Abstract. The previous rather abstract debate about sustainable development has been focused by the introduction of the United Nations (UN) Sustainable Development Goals (SDGs) in 2015 and the related European Union (EU) Green Deal (GD) in 2019. Restricting attention to agriculture, proposed targets and indicators are, however, not specific enough to allow a focus for developing innovative and sustainable management practices. Clarity is needed because farmers are suspicious of governmental actions. To confront these problems, the European Commission (EC) has presented the Mission concept that requires joint learning between farmers, scientists and citizens. For the soil mission, “living labs” are proposed that should evolve into “lighthouses” when environmental thresholds for each of at least six land-related ecosystem services are met. This presents “wicked” problems that can be “tamed” by measuring indicators for ecosystem services that are associated with the land-related SDGs in a given living lab. Thresholds with a character that is occasionally regional are needed to separate the “good” from the “not yet good enough”. Contributions by the soil to ecosystem services can be expressed by assessing soil health. By introducing the mission concept, the policy arena challenges the research community to rise to the occasion by developing effective interaction models with farmers and citizens that can be the foundation for innovative and effective environmental rules and regulations. We argue and illustrate with a specific example, that establishing Living Labs can be an important, if not essential, contribution to realizing the lofty goals of the SDGs and the Green Deal as they relate to agriculture.
{"title":"Transforming living labs into lighthouses: a promising policy to achieve land-related sustainable development","authors":"J. Bouma","doi":"10.5194/soil-8-751-2022","DOIUrl":"https://doi.org/10.5194/soil-8-751-2022","url":null,"abstract":"Abstract. The previous rather abstract debate about sustainable development has been focused by the introduction of the United Nations (UN) Sustainable Development Goals (SDGs) in 2015 and the related European Union (EU) Green Deal (GD) in 2019. Restricting attention to agriculture, proposed targets and indicators are, however, not specific enough to allow a focus for developing innovative and sustainable management practices. Clarity is needed because farmers are suspicious of governmental actions. To confront these problems, the European Commission (EC) has presented the Mission concept that requires joint learning between farmers, scientists and citizens. For the soil mission, “living labs” are proposed that should evolve into “lighthouses” when environmental thresholds for each of at least six land-related ecosystem services are met. This presents “wicked” problems that can be “tamed” by measuring indicators for ecosystem services that\u0000are associated with the land-related SDGs in a given living lab. Thresholds with a character that is occasionally regional are needed to separate the “good” from the “not yet good enough”. Contributions by the soil to ecosystem services can be expressed by assessing soil health. By introducing the mission concept, the policy arena challenges the research community to rise to the occasion by developing effective interaction models with farmers and citizens that can be the foundation for innovative and effective environmental rules and regulations. We argue and illustrate with a specific example, that establishing Living Labs can be an important, if not essential, contribution to realizing the lofty goals of the SDGs and the Green Deal as they relate to agriculture.\u0000","PeriodicalId":22015,"journal":{"name":"Soil Science","volume":"68 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-12-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81111281","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A. Ågren, E. M. Hasselquist, J. Stendahl, M. Nilsson, S. S. Paul
Abstract. To meet the sustainable development goals and enable sustainable management and protection of peatlands, there is a strong need for improving the mapping of peatlands. Here we present a novel approach to identify peat soils based on a high-resolution digital soil moisture map that was produced by combining airborne laser scanning-derived terrain indices and machine learning to model soil moisture at 2 m spatial resolution across the Swedish landscape. As soil moisture is a key factor in peat formation, we fitted an empirical relationship between the thickness of the organic layer (measured at 5479 soil plots across the country) and the continuous SLU (Swedish University of Agricultural Science) soil moisture map (R2= 0.66, p < 0.001). We generated categorical maps of peat occurrence using three different definitions of peat (30, 40, and 50 cm thickness of the organic layer) and a continuous map of organic layer thickness. The predicted peat maps had a higher overall quality (MCC = 0.69–0.73) compared to traditional Quaternary deposits maps (MCC = 0.65) and topographical maps (MCC = 0.61) and captured the peatlands with a recall of ca. 80 % compared to 50 %–70 % on the traditional maps. The predicted peat maps identified more peatland area than previous maps, and the areal coverage estimates fell within the same order as upscaling estimates from national field surveys. Our method was able to identify smaller peatlands resulting in more accurate maps of peat soils, which was not restricted to only large peatlands that can be visually detected from aerial imagery – the historical approach of mapping. We also provided a continuous map of the organic layer, which ranged 6–88 cm organic layer thickness, with an R2 of 0.67 and RMSE (root mean square error) of 19 cm. The continuous map exhibits a smooth transition of organic layers from mineral soil to peat soils and likely provides a more natural representation of the distribution of soils. The continuous map also provides an intuitive uncertainty estimate in the delineation of peat soils, critically useful for sustainable spatial planning, e.g., greenhouse gas or biodiversity inventories and landscape ecological research.
