Soil Biology & Biochemistry最新文献

{"title":"Life at the extreme: Plant-driven hotspots of soil nutrient cycling in the hyper-arid core of the Atacama Desert","authors":"Davey L. Jones ,&nbsp;Bárbara Fuentes ,&nbsp;Franko Arenas-Díaz ,&nbsp;Francisco Remonsellez ,&nbsp;Rutger van Hall ,&nbsp;Brian S. Atkinson ,&nbsp;Sacha J. Mooney ,&nbsp;Roland Bol","doi":"10.1016/j.soilbio.2023.109128","DOIUrl":"10.1016/j.soilbio.2023.109128","url":null,"abstract":"<div><p>The hyperarid core of the Atacama Desert represents one of the most intense environments on Earth, often being used as an analog for Mars regolith. The area is characterized by extremes in climate (e.g., temperature, humidity, UV irradiation) and edaphic factors (e.g., hyper-salinity, high pH, compaction, high perchlorates, and low moisture, phosphorus and organic matter). However, the halophytic C₄ plant <em>Distichlis spicata</em> appears to be one of the few species on the planet that can thrive in this environment. Within this habitat it captures windblown sand leading to the formation of unique structures and the generation of above-ground phyllosphere soil. Using a combination of approaches (e.g., X-ray Computed Tomography, TXRF, δ¹³C/δ¹⁵N isotope profiling, microbial PLFAs, ¹⁴C turnover, phosphate sorption isotherms) we examined the factors regulating the biogeochemical cycling of nitrogen (N), phosphorus (P) and carbon (C) in both vegetated and unvegetated areas. Our results showed that <em>D. spicata</em> rhizomes with large aerenchyma were able to break through the highly cemented topsoil layer leading to root proliferation in the underlying soil. The presence of roots increased soil water content, P availability and induced a change in microbial community structure and promoted microbial growth and activity. In contrast, soil in the phyllosphere exhibited almost no biological activity. Organic C stocks and recent C₄ plant derived input increased as follows: phyllosphere (1941 g C m⁻²; 85% recent) &gt; soils under plants (575–748 g C m⁻²; 55–60%) &gt; bare soils (491–642 g C m⁻²; 9–17%). Due to the high levels of nitrate in soil (&gt;2 t ha⁻¹) and high rates of P sorption/precipitation, our data suggest that the microbial activity is both C and P, but not N limited. Root-mediated salt uptake combined with foliar excretion and dispersal of NaCl into the surrounding area indicated that <em>D. spicata</em> was responsible for actively removing ca. 55% of the salt from the rhizosphere. We also demonstrate that NH₃ emissions may represent a major N loss pathway from these soil ecosystems during the processing of organic N. We attribute this to NH₃ volatilization to the high pH of the soil and slow rates of nitrification. In conclusion, we demonstrate that the extremophile <em>D. spicata</em> physically, chemically and biologically reengineers the soil to create a highly bioactive hotspot within the climate-extreme of the Atacama Desert.</p></div>","PeriodicalId":21888,"journal":{"name":"Soil Biology & Biochemistry","volume":"184 ","pages":"Article 109128"},"PeriodicalIF":9.7,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42265033","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Drying intensity and acidity slow down microbial growth recovery after rewetting dry soils","authors":"Xiankun Li ,&nbsp;Ainara Leizeaga ,&nbsp;Johannes Rousk ,&nbsp;Gustaf Hugelius ,&nbsp;Stefano Manzoni","doi":"10.1016/j.soilbio.2023.109115","DOIUrl":"10.1016/j.soilbio.2023.109115","url":null,"abstract":"<div><p>Soil microbes perceive drying and rewetting (DRW) events as more or less harsh depending on the previous soil moisture history. If a DRW event is not perceived as harsh, microbial growth recovers rapidly after rewetting (referred to as ‘type 1’ response), while a harsh DRW will be followed by a delayed growth recovery (‘type 2’ response). Predicting these responses based on pedoclimatic factors is important because they can determine how carbon is partitioned between growth (soil C stabilization) and respiration (C loss to the atmosphere). To characterize the microbially perceived harshness between the two extreme types 1 and 2, and its pedoclimatic drivers, we described microbial growth with a single logistic function and respiration with a