Geoderma Regional最新文献

{"title":"Physically protected carbon stocks in a Brazilian Oxisol under homogeneous forest systems","authors":"Maicon dos Santos da Silva ,&nbsp;Patrícia Anjos Bittencourt Barreto-Garcia ,&nbsp;Paulo Henrique Marques Monroe ,&nbsp;Marcos Gervasio Pereira ,&nbsp;Luiz Alberto da Silva Rodrigues Pinto ,&nbsp;Marcio Renato Nunes","doi":"10.1016/j.geodrs.2024.e00915","DOIUrl":"10.1016/j.geodrs.2024.e00915","url":null,"abstract":"<div><div>The soil organic carbon (SOC) stock and its occlusion within aggregates is at the center of discussions regarding climate change and global warming, as it is one of the mechanisms capable of mitigating the effects of these phenomena. Despite this, studies on the topic in tropical soils under native forest species plantations are still scarce. Therefore, we developed this study asking how SOC and occluded carbon stocks in aggregates respond to homogeneous <em>Pterogyne nitens</em> (N-fixing species) and <em>Eucalyptus urophylla</em> plantations when compared to a native forest? The study was conducted in Oxisol under three forest systems: two homogeneous plantations (<em>P. nitens</em> and <em>E. urophylla</em>) and a native forest (NF), located in the State of Bahia, Brazil. Litter and soil samples were collected up to a meter deep. The soil samples were subjected to physical fractionation by wet sieving, obtaining three size classes of water-stable aggregates: macroaggegates (2000–250 μm), microaggregates (250–53 μm) silt+clay (&lt; 53 μm). The macroaggegates and microaggegates were sonicated to separate free and occluded particulate carbon. The carbon in whole soil and occluded in the aggregates were determined by the wet acidified oxidation method. The SOC stock (depth 100 cm) showed a reduction in the <em>P. nitens</em> plantation (123.1 Mg ha⁻¹) and maintenance in the <em>E. urophylla</em> plantation (194.4 Mg ha⁻¹) when compared to the NF (240.9 Mg ha⁻¹). Occluded carbon showed a lower value in plantations compared to NF, representing an average of 5.8 % of the SOC. The <em>P. nitens</em> plantation negatively impacted SOC stock as a result of lower litter amounts and higher litter decomposition rates. In contrast, the <em>E. urophylla</em> plantation maintained SOC stocks close to those found in the NF due to the large amounts of litter and its high recalcitrance. Both forest plantations affect carbon occlusion in the aggregates, and therefore the SOC is poorly protected physically.</div></div>","PeriodicalId":56001,"journal":{"name":"Geoderma Regional","volume":"40 ","pages":"Article e00915"},"PeriodicalIF":3.1,"publicationDate":"2025-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143144970","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Faster topsoil organic matter transformation accompanies long-term carbon preservation in virgin Chernozems","authors":"Alla Yu. Yurova ,&nbsp;M.A. Smirnova ,&nbsp;D.N. Kozlov ,&nbsp;D.R. Bardashev ,&nbsp;N.I. Lozbenev ,&nbsp;V.M. Stepanenko","doi":"10.1016/j.geodrs.2024.e00914","DOIUrl":"10.1016/j.geodrs.2024.e00914","url":null,"abstract":"<div><div>This study examines soil organic carbon (SOC) dynamics in different soil types across a micro-topographical gradient, focusing on topsoil SOC stabilization and turnover rates in virgin Chernozems. The thermodynamic origin of differences in SOC decomposability (henceforth referred to as “quality”, or “q”) between soil types is explained using a Q model that treats quality as a continuous variable rather than assuming the presence of discrete SOC pools. The model's calibration is focused on enabling effective assessment of overall SOC stocks in the topsoil (the topmost 10 cm) and the total carbon stock in the uppermost 50 cm while using radiocarbon turnover rates as secondary constraints that may be needed due to limited data availability. The SOC turnover time in the topsoil determined by modeling the SOC quality distribution function was shown to agree well with empirical findings from similar study sites, indicating that SOC turnover times are around 6–10 years in surface layers but millennia in deeper layers. This reinforces the importance of distinguishing between topsoil and subsoil carbon stocks and their respective stabilization mechanisms in Chernozems. The analysis also highlights the influence of soil temperature and moisture conditions on soil organic carbon (SOC) dynamics: high topsoil moisture levels due to lateral water inputs