摘要为了实现可持续发展目标，实现泥炭地的可持续管理和保护，迫切需要改进泥炭地的测绘工作。在这里，我们提出了一种基于高分辨率数字土壤湿度图来识别泥炭土的新方法，该地图是通过结合机载激光扫描导出的地形指数和机器学习来模拟瑞典景观中2米空间分辨率的土壤湿度而产生的。由于土壤湿度是泥炭形成的关键因素，我们拟合了有机层厚度(在全国5479个土壤样地测量)与连续SLU(瑞典农业科学大学)土壤湿度图之间的经验关系(R2= 0.66, p < 0.001)。我们使用三种不同的泥炭定义(有机层厚度30,40和50厘米)和有机层厚度的连续图生成了泥炭发生的分类图。与传统的第四纪沉积图(MCC = 0.65)和地形图(MCC = 0.61)相比，预测泥炭地图的总体质量(MCC = 0.69-0.73)更高，泥炭地的召回率约为80%，而传统地图的召回率为50% - 70%。预测的泥炭地图比以前的地图确定了更多的泥炭地面积，并且面积覆盖估计值与国家实地调查的估计值处于同一顺序。我们的方法能够识别较小的泥炭地，从而绘制出更准确的泥炭土地图，而不仅仅局限于可以从材料图像中视觉检测到的大型泥炭地——这是制图的历史方法。我们还提供了有机层的连续图，有机层厚度范围为6-88 cm, R2为0.67，均方根误差(RMSE)为19 cm。连续图显示了有机层从矿物土到泥炭土的平滑过渡，可能提供了土壤分布的更自然的表示。连续地图还为泥炭土的描绘提供了直观的不确定性估计，这对可持续空间规划至关重要，例如温室气体或生物多样性清单和景观生态学研究。
{"title":"Delineating the distribution of mineral and peat soils at the landscape scale in northern boreal regions","authors":"A. Ågren, E. M. Hasselquist, J. Stendahl, M. Nilsson, S. S. Paul","doi":"10.5194/soil-8-733-2022","DOIUrl":"https://doi.org/10.5194/soil-8-733-2022","url":null,"abstract":"Abstract. To meet the sustainable development goals and enable sustainable\u0000management and protection of peatlands, there is a strong need for improving\u0000the mapping of peatlands. Here we present a novel approach to identify peat\u0000soils based on a high-resolution digital soil moisture map that was produced\u0000by combining airborne laser scanning-derived terrain indices and machine\u0000learning to model soil moisture at 2 m spatial resolution across the Swedish\u0000landscape. As soil moisture is a key factor in peat formation, we fitted an\u0000empirical relationship between the thickness of the organic layer (measured\u0000at 5479 soil plots across the country) and the continuous SLU (Swedish University of Agricultural Science) soil moisture\u0000map (R2= 0.66, p < 0.001). We generated categorical maps of\u0000peat occurrence using three different definitions of peat (30, 40, and 50 cm\u0000thickness of the organic layer) and a continuous map of organic layer\u0000thickness. The predicted peat maps had a higher overall quality (MCC = 0.69–0.73) compared to traditional Quaternary deposits maps (MCC = 0.65)\u0000and topographical maps (MCC = 0.61) and captured the peatlands with a\u0000recall of ca. 80 % compared to 50 %–70 % on the traditional maps. The\u0000predicted peat maps identified more peatland area than previous maps, and\u0000the areal coverage estimates fell within the same order as upscaling\u0000estimates from national field surveys. Our method was able to identify\u0000smaller peatlands resulting in more accurate maps of peat soils, which was\u0000not restricted to only large peatlands that can be visually detected from\u0000aerial imagery – the historical approach of mapping. We also provided a\u0000continuous map of the organic layer, which ranged 6–88 cm organic layer\u0000thickness, with an R2 of 0.67 and RMSE (root mean square error) of 19 cm. The continuous map\u0000exhibits a smooth transition of organic layers from mineral soil to peat\u0000soils and likely provides a more natural representation of the distribution\u0000of soils. The continuous map also provides an intuitive uncertainty estimate\u0000in the delineation of peat soils, critically useful for sustainable spatial\u0000planning, e.g., greenhouse gas or biodiversity inventories and landscape\u0000ecological research.\u0000","PeriodicalId":22015,"journal":{"name":"Soil Science","volume":"11 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-12-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78588627","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Nicolás Riveras-Muñoz, S. Seitz, K. Witzgall, V. Rodríguez, P. Kühn, C. Mueller, R. Oses, O. Seguel, D. Wagner, T. Scholten
Abstract. Biological soil crusts (biocrusts) composed of cyanobacteria, bacteria, algae, fungi, lichens, and bryophytes stabilize the soil surface. This effect has mainly been studied in arid climates, where biocrusts constitute the main biological agent to stabilize and connect soil aggregates. Besides, biocrusts are an integral part of the soil surface under Mediterranean and humid climate conditions, mainly covering open spaces in forests and on denuded lands. They often develop after vegetation disturbances, when their ability to compete with vascular plants increases, acting as pioneer communities and affecting the stability of soil aggregates. To better understand how biocrusts mediate changes in soil aggregate stability under different climate conditions, we analyzed soil aggregate samples collected under biocrust communities from four national parks in Chile along a large climatic gradient ranging from (north to south) arid (Pan de Azúcar, PA), semi-arid (Santa Gracia, SG), Mediterranean (La Campana, LC) to humid (Nahuelbuta, NA). Biocrust communities showed a stabilizing effect on the soil aggregates in dry fractions for the three northern sites and the wet aggregates for the southernmost site. Here, permanent vascular plants and higher contents of organic carbon and nitrogen in the soil control aggregate stability more than biocrusts, which are in intense competition with higher plant communities. Moreover, we found an increase in stability for aggregate size classes < 2.0 and 9.5–30.0 mm. The geometric mean diameter of the soil aggregates showed a clear effect due to the climatic gradient, indicating that the aggregate stability presents a log-normal instead of a normal distribution, with a trend of low change between aggregate size fractions. Based on our results, we assume that biocrusts affect the soil structure in all climates. Their role in aggregate stability is masked under humid conditions by higher vegetation and organic matter contents in the topsoil.