rescaled gamma distribution using ∼100 growth and respiration datasets. These functions captured microbial growth and respiration rates well during the recovery phase after rewetting. Therefore, the fitted parameters from these functions could help us to capture the continuum of microbial recovery between type 1 and 2 and characterize harshness levels. The product of growth parameters <em>τ</em> (delay time) and <em>b</em> (the slope of the growth curve at time <em>τ</em>) was an effective index that could capture and quantify perceived harshness because it allowed separating type 1 and 2 responses better than <em>τ</em> or <em>b</em> alone or than any other parameter describing the growth or respiration response. The drier the soil before rewetting and the lower the pH, the higher was the perceived harshness (<span><math><mi>τ</mi><mo>×</mo><mi>b</mi></math></span>), the longer the delay of growth recovery, and the larger the CO₂ loss at rewetting. Overall, this study places soil microbial responses to DRW along a continuous gradient from fast to slow recovery, where the faster the recovery, the better adapted the microbial community is to the DRW event.</p></div>","PeriodicalId":21888,"journal":{"name":"Soil Biology & Biochemistry","volume":"184 ","pages":"Article 109115"},"PeriodicalIF":9.7,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46235432","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Molecular complexity and diversity of persistent soil organic matter","authors":"Andrew R. Jones ,&nbsp;Ram C. Dalal ,&nbsp;Vadakattu V.S.R. Gupta ,&nbsp;Susanne Schmidt ,&nbsp;Diane E. Allen ,&nbsp;Geraldine E. Jacobsen ,&nbsp;Michael Bird ,&nbsp;A. Stuart Grandy ,&nbsp;Jonathan Sanderman","doi":"10.1016/j.soilbio.2023.109061","DOIUrl":"10.1016/j.soilbio.2023.109061","url":null,"abstract":"<div><p>Managing and increasing organic matter in soil requires greater understanding of the mechanisms driving its persistence through resistance to microbial decomposition. Conflicting evidence exists for whether persistent soil organic matter (SOM) is molecularly complex and diverse. As such, this study used a novel application of graph networks with pyrolysis-gas chromatography-mass spectrometry to quantify the complexity and diversity of persistent SOM, defined as SOM that persists through time (soil radiocarbon age) and soil depth. We analyzed soils from the Cooloola giant podzol chronosequence across a large gradient of soil depths (0–15 m) and SOM radiocarbon ages (modern to 19,000 years BP). We found that the most persistent SOM on this gradient was highly aromatic and had the lowest molecular complexity and diversity. By contrast, fresh surface SOM had higher molecular complexity and diversity, with high contributions of plant-derived lignins and polysaccharides. These findings indicate that persisting SOM declines in molecular complexity and diversity over geological timescales and soil depths, with aromatic SOM compounds persisting longer with mineral association.</p></div>","PeriodicalId":21888,"journal":{"name":"Soil Biology & Biochemistry","volume":"184 ","pages":"Article 109061"},"PeriodicalIF":9.7,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45300580","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Ectomycorrhizal effects on decomposition are highly dependent on fungal traits, climate, and litter properties: A model-based assessment","authors":"Siya Shao ,&nbsp;Nina Wurzburger ,&nbsp;Benjamin Sulman ,&nbsp;Caitlin Hicks Pries","doi":"10.1016/j.soilbio.2023.109073","DOIUrl":"10.1016/j.soilbio.2023.109073","url":null,"abstract":"<div><p>It has been proposed that competition between ectomycorrhizal (ECM) fungi and free-living saprotrophs for resources like nitrogen (N) slows decomposition and increases the soil carbon storage in ECM ecosystems compared to arbuscular (AM) ecosystems. However, empirical evidence for the generality of such ECM effects is equivocal, and confounding mechanisms have been proposed that affect the magnitude and direction of ECM effects on soil carbon. Here we conduct a theoretical modeling experiment, where we explicitly incorporate mycorrhizal processes into the Carbon, Organisms, Rhizosphere, and Protection in the Soil Environment (CORPSE) model. We