Pub Date : 2022-11-02DOI: 10.3389/fsoil.2022.1023743
Hammond Abeka, I. Lawson, E. Nartey, T. Adjadeh, S. Asuming-Brempong, P. Bindraban, W. Atakora
The nitrates produced after mineralization from compost may be prone to leaching, especially in tropical sandy soils, because of the increased rate of nitrification and the porous nature of such soils. This may result in low nitrogen (N) use efficiency and adverse environmental effects. Inorganic nitrification inhibitors are costly and mostly unavailable in Ghana. Research on simple but effective local materials for use as nitrification inhibitors is therefore a priority. Two such materials are neem materials and biochar. Neem materials can suppress nitrifying bacteria due to their antimicrobial properties. Biochar can hold ammonium in the soil, making it temporarily unavailable to nitrifying bacteria. This study aimed to determine the efficacy of neem materials and biochar as nitrification inhibitors and their influence on nitrate leaching. In preliminary studies: 1) pot incubation was conducted for 60 days to estimate the nitrification rate with manure, compost, and NH4Cl as the N source (150 kg N/ha) in one set and neem seeds, bark, and leaves (1.25 µg azadirachtin/g) in another set, using nitrate concentrations; and 2) the ammonium sorption and desorption capacities of sawdust, rice husk, and groundnut husk biochar were determined. In the main study, pot incubation with compost as the N source but treated with milled neem seeds or bark (1.25 µg azadirachtin/g) or sawdust biochar (20 t/ha) was conducted for 60 days, in which the nitrification inhibition was determined using nitrate concentrations. A leaching experiment in columns with similar treatments and maize sown was then conducted to quantify the nitrate in leachates. A high nitrification rate was recorded in compost-amended soil, almost half that of the standard (NH4Cl). The use of sawdust biochar, which showed the highest ammonium sorption and desorption capacity, resulted in 40% nitrification inhibition that lasted the entire incubation period. The use of neem seeds with an azadirachtin concentration of 3.92 mg/g resulted in a similar nitrification inhibition, but this only lasted 40 days. Inhibition caused by both materials resulted in about a 60% reduction in nitrate leached. Thus, neem seeds (498 kg/ha) and sawdust biochar (20 mt/ha) could be used to control nitrate leaching for short-duration and long-duration crops, respectively.
堆肥矿化后产生的硝酸盐可能容易浸出，尤其是在热带沙质土壤中，因为硝化速率增加，而且这种土壤具有多孔性。这可能导致低氮（N）利用效率和不利的环境影响。无机硝化抑制剂价格昂贵，在加纳大多无法获得。因此，研究简单但有效的局部材料用作硝化抑制剂是当务之急。两种这样的材料是neem材料和生物炭。印楝材料具有抗菌性能，可以抑制硝化细菌。生物炭可以在土壤中保持铵，使硝化细菌暂时无法获得铵。本研究旨在确定印楝材料和生物炭作为硝化抑制剂的效果及其对硝酸盐浸出的影响。在初步研究中：1）使用硝酸盐浓度，在一组中以粪肥、堆肥和NH4Cl为氮源（150 kg N/ha），在另一组中使用印楝种子、树皮和叶子（1.25µg印楝素/g），进行60天的盆栽培养，以估计硝化率；2）测定了木屑、稻壳和花生壳生物炭对铵的吸附和解吸能力。在主要研究中，以堆肥为氮源，但用磨碎的印楝种子或树皮（1.25µg印楝素/g）或木屑生物炭（20t/ha）处理的盆栽培养进行了60天，其中使用硝酸盐浓度测定硝化抑制作用。然后在类似处理的柱子和播种的玉米中进行浸出实验，以量化浸出液中的硝酸盐。堆肥改良土壤的硝化速率很高，几乎是标准（NH4Cl）的一半。木屑生物炭表现出最高的铵吸附和解吸能力，可在整个培养期内抑制40%的硝化作用。使用印楝素浓度为3.92 mg/g的印楝种子产生了类似的硝化抑制作用，但这只持续了40天。由这两种材料引起的抑制导致浸出的硝酸盐减少约60%。因此，印楝种子（498公斤/公顷）和木屑生物炭（20公吨/公顷）可分别用于控制短期和长期作物的硝酸盐浸出。
{"title":"Effectiveness of neem materials and biochar as nitrification inhibitors in reducing nitrate leaching in a compost-amended Ferric Luvisol","authors":"Hammond Abeka, I. Lawson, E. Nartey, T. Adjadeh, S. Asuming-Brempong, P. Bindraban, W. Atakora","doi":"10.3389/fsoil.2022.1023743","DOIUrl":"https://doi.org/10.3389/fsoil.2022.1023743","url":null,"abstract":"The nitrates produced after mineralization from compost may be prone to leaching, especially in tropical sandy soils, because of the increased rate of nitrification and the porous nature of such soils. This may result in low nitrogen (N) use efficiency and adverse environmental effects. Inorganic nitrification inhibitors are costly and mostly unavailable in Ghana. Research on simple but effective local materials for use as nitrification inhibitors is therefore a priority. Two such materials are neem materials and biochar. Neem materials can suppress nitrifying bacteria due to their antimicrobial properties. Biochar can hold ammonium in the soil, making it temporarily unavailable to nitrifying bacteria. This study aimed to determine the efficacy of neem materials and biochar as nitrification inhibitors and their influence on nitrate leaching. In preliminary studies: 1) pot incubation was conducted for 60 days to estimate the nitrification rate with manure, compost, and NH4Cl as the N source (150 kg N/ha) in one set and neem seeds, bark, and leaves (1.25 µg azadirachtin/g) in another set, using nitrate concentrations; and 2) the ammonium sorption and desorption capacities of sawdust, rice husk, and groundnut husk biochar were determined. In the main study, pot incubation with compost as the N source but treated with milled neem seeds or bark (1.25 µg azadirachtin/g) or sawdust biochar (20 t/ha) was conducted for 60 days, in which the nitrification inhibition was determined using nitrate concentrations. A leaching experiment in columns with similar treatments and maize sown was then conducted to quantify the nitrate in leachates. A high nitrification rate was recorded in compost-amended soil, almost half that of the standard (NH4Cl). The use of sawdust biochar, which showed the highest ammonium sorption and desorption capacity, resulted in 40% nitrification inhibition that lasted the entire incubation period. The use of neem seeds with an azadirachtin concentration of 3.92 mg/g resulted in a similar nitrification inhibition, but this only lasted 40 days. Inhibition caused by both materials resulted in about a 60% reduction in nitrate leached. Thus, neem seeds (498 kg/ha) and sawdust biochar (20 mt/ha) could be used to control nitrate leaching for short-duration and long-duration crops, respectively.","PeriodicalId":73107,"journal":{"name":"Frontiers in soil science","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43236026","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-10-13DOI: 10.3389/fsoil.2022.1020814
