Pub Date : 2025-06-03DOI: 10.5194/egusphere-2025-1460
Tolulope Ayeyemi, Ramiro Recena, Ana María García-López, José Manuel Quintero, María Carmen del Campillo, Antonio Delgado
Abstract. Although there is relevant knowledge based on the effect of soil properties on the efficiency of common commercial fertilizers, this effect remains poorly understood for the use of vivianite from water purification as an innovative P fertilizer meeting a circular economy approach. This study aimed to evaluate the effect of soil properties on the efficiency of vivianite recovered from water purification as a P fertilizer and to provide practical recommendations for its effective use. Vivianite and a soluble mineral P fertilizer (superphosphate) were compared at two P application rates (50 and 100 mg P kg–1) in soils ranging widely in properties in a pot experiment using wheat. Soluble P fertilizer provided the best results in terms of dry matter (DM) yield, P uptake, and Olsen P in soils, while vivianite led to the best results of DTPA extractable Fe in soils after crop harvest. The application of vivianite as a P fertilizer was more efficient in acidic soils (pH < 6.6). The effect of vivianite on dry matter (DM) yield was equivalent on average to 26 or 40 %, depending on the rate, of the same amount of soluble fertilizer in these acidic soils (i.e., P fertilizer replacement value –PFRV– on DM basis), it being around 50 % in some cases. The effect on Olsen P in soil was equivalent, on average, to 49 or 61 %, depending on the rate, of the same amount applied as soluble mineral fertilizer in acidic soils. This can be explained by the increased solubility of this fertilizer product under acidic conditions, supported by the highest increase in DTPA extractable Fe in these soils. Acidic soils were those with initial Olsen P below the threshold value for fertilizer response (TV). However, PFRV on different approaches (DM, P uptake, and Olsen P) decreased more consistently with increased values of the difference between initial Olsen P and TV (46 to 87 % of the variance explained) than with increased pH. This reveals that besides soil pH, a low P availability to plants can trigger plant and microbial mobilization mechanisms, leading to increased efficiency of vivianite as a P fertilizer. Further studies are needed to assess the residual effect of vivianite and its effectiveness under field conditions, particularly in soils with low P availability status and an acidic pH.
摘要。虽然有相关的知识是基于土壤性质对普通商业肥料效率的影响，但这种影响对于使用净水中的活菌石作为符合循环经济方法的创新磷肥仍然知之甚少。本研究旨在评价土壤性质对水净化回收的橄榄石作为磷肥效率的影响，并为其有效利用提供实用建议。通过盆栽小麦试验，比较了两种施磷量（50 mg和100 mg P kg-1）下的Vivianite和可溶性无机磷肥（过磷酸磷）在不同性状土壤上的差异。在土壤干物质产量、磷素吸收和奥尔森磷方面，可溶性磷肥的效果最好，而在作物收获后，有机磷在土壤中可提取铁的效果最好。在酸性土壤(pH <；6.6)。在这些酸性土壤中，根据相同数量的可溶性肥料（即P肥替代值- pfrv -以DM为基础）的施用量，vivianite对干物质（DM）产量的影响平均相当于26%或40%，在某些情况下约为50%。对土壤中奥尔森磷的影响平均相当于在酸性土壤中施用相同数量的可溶性矿物肥的49%或61%，具体取决于施用量。这可以解释为这种肥料产品在酸性条件下的溶解度增加，在这些土壤中DTPA可提取铁的增幅最大。酸性土壤是指初始奥尔森磷低于肥料响应阈值的土壤。然而，不同处理方法（DM、P吸收和Olsen P）的PFRV随着初始Olsen P和TV差异值的增加而下降（占解释方差的46%至87%），而不是随着pH值的增加而下降。这表明，除了土壤pH值，植物的低磷可利用性可以触发植物和微生物的动员机制，从而提高了vivianite作为P肥的效率。需要进一步的研究来评估橄榄石的残留效应及其在田间条件下的有效性，特别是在低磷有效状态和酸性土壤中。
{"title":"Circular economy approach in phosphorus fertilization based on vivianite must be tailored to soil properties","authors":"Tolulope Ayeyemi, Ramiro Recena, Ana María García-López, José Manuel Quintero, María Carmen del Campillo, Antonio Delgado","doi":"10.5194/egusphere-2025-1460","DOIUrl":"https://doi.org/10.5194/egusphere-2025-1460","url":null,"abstract":"<strong>Abstract.</strong> Although there is relevant knowledge based on the effect of soil properties on the efficiency of common commercial fertilizers, this effect remains poorly understood for the use of vivianite from water purification as an innovative P fertilizer meeting a circular economy approach. This study aimed to evaluate the effect of soil properties on the efficiency of vivianite recovered from water purification as a P fertilizer and to provide practical recommendations for its effective use. Vivianite and a soluble mineral P fertilizer (superphosphate) were compared at two P application rates (50 and 100 mg P kg<sup>–1</sup>) in soils ranging widely in properties in a pot experiment using wheat. Soluble P fertilizer provided the best results in terms of dry matter (DM) yield, P uptake, and Olsen P in soils, while vivianite led to the best results of DTPA extractable Fe in soils after crop harvest. The application of vivianite as a P fertilizer was more efficient in acidic soils (pH < 6.6). The effect of vivianite on dry matter (DM) yield was equivalent on average to 26 or 40 %, depending on the rate, of the same amount of soluble fertilizer in these acidic soils (i.e., P fertilizer replacement value –PFRV– on DM basis), it being around 50 % in some cases. The effect on Olsen P in soil was equivalent, on average, to 49 or 61 %, depending on the rate, of the same amount applied as soluble mineral fertilizer in acidic soils. This can be explained by the increased solubility of this fertilizer product under acidic conditions, supported by the highest increase in DTPA extractable Fe in these soils. Acidic soils were those with initial Olsen P below the threshold value for fertilizer response (TV). However, PFRV on different approaches (DM, P uptake, and Olsen P) decreased more consistently with increased values of the difference between initial Olsen P and TV (46 to 87 % of the variance explained) than with increased pH. This reveals that besides soil pH, a low P availability to plants can trigger plant and microbial mobilization mechanisms, leading to increased efficiency of vivianite as a P fertilizer. Further studies are needed to assess the residual effect of vivianite and its effectiveness under field conditions, particularly in soils with low P availability status and an acidic pH.","PeriodicalId":48610,"journal":{"name":"Soil","volume":"169 1","pages":""},"PeriodicalIF":6.8,"publicationDate":"2025-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144201975","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}