{"title":"Biocrust-linked changes in soil aggregate stability along a climatic gradient in the Chilean Coastal Range","authors":"Nicolás Riveras-Muñoz, S. Seitz, K. Witzgall, V. Rodríguez, P. Kühn, C. Mueller, R. Oses, O. Seguel, D. Wagner, T. Scholten","doi":"10.5194/soil-8-717-2022","DOIUrl":"https://doi.org/10.5194/soil-8-717-2022","url":null,"abstract":"Abstract. Biological soil crusts (biocrusts) composed of cyanobacteria, bacteria, algae, fungi, lichens, and bryophytes stabilize the soil surface. This\u0000effect has mainly been studied in arid climates, where biocrusts constitute the main biological agent to stabilize and connect soil\u0000aggregates. Besides, biocrusts are an integral part of the soil surface under Mediterranean and humid climate conditions, mainly covering open\u0000spaces in forests and on denuded lands. They often develop after vegetation disturbances, when their ability to compete with vascular plants increases, acting as pioneer communities and affecting the stability of soil aggregates. To better understand how biocrusts mediate changes in soil aggregate stability under different climate conditions, we analyzed soil aggregate samples collected under biocrust communities from four national parks in Chile along a large climatic gradient ranging from (north to south) arid (Pan de Azúcar, PA), semi-arid (Santa Gracia, SG), Mediterranean (La Campana, LC) to humid (Nahuelbuta, NA). Biocrust communities showed a stabilizing effect on the soil aggregates in dry fractions for the three northern sites and the wet aggregates for the southernmost site. Here, permanent vascular plants and higher contents of organic carbon and nitrogen in the soil control aggregate stability more than biocrusts, which are in intense competition with higher plant communities. Moreover, we found an increase in stability for aggregate size classes < 2.0 and 9.5–30.0 mm. The geometric mean diameter of the soil aggregates showed a clear effect due to the climatic gradient, indicating that the aggregate stability presents a log-normal instead of a normal distribution, with a trend of low change between aggregate size fractions. Based on our results, we assume that biocrusts affect the soil structure in all climates. Their role in aggregate stability is masked under humid conditions by higher vegetation and organic matter contents in the topsoil.\u0000","PeriodicalId":22015,"journal":{"name":"Soil Science","volume":"33 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-12-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74444970","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract. To understand global soil organic matter (SOM) chemistry and its dynamics, we need tools to efficiently quantify SOM properties, for example, prediction models using mid-infrared spectra. However, the advantages of such models rely on their validity and accuracy. Recently, Hodgkins et al. (2018) developed models to quantitatively predict peat holocellulose and Klason lignin contents, two indicators of SOM stability and major fractions of organic matter. The models may help to understand large-scale SOM gradients and have been used in various studies. A research gap to fill is that these models have not been validated in detail yet. What are their limitations and how can we improve them? This study provides a validation with the aim to identify concrete steps to improve these models. As a first step, we provide several improvements using the original training data. The major limitation we identified is that the original training data are not representative for a range of diverse peat samples. This causes both biased estimates and extrapolation uncertainty under the original models. In addition, the original models can in practice produce unrealistic predictions (negative values or values >100 mass-%). Our improved models partly reduce the observed bias, have a better predictive performance for the training data, and avoid such unrealistic predictions. Finally, we provide a proof of concept that holocellulose contents can also be predicted for mineral-rich samples (e.g., peat with mineral admixtures or potentially mineral soils). A key step to improve the models will be to collect training data that are representative for SOM formed under various conditions. This study opens directions to develop operational models to predict SOM holocellulose and Klason lignin contents from mid-infrared spectra.