use the model to explore the conditions under which ECM N acquisition processes can induce stronger saprotrophic N limitation and result in slower decomposition rates and greater soil organic carbon accumulation compared to AM processes. We found that the ECM fungi more strongly inhibited decomposition when litter inputs were N-depleted and relatively recalcitrant and when ECM fungi possessed a strong capacity to mine N from both recalcitrant soil organic matter and microbial necromass. Climate and seasonality also played a role as the ECM competition effect was strongest at low mean annual temperatures and when litterfall peaked seasonally. Priming effects driven by high root exudation rates in ECM-dominated systems could overwhelm the competition effect and reduce soil carbon under some circumstances. The ECM effect on decomposition in our simulations was highly context dependent. Based on our model results, we expect to see a strong ECM competition effect in temperate deciduous and boreal forests with relatively recalcitrant litter inputs, and with ECM fungi that produce oxidases and necromass-degrading enzymes. However, even a relatively strong ECM competition effect on decomposition only increased soil organic carbon accumulation by ∼10%.</p></div>","PeriodicalId":21888,"journal":{"name":"Soil Biology & Biochemistry","volume":"184 ","pages":"Article 109073"},"PeriodicalIF":9.7,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48283376","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Legacy effects of rhizodeposits on soil microbiomes: A perspective","authors":"Paolo Nannipieri ,&nbsp;S. Emilia Hannula ,&nbsp;Giacomo Pietramellara ,&nbsp;Michael Schloter ,&nbsp;Tom Sizmur ,&nbsp;Shamina Imran Pathan","doi":"10.1016/j.soilbio.2023.109107","DOIUrl":"10.1016/j.soilbio.2023.109107","url":null,"abstract":"<div><p>Plant legacy effects observed in plant-soil feedback experiments have largely been attributed to the root or litter material of the previous plant. The legacy effects of rhizodeposits are defined as changes in the soil microbiome that remain after a plant has died or been removed from the soil and caused by the release of substances of various compositions by living plants (rhizodeposits). Rhizodeposit-mediated legacy effects have been largely ignored mainly due to the high spatial and temporal variability of rhizodeposits and difficulties quantifying and tracking them in the rhizosphere. In this perspective article, we discuss what is known about the legacy effects of rhizodeposits and provide ideas for future experiments to improve understanding of this phenomenon. Only a few studies separate rhizodeposit-mediated plant legacy effects from legacy effects of root decomposition. Results from these experiments indicate that rhizodeposit-mediated legacy effects on soil microbial communities may persist for several months to several years, especially if the same crop is cultivated persistently for several years in a ‘conditioning’ phase. Rhizodeposit-mediated legacy effects on fungal communities usually last longer than those on bacterial communities due to fungal life-cycle strategies (spore formation) and slower reproduction rates, compared to bacterial communities. We highlight the need for further experimentation to investigate the influence that the length of a conditioning phase has on the persistence of the legacy effect, differentiate the effect of root exudates from the effects of sloughed root cells, separate the influence of simple sugars from that of high molecular-weight exudates and plant derived compounds with antimicrobial properties, and explore whether plant species diversity influences the nature of the legacy. To address these questions, we propose the use of contemporary tools such as stable isotope probing, plant genetics, and reverse microdialysis. We think that harnessing rhizodeposit-mediated plant legacy effects could be a promising approach to improve sustainable crop production by creating disease-suppressive soils and simulating plant growth-promoting micro-organisms within soil systems.