Pub Date : 2025-06-03DOI: 10.5194/soil-11-395-2025
Rotem Golan, Ittai Gavrieli, Roee Katzir, Galit Sharabi, Uri Nachshon
Abstract. Due to the presence of highly pollutant industries in arid areas, many of the globe's arid areas are exposed to severe local soil contamination events. In this work, the nature of solute and contaminant transport in the sandy terraces of an ephemeral stream that was exposed to a severe pollution event was examined. Here, the Ashalim Basin in the Judean Desert, Israel, is utilized as a case study. In order to shed new light on contaminant distribution along the soil profile and on transport mechanisms in arid environments, three complementary approaches were used: (1) periodic on-site soil profile sampling, recording the annual solute transport dynamics; (2) laboratory analyses and controlled experiments in a rain simulator to characterize solute release and transport; and (3) numerical simulation, used to define and understand the main associated processes. The study highlights the persistent nature of the pollutants in these natural settings, which dictates that they remain near the soil surface despite the presence of sporadic rain events. It was shown that a vertical circulation of the contaminates is occurring with soil wetting and drying cycles. The “surface evaporation capacitor” concept of Or and Lehmann (2019) was examined and compared to field measurements and numerical simulations and was found to be a useful tool for predicting the fate of the contaminants along the soil profile.
{"title":"Soil contamination in arid environments and assessment of remediation applying surface evaporation capacitor model: a case study from the Judean Desert, Israel","authors":"Rotem Golan, Ittai Gavrieli, Roee Katzir, Galit Sharabi, Uri Nachshon","doi":"10.5194/soil-11-395-2025","DOIUrl":"https://doi.org/10.5194/soil-11-395-2025","url":null,"abstract":"Abstract. Due to the presence of highly pollutant industries in arid areas, many of the globe's arid areas are exposed to severe local soil contamination events. In this work, the nature of solute and contaminant transport in the sandy terraces of an ephemeral stream that was exposed to a severe pollution event was examined. Here, the Ashalim Basin in the Judean Desert, Israel, is utilized as a case study. In order to shed new light on contaminant distribution along the soil profile and on transport mechanisms in arid environments, three complementary approaches were used: (1) periodic on-site soil profile sampling, recording the annual solute transport dynamics; (2) laboratory analyses and controlled experiments in a rain simulator to characterize solute release and transport; and (3) numerical simulation, used to define and understand the main associated processes. The study highlights the persistent nature of the pollutants in these natural settings, which dictates that they remain near the soil surface despite the presence of sporadic rain events. It was shown that a vertical circulation of the contaminates is occurring with soil wetting and drying cycles. The “surface evaporation capacitor” concept of Or and Lehmann (2019) was examined and compared to field measurements and numerical simulations and was found to be a useful tool for predicting the fate of the contaminants along the soil profile.","PeriodicalId":48610,"journal":{"name":"Soil","volume":"19 1","pages":""},"PeriodicalIF":6.8,"publicationDate":"2025-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144201974","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}
Pub Date : 2025-05-30DOI: 10.5194/egusphere-2025-2287
Marijn Van de Broek, Fiona Stewart-Smith, Moritz Laub, Marc Corbeels, Monicah Wanjiku Mucheru-Muna, Daniel Mugendi, Wycliffe Waswa, Bernard Vanlauwe, Johan Six
Abstract. Arable soils are generally characterised by a low soil organic carbon (SOC) content, with negative consequences for soil health, crop yield and global climate. Thus, over the past decades, there has been a focus on how agricultural management practices, such as organic resource addition, can increase the amount of SOC. To sustainably increase SOC stocks, a portion of the organic amendments added to the soil has to be stabilised in persistent fractions such as mineral-associated organic carbon (MAOC). However, there is a lack of research on the magnitude of changes in MAOC in tropical agroecosystems in response to organic resource additions. Here, we show for four long-term field trials in Kenya that the addition of large amounts of organic amendments (farmyard manure or Tithonia diversifolia biomass at 4 t C ha-1 yr-1 for 16 to 19 years) to maize monocropping systems had variable effects on topsoil MAOC stocks (0–15 cm depth), and no significant effect on subsoil MAOC stocks (15–50 cm depth) compared to a control treatment. The addition of mineral N fertiliser did not affect MAOC stocks at any site. Using stable carbon isotopes δ13C, we found that the portion of topsoil MAOC originating from Tithonia biomass was larger in the sandy (25–40 %) compared to the clayey soils (0.5–12 %), while the portion of total added Tithonia biomass that was stabilised over a time period of 16–19 years was below 7 % across all sites, or a SOC stabilisation rate of 0.8–27 g C m-2 yr-1. Using these results, we conclude that while in sandy soils the stabilisation of added OC contributed substantially to limiting SOC losses upon cultivation, this was not the case for clayey soils. These differences were due to the much lower SOC stocks in the sandy soils, compared to the clayey soils. Our results underline the challenges associated with improving soil health in sub-Saharan Africa and stress the need for more research to reliably assess if and how additional SOC can be stabilised over decadal time scales in highly weathered tropical soils.
摘要。耕地土壤通常具有土壤有机碳（SOC）含量低的特点，这对土壤健康、作物产量和全球气候都有负面影响。因此，在过去的几十年里，人们一直关注农业管理实践，如有机资源添加，如何增加有机碳的数量。为了可持续地增加有机碳储量，添加到土壤中的一部分有机改进剂必须稳定在持久性组分中，如矿物相关有机碳（MAOC）。然而，缺乏对热带农业生态系统中MAOC随有机资源添加而变化幅度的研究。在这里，我们在肯尼亚进行了四个长期的田间试验，结果表明，与对照处理相比，在玉米单作系统中添加大量的有机改良剂（农家肥或Tithonia多样性生物量，每公顷4吨，每年1年，持续16至19年）对表层土壤MAOC储量（0-15厘米深度）有不同的影响，对底土MAOC储量（15-50厘米深度）没有显著影响。在任何地点，添加无机氮肥对MAOC存量均无影响。利用稳定碳同位素δ13C分析，我们发现，与粘土土壤（0.5 ~ 12%）相比，沙质土壤中来自铁藻生物量的表层土壤有机碳含量（25 ~ 40%）较大，而在16 ~ 19年的时间内稳定的总添加铁藻生物量的比例在所有样地均低于7%，即SOC稳定率为0.8 ~ 27 g C m-2年-1。利用这些结果，我们得出结论，虽然在沙质土壤中，添加的有机碳的稳定性对限制耕作时的有机碳损失有很大贡献，但在粘性土壤中并非如此。这些差异是由于砂质土壤的有机碳储量远低于粘质土壤。我们的研究结果强调了与改善撒哈拉以南非洲土壤健康相关的挑战，并强调需要更多的研究来可靠地评估在高度风化的热带土壤中是否以及如何在十年时间尺度上稳定额外的有机碳。
{"title":"Limited effect of organic matter addition on stabilised organic carbon in four tropical arable soils","authors":"Marijn Van de Broek, Fiona Stewart-Smith, Moritz Laub, Marc Corbeels, Monicah Wanjiku Mucheru-Muna, Daniel Mugendi, Wycliffe Waswa, Bernard Vanlauwe, Johan Six","doi":"10.5194/egusphere-2025-2287","DOIUrl":"https://doi.org/10.5194/egusphere-2025-2287","url":null,"abstract":"<strong>Abstract.</strong> Arable soils are generally characterised by a low soil organic carbon (SOC) content, with negative consequences for soil health, crop yield and global climate. Thus, over the past decades, there has been a focus on how agricultural management practices, such as organic resource addition, can increase the amount of SOC. To sustainably increase SOC stocks, a portion of the organic amendments added to the soil has to be stabilised in persistent fractions such as mineral-associated organic carbon (MAOC). However, there is a lack of research on the magnitude of changes in MAOC in tropical agroecosystems in response to organic resource additions. Here, we show for four long-term field trials in Kenya that the addition of large amounts of organic amendments (farmyard manure or <em>Tithonia diversifolia</em> biomass at 4 t C ha<sup>-1</sup> yr<sup>-1</sup> for 16 to 19 years) to maize monocropping systems had variable effects on topsoil MAOC stocks (0–15 cm depth), and no significant effect on subsoil MAOC stocks (15–50 cm depth) compared to a control treatment. The addition of mineral N fertiliser did not affect MAOC stocks at any site. Using stable carbon isotopes δ<sup>13</sup>C, we found that the portion of topsoil MAOC originating from <em>Tithonia</em> biomass was larger in the sandy (25–40 %) compared to the clayey soils (0.5–12 %), while the portion of total added <em>Tithonia</em> biomass that was stabilised over a time period of 16–19 years was below 7 % across all sites, or a SOC stabilisation rate of 0.8–27 g C m<sup>-2</sup> yr<sup>-1</sup>. Using these results, we conclude that while in sandy soils the stabilisation of added OC contributed substantially to limiting SOC losses upon cultivation, this was not the case for clayey soils. These differences were due to the much lower SOC stocks in the sandy soils, compared to the clayey soils. Our results underline the challenges associated with improving soil health in sub-Saharan Africa and stress the need for more research to reliably assess if and how additional SOC can be stabilised over decadal time scales in highly weathered tropical soils.","PeriodicalId":48610,"journal":{"name":"Soil","volume":"48 1","pages":""},"PeriodicalIF":6.8,"publicationDate":"2025-05-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144176668","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}
Pub Date : 2025-05-30DOI: 10.5194/egusphere-2025-2117
Luca Peruzzo, Ulrike Werban, Marco Pohle, Mirko Pavoni, Benjamin Mary, Giorgio Cassiani, Simona Consoli, Daniela Vanella