Evans Asenso, Zhimin Wang, Tian Kai, Jiuhao Li, Lian Hu
The microbial population (MP) is considered to be a relatively important part of soil health, quality, and productivity. Therefore, this study aimed to access the effects of tillage and rice cultivation modes on soil MP in Stagnic Anthrosols and Lateritic Red Earth soils. The treatments were as follows: (i) MDS: land tilled twice with a moldboard plow and hill-seeding of pregerminated seeds with a direct seeding machine of four to six seeds per hill at a planting space of 25 × 15 cm, (ii) RDS: land tilled twice with a rotary tiller and hill-seeding of pregerminated seeds with a direct seeding machine of four to six seeds per hill at a planting space of 25 × 15 cm, (iii) MMT: land tilled twice with a moldboard plow and 15-day-old seedlings were mechanically transplanted with a transplanting machine at a transplanting hill of four to six seedlings and at a transplanting space of 25 × 15 cm, and (iv) RMT: land tilled twice with a rotary tiller and 15-day-old seedlings were mechanically transplanted with a transplanting machine at a transplanting hill of four to six seedlings and a transplanting space of 25 × 15 cm. The findings showed that MDS improved the MP and increases rice yield. MDS showed a high increase in MP in both locations and the rice productivity of 32.81% (1H; first harvest) and 13.91% (2H; second harvest) and 16.48% (1H) and 18.13% (2H) for Zeng-Cheng and Yi-Yang, respectively. In conclusion, MDS was found to be better in improving the MP and increasing rice yield and could be adopted as a suitable approach for improving soil health, quality, and productivity.
{"title":"Soil microbial population as affected by tillage and rice cultivation modes in Stagnic Anthrosols and Lateritic Red Earth soils in Southern China","authors":"Evans Asenso, Zhimin Wang, Tian Kai, Jiuhao Li, Lian Hu","doi":"10.3389/fsoil.2022.1020814","DOIUrl":"https://doi.org/10.3389/fsoil.2022.1020814","url":null,"abstract":"The microbial population (MP) is considered to be a relatively important part of soil health, quality, and productivity. Therefore, this study aimed to access the effects of tillage and rice cultivation modes on soil MP in Stagnic Anthrosols and Lateritic Red Earth soils. The treatments were as follows: (i) MDS: land tilled twice with a moldboard plow and hill-seeding of pregerminated seeds with a direct seeding machine of four to six seeds per hill at a planting space of 25 × 15 cm, (ii) RDS: land tilled twice with a rotary tiller and hill-seeding of pregerminated seeds with a direct seeding machine of four to six seeds per hill at a planting space of 25 × 15 cm, (iii) MMT: land tilled twice with a moldboard plow and 15-day-old seedlings were mechanically transplanted with a transplanting machine at a transplanting hill of four to six seedlings and at a transplanting space of 25 × 15 cm, and (iv) RMT: land tilled twice with a rotary tiller and 15-day-old seedlings were mechanically transplanted with a transplanting machine at a transplanting hill of four to six seedlings and a transplanting space of 25 × 15 cm. The findings showed that MDS improved the MP and increases rice yield. MDS showed a high increase in MP in both locations and the rice productivity of 32.81% (1H; first harvest) and 13.91% (2H; second harvest) and 16.48% (1H) and 18.13% (2H) for Zeng-Cheng and Yi-Yang, respectively. In conclusion, MDS was found to be better in improving the MP and increasing rice yield and could be adopted as a suitable approach for improving soil health, quality, and productivity.","PeriodicalId":73107,"journal":{"name":"Frontiers in soil science","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43162888","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-10-06DOI: 10.3389/fsoil.2022.984927
Hualong Hong, Li Ma, David B. Smith, Haoliang Lu, Chongling Yan, K. Xia, M.A.J. Williams
Proteinaceous amino acids composed up to 50% of microbial biomass, are a primary building block of soil organic nitrogen, and play a key role in soil organic N and C cycling. However, the large-scale drivers on these organic nitrogen pools is less explored. We hypothesized that the trends related to vegetation, soil mineralogy and climate will change the composition of hydrolyzable amino acids (HAAs), both within and between each horizon. Herein we report on the patterns of HAAs, and their dependence on soil (e.g., Al, Fe, pH) and climate (e.g., precipitation) factors between soil horizons across the continental U.S. It was found that the effect of vegetation type on HAAs was greater in the A horizon than in the C horizon, which was related to the different stages of the vegetation-associated decomposition and pedogenesis processes. A similar Leu-Phe-Ile-Gly co-occurrence structure was found in both soil horizons suggesting some similarity