</p></div>","PeriodicalId":21888,"journal":{"name":"Soil Biology & Biochemistry","volume":"184 ","pages":"Article 109107"},"PeriodicalIF":9.7,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45288367","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Soil carbon storage and compositional responses of soil microbial communities under perennial grain IWG vs. annual wheat","authors":"Kalyn Taylor ,&nbsp;Sandipan Samaddar ,&nbsp;Radomir Schmidt ,&nbsp;Mark Lundy ,&nbsp;Kate Scow","doi":"10.1016/j.soilbio.2023.109111","DOIUrl":"10.1016/j.soilbio.2023.109111","url":null,"abstract":"<div><p>The introduction of novel perennial grains into annual row crop rotations is proposed to increase soil ecosystem services and enhance plant-soil-microbial linkages because perennials provide deeper root systems and more continuous ground cover than annuals. While soil microbial communities underpin many ecosystem services, we know little about how soil microbial composition and diversity, and soil carbon storage, differ between soils of annual vs. perennial grain crops. We measured soil fungi: bacteria (F/B) ratios and soil carbon within the novel perennial intermediate wheatgrass (IWG; trademarked Kernza®) and tilled annual wheat and compared soil microbial diversity and community composition within their rhizosphere, shallow bulk soil (0–15 cm) and total bulk soil (0–90 cm). After three years, soil depth explained 30–40% and 12–22% of the variance in bacterial and fungal community composition, respectively, while crop type explained 10% and 9–16% of the variance, respectively. Fungal communities were most impacted by crop type in the rhizosphere and shallow bulk soil and less sensitive to differences in soil depth. In contrast, crop type had a smaller effect on bacterial communities which were more influenced by soil depth. IWG trended higher in soil carbon mass at 0–30 cm (p = 0.22) and had a higher (F/B) ratio than tilled annual wheat at depths below 15 cm, but tilled annual wheat had higher soil carbon concentration (p = 0.12) and soil carbon mass (p = 0.09) at the 60–90 cm soil depth. Our results indicate that fungi were more responsive than bacterial communities to crop type and that IWG has a higher fungal biomass and different fungal community composition than annual wheat at depth. However, despite these distinct differences in fungal communities in IWG compared to annual wheat, the differences did not translate into greater soil carbon mass in IWG at depth.</p></div>","PeriodicalId":21888,"journal":{"name":"Soil Biology & Biochemistry","volume":"184 ","pages":"Article 109111"},"PeriodicalIF":9.7,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42679153","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mapping of suitable habitats for earthworms in China","authors":"Xiaoliang Li ,&nbsp;Kening Wu ,&nbsp;Shiheng Hao ,&nbsp;Long Kang ,&nbsp;Jinliang Ma ,&nbsp;Ran Zhao ,&nbsp;Yue Zhang","doi":"10.1016/j.soilbio.2023.109081","DOIUrl":"10.1016/j.soilbio.2023.109081","url":null,"abstract":"<div><p>Earthworms are important soil organisms that play critical roles in ecosystem material cycling and energy flows. Discovering and predicting the distribution of earthworm habitats is critical for managing biodiversity conservation projects and improving ecosystem health. However, earthworm data are challenging to obtain, and studies on the distribution of earthworms and factors affecting this have mainly been conducted in fields at a small scale; the spatial distribution of earthworms throughout China remains unclear. Species distribution models have been effectively used in macro-scale species suitability distribution studies; however, they have certain limitations. Thus, here, we optimized the maximum entropy model (MaxEnt) to achieve low complexity and high transferability, and the model was capable of predicting the potential distribution of earthworms in China. Modeling was based on the use of a developed database containing 286 earthworm occurrence records and 31 environmental variables (19 climatic, 9 soil, and 3 topographic variables). Results show that earthworm distribution is mainly controlled by the following environmental variables (with corresponding contribution rates): minimum temperature of the coldest month (18.47%), digital elevation model (17.65%), coarse fragments (16.72%), soil organic carbon (9.65%), soil type (7.53%), mean diurnal range (5.35%), and