increase SOC stabilization and thus reduce q, so wetter sites have enhanced carbon stocks. This outcome aligns with existing theories of humification in which water availability emerges as a crucial factor influencing SOC preservation and stabilization. Wetter soils also exhibit reduced decomposition due to lower temperature. This interplay between moisture, temperature, and microbial respiration rates necessitates a reevaluation of conventional beliefs about the behavior of SOC in different water regimes that stress the impact of moisture on soil respiration but not SOC stabilization. These findings also highlight the need to account for microtopographic variation, especially in semi-arid regions, in soil management programs seeking to optimize SOC retention and overall soil health. The insights into SOC dynamics presented here will be valuable for improving soil management strategies to enhance carbon sequestration in various soil types under changing climatic conditions.</div></div>","PeriodicalId":56001,"journal":{"name":"Geoderma Regional","volume":"40 ","pages":"Article e00914"},"PeriodicalIF":3.1,"publicationDate":"2024-12-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143144969","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Carbon stock, subsurface characteristics and accommodation settings of sub-tropical peatland Histosols, K'gari, Queensland Australia","authors":"Gareth Chalmers ,&nbsp;Zeinab Ghasemzadeh ,&nbsp;David Chittleborough ,&nbsp;Allen Gontz ,&nbsp;Iroshaka Gregory Cooray ,&nbsp;Catherine Yule ,&nbsp;Darshanaa Chellaiah ,&nbsp;Adrian McCallum","doi":"10.1016/j.geodrs.2024.e00913","DOIUrl":"10.1016/j.geodrs.2024.e00913","url":null,"abstract":"<div><div>Whereas temperate and tropical peatlands have been extensively studied, much less is known about the age, formation history, carbon stock and soil characteristics of subtropical peatlands. Here we investigate the organic carbon density or stock and soil characteristics of three peatlands of K'gari (Fraser Island), Queensland, Australia. The <em>Empodisma minus</em> -dominated peatlands are unique to the subtropics and their bulk density, pH, oxidation-reduction potential, carbon percentages and carbon stocks were compared to other <em>Empodisma</em> sp. peatlands in temperate and montane-alpine climates as well as global peatland estimates. A good agreement occurs between the elemental analyser (LECO) derived carbon percentages and the estimations made by loss-of-ignition-derived carbon percentages using <span><span>Farmer et al. (2014)</span></span> conversion factor. Carbon stock estimation ranges between 381.2 and 1665.5 Mg C ha⁻¹ for the total peat depth and ranges between 444.0 and 1189.7 Mg C ha⁻¹ on a per metre basis. The carbon stock average for the Moon Point and Dilli Swamp peatlands is comparable to global peatland estimates with the Red Lagoon peatland is lower than the average. All three peatlands have a higher average carbon stock than other <em>Empodisma</em>-dominated peatlands in temperate and montane-alpine climates.</div><div>The three peatland sites chosen are within different morphosequences that range in age between Holocene, 7.8 to 132 ka and 132–263 ka. The Moon Point peatland (Holocene; &lt; 11,700 BP) has a higher bulk density, lower moisture content and higher degree of humification compared to the other morphosequence areas. The difference in peat characteristics is not due to the morphosequence, as the climate changed approximately 6000 to 5000 years BP to be more favourable for peat accumulation across south-east Queensland. However, we suspect the older morphosequence (i.e., Yankee Jack) as well as the Holocene coastal sediment setting, due to their lower topography reduces the groundwater level and the accommodation space for peats to accumulate. The lower accommodation setting limits the peat thickness, increases the number of hiatuses and is susceptible to more peat fires. This study shows the K'gari peatlands are significant carbon sinks and careful management is needed to ensure they do not become carbon emitters as climate continues to change.