{"title":"Improving models to predict holocellulose and Klason lignin contents for peat soil organic matter with mid-infrared spectra","authors":"Henning Teickner, K. Knorr","doi":"10.5194/soil-8-699-2022","DOIUrl":"https://doi.org/10.5194/soil-8-699-2022","url":null,"abstract":"Abstract. To understand global soil organic matter (SOM) chemistry and its dynamics, we need tools to efficiently quantify SOM properties, for example, prediction models using mid-infrared spectra. However, the advantages of such models rely on their validity and accuracy. Recently, Hodgkins et al. (2018) developed models to quantitatively predict peat holocellulose and Klason lignin contents, two indicators of SOM stability and major fractions of organic matter. The models may help to understand large-scale SOM gradients and have been used in various studies. A research gap to fill is that these models have not been validated in detail yet. What are their limitations and how can we improve them? This study provides a validation with the aim to identify concrete steps to improve these models. As a first step, we provide several improvements using the original training data. The major limitation we identified is that the original training data are not representative for a range of diverse peat samples. This causes both biased estimates and extrapolation uncertainty under the original models. In addition, the original models can in practice produce unrealistic predictions (negative values or values >100 mass-%). Our improved models partly reduce the observed bias, have a better predictive performance for the training data, and avoid such unrealistic predictions. Finally, we provide a proof of concept that holocellulose contents can also be predicted for mineral-rich samples (e.g., peat with mineral admixtures or potentially mineral soils). A key step to improve the models will be to collect training data that are representative for SOM formed under various conditions. This study opens directions to develop operational models to predict SOM holocellulose and Klason lignin contents from mid-infrared spectra.\u0000","PeriodicalId":22015,"journal":{"name":"Soil Science","volume":"46 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87558763","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
J. Pan, Jinsong Wang, Dashuan Tian, Ruiyang Zhang, Yang Li, Lei Song, Jiaming Yang, C. Wei, S. Niu
Abstract. The soil inorganic carbon (SIC) pool is a major component of soil carbon (C) pools, and clarifying the predictors of SIC stock is urgent for decreasing soil C losses and maintaining soil health and ecosystem functions. However, the drivers and their relative effects on the SIC stock at different soil depths remain largely unexplored. Here, we conducted a large-scale sampling to investigate the effects and relative contributions of abiotic (climate and soil) and biotic (plant and microbe) drivers on the SIC stock between topsoils (0–10 cm) and subsoils (20–30 cm) across Tibetan alpine grasslands. Results showed that the SIC stock had no significant differences between the topsoil and subsoil. The SIC stock showed a significant increase with altitude, pH and sand proportion, but declined with mean annual precipitation (MAP), plant aboveground biomass (PAB), plant coverage (PC), root biomass (RB), available nitrogen (AN), microbial biomass carbon (MBC), and bacterial abundance (BA) and fungal gene abundance (FA). For both soil layers, biotic factors had larger effects on the SIC stock than abiotic factors did. However, the relative importance of these determinants varied with soil depth, with the effects of plant and microbial variables on SIC stock weakening with soil depth, whereas the importance of climatic and edaphic variables increased with soil depth. Specifically, BA, FA and PC played dominant roles in regulating SIC stock in the topsoil, while soil pH contributed largely to the variation of SIC stock in the subsoil. Our findings highlight differential drivers over SIC stock with soil depth, which should be considered in biogeochemical models for better simulating and predicting SIC dynamics and its feedbacks to environmental changes.