in processes that enrich organics in soil. Precipitation, but not temperature, showed significant associations with HAA composition. The chemical properties of the soil, including pH and mineral metals (Fe, Mn, Al, Ca), also influenced the HAAs’ characteristics. In particular, some specific HAAs (Glx, Asn, and Ala) mainly reflected the HAAs’ response to the environmental gradients in both horizons. The effect of precipitation on HAAs exhibits as a complex relationship mediated through organic matter, pH and minerals. To our knowledge, this is the first study to assess continental-wide descriptors of the largest soil organic N pool, showing that pH, Fe, Ca, precipitation and vegetation explain soil AA composition. The role played by each of these drivers in the accrual and turnover of organic matter over large regional scales deserve further scrutiny. The large surface and subsurface HAA data set from this study should help change the way micro-scale conceptual and mechanistic models describe the chemical interactions and source pools that drive soil organic nitrogen, and possibly soil organic matter composition over regional scales.
蛋白质氨基酸占微生物生物量的50%，是土壤有机氮的主要组成部分，在土壤有机氮和有机碳循环中起着关键作用。然而，对这些有机氮库的大规模驱动机制探索较少。我们假设与植被、土壤矿物学和气候相关的趋势将改变每层内和层间可水解氨基酸(HAAs)的组成。本文报道了美国大陆不同土壤层间HAAs的分布模式及其对土壤(如Al、Fe、pH)和气候(如降水)因子的依赖关系。研究发现，植被类型对HAAs的影响在A层大于C层，这与植被相关分解和成土过程的不同阶段有关。在两个土层中发现了相似的leu - phee - ile - gly共现结构，这表明在土壤中富集有机物的过程中存在一些相似性。降水与HAA组成有显著相关性，而温度与HAA组成无显著相关性。土壤的化学性质，包括pH和矿物金属(铁、锰、铝、钙)也影响HAAs的特征。特别是一些特定的HAAs (Glx、Asn和Ala)主要反映了两个层位HAAs对环境梯度的响应。降水对HAAs的影响表现为通过有机质、pH和矿物质介导的复杂关系。据我们所知，这是第一个评估大陆范围内最大的土壤有机氮库描述符的研究，表明pH、Fe、Ca、降水和植被可以解释土壤AA组成。这些驱动因素在大区域范围内有机质的积累和周转中所起的作用值得进一步研究。本研究的大量地表和地下HAA数据集将有助于改变微观尺度的概念和机制模型描述化学相互作用和驱动土壤有机氮的源库的方式，并可能在区域尺度上驱动土壤有机质组成。
{"title":"Precipitation-derived effects on the characteristics of proteinaceous soil organic matter across the continental United States","authors":"Hualong Hong, Li Ma, David B. Smith, Haoliang Lu, Chongling Yan, K. Xia, M.A.J. Williams","doi":"10.3389/fsoil.2022.984927","DOIUrl":"https://doi.org/10.3389/fsoil.2022.984927","url":null,"abstract":"Proteinaceous amino acids composed up to 50% of microbial biomass, are a primary building block of soil organic nitrogen, and play a key role in soil organic N and C cycling. However, the large-scale drivers on these organic nitrogen pools is less explored. We hypothesized that the trends related to vegetation, soil mineralogy and climate will change the composition of hydrolyzable amino acids (HAAs), both within and between each horizon. Herein we report on the patterns of HAAs, and their dependence on soil (e.g., Al, Fe, pH) and climate (e.g., precipitation) factors between soil horizons across the continental U.S. It was found that the effect of vegetation type on HAAs was greater in the A horizon than in the C horizon, which was related to the different stages of the vegetation-associated decomposition and pedogenesis processes. A similar Leu-Phe-Ile-Gly co-occurrence structure was found in both soil horizons suggesting some similarity in processes that enrich organics in soil. Precipitation, but not temperature, showed significant associations with HAA composition. The chemical properties of the soil, including pH and mineral metals (Fe, Mn, Al, Ca), also influenced the HAAs’ characteristics. In particular, some specific HAAs (Glx, Asn, and Ala) mainly reflected the HAAs’ response to the environmental gradients in both horizons. The effect of precipitation on HAAs exhibits as a complex relationship mediated through organic matter, pH and minerals. To our knowledge, this is the first study to assess continental-wide descriptors of the largest soil organic N pool, showing that pH, Fe, Ca, precipitation and vegetation explain soil AA composition. The role played by each of these drivers in the accrual and turnover of organic matter over large regional scales deserve further scrutiny. The large surface and subsurface HAA data set from this study should help change the way micro-scale conceptual and mechanistic models describe the chemical interactions and source pools that drive soil organic nitrogen, and possibly soil organic matter composition over regional scales.","PeriodicalId":73107,"journal":{"name":"Frontiers in soil science","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46452258","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-10-03DOI: 10.3389/fsoil.2022.984963
Ricardo Canal Filho, J. Molin
In soil science, near-infrared (NIR) spectra are being largely tested to acquire data directly in the field. Machine learning (ML) models using these spectra can be calibrated, adding only samples from one field or gathering different areas to augment the data inserted and enhance the models’ accuracy. Robustness assessment of prediction models usually rely on statistical metrics. However, how the spatial distribution of predicted soil attributes can be affected is still little explored, despite the fact that agriculture productive decisions depend on the spatial variability of these attributes. The objective of this study was to use online NIR spectra to predict soil attributes at field level, evaluating the statistical metrics and also the spatial distribution observed in prediction to compare a local prediction model with models that gathered samples from other areas. A total of 383 online NIR spectra were acquired in an experimental field to predict clay, sand, organic matter (OM), cation exchange capacity (CEC), potassium (K), calcium (Ca), and magnesium (Mg). To build ML calibrations, 72 soil spectra from the experimental field (local dataset) were gathered, with 59 samples from another area nearby, in the same geological region (geological dataset) and with this area nearby and more 60 samples from another area in a different region (global dataset). Principal components regression was performed using k-fold (k=10) cross-validation. Clay models reported similar errors of prediction, and although the local model presented a lower R2 (0.17), the spatial distribution of prediction proved that the models had similar performance. Although OM patterns were comparable between the three datasets, local prediction, with the lower R2 (0.75), was the best fitted. However, for secondary NIR response attributes, only CEC could be successfully predicted and only using local dataset, since the statistical metrics were compatible, but the geological and global models misrepresented the spatial patterns in the field. Agronomic plausibility of spatial distribution proved to be a key factor for the evaluation of soil attributes prediction at field level. Results suggest that local calibrations are the best recommendation for diffuse reflectance spectroscopy NIR prediction of soil attributes and that statistical metrics alone can mispresent the accuracy of prediction.
{"title":"Spatial distribution as a key factor for evaluation of soil attributes prediction at field level using online near-infrared spectroscopy","authors":"Ricardo Canal Filho, J. Molin","doi":"10.3389/fsoil.2022.984963","DOIUrl":"https://doi.org/10.3389/fsoil.2022.984963","url":null,"abstract":"In soil science, near-infrared (NIR) spectra are being largely tested to acquire data directly in the field. Machine learning (ML) models using these spectra can be calibrated, adding only samples from one field or gathering different areas to augment the data inserted and enhance the models’ accuracy. Robustness assessment of prediction models usually rely on statistical metrics. However, how the spatial distribution of predicted soil attributes can be affected is still little explored, despite the fact that agriculture productive decisions depend on the spatial variability of these attributes. The objective of this study was to use online NIR spectra to predict soil attributes at field level, evaluating the statistical metrics and also the spatial distribution observed in prediction to compare a local prediction model with models that gathered samples from other areas. A total of 383 online NIR spectra were acquired in an experimental field to predict clay, sand, organic matter (OM), cation exchange capacity (CEC), potassium (K), calcium (Ca), and magnesium (Mg). To build ML calibrations, 72 soil spectra from the experimental field (local dataset) were gathered, with 59 samples from another area nearby, in the same geological region (geological dataset) and with this area nearby and more 60 samples from another area in a different region (global dataset). Principal components regression was performed using k-fold (k=10) cross-validation. Clay models reported similar errors of prediction, and although the local model presented a lower R2 (0.17), the spatial distribution of prediction proved that the models had similar performance. Although OM patterns were comparable between the three datasets, local prediction, with the lower R2 (0.75), was the best fitted. However, for secondary NIR response attributes, only CEC could be successfully predicted and only using local dataset, since the statistical metrics were compatible, but the geological and global models misrepresented the spatial patterns in the field. Agronomic plausibility of spatial distribution proved to be a key factor for the evaluation of soil attributes prediction at field level. Results suggest that local calibrations are the best recommendation for diffuse reflectance spectroscopy NIR prediction of soil attributes and that statistical metrics alone can mispresent the accuracy of prediction.","PeriodicalId":73107,"journal":{"name":"Frontiers in soil science","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45115467","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-09-30DOI: 10.3389/fsoil.2022.1020193
M. Ayilara, M. Abberton, O. Oyatomi, O. Odeyemi, O. O. Babalola
Adopting underutilized legumes in tackling food security is essential, especially in this era of climate change. Underutilized legumes are embedded with inherent potentials such as the ability to survive in extreme conditions (such as temperature, drought, pH, saline, etc.), high nitrogen-fixing potential, weed and disease control ability, and high nutrient status. Underutilized legumes can improve the yield of companion crops in an intercropping system and as a subsequent crop (due to their residual effects). They possess symbiotic and non-symbiotic organisms in their nodules, and also have different organisms in their bulk soil, rhizoplanes and rhizosphere, which can fix nitrogen, solubilize phosphorus or produce exudates which help in improving plant growth. Also, they contain some phytochemicals, including alkaloids, saponin, amino acids, organic and inorganic minerals, and compounds that help improve human health and prevent diseases. Hence, this review discusses the current status, role, challenges and the prospects of underutilized legumes in food security.