</div></div>","PeriodicalId":56001,"journal":{"name":"Geoderma Regional","volume":"40 ","pages":"Article e00913"},"PeriodicalIF":3.1,"publicationDate":"2024-12-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143144966","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Management strategies for regenerative agriculture based on the assessment of soil fertility in northern Mozambique","authors":"Hisashi Nasukawa ,&nbsp;Ryosuke Tajima ,&nbsp;Maria Clarinda Filomena Pereira ,&nbsp;Joao Antonio Pedro ,&nbsp;Satoshi Nakamura ,&nbsp;Monrawee Fukuda ,&nbsp;Junji Koide ,&nbsp;Tetsuji Oya ,&nbsp;Koki Homma","doi":"10.1016/j.geodrs.2024.e00912","DOIUrl":"10.1016/j.geodrs.2024.e00912","url":null,"abstract":"<div><div>Despite having high potential for agricultural production, the maize yield in northern Mozambique is low due to the depletion of macronutrients in soil. Soil fertility analysis serves as a basis for developing regenerative agriculture (RA) strategies. For best results, RA practices suitable to the type of soil in northern Mozambique should be selected and applied. Hence, in this study, we examined soil characteristics and their relationship with maize yield across 196 locations in the Nacala Corridor of northern Mozambique. The results revealed significant variation in soil fertility, which was primarily influenced by organic matter, clay content, and nutrient availability. Cluster analysis identified three distinct soil fertility groups: low-fertility soils were found in the eastern region, with reduced maize yield, whereas high-fertility soils were predominant in the western and central-southern regions, which produced better yield. These findings highlight the importance of detailed soil analysis for the development of targeted soil management strategies, such as conservation agriculture and integrated soil fertility management, that can enhance nutrient retention, increase organic matter content, and improve crop yield. This study provides essential insights for smallholder farmers and policymakers to implement sustainable agriculture and improve long-term productivity in northern Mozambique.</div></div>","PeriodicalId":56001,"journal":{"name":"Geoderma Regional","volume":"40 ","pages":"Article e00912"},"PeriodicalIF":3.1,"publicationDate":"2024-12-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143144967","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Comparison of soil exchangeable calcium estimated using five extractants and near-infrared spectroscopy","authors":"Zhufeng Wang ,&nbsp;Yugang Wang ,&nbsp;Fei Peng ,&nbsp;Dengchun Xing ,&nbsp;Litao Lin ,&nbsp;Wenting Feng","doi":"10.1016/j.geodrs.2024.e00911","DOIUrl":"10.1016/j.geodrs.2024.e00911","url":null,"abstract":"<div><div>Soil exchangeable Ca (Ca_ex) regulates multiple functions, including nutrient provision for plant growth, soil structure maintenance, and carbon sequestration. However, various chemical extraction methods are currently used worldwide to determine soil Ca_ex, each with different mechanisms and purposes. The inconsistency in assessment methods complicates comparisons and predictions regarding soil Ca_ex functions across different environments. To address this issue, we developed equations to convert soil Ca_ex concentrations obtained from five different methods in arid regions. Furthermore, we evaluated the accuracy of predicting five soil Ca_ex proxies and cation exchange capacity (CEC) using near-infrared reflectance (NIR) spectroscopy. The chemical extractants (<em>i.e</em>., sodium acetate (NaOAc), potassium chloride (KCl), sodium sulfate (Na₂SO₄), ethylenediaminetetraacetic acid (EDTA), and copper chloride (CuCl₂)) were used on 308 soil samples representing a wide range of soil Ca_ex, climate, and edaphic properties in arid regions. Our findings reveal that compared to the commonly used NaOAc extraction, Na₂SO₄ extracted a similar amount of soil Ca_ex. In contrast, KCl extraction underestimated soil Ca_ex, whereas EDTA and CuCl₂ extractions overestimated it. Such discrepancies suggest that EDTA and CuCl₂ are inappropriate for soils with Ca-bearing minerals, such as Ca carbonate. Moreover, the quantitative correlation among soil Ca_ex values obtained through five different extractants highlights the need for careful selection based on specific environmental factors (<em>i.e</em>., soil pH and humidity). Notably, NIR-driven partial least squares regression outperformed support vector machine models for the estimation of soil Ca_ex measured by five extractants (0.78 &lt; <em>R</em>² &lt; 0.90) and CEC (<em>R</em>² = 0.96). This capability positions NIR spectroscopy as an efficient and reliable tool for rapid assessment of soil Ca_ex and CEC, particularly in arid regions. In conclusion, the quantitative relationships derived from various extraction methods provide a robust framework for comparing soil Ca_ex values and enhancing our ability to predict changes in its functions under differing environmental conditions.