Abstract. While above-ground precision agriculture technologies provide spatial and temporal datasets ever-increasing in density and precision, below-ground information lags behind and has been typically limited to time series. As recognized in agrogeophysics, geophysical methods can address the lack of subsurface spatial information. This study focuses on high-resolution Frequency-Domain ElectroMagnetic induction (FDEM) mapping as an ideal complement to above- and below-ground time series that are commonly available in precision agriculture. Focused on a Sicilian orange orchard, this study first investigates some methodological challenges behind seemingly simple FDEM survey choices and processing steps, as well as their interplay with the spatial heterogeneity of agricultural sites. Second, this study shows how the detailed FDEM-based spatial information can underpin a surface/subsurface hydrological model that integrates time series from soil moisture sensors and micro-meteorological sensors. While FDEM has long been recognized as a promising solution in agrogeophysics, this study demonstrates how the approach can be successfully applied in a orchard, whose 3D subsurface variability is a complex combination of root water uptake, irrigation, evapotranspiration, and row-interrow dynamics. The resulting hydrological model reproduces the observed spatiotemporal water dynamics with parameters that agree with the results from soil laboratory analysis, supporting gamma-ray and electrical resistivity tomography datasets. The implementation of a hydrological model positively aligns with the increasing number and variety of methods in precision agriculture, as well as with the need for better predictive capability.
{"title":"High-resolution near-surface electromagnetic mapping for the hydrological modeling of an orange orchard","authors":"Luca Peruzzo, Ulrike Werban, Marco Pohle, Mirko Pavoni, Benjamin Mary, Giorgio Cassiani, Simona Consoli, Daniela Vanella","doi":"10.5194/egusphere-2025-2117","DOIUrl":"https://doi.org/10.5194/egusphere-2025-2117","url":null,"abstract":"<strong>Abstract.</strong> While above-ground precision agriculture technologies provide spatial and temporal datasets ever-increasing in density and precision, below-ground information lags behind and has been typically limited to time series. As recognized in agrogeophysics, geophysical methods can address the lack of subsurface spatial information. This study focuses on high-resolution Frequency-Domain ElectroMagnetic induction (FDEM) mapping as an ideal complement to above- and below-ground time series that are commonly available in precision agriculture. Focused on a Sicilian orange orchard, this study first investigates some methodological challenges behind seemingly simple FDEM survey choices and processing steps, as well as their interplay with the spatial heterogeneity of agricultural sites. Second, this study shows how the detailed FDEM-based spatial information can underpin a surface/subsurface hydrological model that integrates time series from soil moisture sensors and micro-meteorological sensors. While FDEM has long been recognized as a promising solution in agrogeophysics, this study demonstrates how the approach can be successfully applied in a orchard, whose 3D subsurface variability is a complex combination of root water uptake, irrigation, evapotranspiration, and row-interrow dynamics. The resulting hydrological model reproduces the observed spatiotemporal water dynamics with parameters that agree with the results from soil laboratory analysis, supporting gamma-ray and electrical resistivity tomography datasets. The implementation of a hydrological model positively aligns with the increasing number and variety of methods in precision agriculture, as well as with the need for better predictive capability.","PeriodicalId":48610,"journal":{"name":"Soil","volume":"13 1","pages":""},"PeriodicalIF":6.8,"publicationDate":"2025-05-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144176666","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}
Pub Date : 2025-05-28DOI: 10.5194/egusphere-2025-2291
Oliver Grothum, Lea Epple, Anne Bienert, Xabier Blanch, Anette Eltner
Abstract. Soil erosion represents a major global threat, necessitating a detailed understanding of its spatial and temporal dynamics. Advanced geospatial technologies such as time-lapse structure-from-motion (SfM) photogrammetry provide high-resolution monitoring of surface changes. This study presents a novel event-driven approach for near-continuous monitoring of hillslope surface dynamics over a multi-annual period. The system employed synchronized DSLR (digital single-lens reflex) cameras at three slope stations, triggered by a rain gauge and a daily timer. Ground control points (GCPs) were surveyed with millimeter accuracy to ensure precise georeferencing. An automated Python-based workflow was developed to synchronize images, detect GCPs using a convolutional neural network (CNN), generate daily digital 3D surface models via SfM, and compute 3D surface models of difference (DoDs). The absolute accuracy of SfM point clouds ranged between 8 mm and 12 mm on average, primarily due to registration errors, with lower deviations (< 5 mm) in central areas after height adjustment. Relative accuracy decreased concentrically with distance from the cameras, with level of detection (LoD) values between 5 mm and 25 mm depending on distance and location. Time series analysis revealed surface changes driven by rainfall, snowmelt, and agricultural activity. The most significant changes often occurred shortly after tillage, even with minimal rainfall, indicating both erosional and non-erosional processes. A strong negative correlation between rainfall and elevation loss was especially evident within the first seven days following tillage. Seasonal surface lowering of 3–5 cm during winter and occasional positive changes due to frost or vegetation growth were also observed. The monitoring system and workflow are transferable, and the resulting high-resolution datasets are valuable for analyzing erosion dynamics and validating soil erosion models.