{"title":"Potentials of underutilized legumes in food security","authors":"M. Ayilara, M. Abberton, O. Oyatomi, O. Odeyemi, O. O. Babalola","doi":"10.3389/fsoil.2022.1020193","DOIUrl":"https://doi.org/10.3389/fsoil.2022.1020193","url":null,"abstract":"Adopting underutilized legumes in tackling food security is essential, especially in this era of climate change. Underutilized legumes are embedded with inherent potentials such as the ability to survive in extreme conditions (such as temperature, drought, pH, saline, etc.), high nitrogen-fixing potential, weed and disease control ability, and high nutrient status. Underutilized legumes can improve the yield of companion crops in an intercropping system and as a subsequent crop (due to their residual effects). They possess symbiotic and non-symbiotic organisms in their nodules, and also have different organisms in their bulk soil, rhizoplanes and rhizosphere, which can fix nitrogen, solubilize phosphorus or produce exudates which help in improving plant growth. Also, they contain some phytochemicals, including alkaloids, saponin, amino acids, organic and inorganic minerals, and compounds that help improve human health and prevent diseases. Hence, this review discusses the current status, role, challenges and the prospects of underutilized legumes in food security.","PeriodicalId":73107,"journal":{"name":"Frontiers in soil science","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41413324","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-09-26DOI: 10.3389/fsoil.2022.995716
L. Marchand, F. Hennion, M. Tarayre, Marie-Claire Martin, Benoit R. Martins, C. Monard
Polar regions are characterized by rocky terrains with sparse vegetation and oligotrophic soils, i.e. “fellfields”. In such ecosystems, microbial communities should be essential for soil-plant functioning but their diversity is poorly explored. The sub-Antarctic Kerguelen Islands fellfields are characterized by an endemic long-lived cushion plant, Lyallia kerguelensis which rhizosphere may be a shelter for microbes in this harsh environment. Cushions are affected by necrosis and we expect the rhizomicrobiome composition to be related to plant necrosis. We analysed bacterial and fungal communities in bulk- and rhizospheric soils from L. kerguelensis in five different fellfields across the Kerguelen Islands using 16S rRNA and ITS1 metabarcoding. We found that soil microbial communities were composed of both restricted and cosmopolitan taxa. While all sites were dominated by the same bacterial taxa (Chloroflexi, Actinobacteria, α-Proteobacteria and Acidobacteria), the relative abundance of the main fungal phyla (Ascomycota, Basidiomycota, Mortierellomycota and Rozellomycota) highly differed between sites. L. kerguelensis rhizomicrobiome was at least as diverse as the bulk soil, making the rhizosphere a possible reservoir of microbial diversity. It was composed of the same main bacterial phyla than detected in the bulk soil while the composition of the rhizosphere fungal communities was specific to each plant. No common microorganisms were identified regarding cushion necrosis extent across plants and sites, but several microbial putative functions were shared, suggesting a possible shift in soil functioning with cushion necrosis increase. Our study brings new information on the diversity and composition of the microbial communities of fellfield soils in a sub-Antarctic Island and the rhizomicrobiome of a characteristic endemic cushion plant.
{"title":"Fellfields of the Kerguelen Islands harbour specific soil microbiomes and rhizomicrobiomes of an endemic plant facing necrosis","authors":"L. Marchand, F. Hennion, M. Tarayre, Marie-Claire Martin, Benoit R. Martins, C. Monard","doi":"10.3389/fsoil.2022.995716","DOIUrl":"https://doi.org/10.3389/fsoil.2022.995716","url":null,"abstract":"Polar regions are characterized by rocky terrains with sparse vegetation and oligotrophic soils, i.e. “fellfields”. In such ecosystems, microbial communities should be essential for soil-plant functioning but their diversity is poorly explored. The sub-Antarctic Kerguelen Islands fellfields are characterized by an endemic long-lived cushion plant, Lyallia kerguelensis which rhizosphere may be a shelter for microbes in this harsh environment. Cushions are affected by necrosis and we expect the rhizomicrobiome composition to be related to plant necrosis. We analysed bacterial and fungal communities in bulk- and rhizospheric soils from L. kerguelensis in five different fellfields across the Kerguelen Islands using 16S rRNA and ITS1 metabarcoding. We found that soil microbial communities were composed of both restricted and cosmopolitan taxa. While all sites were dominated by the same bacterial taxa (Chloroflexi, Actinobacteria, α-Proteobacteria and Acidobacteria), the relative abundance of the main fungal phyla (Ascomycota, Basidiomycota, Mortierellomycota and Rozellomycota) highly differed between sites. L. kerguelensis rhizomicrobiome was at least as diverse as the bulk soil, making the rhizosphere a possible reservoir of microbial diversity. It was composed of the same main bacterial phyla than detected in the bulk soil while the composition of the rhizosphere fungal communities was specific to each plant. No common microorganisms were identified regarding cushion necrosis extent across plants and sites, but several microbial putative functions were shared, suggesting a possible shift in soil functioning with cushion necrosis increase. Our study brings new information on the diversity and composition of the microbial communities of fellfield soils in a sub-Antarctic Island and the rhizomicrobiome of a characteristic endemic cushion plant.","PeriodicalId":73107,"journal":{"name":"Frontiers in soil science","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43743035","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-09-23DOI: 10.3389/fsoil.2022.987178
