析的影响。本研究以中国南方东江源头地区为研究区域，对水土评估工具（SWAT）模型进行了测试。开发了 13 种计算单元划分方案，以分析计算单元划分引起的土地利用泛化对 SWAT 模拟径流和泥沙负荷的影响。采用土地利用识别精度（LUIA）和土地利用变化识别精度（LUCIA）两个指标来量化模型在不同情景下描述土地利用和变化的精度。此外，本研究还探讨了计算单位划分导致的土地利用描述差异如何影响 SWAT 模型中土地利用变化的水文效应。研究结果表明(1) 计算单元划分导致 SWAT 模型识别的土地利用的泛化。随着子流域排水面积阈值（DAT）的增加，小土地利用类型趋向于聚合为大土地利用类型。(2) 计算单元划分导致的土地利用泛化会对径流和泥沙负荷模拟产生重大影响。DAT 的增加会导致模拟径流和泥沙负荷的显著增加（P<0.001）。(3) 计算单元划分对模型的土地利用描述有很大影响。随着 DAT 的增加，LUIA 和 LUCIA 呈显著下降趋势。(4) 计算单元划分极大地改变了土地利用变化的水文效应分析结果。不同的计算单元划分方案会产生不同的土地利用变化水文效应分析结果。这些结果表明，SWAT 模型中计算单元的划分会导致土地利用的泛化，从而影响模型对土地利用变化的描述，进而影响土地利用变化的水文效应评估。研究结果表明，在分析土地利用变化的水文效应时，应尽量采用更精细的计算单元划分方案，以提高模型对土地利用变化描述的准确性，降低模型模拟结果的不确定性。

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引用次数: 0

The effects of roots and earthworms on aggregate size distribution and their associated carbon under contrasting soil types and soil moisture conditions 在不同土壤类型和土壤湿度条件下，根系和蚯蚓对骨料大小分布及其相关碳的影响

IF 5.4 1区农林科学 Q1 GEOSCIENCES, MULTIDISCIPLINARY

Catena

Pub Date : 2024-10-08 DOI: 10.1016/j.catena.2024.108434

Soil’s potential as a carbon sink is uncertain due to biotic and abiotic interactions. Soil aggregates are important carriers of organic carbon (OC), and clarifying the response of aggregates and their associated OC to plant roots and earthworms can better understand the carbon cycle in terrestrial ecosystems. Herein, we determined the regulatory role of plant roots (Lolium perenne) and earthworms (Metaphire tschiliensis) in isolation and in combination on aggregate size distribution and their associated OC and readily oxidizable OC (ROOC) under contrasting soil types (Phaeozems and Anthrosols) and soil moisture conditions (constant wetting, CW; wetting–drying cycle repeated four times, 4WD) by a laboratory microcosm experiment. Results showed that earthworm presence significantly increased plant biomass by 30 % and 221 % in Phaeozems and Anthrosols, respectively (p < 0.05). For Phaeozems, plant alone (P) and plant and earthworm in combination (PE) had lower proportion of large aggregate (5–8 and 2–5 mm) than bare soil (CK) under 4WD condition (p < 0.05). For Anthrosols, the PE treatment decreased the proportion of 5–8 and 2–5 mm aggregate by 45 % and 25 %, respectively, under CW condition, and decreased the proportion of 5–8 mm aggregate by 37 % under 4WD condition (p < 0.05). Moreover, the proportion of 5–8 and 2–5 mm aggregate in P treatment was lower under CW condition (6.92 % and 22.13 %) but was higher under 4WD condition (11.49 % and 32.55 %) than those in CK (14.69 % and 29.91 %; 8.85 % and 20.56 %) (p < 0.05). Our results further indicated that the PE treatment had relatively higher OC and ROOC contents, especially for small aggregates in Anthrosols. The study indicates that plant roots and earthworms significantly influence aggregate turnover and the carbon cycle, with soil type and moisture playing a crucial role.

由于生物和非生物的相互作用，土壤作为碳汇的潜力尚不确定。土壤团聚体是有机碳（OC）的重要载体，弄清团聚体及其相关的有机碳对植物根系和蚯蚓的反应可以更好地了解陆地生态系统的碳循环。在此，我们通过实验室微观世界实验，确定了在不同土壤类型（辉绿岩和炭质岩）和土壤湿度条件（恒定湿润，CW；湿润-干燥循环重复四次，4WD）下，植物根系（Lolium perenne）和蚯蚓（Metaphire tschiliensis）单独或联合对团聚体大小分布及其相关有机碳和易氧化有机碳（ROOC）的调控作用。结果表明，在 Phaeozems 和 Anthrosols 中，蚯蚓的存在分别使植物生物量增加了 30% 和 221%（p <0.05）。对于辉绿岩，在四轮驱动条件下，单独植物（P）和植物与蚯蚓结合（PE）的大骨料（5-8 毫米和 2-5 毫米）比例低于裸土（CK）（p <0.05）。就炭质土而言，在 CW 条件下，PE 处理使 5-8 毫米和 2-5 毫米骨料的比例分别降低了 45% 和 25%，而在 4WD 条件下，5-8 毫米骨料的比例降低了 37% (p<0.05)。此外，与 CK（14.69 % 和 29.91 %；8.85 % 和 20.56 %）相比，P 处理的 5-8 和 2-5 mm 骨料比例在 CW 条件下较低（6.92 % 和 22.13 %），但在 4WD 条件下较高（11.49 % 和 32.55 %）（p < 0.05）。我们的研究结果进一步表明，PE 处理中的 OC 和 ROOC 含量相对较高，尤其是在炭溶胶中的小集料中。该研究表明，植物根系和蚯蚓对骨料周转和碳循环有重大影响，而土壤类型和水分则起着关键作用。

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