{"title":"Biotic factors dominantly determine soil inorganic carbon stock across Tibetan alpine grasslands","authors":"J. Pan, Jinsong Wang, Dashuan Tian, Ruiyang Zhang, Yang Li, Lei Song, Jiaming Yang, C. Wei, S. Niu","doi":"10.5194/soil-8-687-2022","DOIUrl":"https://doi.org/10.5194/soil-8-687-2022","url":null,"abstract":"Abstract. The soil inorganic carbon (SIC) pool is a major component of soil carbon (C) pools, and clarifying the predictors of SIC stock is urgent for decreasing soil C losses and maintaining soil health and ecosystem functions. However, the drivers and their relative effects on the SIC stock at different soil depths remain largely unexplored. Here, we conducted a large-scale sampling to investigate the effects and relative contributions of abiotic (climate and soil) and biotic (plant and microbe) drivers on the SIC stock between topsoils (0–10 cm) and subsoils (20–30 cm) across Tibetan alpine grasslands. Results showed that the SIC stock had no significant differences between the topsoil and subsoil. The SIC stock showed a significant increase with altitude, pH and sand proportion, but declined with mean annual precipitation (MAP), plant aboveground biomass (PAB), plant coverage (PC), root biomass (RB), available nitrogen (AN), microbial biomass carbon (MBC), and bacterial abundance (BA) and fungal gene abundance (FA). For both soil layers, biotic factors had larger effects on the SIC stock than abiotic factors did. However, the relative importance of these determinants varied with soil depth, with the effects of plant and microbial variables on SIC stock weakening with soil depth, whereas the importance of climatic and edaphic variables increased with soil depth. Specifically, BA, FA and PC played dominant roles in regulating SIC stock in the topsoil, while soil pH contributed largely to the variation of SIC stock in the subsoil. Our findings highlight differential drivers over SIC stock with soil depth, which should be considered in biogeochemical models for better simulating and predicting SIC dynamics and its feedbacks to environmental changes.\u0000","PeriodicalId":22015,"journal":{"name":"Soil Science","volume":"3 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78234969","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The quest for circular designs and ways to reuse polymer materials demands further advances in the development of reversible chemistries. Stimuli-responsive systems incorporated into polymer materials that enable the formation and cleavage of covalent bonds, hold great potential to reversibly decompose materials into their original building blocks. [2π+2π] photocycloadditions, for which the addition and reversion mechanism can be triggered by disparate wavelengths, stand as an attractive platform for triggering such controlled and reversible photoligation towards achieving renewable polymer materials. This perspective highlights the potential of this type of photochemistry to incorporate solid polymer materials and generate reversible polymerizations. The design of effective photoresponsive materials with specific functions requires the consideration of a number of parameters. Following a bottom-up approach - from molecular chemistry to macromolecular functionality - this perspective provides a recipe of the key aspects to consider in the design of such advanced renewable materials. Furthermore, examples of the state of the art in the field are highlighted and an overview of the fundamental challenges that remain is provided. Finally, an outlook on the next frontiers to cross is proposed.
{"title":"Photocycloadditions for the Design of Reversible Photopolymerizations.","authors":"Celine Calvino","doi":"10.2533/chimia.2022.816","DOIUrl":"10.2533/chimia.2022.816","url":null,"abstract":"<p><p>The quest for circular designs and ways to reuse polymer materials demands further advances in the development of reversible chemistries. Stimuli-responsive systems incorporated into polymer materials that enable the formation and cleavage of covalent bonds, hold great potential to reversibly decompose materials into their original building blocks. [2π+2π] photocycloadditions, for which the addition and reversion mechanism can be triggered by disparate wavelengths, stand as an attractive platform for triggering such controlled and reversible photoligation towards achieving renewable polymer materials. This perspective highlights the potential of this type of photochemistry to incorporate solid polymer materials and generate reversible polymerizations. The design of effective photoresponsive materials with specific functions requires the consideration of a number of parameters. Following a bottom-up approach - from molecular chemistry to macromolecular functionality - this perspective provides a recipe of the key aspects to consider in the design of such advanced renewable materials. Furthermore, examples of the state of the art in the field are highlighted and an overview of the fundamental challenges that remain is provided. Finally, an outlook on the next frontiers to cross is proposed.</p>","PeriodicalId":22015,"journal":{"name":"Soil Science","volume":"143 1","pages":"816-825"},"PeriodicalIF":1.2,"publicationDate":"2022-10-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83784302","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract. The maintenance of the large soil organic carbon (SOC) stocks of the boreal forest under climate change is a matter of concern. In this study, major soil carbon pools and fluxes were assessed in 22 closed-canopy forests located along an elevation and latitudinal climatic gradient expanding 4 ∘C in mean annual temperature (MAT) for two important boreal conifer forest stand types: balsam fir (Abies balsamea), a fire avoider, and black spruce (Picea mariana), a fire-tolerant species. SOC stocks were not influenced by a warmer climate or by forest type. However, carbon fluxes, including aboveground litterfall rates, as well as total soil respiration (Rs) and heterotrophic (Rh) and autotrophic soil respiration (Ra), were linearly related to temperature (cumulative degree days >5 ∘C). The sensitivity of soil organic matter (SOM) degradation to temperature, assessed by comparing Q10 (rate of change for a T increase of 10 ∘C) of soil respiration and Rs10 (soil respiration rates corrected to 10 ∘C), did not vary along the temperature gradient, while the proportion of bioreactive carbon and nitrogen showed higher values for balsam fir and for warmer sites. Balsam fir forests showed a greater litterfall rate, a better litter quality (lower C : N ratio) and a higher Rs10 than black spruce ones, suggesting that their soils cycle a larger amount of C and N under a similar climate regime. Altogether, these results suggest that a warmer climate and a balsam fir forest composition induce a more rapid SOC turnover. Contrary to common soil organic matter stabilisation hypotheses, greater litter input rates did not lead to higher total SOC stocks, and a warmer climate did not lead to the depletion of bioreactive soil C and N. Positive effects of warming both on fluxes to and from the soil as well as a potential saturation of stabilised SOC could explain these results which apply to the context of this study: a cold and wet environment and a stable vegetation composition along the temperature gradient. While the entire study area is subject to a humid climate, a negative relationship was found between aridity and SOM stocks in the upper mineral soil layer for black spruce forests, suggesting that water balance is more critical than temperature to maintain SOM stocks.