Megan F. Mitchell, M. G. MacLean, Kristen M. DeAngelis
Microbial-derived soil organic matter (SOM), or necromass, is an important source of SOM and is sensitive to climate warming. Soil classification systems consider soil physicochemical properties that influence SOM, hinting at the potential utility of incorporating classification systems in soil carbon (C) projections. Currently, there is no consensus on climate warming effects on necromass and if these responses vary across reference soil groups. To estimate the vulnerability of necromass to climate warming, we performed a meta-analysis of publications examining in situ experimental soil warming effects on microbial necromass via amino sugar analysis. We built generalized linear models (GLM) to explore if soil groups and warming methodologies can be used to predict necromass stocks. Our results showed that warming effect sizes on necromass were not uniform across reference soil groups. Specifically, warming effect sizes were generally positive in permafrost soils but negative in calcic soils. However, warming did not significantly change average necromass. Our GLMs detected significant differences in necromass across soil groups with similar texture and clay percentage. Thus, we advocate for further research to define what predictors of necromass are captured in soil group but not in soil texture. We also show warming methodology is a significant predictor of necromass, depending on the necromass biomarker. Future research efforts should uncover the mechanistic reason behind how passive versus active warming methodology influences necromass responses. Our study highlights the need for more in situ soil warming experiments measuring microbial necromass as this will improve predictions of SOM feedback under future climate scenarios.
{"title":"Microbial necromass response to soil warming: A meta-analysis","authors":"Megan F. Mitchell, M. G. MacLean, Kristen M. DeAngelis","doi":"10.3389/fsoil.2022.987178","DOIUrl":"https://doi.org/10.3389/fsoil.2022.987178","url":null,"abstract":"Microbial-derived soil organic matter (SOM), or necromass, is an important source of SOM and is sensitive to climate warming. Soil classification systems consider soil physicochemical properties that influence SOM, hinting at the potential utility of incorporating classification systems in soil carbon (C) projections. Currently, there is no consensus on climate warming effects on necromass and if these responses vary across reference soil groups. To estimate the vulnerability of necromass to climate warming, we performed a meta-analysis of publications examining in situ experimental soil warming effects on microbial necromass via amino sugar analysis. We built generalized linear models (GLM) to explore if soil groups and warming methodologies can be used to predict necromass stocks. Our results showed that warming effect sizes on necromass were not uniform across reference soil groups. Specifically, warming effect sizes were generally positive in permafrost soils but negative in calcic soils. However, warming did not significantly change average necromass. Our GLMs detected significant differences in necromass across soil groups with similar texture and clay percentage. Thus, we advocate for further research to define what predictors of necromass are captured in soil group but not in soil texture. We also show warming methodology is a significant predictor of necromass, depending on the necromass biomarker. Future research efforts should uncover the mechanistic reason behind how passive versus active warming methodology influences necromass responses. Our study highlights the need for more in situ soil warming experiments measuring microbial necromass as this will improve predictions of SOM feedback under future climate scenarios.","PeriodicalId":73107,"journal":{"name":"Frontiers in soil science","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45094962","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Optimizing row spacing is an important measure to exploit the full yield potential, achieve a continuous increase in wheat yield and green development without increasing input. The objective of this study was to compare the effects of wide–narrow row spacing pattern (12 cm-12 cm-12 cm-24 cm, R1) and conventional uniform row spacing mode (20 cm, CK; 12 cm. R2) on nitrogen (N) availability in soil, canopy structure, photosynthetic characteristics, radiation use efficiency (RUE) and yield. The results showed that R1 increased the relative abundance of ammonia-oxidizing bacteria and ammonia-oxidizing archaea in the rhizosphere compared to CK. Nitrate in soils treated R1 at post-anthesis and nitrogen use efficiency of the plant were 59.92% and 27.01% higher than those treated with CK, respectively. Above-ground growth of wheat showed that R1 increased leaf area index by 27.42%, specific leaf weight by 22.67% and leaf photosynthetic rate by 8.86%, respectively compared to CK. R2 had similar availability of N and plant growth as CK. Moreover, the ability of the plant to allocate more nitrogen to grains was enhanced at post-anthesis with R1 than it with CK and R2, which greatly improved the RUE by 10.13% and 2.27%. As the result, the yield for R1 increased by 27.54% and 21.46%, respectively, compared to CK and R2. Therefore, using wide–narrow row spacing pattern (R1) is a practically and environmentally feasible approach for wheat production without extra input in the straw-returning wheat-corn rotation system.