{"title":"Near-continuous observation of soil surface changes at single slopes with high spatial resolution via an automated SfM photogrammetric mapping approach","authors":"Oliver Grothum, Lea Epple, Anne Bienert, Xabier Blanch, Anette Eltner","doi":"10.5194/egusphere-2025-2291","DOIUrl":"https://doi.org/10.5194/egusphere-2025-2291","url":null,"abstract":"<strong>Abstract.</strong> Soil erosion represents a major global threat, necessitating a detailed understanding of its spatial and temporal dynamics. Advanced geospatial technologies such as time-lapse structure-from-motion (SfM) photogrammetry provide high-resolution monitoring of surface changes. This study presents a novel event-driven approach for near-continuous monitoring of hillslope surface dynamics over a multi-annual period. The system employed synchronized DSLR (digital single-lens reflex) cameras at three slope stations, triggered by a rain gauge and a daily timer. Ground control points (GCPs) were surveyed with millimeter accuracy to ensure precise georeferencing. An automated Python-based workflow was developed to synchronize images, detect GCPs using a convolutional neural network (CNN), generate daily digital 3D surface models via SfM, and compute 3D surface models of difference (DoDs). The absolute accuracy of SfM point clouds ranged between 8 mm and 12 mm on average, primarily due to registration errors, with lower deviations (< 5 mm) in central areas after height adjustment. Relative accuracy decreased concentrically with distance from the cameras, with level of detection (LoD) values between 5 mm and 25 mm depending on distance and location. Time series analysis revealed surface changes driven by rainfall, snowmelt, and agricultural activity. The most significant changes often occurred shortly after tillage, even with minimal rainfall, indicating both erosional and non-erosional processes. A strong negative correlation between rainfall and elevation loss was especially evident within the first seven days following tillage. Seasonal surface lowering of 3–5 cm during winter and occasional positive changes due to frost or vegetation growth were also observed. The monitoring system and workflow are transferable, and the resulting high-resolution datasets are valuable for analyzing erosion dynamics and validating soil erosion models.","PeriodicalId":48610,"journal":{"name":"Soil","volume":"43 1","pages":""},"PeriodicalIF":6.8,"publicationDate":"2025-05-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144153684","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}
Pub Date : 2025-05-27DOI: 10.5194/egusphere-2025-2048
Tao Anh Khoi
Abstract. Long-term monoculture systems such as tea (Camellia sinensis) plantations can lead to significant changes in soil quality, directly influencing crop productivity and sustainability. This study investigates the impacts of tea cultivation over a 20-year period on key soil quality indicators in Lam Dong province, Vietnam—a major highland tea-growing region. Soils were sampled from plantations of varying ages (5, 10, and 20 years) and compared with native forest soils. Chemical, physical, and biological properties were assessed, including soil organic carbon (SOC), nutrient availability (N, P, K, S), pH, bulk density, plant-available water capacity (PAWC), aggregate stability, and earthworm populations. Results show a significant decline in SOC, available P and K, and PAWC with increasing plantation age, while bulk density and mechanical resistance increased, indicating progressive soil compaction. A multiple regression analysis revealed that SOC, available P, total K, and PAWC were the most predictive indicators of long-term tea productivity. Economic analysis suggests that tea cultivation remains marginally profitable after 20 years, provided that adequate fertilization is maintained. This study proposes critical threshold levels for soil quality indicators to support sustainable tea production in tropical highland systems.