</div></div>","PeriodicalId":56001,"journal":{"name":"Geoderma Regional","volume":"40 ","pages":"Article e00911"},"PeriodicalIF":3.1,"publicationDate":"2024-12-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143144968","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Enhancing agroecosystem sustainability: Integrative soil health strategies in regenerative organic soybean production on Andosol in Japan","authors":"Ratih Kemala Dewi ,&nbsp;Qiliang Huang ,&nbsp;Rahmatullah Hashimi ,&nbsp;Masakazu Komatsuzaki","doi":"10.1016/j.geodrs.2024.e00910","DOIUrl":"10.1016/j.geodrs.2024.e00910","url":null,"abstract":"<div><div>Regenerative agriculture prioritizes soil health to enhance ecosystems and crop production. No-tillage organic farming with cover crop rotation improves sustainability. However, economic barriers must be considered. This study evaluated the involvement of biochar into long-term no-tillage combined with cover crop as a regenerative organic approach on soil health and carbon sequestration as well as to assess the economic viability of this farming system. The field experiment was designed as a randomized complete block with a split–split plot arrangement consisting of different tillage practices (no-tillage, rotary cultivator, and moldboard plowing), cover crop (rye, hairy vetch, and fallow), and biochar applications (with and without biochar), in four replications. The study also included two farming scenarios, soybean and soybean + rice production, for economic analysis. Results showed that incorporating biochar into the continuous no-tillage with cover crop rotation increased soil organic carbon and its stock in the topsoil profile (0–30 cm), improved soil health indicators by reducing soil bulk density and penetration resistance, and increased microbial activity, thereby promoting nutrient cycling. Soybean yield varied under the no-tillage system, resulting in a low benefit–cost ratio; however, the integration of soybean with rice production improved this ratio in organic farming–based no-tillage management. Compared with moldboard plowing, no-tillage with rye resulted in the lowest cost of soil organic carbon production. Given these findings, integrating biochar into long-term no-tillage management centered on regenerative organic farming would improve environmental quality and provide economic advantages, strengthening the resilience of natural system, specifically in Andosol, Japan.</div></div>","PeriodicalId":56001,"journal":{"name":"Geoderma Regional","volume":"40 ","pages":"Article e00910"},"PeriodicalIF":3.1,"publicationDate":"2024-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143145022","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Exploring phosphorous dynamics within soil aggregate after 17 years long-term manuring in lateritic Inceptisols in rice paddies","authors":"Nafid Cheekilote ,&nbsp;Prasanna Kumar Samant ,&nbsp;Sanat Kumar Dwibedi ,&nbsp;Bandita Jena ,&nbsp;Kiran Kumar Mohapatra ,&nbsp;Hari Sankar Nayak ,&nbsp;Saheed Garnaik","doi":"10.1016/j.geodrs.2024.e00908","DOIUrl":"10.1016/j.geodrs.2024.e00908","url":null,"abstract":"<div><div>Understanding phosphorous dynamics can provide valuable insights for sustainable nutrient management and long-term fertilizer experiments are better source for elucidating such mechanism. In this study, eight distinct nutrient management treatments (combination of N, P, K fertilizer along with FYM and lime) were evaluated in an ongoing long-term fertilizer experiment. The experiment investigated the prolonged effects of both balanced and imbalanced fertilizer applications, the combined use of organic manure and inorganic fertilizers, and the application of liming material in a rice-rice cropping system on yield attributes and changes in soil properties. Integrated use of organic manure with NPK fertilizers and lime application (100% NPK + FYM + Lime) positively influenced soil properties and significantly increased yield by 41.4% and P-uptake by 88.4% compared to sole NPK application. The long-term fertilization contributed to significant relative accumulation of Ca<img>P fraction (∼240% increase) in 100% NPK + FYM + Lime in comparison to initial Ca<img>P fraction. The distribution pattern of inorganic phosphorus