{"title":"Effects of a warmer climate and forest composition on soil carbon cycling, soil organic matter stability and stocks in a humid boreal region","authors":"D. Paré, J. Laganière, G. Larocque, R. Boutin","doi":"10.5194/soil-8-673-2022","DOIUrl":"https://doi.org/10.5194/soil-8-673-2022","url":null,"abstract":"Abstract. The maintenance of the large soil organic carbon (SOC) stocks of the boreal\u0000forest under climate change is a matter of concern. In this study, major\u0000soil carbon pools and fluxes were assessed in 22 closed-canopy\u0000forests located along an elevation and latitudinal climatic gradient\u0000expanding 4 ∘C in mean annual temperature (MAT) for two important boreal\u0000conifer forest stand types: balsam fir (Abies balsamea), a fire avoider, and black spruce\u0000(Picea mariana), a fire-tolerant species. SOC stocks were not influenced by a warmer\u0000climate or by forest type. However, carbon fluxes, including aboveground\u0000litterfall rates, as well as total soil respiration (Rs) and heterotrophic\u0000(Rh) and autotrophic soil respiration (Ra), were linearly related\u0000to temperature (cumulative degree days >5 ∘C). The\u0000sensitivity of soil organic matter (SOM) degradation to temperature, assessed by comparing\u0000Q10 (rate of change for a T increase of 10 ∘C) of soil respiration\u0000and Rs10 (soil respiration rates corrected to 10 ∘C), did not vary\u0000along the temperature gradient, while the proportion of bioreactive carbon\u0000and nitrogen showed higher values for balsam fir and for warmer sites.\u0000Balsam fir forests showed a greater litterfall rate, a better litter quality\u0000(lower C : N ratio) and a higher Rs10 than black spruce ones,\u0000suggesting that their soils cycle a larger amount of C and N under a similar\u0000climate regime. Altogether, these results suggest that a warmer climate and\u0000a balsam fir forest composition induce a more rapid SOC turnover. Contrary\u0000to common soil organic matter stabilisation hypotheses, greater litter input\u0000rates did not lead to higher total SOC stocks, and a warmer climate did not\u0000lead to the depletion of bioreactive soil C and N. Positive effects of\u0000warming both on fluxes to and from the soil as well as a potential\u0000saturation of stabilised SOC could explain these results which apply to the\u0000context of this study: a cold and wet environment and a stable vegetation\u0000composition along the temperature gradient. While the entire study area is\u0000subject to a humid climate, a negative relationship was found between\u0000aridity and SOM stocks in the upper mineral soil layer for black spruce\u0000forests, suggesting that water balance is more critical than temperature to\u0000maintain SOM stocks.\u0000","PeriodicalId":22015,"journal":{"name":"Soil Science","volume":"75 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-10-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73206466","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
I. Panagea, A. Apostolakis, A. Berti, J. Bussell, P. Čermák, J. Diels, A. Elsen, H. Kusá, I. Piccoli, J. Poesen, C. Stoate, M. Tits, Z. Tóth, G. Wyseure
Abstract. Inversion tillage is a commonly applied soil cultivation practice in Europe, which often has been blamed for deteriorating topsoil stability and organic carbon (OC) content. In this study, the potential to reverse these negative effects in the topsoil by alternative agricultural management practices are evaluated in seven long-term experiments (running from 8 to 54 years the moment of sampling) in five European countries (Belgium, Czech Republic, Hungary, Italy and UK). Topsoil samples (0–15 cm) were collected and analysed to evaluate the effects of conservation tillage (reduced and no tillage) and increased organic inputs of different origin (farmyard manure, compost, crop residues) combined with inversion tillage on topsoil stability, soil aggregates and, within these, OC distribution using wet sieving after slaking. Effects from the treatments on the two main components of organic matter, i.e. particulate (POM) and mineral associated (MAOM), were also evaluated using dispersion and size fractionation. Reduced and no-tillage practices, as well as the additions of manure or compost, increased the aggregates mean weight diameter (MWD) (up to 49 % at the Belgian study site) and topsoil OC (up to 51 % at the Belgian study site), as well as the OC corresponding to the different aggregate size fractions. The incorporation of crop residues had a positive impact on the MWD but a less profound effect both on total OC and on OC associated with the different aggregates. A negative relationship between the mass and the OC content of the microaggregates (53–250 µm) was identified in all experiments. There was no effect on the mass of the macroaggregates and the occluded microaggregates (mM) within these macroaggregates, while the corresponding OC contents increased with less tillage and more organic inputs. Inversion tillage led to less POM within the mM, whereas the different organic inputs did not affect it. In all experiments where the total POM increased, the total soil organic carbon (SOC) was also affected positively. We concluded that the negative effects of inversion tillage on topsoil can be mitigated by reducing the tillage intensity or adding organic materials, optimally combined with non-inversion tillage methods.