{"title":"Assessing Long-Term Effects of Tea (Camellia sinensis) Cultivation on Soil Quality in Highland Agroecosystems: A Case Study in Lam Dong, Vietnam","authors":"Tao Anh Khoi","doi":"10.5194/egusphere-2025-2048","DOIUrl":"https://doi.org/10.5194/egusphere-2025-2048","url":null,"abstract":"<strong>Abstract.</strong> Long-term monoculture systems such as tea (Camellia sinensis) plantations can lead to significant changes in soil quality, directly influencing crop productivity and sustainability. This study investigates the impacts of tea cultivation over a 20-year period on key soil quality indicators in Lam Dong province, Vietnam—a major highland tea-growing region. Soils were sampled from plantations of varying ages (5, 10, and 20 years) and compared with native forest soils. Chemical, physical, and biological properties were assessed, including soil organic carbon (SOC), nutrient availability (N, P, K, S), pH, bulk density, plant-available water capacity (PAWC), aggregate stability, and earthworm populations. Results show a significant decline in SOC, available P and K, and PAWC with increasing plantation age, while bulk density and mechanical resistance increased, indicating progressive soil compaction. A multiple regression analysis revealed that SOC, available P, total K, and PAWC were the most predictive indicators of long-term tea productivity. Economic analysis suggests that tea cultivation remains marginally profitable after 20 years, provided that adequate fertilization is maintained. This study proposes critical threshold levels for soil quality indicators to support sustainable tea production in tropical highland systems.","PeriodicalId":48610,"journal":{"name":"Soil","volume":"43 1","pages":""},"PeriodicalIF":6.8,"publicationDate":"2025-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144145494","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}
Pub Date : 2025-05-21DOI: 10.5194/soil-11-389-2025
Siobhan Staunton, Chiara Pistocchi
Abstract. Mineral P is an increasingly scarce resource, and therefore the mobilisation of legacy soil P must be optimised to maintain soil fertility. We have used isotopic exchangeability to probe the lability of native soil P in four contrasting soils following acidification and the addition of carboxylate anions (citrate and oxalate) in soil suspension. Acidification tended to cause immobilisation of soil P, but this was attributed to a salt effect. Addition of both citrate and oxalate led to marked increases in mobilisation of soil P. This would result from both competition between carboxylate and phosphate ions at adsorption sites and chelation of charge-compensating cations. The carboxylate effects were similar at each level of acidification, indicating that effects were largely additive. This is not true for the most calcareous soil where calcium oxalate may have been precipitated at the highest oxalate addition. Promoting carboxylate anions in soil by soil amendment or the use of crops that exude large amounts of such organic anions is a promising approach to improve soil-P availability.
{"title":"Isotopic exchangeability reveals that soil phosphate is mobilised by carboxylate anions, whereas acidification had the reverse effect","authors":"Siobhan Staunton, Chiara Pistocchi","doi":"10.5194/soil-11-389-2025","DOIUrl":"https://doi.org/10.5194/soil-11-389-2025","url":null,"abstract":"Abstract. Mineral P is an increasingly scarce resource, and therefore the mobilisation of legacy soil P must be optimised to maintain soil fertility. We have used isotopic exchangeability to probe the lability of native soil P in four contrasting soils following acidification and the addition of carboxylate anions (citrate and oxalate) in soil suspension. Acidification tended to cause immobilisation of soil P, but this was attributed to a salt effect. Addition of both citrate and oxalate led to marked increases in mobilisation of soil P. This would result from both competition between carboxylate and phosphate ions at adsorption sites and chelation of charge-compensating cations. The carboxylate effects were similar at each level of acidification, indicating that effects were largely additive. This is not true for the most calcareous soil where calcium oxalate may have been precipitated at the highest oxalate addition. Promoting carboxylate anions in soil by soil amendment or the use of crops that exude large amounts of such organic anions is a promising approach to improve soil-P availability.","PeriodicalId":48610,"journal":{"name":"Soil","volume":"236 1","pages":""},"PeriodicalIF":6.8,"publicationDate":"2025-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144104820","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}
Pub Date : 2025-05-20DOI: 10.5194/egusphere-2025-1896
David G. Rossiter, Laura Poggio
Abstract. Since the earliest days of soil geography, it has been clear that soils occur in more-or-less clearly mappable bodies, within which soil forming factors have been fairly homogeneous or in a regular pattern, and between which there is usually a clear transition in one or more factors. This has been the basis for polygon-based soil mapping: make a concept map from landscape elements leading to a mental model of the landscape, confirm or modify it with strategically-placed observations, find the transitions, delineate the soil bodies, and characterise them. By contrast, common methods of Digital Soil Mapping (DSM) predict per pixel over a regular grid, from training observations at pedon support. Accuracy assessment of DSM products has been at this “point” support, ignoring the existence of spatial soil bodies and the relations between pixels. Different approaches to DSM – datasets, model forms, analyst choices – result in maps with distinctly different patterns of predicted soil properties or types. Techniques from landscape ecology have been used to characterize spatial patterns of DSM products. The question remains as to how well these products reproduce the actual soil patterns at a given cartographic scale and categorical level of detail. Our approach is to let DSM maps “speak for themselves” to reveal spatial patterns. We do this by grouping pixels, either (1) by aggregation based on property homogeneity using the supercells algorithm, or (2) by segmentation based on within-block property pattern similarity, using the GeoPAT suite of computer programs. Segments can be hierarchically clustered into groups of presumed soil landscape elements. Supercells and segments can be compared to existing soil maps, other land resource maps, and expert judgement. To the extent that presumed soilscape patterns are reproduced, this is evidence that DSM has identified the soil landscape at the chosen scale. Since map users perceive patterns, and most land use decisions are for areas rather than pixels, we propose that DSM products be evaluated by their patterns, as well as by pointwise evaluation statistics.