fractions varied with following sequence: Fe-P &gt; Red-P &gt; Al-P &gt; Ca-P &gt; Occl-P &gt; Sal-P. Among these fractions, Ca<img>P (<em>r</em> = 0.949**), Occl-P (<em>r</em> = 0.884**), and Sal-P (<em>r</em> = 0.866**) were correlated with available P. The mean weight diameter (MWD) exhibited the strongest correlation with Occl-P (<em>r</em> = 0.936**), whereas the geometric mean diameter (GMD) and water stable aggregate (WSA) had the strongest correlation with Ca<img>P (0.893** and 0.875**, respectively). The adjusted R² values indicated that the total contribution of all inorganic P fractions accounted for 99.9% of the variability in available P, 80.6 % in P uptakes, and 67.9% in grain yield. This study underscores the critical relationship among soil structure, crop yield, and P availability, emphasizing that macroaggregates play a crucial role in improving soil health and enhancing P retention and availability.</div></div>","PeriodicalId":56001,"journal":{"name":"Geoderma Regional","volume":"40 ","pages":"Article e00908"},"PeriodicalIF":3.1,"publicationDate":"2024-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143144991","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 benchmarks and cropland management effects: Insights from the Bavarian soil organic matter monitoring","authors":"Manuel Sümmerer ,&nbsp;Christopher Just ,&nbsp;Martin Wiesmeier","doi":"10.1016/j.geodrs.2024.e00909","DOIUrl":"10.1016/j.geodrs.2024.e00909","url":null,"abstract":"<div><div>Soil organic carbon (SOC) is a key property for soil productivity and functionality. According to the Federal Soil Protection Act in Germany, site-specific SOC contents need to be maintained in the course of agricultural land use in order to ensure soil fertility and the performance of soils as a natural resource. In this study, representative SOC benchmarks have been derived for arable mineral soils in Bavaria on the basis of a comprehensive soil organic matter (SOM) monitoring program as reference values for farmers and other stakeholders. Data from 283 representative study sites across Bavaria has been stratified according to the most influential site factors on SOC, particularly clay content and the elevation above sea level as a proxy for climate (temperature and precipitation). Due to an evaluation of the study sites in terms of agricultural management according to the principles of good agricultural practice combined with statistical exclusion of 25 % of extreme SOC contents, the benchmarks presented here can be regarded as representative reference values under specific environmental conditions. However, different management measures within the principles of good agricultural practice also influenced SOC, as organic fertilization and the cultivation of perennial forage crops positively affected SOC contents. In contrast, the cultivation of root crops negatively influenced SOC contents, while the proportion of corn within the crop rotation of up to 50 % did not affect SOC negatively. We further evaluated the suitability of the SOC/clay ratio as alternative SOC and soil structure indicator. However, the SOC/clay ratio seems to be inappropriate due to a high number of degraded sites and a systematic bias towards degradation with high clay contents. The SOC benchmarks presented here provide valuable reference values for farmers policymakers and agricultural stakeholders in optimizing cropland management practices for sustainable soil health and fertility in Bavaria and beyond. However, further research is required regarding the stratification approach and the calculation method for a widespread implementation of SOC benchmarks. Furthermore, the shifting baseline syndrome has to accounted for, so up to date SOC benchmarks remain within a range in which soils are considered healthy and fertile.