{"title":"Impact of agricultural management on soil aggregates and associated organic carbon fractions: analysis of long-term experiments in Europe","authors":"I. Panagea, A. Apostolakis, A. Berti, J. Bussell, P. Čermák, J. Diels, A. Elsen, H. Kusá, I. Piccoli, J. Poesen, C. Stoate, M. Tits, Z. Tóth, G. Wyseure","doi":"10.5194/soil-8-621-2022","DOIUrl":"https://doi.org/10.5194/soil-8-621-2022","url":null,"abstract":"Abstract. Inversion tillage is a commonly applied soil cultivation practice in Europe, which often has been blamed for deteriorating topsoil stability and organic carbon (OC) content. In this study, the potential to reverse these negative effects in the topsoil by alternative agricultural management practices are evaluated in seven long-term experiments (running from 8 to 54 years the moment of sampling) in five European countries (Belgium, Czech Republic, Hungary, Italy and UK). Topsoil samples (0–15 cm) were collected and analysed to evaluate the effects of conservation tillage (reduced and no tillage) and increased organic inputs of different origin (farmyard manure, compost, crop residues) combined with inversion tillage on topsoil stability, soil aggregates and, within these, OC distribution using wet sieving after slaking. Effects from the treatments on the two main components of organic matter, i.e. particulate (POM) and mineral associated (MAOM), were also evaluated using dispersion and size fractionation. Reduced and no-tillage practices, as well as the additions of manure or compost, increased the aggregates mean weight diameter (MWD) (up to 49 % at the Belgian study site) and topsoil OC (up to 51 % at the Belgian study site), as well as the OC corresponding to the different aggregate size fractions. The incorporation of crop residues had a positive impact on the MWD but a less profound effect both on total OC and on OC associated with the different aggregates. A negative relationship between the mass and the OC content of the microaggregates (53–250 µm) was identified in all experiments. There was no effect on the mass of the macroaggregates and the occluded microaggregates (mM) within these macroaggregates, while the corresponding OC contents increased with less tillage and more organic inputs. Inversion tillage led to less POM within the mM, whereas the different organic inputs did not affect it. In all experiments where the total POM increased, the total soil organic carbon (SOC) was also affected positively. We concluded that the negative effects of inversion tillage on topsoil can be mitigated by reducing the tillage intensity or adding organic materials, optimally combined with non-inversion tillage methods.\u0000","PeriodicalId":22015,"journal":{"name":"Soil Science","volume":"14 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87555285","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract. The shortage of water resources and the decline in soil organic matter (SOM) are critical limiting factors affecting the improvement in rice productivity, while alternate wetting and drying (AWD) irrigation and recycling application of rice straw (S) are considered favorable mitigation measures. However, the impact of such measures on rice yield and greenhouse gas (GHG) emissions, especially nitrous oxide (N2O) emissions, needs to be further clarified to ensure that agronomic practices save water, conserve soil, and reduce GHG emissions. Therefore, we explored the effects of mild AWD irrigation combined with on-site rice straw recycling on N2O emissions and rice yield through rice pot experiments. This experiment included 2 irrigation methods (continuous flooding (CF) irrigation and mild AWD irrigation), 2 nitrogen (N) application levels (0 and 225 kg N ha−1) and 2 rice straw return levels (0 and 9000 kg ha−1), for a total of 10 treatments, and each treatment had 3 replicates. The 15N-urea and 15N-S were added to the soil. The results showed that N2O emissions were primarily affected by urea application and irrigation methods, with urea application being most important. Compared with CF irrigation, mild AWD irrigation increased cumulative N2O emissions, with an average increase of 28.8 %. In addition, adding rice straw to mild AWD irrigation further stimulated N2O emissions by 18.1 %. Under the condition of urea application, compared with CF irrigation, mild AWD irrigation increased the yield-scaled N2O emissions by 17.9 %, and the addition of rice straw further promoted the yield-scaled N2O emissions under mild AWD irrigation by 17.4 % but reduced the global warming potential (GWP) (methane (CH4) + N2O) by 62.9 %. Under the condition of urea application, compared with CF irrigation, mild AWD irrigation reduced the uptake of soil-derived N and aboveground biomass of rice but did not reduce rice yield. Therefore, mild AWD irrigation combined with rice straw return may be a promising agronomic method to maintain rice yield, reduce GHGs, and protect or improve soil fertility.
