首页期刊导航|Geoderma: An International Journal of Soil Science
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Geoderma: An International Journal of Soil Science
Elsevier Science Publishers
Geoderma: An International Journal of Soil Science

Elsevier Science Publishers

0016-7061

Geoderma: An International Journal of Soil Science/Journal Geoderma: An International Journal of Soil Science
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    Efficiency of additional organic inputs for carbon sequestration in agricultural soils modulated by the priming effect and physical accessibility

    Wang, GuochengWang, MingmingGuo, XiaoweiYu, Yongqiang...
    12页
    查看更多>>摘要：Increasing carbon input (CI) to soil has been widely recommended (e.g., residue retention and manure application) to sequester more carbon in agricultural soils thereby mitigating climate change and improving soil quality. However, carbon sequestration may not respond linearly to additional CI due to their active interactions with the turnover of native soil organic carbon (SOC) via such as the priming effect and mediating SOC accessibility to decomposition. In this study, we collected SOC measurements from 22 long-term paired trials (12-142 years) with two levels of CI [i.e., a treatment with carbon input (+CI) and another treatment with less carbon input (-CI) compared with + CI] across the globe. We used these observed SOC to constrain a carbon model and analyse SOC turnover processes as impacted by CI to the soil. The results show that there are divergent responses of SOC turnover processes to CI, indicated by large variability of changes in decay rates of carbon pools, transfer coefficient of carbon flow from fast to slow pools, and physical accessibility to decomposition. Initial SOC at the start of the trial, the average amount of CI during the experiment, and soil bulk density are the three most important variables underlying such divergent responses. Simulation experiments suggest that these discrepancies in SOC turnover processes induced by CI have significant consequences on the efficiency of increasing carbon inputs for SOC sequestration. Ignoring the effect of additional CI leads to overestimation or underestimation of CI required to achieve typical SOC sequestration targets depending on baseline SOC content and temperature. Our results demonstrate the vital role of CI in regulating SOC turnover processes, which have site-specific consequences on the management of carbon inputs to sequester SOC.
      原文链接:
    • NSTL
    • Elsevier

    National-scale 3D mapping of soil organic carbon in a Japanese forest considering microtopography and tephra deposition

    Yamashita, NaoyukiIshizuka, ShigehiroHashimoto, ShojiUgawa, Shin...
    18页
    查看更多>>摘要：Geographic information on soil organic carbon (SOC) is important for climate change research and understanding the global carbon cycle. At present, this information is limited for forest soils in mountainous regions that have complex topographies and are affected by tephra deposition. This study predicted the SOC concentration (OC), bulk density (BD), apparent rock coarse fraction (CF), and SOC stock (OCS) at 0-5, 5-15, and 15-30 cm in the soil horizon for the forested areas (ca. 230 000 km(2)) of Japan. This was carried out with a 10 m grid resolution using a digital soil mapping (DSM) approach. To determine the appropriate spatial prediction model, we evaluated the accuracy of a two dimensional approach for ordinary kriging (OK) and regression kriging (RK), and a three dimensional approach for random forest model (RF). The RF was based on topography, climate and vegetation factors (RFenv), distance and direction from 152 volcanos (RFenv+vol), distance from survey points (RFenv+sp); these factors were also combined (RFall) as explanatory attributes. The results demonstrated an improvement in the average root mean square errors (RMSEs) of RFenv+vol, RFenv+sp, and RFall by approximately 12%, 14%, 5%, and 21% for OC, BD, CF, and OCS using 10-fold cross-validation on a site-bysite basis, respectively, compared with OK. Based on the relatively small difference in improvement among RFenv+vol, RFenv+sp, and RFall (<0.5%), and the considerably high computational cost of RFenv+sp and RFall, RFenv+vol was considered as the appropriate model for the area. The R-2 of RFenv+vol was calculated at 0.59, 0.44, 0.30, and 0.38 in OC, BD, CF, and OCS, respectively, using 10-fold cross validation on a site-by-site basis. The predicted map by RFenv+vol accurately reproduced the large spatial variation in OCS at small watershed, regional, and national scales; this have been derived from the effect of microtopography, tephra deposition, and the gradient of temperature with latitude, respectively. A larger OCS was predicted to accumulate on the ridges, highland slopes, near volcanos, and higher latitudes than at other areas. The mean OCS was estimated to be 7.6 kg.m(-2) for a soil depth of 0-30 cm in Japanese forests. The results also suggest that the fine-scale three dimensional random forest approach using the distances from volcanoes showed promise for regional-scale OCS prediction. This approach was considered particularly effective in hills and mountainous areas that are strongly exposed to tephra deposition, this includes the Pacific Rim regions and other volcanic countries.
      原文链接:
    • NSTL
    • Elsevier