{"title":"Effects of row spacing on soil nitrogen availability, wheat morpho-physiological traits and radiation use efficiency","authors":"Jie Zhang, Rui-Hua Cao, Zhiyong Zhang, Xiaochun Wang, Xinming Ma, Shuping Xiong","doi":"10.3389/fsoil.2022.981263","DOIUrl":"https://doi.org/10.3389/fsoil.2022.981263","url":null,"abstract":"Optimizing row spacing is an important measure to exploit the full yield potential, achieve a continuous increase in wheat yield and green development without increasing input. The objective of this study was to compare the effects of wide–narrow row spacing pattern (12 cm-12 cm-12 cm-24 cm, R1) and conventional uniform row spacing mode (20 cm, CK; 12 cm. R2) on nitrogen (N) availability in soil, canopy structure, photosynthetic characteristics, radiation use efficiency (RUE) and yield. The results showed that R1 increased the relative abundance of ammonia-oxidizing bacteria and ammonia-oxidizing archaea in the rhizosphere compared to CK. Nitrate in soils treated R1 at post-anthesis and nitrogen use efficiency of the plant were 59.92% and 27.01% higher than those treated with CK, respectively. Above-ground growth of wheat showed that R1 increased leaf area index by 27.42%, specific leaf weight by 22.67% and leaf photosynthetic rate by 8.86%, respectively compared to CK. R2 had similar availability of N and plant growth as CK. Moreover, the ability of the plant to allocate more nitrogen to grains was enhanced at post-anthesis with R1 than it with CK and R2, which greatly improved the RUE by 10.13% and 2.27%. As the result, the yield for R1 increased by 27.54% and 21.46%, respectively, compared to CK and R2. Therefore, using wide–narrow row spacing pattern (R1) is a practically and environmentally feasible approach for wheat production without extra input in the straw-returning wheat-corn rotation system.","PeriodicalId":73107,"journal":{"name":"Frontiers in soil science","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44140002","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-09-12DOI: 10.3389/fsoil.2022.999139
K. Dhakal, Madhav Parajuli, Siyang Jian, Jianwei Li, D. Nandwani
The effects of organic and conventional production systems on crop productivity have been greatly explored, but their effects on soil microbial processes were often neglected. A comparative field study of organic and conventional production systems was conducted at the Tennessee State University research farm to determine soil heterotrophic respiration and microbial biomass carbon. Leafy green vegetables were grown in a conventional production system in an open field, and they were grown in an organic production system, using three different row covers (agribon cloth, insect net, and plastic), and in an open field. Soil samples (0-15cm) were collected from the two production systems. Soil heterotrophic respiration rate (RH), microbial biomass carbon (MBC), and biomass-specific heterotrophic respiration rate (the inverse is used as a proxy for microbial carbon use efficiency) were quantified. The results showed that the conventional production system significantly increased RH relative to the organic system. Organic production system, however, significantly enhanced MBC and reduced biomass-specific respiration rate indicating an increase in carbon use efficiency. Although MBC remained unchanged among the row covers, insect net increased RH and biomass-specific heterotrophic respiration rate. Our results suggest that the organic production system not only promoted soil microbial abundance but also limited soil heterotrophic respiration to the atmosphere governed by the elevated carbon use efficiency.
{"title":"Responses of soil heterotrophic respiration and microbial biomass to organic and conventional production systems","authors":"K. Dhakal, Madhav Parajuli, Siyang Jian, Jianwei Li, D. Nandwani","doi":"10.3389/fsoil.2022.999139","DOIUrl":"https://doi.org/10.3389/fsoil.2022.999139","url":null,"abstract":"The effects of organic and conventional production systems on crop productivity have been greatly explored, but their effects on soil microbial processes were often neglected. A comparative field study of organic and conventional production systems was conducted at the Tennessee State University research farm to determine soil heterotrophic respiration and microbial biomass carbon. Leafy green vegetables were grown in a conventional production system in an open field, and they were grown in an organic production system, using three different row covers (agribon cloth, insect net, and plastic), and in an open field. Soil samples (0-15cm) were collected from the two production systems. Soil heterotrophic respiration rate (RH), microbial biomass carbon (MBC), and biomass-specific heterotrophic respiration rate (the inverse is used as a proxy for microbial carbon use efficiency) were quantified. The results showed that the conventional production system significantly increased RH relative to the organic system. Organic production system, however, significantly enhanced MBC and reduced biomass-specific respiration rate indicating an increase in carbon use efficiency. Although MBC remained unchanged among the row covers, insect net increased RH and biomass-specific heterotrophic respiration rate. Our results suggest that the organic production system not only promoted soil microbial abundance but also limited soil heterotrophic respiration to the atmosphere governed by the elevated carbon use efficiency.","PeriodicalId":73107,"journal":{"name":"Frontiers in soil science","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43693498","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-09-08DOI: 10.3389/fsoil.2022.931266
A. J. Kedir, J. Nyiraneza, K. Hawboldt, D. B. McKenzie, Adrian Unc
Repetitive long-term fertilizer application leads to phosphorus (P) accumulation in agricultural soils. This can pose environmental risks if the soil’s phosphorus storage capacity is not well understood and considered when planning nutrient management. We investigated the P sorption capacity (PSC) in the surface (0-20 cm, n = 23) and subsurface (20-40 cm, n = 23) of long-term managed podzolic soils in Newfoundland (Nfld), Canada, through batch adsorption using two P concentrations of 150 and 500 mg P L-1, and developed pedotransfer functions to estimate PSC using selected soil properties. Also, the correlation between actual PSC, soil properties, and estimated Phosphorus saturation index (PSI) and soil P sorption capacity (SPSC) both from standard soil test were evaluated. The surface and subsurface soils provided similar median PSC (1.34 and 1.32 mg g-1, respectively, p = 0.16) when examined with the 150 mg P L-1 solution. With 500 mg P L-1 solution, the subsurface soils had significantly higher median PSC than the surface soils of the same fields (2.74 and 2.27 mg g-1, respectively, p = 0.02); and had a better linear relationship (R2 >0.40, p <0.05) with SPSC than at the lower P concentration. The surface soils had significantly higher extractable median P in water, citric acid, and Mehlich-3, higher soil organic matter (SOM), moisture content, Mehlich-3-Fe, -Ca, and -K, PSI, electrical conductivity, silt, and clay contents, while Mehlich-3-Al, Mehlich-3-Al : Fe ratio, SPSC, and sand were lower than those in the subsurface soils. All soils had comparable pH (~6.3). Pedotransfer function revealed that the PSC could be predicted using SOM, Mehlich-3-Al, and Mehlich-3-PICP and thus may be employed for developing testable hypotheses relevant to environmentally and economically viable P management strategies for acidic soils in boreal regions.