摘要水资源短缺和土壤有机质(SOM)下降是影响水稻生产力提高的关键限制因素，而干湿交替灌溉(AWD)和秸秆循环利用(S)被认为是有利的缓解措施。然而，这些措施对水稻产量和温室气体(GHG)排放，特别是一氧化二氮(N2O)排放的影响需要进一步澄清，以确保农业实践节水、保土和减少温室气体排放。因此，我们通过水稻盆栽试验，探索轻度AWD灌溉配合秸秆就地回收对N2O排放和水稻产量的影响。本试验包括2种灌溉方式(连续淹水灌溉和轻度aw灌溉)、2种施氮水平(0和225 kg N ha−1)和2种水稻秸秆还田水平(0和9000 kg ha−1)，共10个处理，每个处理3个重复。在土壤中添加15n -尿素和15N-S。结果表明:氮肥施用量和灌溉方式对N2O排放影响最大，其中氮肥施用量影响最大;与CF灌溉相比，轻度AWD灌溉增加了累积N2O排放量，平均增加28.8%。此外，在轻度AWD灌溉中添加稻草进一步刺激了18.1%的N2O排放。在施尿素条件下，与CF灌溉相比，轻度AWD灌溉使产量标度N2O排放量增加了17.9%，秸秆的添加进一步促进了轻度AWD灌溉下产量标度N2O排放量增加了17.4%，但使全球变暖潜能值(GWP)(甲烷(CH4) + N2O)降低了62.9%。在施尿素条件下，与CF灌溉相比，轻度AWD灌溉降低了水稻对土源氮的吸收和地上生物量，但没有降低水稻产量。因此，轻度AWD灌溉配合秸秆还田可能是维持水稻产量、减少温室气体排放、保护或提高土壤肥力的一种有前景的农艺方法。
{"title":"Effects of mild alternate wetting and drying irrigation and rice straw application on N2O emissions in rice cultivation","authors":"Kaikuo Wu, Wentao Li, Zhanbo Wei, Zhi Dong, Yue Meng, Na Lv, Lili Zhang","doi":"10.5194/soil-8-645-2022","DOIUrl":"https://doi.org/10.5194/soil-8-645-2022","url":null,"abstract":"Abstract. The shortage of water resources and the decline in soil organic\u0000matter (SOM) are critical limiting factors affecting the improvement in rice productivity, while alternate wetting and drying (AWD) irrigation and\u0000recycling application of rice straw (S) are considered favorable mitigation\u0000measures. However, the impact of such measures on rice yield and greenhouse\u0000gas (GHG) emissions, especially nitrous oxide (N2O) emissions, needs to be further clarified to ensure that agronomic practices save water, conserve soil, and reduce GHG emissions. Therefore, we explored the effects of mild AWD irrigation combined with on-site rice straw recycling on N2O emissions and rice yield through rice pot experiments. This experiment included 2 irrigation methods (continuous flooding (CF) irrigation and mild AWD\u0000irrigation), 2 nitrogen (N) application levels (0 and 225 kg N ha−1) and 2 rice straw return levels (0 and 9000 kg ha−1), for a total of 10 treatments, and each treatment had 3 replicates. The 15N-urea and 15N-S were added to the soil. The results showed that N2O emissions were primarily affected by urea application and irrigation methods, with urea application being most important. Compared with CF irrigation, mild AWD irrigation increased cumulative N2O emissions, with an average increase of 28.8 %. In addition, adding rice straw to mild AWD irrigation further stimulated N2O emissions by 18.1 %. Under the condition of urea application, compared with CF irrigation, mild AWD\u0000irrigation increased the yield-scaled N2O emissions by 17.9 %, and\u0000the addition of rice straw further promoted the yield-scaled N2O\u0000emissions under mild AWD irrigation by 17.4 % but reduced the global\u0000warming potential (GWP) (methane (CH4) + N2O) by 62.9 %. Under the condition of urea application, compared with CF irrigation, mild AWD irrigation reduced the uptake of soil-derived N and aboveground biomass of rice but did not reduce rice yield. Therefore, mild AWD irrigation combined with rice straw return may be a promising agronomic method to maintain rice yield, reduce GHGs, and protect or improve soil fertility.\u0000","PeriodicalId":22015,"journal":{"name":"Soil Science","volume":"92 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75931173","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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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