    High N relative to C mineralization of clover leaves at low temperatures in two contrasting soils

    Froseth, Randi BerlandThorup-Kristensen, KristianHansen, SisselBleken, Marina Azzaroli...
    9页
    查看更多>>摘要：Predicting N mineralization from green manure in different soil types during the cold season is instrumental for improving crop management with higher N use efficiency and reduced risks of N losses in a cool and humid climate. The objective of our work was to study the effects of low temperatures and soil type on the net nitrogen (N) mineralization and the relationship between N and carbon (C) mineralization from N-rich plant material. A silty clay loam and a sandy loam were incubated with or without clover leaves for 80 days at 0, 4, 8.5 or 15 degrees C. The results showed a substantial mineralization of N in clover leaves (7% of N added), unaffected by temperature, already on 3rd day. This was followed by net N immobilization for about 4 weeks in the clay soil, with similar tendencies in the sandy soil, and more severely at the higher than the lower temperatures. After 80 days of incubation, net N mineralization was only 13-22% of total N in clover leaves. The ratio of net mineralized N to C was higher at lower temperatures, and higher in the sandy than in the clay soil. After the immobilization period, the N mineralization increased, positively related to temperature, and the ratio of net mineralized N to C became constant. In conclusion, low temperature during the initial phase of mineralization altered the ratio between net N and C mineralization from easily decomposable plant material, and the net N mineralization occurred more rapidly in the sandy soil. The change in stoichiometry at low temperatures, as well as the modifying effect of soil type, should be considered when predicting N mineralization of N-rich plant material.
      原文链接:
    • NSTL
    • Elsevier

    Characterizing plant root parameters with deep learning-based heat pulse method

    Xie, XiaotingYan, HengnianZeng, Lingzao
    8页
    查看更多>>摘要：Accurate quantification of root structure is essential for understanding plant ecological system. Nevertheless, the lack of in-situ root characterization methods has limited further research of the relevant field. Heat pulse (HP) technique has emerged as a promising, cost-effective in situ monitoring approach. The existing HP technique relies on the analytical solution of heat transfer model with the assumption that the medium under test is homogeneous. Thus, its performance is compromised in dealing with heterogeneous formations. The objective of this study is to establish a novel in-situ HP method to characterize root parameters based on a deep learning technique. With the fully connected neural networks (FCNN), the number of root fragments was firstly estimated by solving a classification problem, and then the size and location of each fragment were estimated by solving regression problems. All FCNNs were firstly pre-trained using synthetic dataset generated by the numerical heat transfer model. Although FCNNs showed promising accuracy on the synthetic testing dataset, they failed to provide satisfactory results on real-world experimental data due to the model error and observation noise, i.e., the deviations between the numerical model and actual situation. To this end, FCNNs were fine-tuned with some experimental data through transfer learning for performance improvement. Under controlled indoor experiment in a sandy soil, the proposed method provided satisfactory results for the estimation of mot fragment number and diameters with 83.3% accuracy and RMSE of 1.87 x 10(-4) m, respectively. The position estimation had relatively larger error, i.e., RMSE 2.41 x 10(-3) m. This study is the first step in translating heat pulse signals to root parameters, which indicates the potential of combining HP technique and deep learning in studying root system.
      原文链接:
    • NSTL
    • Elsevier