soil thickness (5.05%). The variables with the strongest influence on distribution are climate followed by landforms and soils. The relationship between the effect of environmental variables and earthworm distribution is not simple and linear, and each element has a certain threshold range. Only 50.67% of the total land area of China provides a suitable habitat for earthworms, and there are remarkable spatial differences. Of the various ecosystems, woodland ecosystems provide most of the suitable habitats, followed by cropland and grassland ecosystems, which together account for 45.74% of the land area. This study can be used as a reference for understanding and assessing ecosystem health, sustainability, and for enabling biodiversity conservation.</p></div>","PeriodicalId":21888,"journal":{"name":"Soil Biology & Biochemistry","volume":"184 ","pages":"Article 109081"},"PeriodicalIF":9.7,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48446330","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Light grazing reduces gaseous nitrogen emissions from temperate grassland soils during freeze‒thaw cycles: An intact core incubation study","authors":"Chenjun Du ,&nbsp;Xing Wu ,&nbsp;Fangfang Wang ,&nbsp;Rui Wang ,&nbsp;Xunhua Zheng ,&nbsp;Yihe Lü ,&nbsp;Bojie Fu","doi":"10.1016/j.soilbio.2023.109166","DOIUrl":"10.1016/j.soilbio.2023.109166","url":null,"abstract":"<div><p>Livestock grazing and soil freeze‒thaw cycles (FTCs) can affect the biogeochemical processes of nitrogen (N) and gaseous N (N₂O, NO, and N₂) emissions from grassland soils. However, the effect of grazing intensity on soil gaseous N emissions during FTCs and the underlying mechanisms are not clearly understood. In this intact core incubation study, soil gaseous N emissions during two FTCs were simultaneously quantified from temperate grasslands that included grazing exclusion (GE), light grazing (LG), and heavy grazing (HG) in Inner Mongolia. Additionally, the abundance of N cycle-related functional genes and the main soil characteristics were determined to better understand the drivers of gaseous N emissions. The results showed that N₂ emissions dominate the gaseous N loss from all investigated soils during FTCs, with cumulative N₂ exceeding NO and N₂O emissions by factors of 47–135 and 71–161, respectively. Increased soil moisture during thawing promoted N₂ and N₂O emissions from all three sites, except for N₂O at the LG site. However, no obvious NO emission peak was observed from all investigated soils during FTCs. Soil C and N availability and aeration changed by grazing regulated soil N₂O fluxes, while the abundances of key functional genes generally did not show significant correlations with gaseous N emissions. Moreover, compared to the GE and HG sites, LG substantially decreased the soil N₂O and total gaseous N emissions during FTCs, suggesting that light grazing rather than long-term grazing exclusion could be a promising measure to reduce gaseous N losses during spring thaw. Our results highlighted the importance of the simultaneous determination of all kinds of gaseous N emissions during FTCs for closing the ecosystem N balance and developing appropriate strategies for grassland management.</p></div>","PeriodicalId":21888,"journal":{"name":"Soil Biology & Biochemistry","volume":"186 ","pages":"Article 109166"},"PeriodicalIF":9.7,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47787591","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Revisiting soil microbial biomass: Considering changes in composition with growth rate","authors":"Petr Čapek ,&nbsp;Michal Choma ,&nbsp;Eva Kaštovská ,&nbsp;Karolina Tahovská ,&nbsp;Helen C. Glanville ,&nbsp;Hana Šantrůčková","doi":"10.1016/j.soilbio.2023.109103","DOIUrl":"10.1016/j.soilbio.2023.109103","url":null,"abstract":"<div><p>Soil microbial biomass is assumed to have stable chemical composition. Various components of the biomass such as DNA, ATP, or chloroform-labile organic carbon are measured in soil and converted into total microbial biomass using experimentally derived conversion factors, which are also assumed to be constant. However, several observations suggest the opposite. The composition of soil microbial biomass is likely changing with specific growth rate