长期重复施肥导致农业土壤中磷的积累。如果在规划养分管理时没有很好地了解和考虑土壤的磷储存能力，这可能会造成环境风险。研究了加拿大纽芬兰(Nfld)长期管理的灰化土在表层(0-20 cm, n = 23)和地下(20-40 cm, n = 23)的磷吸附能力(PSC)，采用150和500 mg P -1两种浓度的磷进行批量吸附，并利用选定的土壤性质建立了土壤传递函数来估算PSC。此外，还评价了土壤实际磷含量与土壤性质、磷饱和指数(PSI)和土壤磷吸收量(SPSC)之间的相关性。当使用150 mg L-1溶液检测时，表层和地下土壤的PSC中值相似(分别为1.34和1.32 mg g-1, p = 0.16)。在500 mg L-1溶液下，地下土壤PSC中值显著高于表层土壤(分别为2.74和2.27 mg g-1, P = 0.02);且与SPSC呈较好的线性关系(R2 >0.40, p <0.05)。表层土壤水、柠檬酸、迈赫里克-3中可提取磷含量显著高于表层土壤，土壤有机质(SOM)、含水量、迈赫里克-3-Fe、-Ca、-K、PSI、电导率、粉土和粘土含量显著高于表层土壤，而迈赫里克-3- al、迈赫里克-3- al: Fe比、SPSC和砂土含量均低于地下土壤。所有土壤的pH值(~6.3)相当。土壤传递函数表明，土壤磷含量可以用SOM、Mehlich-3-Al和Mehlich-3-PICP预测，因此可以用于开发与环境和经济上可行的北方地区酸性土壤磷管理策略相关的可测试假设。
{"title":"Phosphorus Sorption Capacity and Its Relationships With Soil Properties Under Podzolic Soils of Atlantic Canada","authors":"A. J. Kedir, J. Nyiraneza, K. Hawboldt, D. B. McKenzie, Adrian Unc","doi":"10.3389/fsoil.2022.931266","DOIUrl":"https://doi.org/10.3389/fsoil.2022.931266","url":null,"abstract":"Repetitive long-term fertilizer application leads to phosphorus (P) accumulation in agricultural soils. This can pose environmental risks if the soil’s phosphorus storage capacity is not well understood and considered when planning nutrient management. We investigated the P sorption capacity (PSC) in the surface (0-20 cm, n = 23) and subsurface (20-40 cm, n = 23) of long-term managed podzolic soils in Newfoundland (Nfld), Canada, through batch adsorption using two P concentrations of 150 and 500 mg P L-1, and developed pedotransfer functions to estimate PSC using selected soil properties. Also, the correlation between actual PSC, soil properties, and estimated Phosphorus saturation index (PSI) and soil P sorption capacity (SPSC) both from standard soil test were evaluated. The surface and subsurface soils provided similar median PSC (1.34 and 1.32 mg g-1, respectively, p = 0.16) when examined with the 150 mg P L-1 solution. With 500 mg P L-1 solution, the subsurface soils had significantly higher median PSC than the surface soils of the same fields (2.74 and 2.27 mg g-1, respectively, p = 0.02); and had a better linear relationship (R2 >0.40, p <0.05) with SPSC than at the lower P concentration. The surface soils had significantly higher extractable median P in water, citric acid, and Mehlich-3, higher soil organic matter (SOM), moisture content, Mehlich-3-Fe, -Ca, and -K, PSI, electrical conductivity, silt, and clay contents, while Mehlich-3-Al, Mehlich-3-Al : Fe ratio, SPSC, and sand were lower than those in the subsurface soils. All soils had comparable pH (~6.3). Pedotransfer function revealed that the PSC could be predicted using SOM, Mehlich-3-Al, and Mehlich-3-PICP and thus may be employed for developing testable hypotheses relevant to environmentally and economically viable P management strategies for acidic soils in boreal regions.","PeriodicalId":73107,"journal":{"name":"Frontiers in soil science","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45543687","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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