    Spatial and temporal dynamics of soil organic carbon stock and carbon sequestration affected by major land-use conversions in Northwestern highlands of Ethiopia

    Tilahun, EyobHaile, MitikuGebresamuel, GirmayZeleke, Gete...
    10页
    查看更多>>摘要：Soil organic carbon (SOC) is the major component of the terrestrial carbon (C) budget, a key indicator of environmental sustainability. So, estimating SOC stock and soil carbon (C) sequestration dynamics is important for evidence-based and carbon-conscious decisions. Quantification of SOC stock and soil C sequestration affected by land-use changes (LUCs) have received much attention in addressing food and climate security. This study aims to estimate the dynamics of SOC stock, soil C sequestration and associated soil parameters affected by major LUCs from 2012 to 2021 in Awi highlands of Amhara Regional State of Ethiopia. The study area has experienced dramatic LUC, particularly plantation and growing of Acacia decurrens (J.C. Wendl.) tree followed by recurrent deforestation and then cropping and back to the plantation. The study quantified spatial and temporal dynamics of SOC stock, soil C sequestration and associated changes affected by the LUCs. A total of 22 topsoil (0-20 cm) legacy data was obtained from the Ethiopian Soil Information System (EthiSIS) database of 2012. The same number of samples were collected at the same locations in 2021 by using the same sampling procedure as that of 2012. In addition, the same number of core samples were collected in 2021 for bulk density analysis. To estimate the unmeasured bulk density of legacy data, we applied a pedotransfer function. We used empirical equations and basic statistics to assess changes in SOC stock and C sequestration rate between the two periods. Statistically significant variation (P < 0.01) in SOC stock and C sequestration was observed between the two periods. LUC from acacia plantation to croplands caused a decline of SOC stock by -30.16%, and it also caused the decline of total nitrogen stock, available phosphorus, cation exchange capacity (CEC). However, the reverse LUC caused an increase in SOC by 27.74% and the abovementioned soil parameters. LUC from plantation forest to cropland caused emission of 8.3 tons of CO2 year(-1). Generally, overall LUCs caused the net negative change in SOC stock by (-2.42 %) and associated soil parameters in the last ten years. Our study provides evidence that overall LUCs in the current study site caused a decline in SOC stock, along with associated soil parameters with carbon emitted to the atmosphere. Hence, sustainable land-use management options which can offset losses in SOC stock should be implemented soon.
      原文链接:
    • NSTL
    • Elsevier

    High nitrogen enrichment increases the allocation of new organic carbon to deep soil layers

    Yu, HanxiaWei, XiaoshuTan, Wenbing
    4页
    查看更多>>摘要：The response of soil organic carbon (SOC) dynamics to nitrogen enrichment in the scale of whole-soil profiles, especially in deeper soil layers containing approximately half of SOC, remains unclear. Here, the incorporation of new vegetation-derived carbon into whole-soil profiles is estimated by combining natural stable isotopes (C-13 and N-15) with radiocarbon analyses under elevated nitrogen inputs with field experiments. The new mechanism responsible for nitrogen-induced carbon sinking in soils is the increased allocation of new carbon to deep soil layers at high nitrogen enrichment resulting from enhanced vertical transport of SOC. Our work provides an unprecedented representation of deep carbon dynamics under elevated nitrogen input and thus supports the development of policies on soil carbon management.
      原文链接:
    • NSTL
    • Elsevier

    Impact of podzolization on lamellae transformation in sandy soils in a temperate climate - A case study from southern Poland