</div></div>","PeriodicalId":56001,"journal":{"name":"Geoderma Regional","volume":"40 ","pages":"Article e00909"},"PeriodicalIF":3.1,"publicationDate":"2024-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143144990","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Sources of soil organic carbon under Eucalyptus silvopastures and other land-use systems in Brazilian Oxisols","authors":"Felipe M. Pinheiro ,&nbsp;P.K. Ramachandran Nair ,&nbsp;Vimala D. Nair ,&nbsp;Rafael G. Tonucci ,&nbsp;Regis P. Venturin","doi":"10.1016/j.geodrs.2024.e00907","DOIUrl":"10.1016/j.geodrs.2024.e00907","url":null,"abstract":"<div><div>Silvopastoral systems (SPS) incorporating non-native tree species such as Eucalyptus are increasingly being adopted in the Cerrado region of Brazil. The climate-change mitigation potential of the practice, although hypothesized, has not been assessed vigorously. The objective of this research was to measure the extent of SOC accumulation under SPS involving C3 and C4 plants and other prevalent land-use systems in an Oxisol-dominated location in Minas Gerais, Brazil. We determined the overall δ13C in three soil fraction-size groups within six land-use systems. These systems consisted of 8-year-old planted forests, native forest, managed pastures, and three variations of 8-year-old SPS with diverse tree-planting layouts. In the SPS and planted forest treatments, the tree species was Eucalyptus hybrid, and <em>Urochloa decumbens</em> was the grass species in the SPS and pasture treatments. For each treatment, soil samples were collected at depths of 0–10, 10–30, 30–60, and 60–100 cm. These samples were fractionated into three size classes (2000-250 μm, 250-53 μm, and &lt;53 μm) and analyzed for δ13C. The native forest had higher C3 contribution in the topsoil layers. The highest C3 derived SOC stock up to 1 m depth was in the pasture (137 Mg ha^-1), and the lowest in the forest (74 Mg ha^-1). The pasture also had the highest C4 derived SOC stock and the forest the lowest, but not significantly. The SPS had intermediate values. We infer that the study site had a mixed vegetation in the past, and after the conversion of the land to planted forest/SPS/pasture, the “native” SOC stock could be maintained better in a well-managed pasture than in a degraded native forest. The higher C3-derived SOC stock in the pasture treatment suggests that managed SPS could help retain more soil C in a stable form than in degraded forests.</div></div>","PeriodicalId":56001,"journal":{"name":"Geoderma Regional","volume":"40 ","pages":"Article e00907"},"PeriodicalIF":3.1,"publicationDate":"2024-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143144989","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Superior nutrient recovery and release by chicken manure-derived biochar over hydrochar and compost for soil fertilization","authors":"Mahmudul Islam Piash ,&nbsp;Takanori Itoh ,&nbsp;Kazusa Abe ,&nbsp;Kazunori Iwabuchi","doi":"10.1016/j.geodrs.2024.e00906","DOIUrl":"10.1016/j.geodrs.2024.e00906","url":null,"abstract":"<div><div>Recycling nutrient-rich organic waste materials in agriculture is increasingly recognized for its potential to establish sustainable systems, especially considering the diminishing availability of chemical fertilizers. However, appropriate pretreatment methods are essential for safe and efficient utilization in soil systems. In this study, we compared conventional composting (compost) with low-temperature pyrolysis (biochar) and hydrothermal carbonization (hydrochar) for conserving nutrients from chicken manure (CM) and producing stable organic fertilizer. Biochar exhibited superior nutrient recovery, with 76.4 % of N retrieved from CM compared to 37.4 % for hydrochar and 36.2 % for compost. The escape of NH₃ gas from deaminated hydrochar slurry and volatilization loss during composting might have caused such low N recovery in hydrochar and compost, respectively. When applied to soil, biochar released nearly 100 % of its nitrogen in phyto-available form and may satisfy 88.5 % of the N requirements for optimum sweetcorn production. Decomposition of pyridinic- and pyrrolic-N in low-temperature CM biochar might have contributed to this high N release. In contrast, compost released 85 % of its N, and hydrochar released only 33 %. Biochar also preserved the highest amount of carbon (67.6 %) during production, with a significantly higher fixed carbon content (19.2 %). Over a 140-day incubation period, while 26.6 % of compost‑carbon was emitted as CO₂ from soil, biochar remained significantly stable (11.5 %). These findings underscore manure biochar's potential as an effective tool for soil fertilization and carbon sequestration, surpassing compost and hydrochar in nitrogen recovery, nitrogen release, and carbon stability in soil.</div></div>","PeriodicalId":56001,"journal":{"name":"Geoderma Regional","volume":"40 ","pages":"Article e00906"},"PeriodicalIF":3.1,"publicationDate":"2024-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143145021","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}