{"title":"Representing soil landscapes from digital soil mapping products – let the map speak for itself","authors":"David G. Rossiter, Laura Poggio","doi":"10.5194/egusphere-2025-1896","DOIUrl":"https://doi.org/10.5194/egusphere-2025-1896","url":null,"abstract":"<strong>Abstract.</strong> Since the earliest days of soil geography, it has been clear that soils occur in more-or-less clearly mappable bodies, within which soil forming factors have been fairly homogeneous or in a regular pattern, and between which there is usually a clear transition in one or more factors. This has been the basis for polygon-based soil mapping: make a concept map from landscape elements leading to a mental model of the landscape, confirm or modify it with strategically-placed observations, find the transitions, delineate the soil bodies, and characterise them. By contrast, common methods of Digital Soil Mapping (DSM) predict per pixel over a regular grid, from training observations at pedon support. Accuracy assessment of DSM products has been at this “point” support, ignoring the existence of spatial soil bodies and the relations between pixels. Different approaches to DSM – datasets, model forms, analyst choices – result in maps with distinctly different patterns of predicted soil properties or types. Techniques from landscape ecology have been used to characterize spatial patterns of DSM products. The question remains as to how well these products reproduce the actual soil patterns at a given cartographic scale and categorical level of detail. Our approach is to let DSM maps “speak for themselves” to reveal spatial patterns. We do this by grouping pixels, either (1) by aggregation based on property homogeneity using the supercells algorithm, or (2) by segmentation based on within-block property pattern similarity, using the GeoPAT suite of computer programs. Segments can be hierarchically clustered into groups of presumed soil landscape elements. Supercells and segments can be compared to existing soil maps, other land resource maps, and expert judgement. To the extent that presumed soilscape patterns are reproduced, this is evidence that DSM has identified the soil landscape at the chosen scale. Since map users perceive patterns, and most land use decisions are for areas rather than pixels, we propose that DSM products be evaluated by their patterns, as well as by pointwise evaluation statistics.","PeriodicalId":48610,"journal":{"name":"Soil","volume":"40 1","pages":""},"PeriodicalIF":6.8,"publicationDate":"2025-05-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144097772","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}
Pub Date : 2025-05-20DOI: 10.5194/soil-11-381-2025
Mike C. Rowley, Jasquelin Pena, Matthew A. Marcus, Rachel Porras, Elaine Pegoraro, Cyrill Zosso, Nicholas O. E. Ofiti, Guido L. B. Wiesenberg, Michael W. I. Schmidt, Margaret S. Torn, Peter S. Nico
Abstract. Calcium (Ca) may contribute to the preservation of soil organic carbon (SOC) in more ecosystems than previously thought. Here, we provide evidence that Ca is co-located with SOC compounds that are enriched in aromatic and phenolic groups, across different acidic soil types and locations with different ecosystem properties, differing in terms of climate, parent material, soil type, and vegetation. In turn, this co-localised fraction of Ca–SOC is removed through cation exchange, and the association is then only re-established during decomposition in the presence of Ca (Ca addition incubation). Thus, this highlights a causative link between decomposition and the co-location of Ca with a characteristic fraction of SOC. Decomposition increases the relative proportion of negatively charged functional groups, which can increase the propensity for the association between SOC and Ca; in turn, this association can inhibit dissolved organic carbon export or further decomposition. We propose that this mechanism could be driven by Ca hotspots at the microscale shifting local decomposition processes and thereby explaining the co-location of Ca with SOC of a specific composition across different acidic soil environments. Incorporating this biogeochemical process into Earth system models could improve our understanding, predictions, and management of carbon dynamics in soils, as well as accounting for their response to Ca-rich amendments.