    Gus-Stolarczyk, MagdalenaDrewnik, MarekSzymanski, WojciechStolarczyk, Mateusz...
    17页
    查看更多>>摘要：Lamellae occur in Podzols around the world, mostly in illuvial horizons and parent material, while in eluvial horizons they are often absent or very rare. While many studies have been conducted on lamellae origins, there has been little research focused on their transformation in the soil profile, including the disappearance of lamellae in the course of soil formation. Some studies show that the transformation of lamellae toward physical degradation over time occurs frequently. However, there still exists a lack of studies on lamellae transformation in soils occurring in similar environmental conditions, formed from the same parent material, and varying only in terms of type of dominant soil-forming process. The main aims of this study were: (1) to determine the mechanism of lamellae transformation in sandy soils in a moderately humid climate in southern Poland in relation to progressing podzolization and (2) to compare lamellae transformation mechanisms in well-developed sandy soils affected and not affected by podzolization. The obtained results indicate that soil lamellae commonly occur in the sandy soils of southern Poland - and are characterized by very diverse morphology as well as diverse physical and chemical properties. Soil lamellae exhibit a higher content of fine fractions, iron, aluminum and total organic carbon compared with interlamellae. Soil lamellae are affected by different mechanisms of transformation that depend on their position in the soil profile, predominant soil-forming process, and stage of soil development. Soil lamellae in the upper part of initial sandy soils are mainly transformed by mechanical degradation related to bioturbation. Mechanical degradation of soil lamellae due to clay translocation as well as chemical degradation due to dissolution of iron compounds occur in the upper part of well-developed sandy soils in which podzolization takes place and the eluvial horizon is well-developed. Mechanical degradation of soil lamellae due to bioturbation and clay translocation occurs in the upper part of well-developed sandy soils, which do not exhibit podzolization. Soil lamellae occurring in the lower part of initial and well-developed sandy soils develop progressively due to the illuviation and accumulation of clay and iron compounds as well as lack of biological activity.
      原文链接:
    • NSTL
    • Elsevier

    Pyrolysis-assisted transesterification for accurate quantification of phospholipid fatty acids: Application to microbial community analysis in 1000-years paddy soil chronosequence

    Cai, KaiZhao, YongpengKang, ZongjingMa, Rui...
    10页
    查看更多>>摘要：Phospholipid fatty acids (PLFAs) are widely used to assess soil microbial community and metabolic activity in various environmental samples. However, the transesterification of phospholipids into PLFAs still utilize homogeneous acid/alkaline catalyst, which may increase environment risk. This study developed and validated an accurate method for the determination of PLFAs in soil utilizing pyrolysis-assisted transesterification with diatomaceous earth. The thermolysis behavior of phospholipids, optimal pyrolysis conditions, tolerance against impurities, and recyclability of porous material were evaluated. Under optimal conditions, the transesterification can complete in only 8 min, with high impurity tolerance. The repeatability (relative standard deviation (RSD) between 2.59% and 12.12%), reproducibility (RSD between 5.22% and 16.22%), and linearity (r between 0.9259 and 0.9999) were excellent. This method was applied to analyze the PLFAs to evaluate microbial community of 1000-years paddy soil chronosequences and the relationships among soil chemical properties, enzyme activities and microbial community composition. Soil microbial biomass PLFAs increased significantly over time followed by slight fluctuation at 60-1000 years, but the ratios of soil fungal to bacterial and gram-positive to gram-negative PLFAs remained constant. In addition to soil total N and organic matter, soil enzyme activities related to N cycling metabolism also positively significantly influenced microbial communities. Overall, the developed PLFAs method using pyrolysis-assisted transesterification was environmentally friendly, efficient, accurate, stable, and suitable alternative to acid/alkaline transesterification of phospholipids.
      原文链接:
    • NSTL
    • Elsevier

    Biocrust cyanobacteria inoculants biomineralize gypsum and preserve indigenous bacterial communities in dryland topsoil