as observed in pure cultures of single microbial species. In this study, we define a “sub-Microbial” model that explicitly represents changes in composition of soil microbial biomass associated with changes in specific growth rate. We calibrate the model with published data and compare its performance with the simpler Monod and Pirt models, which consider microbial biomass as a single pool with invariant chemical composition. The model explains well the variability in chloroform-labile content of microbial biomass following organic substrate additions as well as variability in ratios of different components of microbial biomass. Changes in composition of soil microbial biomass are quantitatively significant and occur over hours and days resulting in our sub-Microbial model outperforming both the Monod and Pirt models. Our results further indicate that the composition of soil microbial biomass changes consistently with growth rate across various soils. Here, we provide a methodological recommendation how to determine total soil microbial biomass and its physiological characteristics such as growth rate, turnover rate and substrate use efficiency as accurately as possible. In light of the presented results, we would like to initiate a discussion about the methodological issues associated with measurement of soil microbial biomass as these measurements are expected to inform a new generation of microbially-explicit soil biogeochemical models predicting development of terrestrial ecosystems under various scenarios.</p></div>","PeriodicalId":21888,"journal":{"name":"Soil Biology & Biochemistry","volume":"184 ","pages":"Article 109103"},"PeriodicalIF":9.7,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44892247","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Tracing service crops' net carbon and nitrogen rhizodeposition into soil organic matter fractions using dual isotopic brush-labeling","authors":"Paula Berenstecher ,&nbsp;Georgina Conti ,&nbsp;Ana Faigón ,&nbsp;Gervasio Piñeiro","doi":"10.1016/j.soilbio.2023.109096","DOIUrl":"10.1016/j.soilbio.2023.109096","url":null,"abstract":"<div><p>Recent studies emphasize the importance of rhizodeposition in soil organic matter (SOM) formation. However, its quantification in different soil fractions is still uncommon. To estimate the net carbon (C) and nitrogen (N) rhizodeposition into particulate (POM) and mineral-associated (MAOM) organic matter, we conducted a pot experiment to trace plant-derived C and N into the soil. In this study, we first evaluated the effectiveness of the dual isotope (¹³C and ¹⁵N) brush-labeling method on oat and vetch plants, two species commonly sown as service crops, to investigate <em>in situ</em> plant-soil interactions. Our results indicate that foliar brushing successfully labeled plant tissues and traced plant-derived C and N into the soil, allowing us to make a conservative estimate of net rhizodeposition. Based on soil δ¹³C and δ¹⁵N changes, we show that most of the net C (81.5 and 100% for oats and vetch, respectively) and N (92.4 and 93.2% for oats and vetch, respectively) rhizodeposition contributes directly to the formation of MAOM and not POM. Both species contributed similar amounts of net C rhizodeposition to the MAOM fraction (about 0.59 g plant⁻¹), while oat net C rhizodeposition also formed a small amount of POM (0.138 g plant⁻¹). Because vetch had low root biomass, the net C rhizodeposition:root C ratio was much higher in vetch than in oats (12.3 and 0.65, respectively). For net N rhizodeposition, vetch contributions were greater than oats in both fractions (71.4% greater in MAOM and 50.4% greater in POM). Our estimates of net C and N rhizodeposition range from 15 to 40% of the total recovered C or N. Our results demonstrate the importance of incorporating rhizodeposition into belowground biomass estimates and SOM models, and suggest that service crops provide large amounts of C and N inputs from living roots that are mainly retained in MAOM.</p></div>","PeriodicalId":21888,"journal":{"name":"Soil Biology & Biochemistry","volume":"184 ","pages":"Article 109096"},"PeriodicalIF":9.7,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47234629","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}