{"title":"Calcium is associated with specific soil organic carbon decomposition products","authors":"Mike C. Rowley, Jasquelin Pena, Matthew A. Marcus, Rachel Porras, Elaine Pegoraro, Cyrill Zosso, Nicholas O. E. Ofiti, Guido L. B. Wiesenberg, Michael W. I. Schmidt, Margaret S. Torn, Peter S. Nico","doi":"10.5194/soil-11-381-2025","DOIUrl":"https://doi.org/10.5194/soil-11-381-2025","url":null,"abstract":"Abstract. Calcium (Ca) may contribute to the preservation of soil organic carbon (SOC) in more ecosystems than previously thought. Here, we provide evidence that Ca is co-located with SOC compounds that are enriched in aromatic and phenolic groups, across different acidic soil types and locations with different ecosystem properties, differing in terms of climate, parent material, soil type, and vegetation. In turn, this co-localised fraction of Ca–SOC is removed through cation exchange, and the association is then only re-established during decomposition in the presence of Ca (Ca addition incubation). Thus, this highlights a causative link between decomposition and the co-location of Ca with a characteristic fraction of SOC. Decomposition increases the relative proportion of negatively charged functional groups, which can increase the propensity for the association between SOC and Ca; in turn, this association can inhibit dissolved organic carbon export or further decomposition. We propose that this mechanism could be driven by Ca hotspots at the microscale shifting local decomposition processes and thereby explaining the co-location of Ca with SOC of a specific composition across different acidic soil environments. Incorporating this biogeochemical process into Earth system models could improve our understanding, predictions, and management of carbon dynamics in soils, as well as accounting for their response to Ca-rich amendments.","PeriodicalId":48610,"journal":{"name":"Soil","volume":"32 1","pages":""},"PeriodicalIF":6.8,"publicationDate":"2025-05-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144097771","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}
Pub Date : 2025-05-14DOI: 10.5194/soil-11-371-2025
Aelis Spiller, Cynthia M. Kallenbach, Melanie S. Burnett, David Olefeldt, Christopher Schulze, Roxane Maranger, Peter M. J. Douglas
Abstract. Permafrost thawing of northern peatlands can cause the local collapse of peat plateaus into much wetter thermokarst bogs and fens, dominated by Sphagnum mosses and graminoids, respectively. However, permafrost thaw can also improve landscape drainage and, thus, lead to the regional drying of peatlands. How gradual drying of these thawing permafrost peatlands affects the subsequent microbial production of carbon dioxide (CO2) and nitrous oxide (N2O) is uncertain because of landscape heterogeneity in moisture, peat quality, and vegetation. Here, we collected near-surface peat samples (5–20 cm) from Alberta, Canada, across transects representing a thaw gradient from peat plateaus to a fen or bog. We incubated the samples for 2 weeks under either field moisture or under gradual drying to reduce moisture by ∼ 80 %. Only the fen sites, which had high moisture and a high percentage of total N, produced N2O (0.06–6.7 µg N2O-N per gram of dry peat), but N2O production was unaffected by the drying treatments. Peat CO2 production was greatest from the fen and the youngest stage of the thermokarst bog, despite them having the most water-saturated field conditions, likely reflecting their more labile plant inputs and, thus, more decomposable peat. We found that CO2 respiration was enhanced by drying at relatively wet sites like the fens and young bog but was suppressed by drying in relatively drier peat plateaus. Further, gradual drying increased 13C-CO2 respiration, suggesting a possible shift to more decomposed, older C being lost with peat drying. Thus, our study suggests that future peat CO2 and N2O production from peatlands will depend on whether peat plateaus thaw into fens or bogs and on their diverging responses of peat respiration to more moisture-limited conditions.
{"title":"Gradual drying of permafrost peat decreases carbon dioxide production in drier peat plateaus but not in wetter fens and bogs","authors":"Aelis Spiller, Cynthia M. Kallenbach, Melanie S. Burnett, David Olefeldt, Christopher Schulze, Roxane Maranger, Peter M. J. Douglas","doi":"10.5194/soil-11-371-2025","DOIUrl":"https://doi.org/10.5194/soil-11-371-2025","url":null,"abstract":"Abstract. Permafrost thawing of northern peatlands can cause the local collapse of peat plateaus into much wetter thermokarst bogs and fens, dominated by Sphagnum mosses and graminoids, respectively. However, permafrost thaw can also improve landscape drainage and, thus, lead to the regional drying of peatlands. How gradual drying of these thawing permafrost peatlands affects the subsequent microbial production of carbon dioxide (CO2) and nitrous oxide (N2O) is uncertain because of landscape heterogeneity in moisture, peat quality, and vegetation. Here, we collected near-surface peat samples (5–20 cm) from Alberta, Canada, across transects representing a thaw gradient from peat plateaus to a fen or bog. We incubated the samples for 2 weeks under either field moisture or under gradual drying to reduce moisture by ∼ 80 %. Only the fen sites, which had high moisture and a high percentage of total N, produced N2O (0.06–6.7 µg N2O-N per gram of dry peat), but N2O production was unaffected by the drying treatments. Peat CO2 production was greatest from the fen and the youngest stage of the thermokarst bog, despite them having the most water-saturated field conditions, likely reflecting their more labile plant inputs and, thus, more decomposable peat. We found that CO2 respiration was enhanced by drying at relatively wet sites like the fens and young bog but was suppressed by drying in relatively drier peat plateaus. Further, gradual drying increased 13C-CO2 respiration, suggesting a possible shift to more decomposed, older C being lost with peat drying. Thus, our study suggests that future peat CO2 and N2O production from peatlands will depend on whether peat plateaus thaw into fens or bogs and on their diverging responses of peat respiration to more moisture-limited conditions.","PeriodicalId":48610,"journal":{"name":"Soil","volume":"4 1","pages":""},"PeriodicalIF":6.8,"publicationDate":"2025-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143945598","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}
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