    Jimenez-Gonzalez, Marco A.de Lima, Nathali MachadoChilton, Angela M.Almendros, Gonzalo...
    4页
    查看更多>>摘要：Biocrust cyanobacteria are ubiquitous organisms in dryland environments that can enhance soil stability and improve nutrient conditions in reconstructed or disturbed soils. Despite the demonstrated benefits of cyanobacterial inoculation for promoting soil fertility, there is limited knowledge about the impacts of introducing cultured cyanobacteria on the indigenous microbial communities. Here, we conducted a microcosm experiment under controlled conditions using indigenous biocrust cyanobacteria and locally sourced topsoil substrate commonly used in dryland restoration in the Australian arid zone. We inoculated the topsoil with a consortium composed of Leptolyngbya sp. and Scytonema sp. cyanobacteria, to assess the effects of the inoculated cyanobacteria on (i) the soil chemical properties, i.e., pH, electrical conductivity (EC), total organic carbon (TOC), and nitrogen (TN) of the inoculated topsoil, (ii) the early formation of an artificial soil biocrust and iii) the composition and diversity of the resident bacterial community. Our results showed that the inoculated cyanobacterial consortia decreased the EC, but changes in the TOC and TN were not significant after 80 days. A higher content of chlorophyll a in the inoculated samples compared to the control, confirmed the survival of the cyanobacterial inoculants after 80 days. The inoculated cyanobacteria promoted gypsum formation on the soil surface indicating that they are actively modifying the upper layers of the soil profile and improving habitability. Although immediately after inoculation cyanobacteria dominated the abundance of bacterial phylotypes, these were replaced by other phyla such as Actinobacteria, after 80 days. The Shannon diversity and Simpson diversity indexes between control and inoculated soils differed at the time of inoculation but were similar at the end of the experiment. These results suggest that, in the short term, the introduced cyanobacteria do not significantly affect the native resident bacterial communities and are capable of colonizing the topsoil without affecting the natural community.
      原文链接:
    • NSTL
    • Elsevier

    Surface reactivity of the natural metal (hydr)oxides in weathered tropical soils

    Mendez, Juan C.Van Eynde, EliseHiemstra, TjisseComans, Rob N. J....
    12页
    查看更多>>摘要：Assessing the surface reactivity of metal (hydr)oxides in soils is essential for quantifying ion adsorption phenomena that control the availability of nutrients and pollutants. Despite the high natural abundance of Fe and Al (hydr)oxides in intensively weathered environments, the surface reactivity of these pedogenic materials has not been consistently characterized for weathered tropical soils. Here, we used a novel probe-ion methodology combined with state-of-the-art surface complexation modelling (SCM) to derive the reactive surface area (RSA) of the soils, as well as the amount of phosphate (PO4) that can be potentially desorbed (R-PO4) from the natural fraction of metal (hydr)oxides and thereby controlling the solid-solution partitioning of PO4. We applied this methodology to a series of weathered topsoils from the sub-Saharan region. The results showed that nanocrystalline ferrihydrite (Fh) is a better proxy than well-crystallized goethite for describing with SCM the reactivity of the natural metal (hydr)oxides, even though well-crystallized materials dominate the mass fraction of metal (hydr)oxides of these weathered tropical soils. Using Fh as a proxy in the SCM, the RSA ranged from similar to 2 to 40 m(2) g(-1)- soil. Nanoparticles with a mean diameter of similar to 1.5-5.0 nm dominate the reactive fraction of metal (hydr)oxides in these tropical topsoils. Our SCM in conjunction with soil extractions indicates that only a fraction of the total PO4 associated with the metal (hydr)oxides is reversibly adsorbed, whereas the majority of the total PO4 pool, on average similar to 64%, is occluded in the crystalline Fe and Al (hydr)oxide fraction. Only this smaller reversibly adsorbed fraction is thus available for participating in sorption reactions that determine the solid-solution partitioning of PO4. Overall, this research provides new insights into the reactivity of the metal (hydr)oxide fraction in weathered tropical soils and highlights the relevance of these pedogenic materials in determining the speciation and availability of PO4.
      原文链接:
    • NSTL
    • Elsevier